rust-postgres/src/lib.rs

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//! Rust-Postgres is a pure-Rust frontend for the popular PostgreSQL database. It
//! exposes a high level interface in the vein of JDBC or Go's `database/sql`
//! package.
//!
//! ```rust,no_run
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//! # #![allow(unstable)]
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//! extern crate postgres;
//! extern crate time;
//!
//! use time::Timespec;
//!
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//! use postgres::{Connection, SslMode};
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//!
//! struct Person {
//! id: i32,
//! name: String,
//! time_created: Timespec,
//! data: Option<Vec<u8>>
//! }
//!
//! fn main() {
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//! let conn = Connection::connect("postgresql://postgres@localhost", &SslMode::None)
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//! .unwrap();
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//!
//! conn.execute("CREATE TABLE person (
//! id SERIAL PRIMARY KEY,
//! name VARCHAR NOT NULL,
//! time_created TIMESTAMP NOT NULL,
//! data BYTEA
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//! )", &[]).unwrap();
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//! let me = Person {
//! id: 0,
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//! name: "Steven".to_string(),
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//! time_created: time::get_time(),
//! data: None
//! };
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//! conn.execute("INSERT INTO person (name, time_created, data) VALUES ($1, $2, $3)",
//! &[&me.name, &me.time_created, &me.data]).unwrap();
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//!
//! let stmt = conn.prepare("SELECT id, name, time_created, data FROM person")
//! .unwrap();
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//! for row in stmt.query(&[]).unwrap() {
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//! let person = Person {
//! id: row.get(0),
//! name: row.get(1),
//! time_created: row.get(2),
//! data: row.get(3)
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//! };
//! println!("Found person {}", person.name);
//! }
//! }
//! ```
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#![doc(html_root_url="https://sfackler.github.io/doc")]
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#![feature(plugin, unsafe_destructor, collections, io, core, path, std_misc)]
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#![warn(missing_docs)]
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extern crate byteorder;
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#[macro_use]
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extern crate log;
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extern crate openssl;
extern crate phf;
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#[plugin] #[no_link]
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extern crate phf_macros;
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extern crate "rustc-serialize" as serialize;
extern crate time;
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use openssl::crypto::hash::{self, Hasher};
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use openssl::ssl::{SslContext, MaybeSslStream};
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use serialize::hex::ToHex;
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use std::borrow::ToOwned;
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use std::cell::{Cell, RefCell};
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use std::cmp::max;
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use std::collections::{RingBuf, HashMap};
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use std::fmt;
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use std::old_io::{BufferedStream, IoResult, IoError, IoErrorKind};
use std::old_io::net::ip::Port;
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use std::mem;
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use std::result;
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use std::time::Duration;
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use time::SteadyTime;
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use url::Url;
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pub use error::{Error, ConnectError, SqlState, DbError, ErrorPosition};
#[doc(inline)]
pub use types::{Oid, Type, ToSql, FromSql};
use io::{InternalStream, Timeout};
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use message::BackendMessage::*;
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use message::FrontendMessage::*;
use message::{FrontendMessage, BackendMessage, RowDescriptionEntry};
use message::{WriteMessage, ReadMessage};
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#[macro_use]
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mod macros;
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mod error;
mod io;
mod message;
mod url;
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mod util;
pub mod types;
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const CANARY: u32 = 0xdeadbeef;
const TYPEINFO_QUERY: &'static str = "t";
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/// A type alias of the result returned by many methods.
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pub type Result<T> = result::Result<T, Error>;
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/// Specifies the target server to connect to.
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#[derive(Clone, Debug)]
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pub enum ConnectTarget {
/// Connect via TCP to the specified host.
Tcp(String),
/// Connect via a Unix domain socket in the specified directory.
Unix(Path)
}
/// Authentication information
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#[derive(Clone, Debug)]
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pub struct UserInfo {
/// The username
pub user: String,
/// An optional password
pub password: Option<String>,
}
/// Information necessary to open a new connection to a Postgres server.
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#[derive(Clone, Debug)]
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pub struct ConnectParams {
/// The target server
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pub target: ConnectTarget,
/// The target port.
///
/// Defaults to 5432 if not specified.
pub port: Option<Port>,
/// The user to login as.
///
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/// `Connection::connect` requires a user but `cancel_query` does not.
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pub user: Option<UserInfo>,
/// The database to connect to. Defaults the value of `user`.
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pub database: Option<String>,
/// Runtime parameters to be passed to the Postgres backend.
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pub options: Vec<(String, String)>,
}
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/// A trait implemented by types that can be converted into a `ConnectParams`.
pub trait IntoConnectParams {
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/// Converts the value of `self` into a `ConnectParams`.
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fn into_connect_params(self) -> result::Result<ConnectParams, ConnectError>;
}
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impl IntoConnectParams for ConnectParams {
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fn into_connect_params(self) -> result::Result<ConnectParams, ConnectError> {
Ok(self)
}
}
impl<'a> IntoConnectParams for &'a str {
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fn into_connect_params(self) -> result::Result<ConnectParams, ConnectError> {
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match Url::parse(self) {
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Ok(url) => url.into_connect_params(),
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Err(err) => return Err(ConnectError::InvalidUrl(err)),
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}
}
}
impl IntoConnectParams for Url {
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fn into_connect_params(self) -> result::Result<ConnectParams, ConnectError> {
let Url {
host,
port,
user,
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path: url::Path { path, query: options, .. },
..
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} = self;
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let maybe_path = try!(url::decode_component(&host).map_err(ConnectError::InvalidUrl));
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let target = if maybe_path.starts_with("/") {
ConnectTarget::Unix(Path::new(maybe_path))
} else {
ConnectTarget::Tcp(host)
};
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let user = user.map(|url::UserInfo { user, pass }| {
UserInfo { user: user, password: pass }
});
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// path contains the leading /
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let database = path.slice_shift_char().map(|(_, path)| path.to_owned());
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Ok(ConnectParams {
target: target,
port: port,
user: user,
database: database,
options: options,
})
}
}
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/// Trait for types that can handle Postgres notice messages
pub trait NoticeHandler: Send {
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/// Handle a Postgres notice message
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fn handle(&mut self, notice: DbError);
}
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/// A notice handler which logs at the `info` level.
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///
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/// This is the default handler used by a `Connection`.
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#[derive(Copy, Debug)]
pub struct DefaultNoticeHandler;
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impl NoticeHandler for DefaultNoticeHandler {
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fn handle(&mut self, notice: DbError) {
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info!("{}: {}", notice.severity(), notice.message());
}
}
/// An asynchronous notification
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#[derive(Clone, Debug)]
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pub struct Notification {
/// The process ID of the notifying backend process
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pub pid: u32,
/// The name of the channel that the notify has been raised on
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pub channel: String,
/// The "payload" string passed from the notifying process
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pub payload: String,
}
/// An iterator over asynchronous notifications
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pub struct Notifications<'conn> {
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conn: &'conn Connection
}
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impl<'a> fmt::Debug for Notifications<'a> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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write!(fmt, "Notifications {{ pending: {} }}", self.conn.conn.borrow().notifications.len())
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}
}
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impl<'conn> Iterator for Notifications<'conn> {
type Item = Notification;
/// Returns the oldest pending notification or `None` if there are none.
///
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/// ## Note
///
/// `next` may return `Some` notification after returning `None` if a new
/// notification was received.
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fn next(&mut self) -> Option<Notification> {
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self.conn.conn.borrow_mut().notifications.pop_front()
}
}
impl<'conn> Notifications<'conn> {
/// Returns the oldest pending notification.
///
/// If no notifications are pending, blocks until one arrives.
pub fn next_block(&mut self) -> Result<Notification> {
if let Some(notification) = self.next() {
return Ok(notification);
}
let mut conn = self.conn.conn.borrow_mut();
check_desync!(conn);
match try!(conn.read_message_with_notification()) {
NotificationResponse { pid, channel, payload } => {
Ok(Notification {
pid: pid,
channel: channel,
payload: payload
})
}
_ => unreachable!()
}
}
/// Returns the oldest pending notification
///
/// If no notifications are pending, blocks for up to `timeout` time, after
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/// which `None` is returned.
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///
/// ## Example
///
/// ```rust,no_run
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/// # #![allow(unstable)]
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/// use std::old_io::{IoError, IoErrorKind};
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/// use std::time::Duration;
///
/// use postgres::Error;
///
/// # let conn = postgres::Connection::connect("", &postgres::SslMode::None).unwrap();
/// match conn.notifications().next_block_for(Duration::seconds(2)) {
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/// Some(Ok(notification)) => println!("notification: {}", notification.payload),
/// Some(Err(e)) => println!("Error: {:?}", e),
/// None => println!("Wait for notification timed out"),
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/// }
/// ```
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pub fn next_block_for(&mut self, timeout: Duration) -> Option<Result<Notification>> {
if let Some(notification) = self.next() {
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return Some(Ok(notification));
}
let mut conn = self.conn.conn.borrow_mut();
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if conn.desynchronized {
return Some(Err(Error::StreamDesynchronized));
}
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let end = SteadyTime::now() + timeout;
loop {
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let timeout = max(Duration::zero(), end - SteadyTime::now()).num_milliseconds() as u64;
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conn.stream.set_read_timeout(Some(timeout));
match conn.read_one_message() {
Ok(Some(NotificationResponse { pid, channel, payload })) => {
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return Some(Ok(Notification {
pid: pid,
channel: channel,
payload: payload
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}))
}
Ok(Some(_)) => unreachable!(),
Ok(None) => {}
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Err(IoError { kind: IoErrorKind::TimedOut, .. }) => {
conn.desynchronized = false;
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return None;
}
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Err(e) => return Some(Err(Error::IoError(e))),
}
}
}
}
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/// Contains information necessary to cancel queries for a session
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#[derive(Copy, Clone, Debug)]
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pub struct CancelData {
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/// The process ID of the session
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pub process_id: u32,
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/// The secret key for the session
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pub secret_key: u32,
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}
/// Attempts to cancel an in-progress query.
///
/// The backend provides no information about whether a cancellation attempt
/// was successful or not. An error will only be returned if the driver was
/// unable to connect to the database.
///
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/// A `CancelData` object can be created via `Connection::cancel_data`. The
/// object can cancel any query made on that connection.
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///
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/// Only the host and port of the connection info are used. See
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/// `Connection::connect` for details of the `params` argument.
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///
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/// ## Example
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///
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/// ```rust,no_run
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/// # #![allow(unstable)]
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/// # use postgres::{Connection, SslMode};
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/// # use std::thread::Thread;
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/// # let url = "";
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/// let conn = Connection::connect(url, &SslMode::None).unwrap();
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/// let cancel_data = conn.cancel_data();
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/// Thread::spawn(move || {
/// conn.execute("SOME EXPENSIVE QUERY", &[]).unwrap();
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/// });
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/// # let _ =
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/// postgres::cancel_query(url, &SslMode::None, cancel_data);
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/// ```
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pub fn cancel_query<T>(params: T, ssl: &SslMode, data: CancelData)
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-> result::Result<(), ConnectError> where T: IntoConnectParams {
let params = try!(params.into_connect_params());
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let mut socket = try!(io::initialize_stream(&params, ssl));
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try!(socket.write_message(&CancelRequest {
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code: message::CANCEL_CODE,
process_id: data.process_id,
secret_key: data.secret_key
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}));
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try!(socket.flush());
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Ok(())
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}
#[derive(Clone)]
struct CachedStatement {
name: String,
param_types: Vec<Type>,
result_desc: Vec<ResultDescription>,
}
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struct InnerConnection {
stream: BufferedStream<MaybeSslStream<InternalStream>>,
notice_handler: Box<NoticeHandler>,
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notifications: RingBuf<Notification>,
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cancel_data: CancelData,
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unknown_types: HashMap<Oid, Type>,
cached_statements: HashMap<String, CachedStatement>,
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next_stmt_id: u32,
trans_depth: u32,
canary: u32,
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desynchronized: bool,
finished: bool,
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}
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impl Drop for InnerConnection {
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fn drop(&mut self) {
if !self.finished {
let _ = self.finish_inner();
}
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}
}
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impl InnerConnection {
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fn connect<T>(params: T, ssl: &SslMode) -> result::Result<InnerConnection, ConnectError>
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where T: IntoConnectParams {
let params = try!(params.into_connect_params());
let stream = try!(io::initialize_stream(&params, ssl));
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let ConnectParams { user, database, mut options, .. } = params;
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let user = try!(user.ok_or(ConnectError::MissingUser));
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let mut conn = InnerConnection {
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stream: BufferedStream::new(stream),
next_stmt_id: 0,
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notice_handler: Box::new(DefaultNoticeHandler),
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notifications: RingBuf::new(),
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cancel_data: CancelData { process_id: 0, secret_key: 0 },
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unknown_types: HashMap::new(),
cached_statements: HashMap::new(),
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desynchronized: false,
finished: false,
trans_depth: 0,
canary: CANARY,
};
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options.push(("client_encoding".to_owned(), "UTF8".to_owned()));
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// Postgres uses the value of TimeZone as the time zone for TIMESTAMP
// WITH TIME ZONE values. Timespec converts to GMT internally.
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options.push(("TimeZone".to_owned(), "GMT".to_owned()));
// We have to clone here since we need the user again for auth
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options.push(("user".to_owned(), user.user.clone()));
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if let Some(database) = database {
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options.push(("database".to_owned(), database));
}
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try!(conn.write_messages(&[StartupMessage {
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version: message::PROTOCOL_VERSION,
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parameters: &options
}]));
try!(conn.handle_auth(user));
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loop {
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match try!(conn.read_message()) {
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BackendKeyData { process_id, secret_key } => {
conn.cancel_data.process_id = process_id;
conn.cancel_data.secret_key = secret_key;
}
ReadyForQuery { .. } => break,
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ErrorResponse { fields } => return DbError::new_connect(fields),
_ => return Err(ConnectError::BadResponse),
}
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}
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try!(conn.setup_typeinfo_query());
Ok(conn)
}
fn setup_typeinfo_query(&mut self) -> result::Result<(), ConnectError> {
match self.raw_prepare(TYPEINFO_QUERY,
"SELECT t.typname, t.typelem, r.rngsubtype \
FROM pg_catalog.pg_type t \
LEFT OUTER JOIN pg_catalog.pg_range r \
ON r.rngtypid = t.oid \
WHERE t.oid = $1") {
Ok(..) => return Ok(()),
Err(Error::IoError(e)) => return Err(ConnectError::IoError(e)),
// Range types weren't added until Postgres 9.2, so pg_range may not exist
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Err(Error::DbError(ref e)) if e.code() == &SqlState::UndefinedTable => {}
Err(Error::DbError(e)) => return Err(ConnectError::DbError(e)),
_ => unreachable!()
}
match self.raw_prepare(TYPEINFO_QUERY,
"SELECT typname, typelem, NULL::OID FROM pg_catalog.pg_type \
WHERE oid = $1") {
Ok(..) => Ok(()),
Err(Error::IoError(e)) => Err(ConnectError::IoError(e)),
Err(Error::DbError(e)) => Err(ConnectError::DbError(e)),
_ => unreachable!()
}
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}
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fn write_messages(&mut self, messages: &[FrontendMessage]) -> IoResult<()> {
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debug_assert!(!self.desynchronized);
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for message in messages {
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try_desync!(self, self.stream.write_message(message));
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}
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Ok(try_desync!(self, self.stream.flush()))
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}
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fn read_one_message(&mut self) -> IoResult<Option<BackendMessage>> {
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debug_assert!(!self.desynchronized);
match try_desync!(self, self.stream.read_message()) {
NoticeResponse { fields } => {
if let Ok(err) = DbError::new_raw(fields) {
self.notice_handler.handle(err);
}
Ok(None)
}
ParameterStatus { parameter, value } => {
debug!("Parameter {} = {}", parameter, value);
Ok(None)
}
val => Ok(Some(val))
}
}
fn read_message_with_notification(&mut self) -> IoResult<BackendMessage> {
loop {
if let Some(msg) = try!(self.read_one_message()) {
return Ok(msg);
}
}
}
fn read_message(&mut self) -> IoResult<BackendMessage> {
loop {
match try!(self.read_message_with_notification()) {
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NotificationResponse { pid, channel, payload } => {
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self.notifications.push_back(Notification {
pid: pid,
channel: channel,
payload: payload
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})
}
val => return Ok(val)
}
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}
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}
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fn handle_auth(&mut self, user: UserInfo) -> result::Result<(), ConnectError> {
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match try!(self.read_message()) {
AuthenticationOk => return Ok(()),
AuthenticationCleartextPassword => {
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let pass = try!(user.password.ok_or(ConnectError::MissingPassword));
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try!(self.write_messages(&[PasswordMessage {
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password: &pass,
}]));
}
AuthenticationMD5Password { salt } => {
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let pass = try!(user.password.ok_or(ConnectError::MissingPassword));
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let mut hasher = Hasher::new(hash::Type::MD5);
let _ = hasher.write_all(pass.as_bytes());
let _ = hasher.write_all(user.user.as_bytes());
let output = hasher.finish().to_hex();
let _ = hasher.write_all(output.as_bytes());
let _ = hasher.write_all(&salt);
let output = format!("md5{}", hasher.finish().to_hex());
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try!(self.write_messages(&[PasswordMessage {
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password: &output
}]));
}
AuthenticationKerberosV5
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| AuthenticationSCMCredential
| AuthenticationGSS
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| AuthenticationSSPI => return Err(ConnectError::UnsupportedAuthentication),
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ErrorResponse { fields } => return DbError::new_connect(fields),
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_ => return Err(ConnectError::BadResponse)
}
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match try!(self.read_message()) {
AuthenticationOk => Ok(()),
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ErrorResponse { fields } => return DbError::new_connect(fields),
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_ => return Err(ConnectError::BadResponse)
}
}
fn set_notice_handler(&mut self, handler: Box<NoticeHandler>) -> Box<NoticeHandler> {
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mem::replace(&mut self.notice_handler, handler)
}
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fn raw_prepare(&mut self, stmt_name: &str, query: &str)
-> Result<(Vec<Type>, Vec<ResultDescription>)> {
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try!(self.write_messages(&[
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Parse {
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name: stmt_name,
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query: query,
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param_types: &[]
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},
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Describe {
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variant: b'S',
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name: stmt_name,
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},
Sync]));
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match try!(self.read_message()) {
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ParseComplete => {}
ErrorResponse { fields } => {
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try!(self.wait_for_ready());
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return DbError::new(fields);
}
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_ => bad_response!(self),
}
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let raw_param_types = match try!(self.read_message()) {
ParameterDescription { types } => types,
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_ => bad_response!(self),
};
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let raw_result_desc = match try!(self.read_message()) {
RowDescription { descriptions } => descriptions,
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NoData => vec![],
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_ => bad_response!(self)
};
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try!(self.wait_for_ready());
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let mut param_types = vec![];
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for oid in raw_param_types {
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param_types.push(try!(self.get_type(oid)));
}
let mut result_desc = vec![];
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for RowDescriptionEntry { name, type_oid, .. } in raw_result_desc {
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result_desc.push(ResultDescription {
name: name,
ty: try!(self.get_type(type_oid)),
});
}
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Ok((param_types, result_desc))
}
fn make_stmt_name(&mut self) -> String {
let stmt_name = format!("s{}", self.next_stmt_id);
self.next_stmt_id += 1;
stmt_name
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}
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fn prepare<'a>(&mut self, query: &str, conn: &'a Connection) -> Result<Statement<'a>> {
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let stmt_name = self.make_stmt_name();
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let (param_types, result_desc) = try!(self.raw_prepare(&stmt_name, query));
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Ok(Statement {
conn: conn,
name: stmt_name,
param_types: param_types,
result_desc: result_desc,
next_portal_id: Cell::new(0),
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finished: false,
})
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}
fn prepare_cached<'a>(&mut self, query: &str, conn: &'a Connection) -> Result<Statement<'a>> {
let stmt = self.cached_statements.get(query).map(|e| e.clone());
let CachedStatement { name, param_types, result_desc } = match stmt {
Some(stmt) => stmt,
None => {
let stmt_name = self.make_stmt_name();
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let (param_types, result_desc) = try!(self.raw_prepare(&stmt_name, query));
let stmt = CachedStatement {
name: stmt_name,
param_types: param_types,
result_desc: result_desc,
};
self.cached_statements.insert(query.to_owned(), stmt.clone());
stmt
}
};
Ok(Statement {
conn: conn,
name: name,
param_types: param_types,
result_desc: result_desc,
next_portal_id: Cell::new(0),
finished: true, // << !
})
}
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fn prepare_copy_in<'a>(&mut self, table: &str, rows: &[&str], conn: &'a Connection)
-> Result<CopyInStatement<'a>> {
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let mut query = vec![];
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let _ = write!(&mut query, "SELECT ");
let _ = util::comma_join(&mut query, rows.iter().cloned());
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let _ = write!(&mut query, " FROM {}", table);
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let query = String::from_utf8(query).unwrap();
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let (_, result_desc) = try!(self.raw_prepare("", &query));
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let column_types = result_desc.into_iter().map(|desc| desc.ty).collect();
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let mut query = vec![];
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let _ = write!(&mut query, "COPY {} (", table);
let _ = util::comma_join(&mut query, rows.iter().cloned());
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let _ = write!(&mut query, ") FROM STDIN WITH (FORMAT binary)");
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let query = String::from_utf8(query).unwrap();
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let stmt_name = self.make_stmt_name();
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try!(self.raw_prepare(&stmt_name, &query));
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Ok(CopyInStatement {
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conn: conn,
name: stmt_name,
column_types: column_types,
finished: false,
})
}
fn close_statement(&mut self, name: &str, type_: u8) -> Result<()> {
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try!(self.write_messages(&[
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Close {
variant: type_,
name: name,
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},
Sync]));
let resp = match try!(self.read_message()) {
CloseComplete => Ok(()),
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ErrorResponse { fields } => DbError::new(fields),
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_ => bad_response!(self)
};
try!(self.wait_for_ready());
resp
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}
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fn get_type(&mut self, oid: Oid) -> Result<Type> {
if let Some(ty) = Type::from_oid(oid) {
return Ok(ty);
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}
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if let Some(ty) = self.unknown_types.get(&oid) {
return Ok(ty.clone());
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}
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// Ew @ doing this manually :(
try!(self.write_messages(&[
Bind {
portal: "",
statement: TYPEINFO_QUERY,
formats: &[1],
values: &[try!(oid.to_sql(&Type::Oid))],
result_formats: &[1]
},
Execute {
portal: "",
max_rows: 0,
},
Sync]));
match try!(self.read_message()) {
BindComplete => {}
ErrorResponse { fields } => {
try!(self.wait_for_ready());
return DbError::new(fields);
}
_ => bad_response!(self)
}
let (name, elem_oid, rngsubtype): (String, Oid, Option<Oid>) =
match try!(self.read_message()) {
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DataRow { row } => {
(try!(FromSql::from_sql(&Type::Name, row[0].as_ref().map(|r| &**r))),
try!(FromSql::from_sql(&Type::Oid, row[1].as_ref().map(|r| &**r))),
try!(FromSql::from_sql(&Type::Oid, row[2].as_ref().map(|r| &**r))))
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}
ErrorResponse { fields } => {
try!(self.wait_for_ready());
return DbError::new(fields);
}
_ => bad_response!(self)
};
match try!(self.read_message()) {
CommandComplete { .. } => {}
ErrorResponse { fields } => {
try!(self.wait_for_ready());
return DbError::new(fields);
}
_ => bad_response!(self)
}
try!(self.wait_for_ready());
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let elem_oid = if elem_oid != 0 {
Some(elem_oid)
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} else {
rngsubtype
};
let element_type = match elem_oid {
Some(oid) => Some(Box::new(try!(self.get_type(oid)))),
None => None,
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};
let type_ = Type::Unknown {
oid: oid,
name: name,
element_type: element_type,
};
self.unknown_types.insert(oid, type_.clone());
Ok(type_)
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}
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fn is_desynchronized(&self) -> bool {
self.desynchronized
}
fn canary(&self) -> u32 {
self.canary
}
2014-11-01 23:12:05 +00:00
fn wait_for_ready(&mut self) -> Result<()> {
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match try!(self.read_message()) {
ReadyForQuery { .. } => Ok(()),
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_ => bad_response!(self)
}
}
2013-12-04 07:48:46 +00:00
2014-11-01 23:12:05 +00:00
fn quick_query(&mut self, query: &str) -> Result<Vec<Vec<Option<String>>>> {
check_desync!(self);
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try!(self.write_messages(&[Query { query: query }]));
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2014-05-26 18:41:18 +00:00
let mut result = vec![];
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loop {
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match try!(self.read_message()) {
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ReadyForQuery { .. } => break,
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DataRow { row } => {
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result.push(row.into_iter().map(|opt| {
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opt.map(|b| String::from_utf8_lossy(&b).into_owned())
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}).collect());
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}
2014-10-06 00:31:25 +00:00
CopyInResponse { .. } => {
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try!(self.write_messages(&[
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CopyFail {
message: "COPY queries cannot be directly executed",
},
Sync]));
}
ErrorResponse { fields } => {
2014-02-22 07:18:39 +00:00
try!(self.wait_for_ready());
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return DbError::new(fields);
}
2013-12-04 07:48:46 +00:00
_ => {}
}
}
Ok(result)
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}
2014-11-01 23:12:05 +00:00
fn finish_inner(&mut self) -> Result<()> {
check_desync!(self);
self.canary = 0;
2014-11-19 17:58:30 +00:00
try!(self.write_messages(&[Terminate]));
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Ok(())
}
}
2013-09-30 02:12:20 +00:00
/// A connection to a Postgres database.
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pub struct Connection {
conn: RefCell<InnerConnection>
}
2015-01-23 18:44:15 +00:00
impl fmt::Debug for Connection {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
let conn = self.conn.borrow();
write!(fmt,
"Connection {{ cancel_data: {:?}, notifications: {:?}, transaction_depth: {:?}, \
desynchronized: {:?}, cached_statements: {:?} }}",
conn.cancel_data,
conn.notifications.len(),
conn.trans_depth,
conn.desynchronized,
conn.cached_statements.len())
2015-01-10 04:48:47 +00:00
}
}
2014-11-01 23:21:47 +00:00
impl Connection {
/// Creates a new connection to a Postgres database.
2013-09-30 02:12:20 +00:00
///
/// Most applications can use a URL string in the normal format:
2013-09-30 02:12:20 +00:00
///
2014-03-09 06:01:24 +00:00
/// ```notrust
/// postgresql://user[:password]@host[:port][/database][?param1=val1[[&param2=val2]...]]
2013-09-30 02:12:20 +00:00
/// ```
///
/// The password may be omitted if not required. The default Postgres port
/// (5432) is used if none is specified. The database name defaults to the
/// username if not specified.
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///
/// To connect to the server via Unix sockets, `host` should be set to the
2014-04-21 05:53:54 +00:00
/// absolute path of the directory containing the socket file. Since `/` is
/// a reserved character in URLs, the path should be URL encoded. If the
2014-11-01 23:15:30 +00:00
/// path contains non-UTF 8 characters, a `ConnectParams` struct
/// should be created manually and passed in. Note that Postgres does not
/// support SSL over Unix sockets.
///
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/// ## Examples
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///
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/// ```rust,no_run
2015-01-01 05:40:21 +00:00
/// # use postgres::{Connection, SslMode, ConnectError};
/// # fn f() -> Result<(), ConnectError> {
/// let url = "postgresql://postgres:hunter2@localhost:2994/foodb";
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/// let conn = try!(Connection::connect(url, &SslMode::None));
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/// # Ok(()) };
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/// ```
///
2014-04-19 18:10:27 +00:00
/// ```rust,no_run
2015-01-01 05:40:21 +00:00
/// # use postgres::{Connection, SslMode, ConnectError};
/// # fn f() -> Result<(), ConnectError> {
/// let url = "postgresql://postgres@%2Frun%2Fpostgres";
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/// let conn = try!(Connection::connect(url, &SslMode::None));
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/// # Ok(()) };
/// ```
///
/// ```rust,no_run
2015-01-09 19:20:43 +00:00
/// # #![allow(unstable)]
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/// # use postgres::{Connection, UserInfo, ConnectParams, SslMode, ConnectTarget, ConnectError};
/// # fn f() -> Result<(), ConnectError> {
/// # let some_crazy_path = Path::new("");
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/// let params = ConnectParams {
/// target: ConnectTarget::Unix(some_crazy_path),
/// port: None,
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/// user: Some(UserInfo {
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/// user: "postgres".to_string(),
/// password: None
/// }),
/// database: None,
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/// options: vec![],
/// };
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/// let conn = try!(Connection::connect(params, &SslMode::None));
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/// # Ok(()) };
/// ```
2014-11-04 06:24:11 +00:00
pub fn connect<T>(params: T, ssl: &SslMode) -> result::Result<Connection, ConnectError>
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where T: IntoConnectParams {
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InnerConnection::connect(params, ssl).map(|conn| {
Connection { conn: RefCell::new(conn) }
})
}
2013-09-30 02:12:20 +00:00
/// Sets the notice handler for the connection, returning the old handler.
pub fn set_notice_handler(&self, handler: Box<NoticeHandler>) -> Box<NoticeHandler> {
2014-03-19 04:00:06 +00:00
self.conn.borrow_mut().set_notice_handler(handler)
}
/// Returns an iterator over asynchronous notification messages.
///
/// Use the `LISTEN` command to register this connection for notifications.
2014-11-01 23:18:09 +00:00
pub fn notifications<'a>(&'a self) -> Notifications<'a> {
Notifications { conn: self }
}
/// Creates a new prepared statement.
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///
/// A statement may contain parameters, specified by `$n` where `n` is the
/// index of the parameter in the list provided at execution time,
/// 1-indexed.
///
/// The statement is associated with the connection that created it and may
/// not outlive that connection.
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///
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/// ## Example
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///
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/// ```rust,no_run
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/// # use postgres::{Connection, SslMode};
/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// let maybe_stmt = conn.prepare("SELECT foo FROM bar WHERE baz = $1");
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/// let stmt = match maybe_stmt {
/// Ok(stmt) => stmt,
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/// Err(err) => panic!("Error preparing statement: {:?}", err)
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/// };
2014-11-01 23:24:24 +00:00
pub fn prepare<'a>(&'a self, query: &str) -> Result<Statement<'a>> {
self.conn.borrow_mut().prepare(query, self)
}
/// Creates cached prepared statement.
///
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/// Like `prepare`, except that the statement is only prepared once over
/// the lifetime of the connection and then cached. If the same statement
/// is going to be used frequently, caching it can improve performance by
/// reducing the number of round trips to the Postgres backend.
///
/// ## Example
///
/// ```rust,no_run
/// # use postgres::{Connection, SslMode};
/// # fn f() -> postgres::Result<()> {
/// # let x = 10i32;
/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// let stmt = try!(conn.prepare_cached("SELECT foo FROM bar WHERE baz = $1"));
/// for row in try!(stmt.query(&[&x])) {
/// println!("foo: {}", row.get::<_, String>(0));
/// }
/// # Ok(()) };
/// ```
pub fn prepare_cached<'a>(&'a self, query: &str) -> Result<Statement<'a>> {
self.conn.borrow_mut().prepare_cached(query, self)
}
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/// Creates a new COPY FROM STDIN prepared statement.
///
/// These statements provide a method to efficiently bulk-upload data to
/// the database.
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pub fn prepare_copy_in<'a>(&'a self, table: &str, rows: &[&str])
-> Result<CopyInStatement<'a>> {
self.conn.borrow_mut().prepare_copy_in(table, rows, self)
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}
/// Begins a new transaction.
2013-09-30 02:12:20 +00:00
///
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/// Returns a `Transaction` object which should be used instead of
2013-10-14 01:58:31 +00:00
/// the connection for the duration of the transaction. The transaction
2014-11-01 23:25:11 +00:00
/// is active until the `Transaction` object falls out of scope.
2014-07-26 05:41:10 +00:00
///
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/// ## Note
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/// A transaction will roll back by default. The `set_commit`,
/// `set_rollback`, and `commit` methods alter this behavior.
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///
/// ## Panics
///
/// Panics if a transaction is already active.
///
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/// ## Example
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///
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/// ```rust,no_run
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/// # use postgres::{Connection, SslMode};
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/// # fn foo() -> Result<(), postgres::Error> {
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/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// let trans = try!(conn.transaction());
/// try!(trans.execute("UPDATE foo SET bar = 10", &[]));
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/// // ...
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///
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/// try!(trans.commit());
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/// # Ok(())
/// # }
/// ```
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pub fn transaction<'a>(&'a self) -> Result<Transaction<'a>> {
let mut conn = self.conn.borrow_mut();
check_desync!(conn);
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assert!(conn.trans_depth == 0, "`transaction` must be called on the active transaction");
try!(conn.quick_query("BEGIN"));
conn.trans_depth += 1;
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Ok(Transaction {
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conn: self,
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commit: Cell::new(false),
depth: 1,
finished: false,
})
}
/// A convenience function for queries that are only run once.
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///
/// If an error is returned, it could have come from either the preparation
/// or execution of the statement.
///
/// On success, returns the number of rows modified or 0 if not applicable.
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///
/// ## Panics
///
/// Panics if the number of parameters provided does not match the number
/// expected.
pub fn execute(&self, query: &str, params: &[&ToSql]) -> Result<u64> {
let (param_types, result_desc) = try!(self.conn.borrow_mut().raw_prepare("", query));
let stmt = Statement {
conn: self,
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name: "".to_owned(),
param_types: param_types,
result_desc: result_desc,
next_portal_id: Cell::new(0),
finished: true, // << !!
};
stmt.execute(params)
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}
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/// Execute a sequence of SQL statements.
///
/// Statements should be separated by `;` characters. If an error occurs,
/// execution of the sequence will stop at that point. This is intended for
/// execution of batches of non-dynamic statements - for example, creation
/// of a schema for a fresh database.
///
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/// ## Warning
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///
/// Prepared statements should be used for any SQL statement which contains
/// user-specified data, as it provides functionality to safely embed that
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/// data in the statement. Do not form statements via string concatenation
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/// and feed them into this method.
///
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/// ## Example
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///
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/// ```rust,no_run
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/// # use postgres::{Connection, Result};
/// fn init_db(conn: &Connection) -> Result<()> {
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/// conn.batch_execute("
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/// CREATE TABLE person (
/// id SERIAL PRIMARY KEY,
/// name NOT NULL
/// );
///
/// CREATE TABLE purchase (
/// id SERIAL PRIMARY KEY,
/// person INT NOT NULL REFERENCES person (id),
/// time TIMESTAMPTZ NOT NULL,
/// );
///
/// CREATE INDEX ON purchase (time);
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/// ")
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/// }
/// ```
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pub fn batch_execute(&self, query: &str) -> Result<()> {
self.conn.borrow_mut().quick_query(query).map(|_| ())
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}
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/// Returns information used to cancel pending queries.
///
/// Used with the `cancel_query` function. The object returned can be used
/// to cancel any query executed by the connection it was created from.
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pub fn cancel_data(&self) -> CancelData {
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self.conn.borrow().cancel_data
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}
/// Returns whether or not the stream has been desynchronized due to an
/// error in the communication channel with the server.
///
/// If this has occurred, all further queries will immediately return an
/// error.
pub fn is_desynchronized(&self) -> bool {
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self.conn.borrow().is_desynchronized()
}
/// Determines if the `Connection` is currently "active", that is, if there
/// are no active transactions.
///
/// The `transaction` method can only be called on the active `Connection`
/// or `Transaction`.
pub fn is_active(&self) -> bool {
self.conn.borrow().trans_depth == 0
}
/// Consumes the connection, closing it.
///
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/// Functionally equivalent to the `Drop` implementation for `Connection`
/// except that it returns any error encountered to the caller.
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pub fn finish(self) -> Result<()> {
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let mut conn = self.conn.borrow_mut();
conn.finished = true;
conn.finish_inner()
}
fn canary(&self) -> u32 {
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self.conn.borrow().canary()
}
fn write_messages(&self, messages: &[FrontendMessage]) -> IoResult<()> {
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self.conn.borrow_mut().write_messages(messages)
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}
}
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/// Specifies the SSL support requested for a new connection
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#[derive(Debug)]
pub enum SslMode {
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/// The connection will not use SSL
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None,
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/// The connection will use SSL if the backend supports it
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Prefer(SslContext),
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/// The connection must use SSL
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Require(SslContext)
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}
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/// Represents a transaction on a database connection.
///
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/// The transaction will roll back by default.
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pub struct Transaction<'conn> {
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conn: &'conn Connection,
depth: u32,
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commit: Cell<bool>,
finished: bool,
}
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impl<'a> fmt::Debug for Transaction<'a> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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write!(fmt, "Transaction {{ commit: {:?}, depth: {:?} }}", self.commit.get(), self.depth)
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}
}
#[unsafe_destructor]
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impl<'conn> Drop for Transaction<'conn> {
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fn drop(&mut self) {
if !self.finished {
let _ = self.finish_inner();
}
}
}
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impl<'conn> Transaction<'conn> {
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fn finish_inner(&mut self) -> Result<()> {
let mut conn = self.conn.conn.borrow_mut();
debug_assert!(self.depth == conn.trans_depth);
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let query = match (self.commit.get(), self.depth != 1) {
(false, true) => "ROLLBACK TO sp",
(false, false) => "ROLLBACK",
(true, true) => "RELEASE sp",
(true, false) => "COMMIT",
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};
conn.trans_depth -= 1;
conn.quick_query(query).map(|_| ())
}
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/// Like `Connection::prepare`.
pub fn prepare(&self, query: &str) -> Result<Statement<'conn>> {
self.conn.prepare(query)
}
/// Like `Connection::prepare_cached`.
///
/// Note that the statement will be cached for the duration of the
/// connection, not just the duration of this transaction.
pub fn prepare_cached(&self, query: &str) -> Result<Statement<'conn>> {
self.conn.prepare_cached(query)
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}
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/// Like `Connection::prepare_copy_in`.
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pub fn prepare_copy_in(&self, table: &str, cols: &[&str]) -> Result<CopyInStatement<'conn>> {
self.conn.prepare_copy_in(table, cols)
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}
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/// Like `Connection::execute`.
pub fn execute(&self, query: &str, params: &[&ToSql]) -> Result<u64> {
self.conn.execute(query, params)
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}
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/// Like `Connection::batch_execute`.
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pub fn batch_execute(&self, query: &str) -> Result<()> {
self.conn.batch_execute(query)
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}
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/// Like `Connection::transaction`.
///
/// ## Panics
///
/// Panics if there is an active nested transaction.
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pub fn transaction<'a>(&'a self) -> Result<Transaction<'a>> {
let mut conn = self.conn.conn.borrow_mut();
check_desync!(conn);
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assert!(conn.trans_depth == self.depth, "`transaction` may only be called on the active \
transaction");
try!(conn.quick_query("SAVEPOINT sp"));
conn.trans_depth += 1;
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Ok(Transaction {
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conn: self.conn,
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commit: Cell::new(false),
depth: self.depth + 1,
finished: false,
})
}
/// Like `Connection::is_active`.
pub fn is_active(&self) -> bool {
self.conn.conn.borrow().trans_depth == self.depth
}
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/// Determines if the transaction is currently set to commit or roll back.
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pub fn will_commit(&self) -> bool {
self.commit.get()
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}
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/// Sets the transaction to commit at its completion.
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pub fn set_commit(&self) {
self.commit.set(true);
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}
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/// Sets the transaction to roll back at its completion.
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pub fn set_rollback(&self) {
self.commit.set(false);
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}
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/// A convenience method which consumes and commits a transaction.
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pub fn commit(self) -> Result<()> {
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self.set_commit();
self.finish()
}
/// Consumes the transaction, commiting or rolling it back as appropriate.
///
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/// Functionally equivalent to the `Drop` implementation of `Transaction`
/// except that it returns any error to the caller.
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pub fn finish(mut self) -> Result<()> {
self.finished = true;
self.finish_inner()
}
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}
/// A prepared statement
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pub struct Statement<'conn> {
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conn: &'conn Connection,
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name: String,
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param_types: Vec<Type>,
result_desc: Vec<ResultDescription>,
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next_portal_id: Cell<u32>,
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finished: bool,
}
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impl<'a> fmt::Debug for Statement<'a> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt,
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"Statement {{ name: {:?}, parameter_types: {:?}, result_descriptions: {:?} }}",
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self.name,
self.param_types,
self.result_desc)
}
}
#[unsafe_destructor]
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impl<'conn> Drop for Statement<'conn> {
fn drop(&mut self) {
let _ = self.finish_inner();
}
}
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impl<'conn> Statement<'conn> {
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fn finish_inner(&mut self) -> Result<()> {
if !self.finished {
self.finished = true;
let mut conn = self.conn.conn.borrow_mut();
check_desync!(conn);
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conn.close_statement(&self.name, b'S')
} else {
Ok(())
}
}
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fn inner_execute(&self, portal_name: &str, row_limit: i32, params: &[&ToSql]) -> Result<()> {
let mut conn = self.conn.conn.borrow_mut();
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assert!(self.param_types().len() == params.len(),
"expected {} parameters but got {}",
self.param_types.len(),
params.len());
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let mut values = vec![];
for (param, ty) in params.iter().zip(self.param_types.iter()) {
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values.push(try!(param.to_sql(ty)));
};
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try!(conn.write_messages(&[
Bind {
portal: portal_name,
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statement: &self.name,
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formats: &[1],
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values: &values,
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result_formats: &[1]
},
Execute {
portal: portal_name,
max_rows: row_limit
},
Sync]));
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match try!(conn.read_message()) {
BindComplete => Ok(()),
ErrorResponse { fields } => {
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try!(conn.wait_for_ready());
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DbError::new(fields)
}
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_ => {
conn.desynchronized = true;
Err(Error::BadResponse)
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}
}
}
fn inner_query<'a>(&'a self, portal_name: &str, row_limit: i32, params: &[&ToSql])
-> Result<(Rows<'a>, bool)> {
try!(self.inner_execute(portal_name, row_limit, params));
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let mut result = Rows {
stmt: self,
data: RingBuf::new(),
};
let more_rows = try!(result.read_rows());
Ok((result, more_rows))
}
/// Returns a slice containing the expected parameter types.
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pub fn param_types(&self) -> &[Type] {
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&self.param_types
}
/// Returns a slice describing the columns of the result of the query.
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pub fn result_descriptions(&self) -> &[ResultDescription] {
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&self.result_desc
}
/// Executes the prepared statement, returning the number of rows modified.
///
/// If the statement does not modify any rows (e.g. SELECT), 0 is returned.
///
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/// ## Panics
///
/// Panics if the number of parameters provided does not match the number
/// expected.
///
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/// ## Example
///
/// ```rust,no_run
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/// # use postgres::{Connection, SslMode};
/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// # let bar = 1i32;
/// # let baz = true;
/// let stmt = conn.prepare("UPDATE foo SET bar = $1 WHERE baz = $2").unwrap();
/// match stmt.execute(&[&bar, &baz]) {
/// Ok(count) => println!("{} row(s) updated", count),
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/// Err(err) => println!("Error executing query: {:?}", err)
/// }
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/// ```
pub fn execute(&self, params: &[&ToSql]) -> Result<u64> {
check_desync!(self.conn);
try!(self.inner_execute("", 0, params));
let mut conn = self.conn.conn.borrow_mut();
let num;
loop {
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match try!(conn.read_message()) {
DataRow { .. } => {}
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
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return DbError::new(fields);
}
CommandComplete { tag } => {
num = util::parse_update_count(tag);
break;
}
EmptyQueryResponse => {
num = 0;
break;
}
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CopyInResponse { .. } => {
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try!(conn.write_messages(&[
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CopyFail {
message: "COPY queries cannot be directly executed",
},
Sync]));
}
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_ => {
conn.desynchronized = true;
return Err(Error::BadResponse);
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}
}
}
try!(conn.wait_for_ready());
Ok(num)
}
/// Executes the prepared statement, returning an iterator over the
/// resulting rows.
///
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/// ## Panics
///
/// Panics if the number of parameters provided does not match the number
/// expected.
///
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/// ## Example
///
/// ```rust,no_run
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/// # use postgres::{Connection, SslMode};
/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// let stmt = conn.prepare("SELECT foo FROM bar WHERE baz = $1").unwrap();
/// # let baz = true;
/// let mut rows = match stmt.query(&[&baz]) {
/// Ok(rows) => rows,
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/// Err(err) => panic!("Error running query: {:?}", err)
/// };
/// for row in rows {
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/// let foo: i32 = row.get("foo");
/// println!("foo: {}", foo);
/// }
/// ```
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pub fn query<'a>(&'a self, params: &[&ToSql]) -> Result<Rows<'a>> {
check_desync!(self.conn);
self.inner_query("", 0, params).map(|t| t.0)
}
/// Executes the prepared statement, returning a lazily loaded iterator
/// over the resulting rows.
///
/// No more than `row_limit` rows will be stored in memory at a time. Rows
/// will be pulled from the database in batches of `row_limit` as needed.
/// If `row_limit` is less than or equal to 0, `lazy_query` is equivalent
/// to `query`.
///
/// This can only be called inside of a transaction, and the `Transaction`
/// object representing the active transaction must be passed to
/// `lazy_query`.
///
/// ## Panics
///
/// Panics if the provided `Transaction` is not associated with the same
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/// `Connection` as this `Statement`, if the `Transaction` is not
/// active, or if the number of parameters provided does not match the
/// number of parameters expected.
pub fn lazy_query<'trans, 'stmt>(&'stmt self,
trans: &'trans Transaction,
params: &[&ToSql],
row_limit: i32)
-> Result<LazyRows<'trans, 'stmt>> {
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assert!(self.conn as *const _ == trans.conn as *const _,
"the `Transaction` passed to `lazy_query` must be associated with the same \
`Connection` as the `Statement`");
let conn = self.conn.conn.borrow();
check_desync!(conn);
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assert!(conn.trans_depth == trans.depth,
"`lazy_query` may only be called on the active transaction");
drop(conn);
let id = self.next_portal_id.get();
self.next_portal_id.set(id + 1);
let portal_name = format!("{}p{}", self.name, id);
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self.inner_query(&portal_name, row_limit, params).map(move |(result, more_rows)| {
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LazyRows {
_trans: trans,
result: result,
name: portal_name,
row_limit: row_limit,
more_rows: more_rows,
finished: false,
}
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})
}
/// Consumes the statement, clearing it from the Postgres session.
///
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/// If this statement was created via the `prepare_cached` method, `finish`
/// does nothing.
///
/// Functionally identical to the `Drop` implementation of the
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/// `Statement` except that it returns any error to the caller.
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pub fn finish(mut self) -> Result<()> {
self.finish_inner()
}
}
/// Information about a column of the result of a query.
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#[derive(PartialEq, Eq, Clone, Debug)]
pub struct ResultDescription {
/// The name of the column
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pub name: String,
/// The type of the data in the column
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pub ty: Type
}
/// An iterator over the resulting rows of a query.
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pub struct Rows<'stmt> {
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stmt: &'stmt Statement<'stmt>,
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data: RingBuf<Vec<Option<Vec<u8>>>>,
}
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impl<'a> fmt::Debug for Rows<'a> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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write!(fmt,
"Rows {{ result_descriptions: {:?}, remaining_rows: {:?} }}",
self.result_descriptions(),
self.data.len())
}
}
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impl<'stmt> Rows<'stmt> {
fn read_rows(&mut self) -> Result<bool> {
let mut conn = self.stmt.conn.conn.borrow_mut();
let more_rows;
loop {
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match try!(conn.read_message()) {
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EmptyQueryResponse | CommandComplete { .. } => {
more_rows = false;
break;
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}
PortalSuspended => {
more_rows = true;
break;
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}
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DataRow { row } => self.data.push_back(row),
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
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return DbError::new(fields);
}
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CopyInResponse { .. } => {
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try!(conn.write_messages(&[
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CopyFail {
message: "COPY queries cannot be directly executed",
},
Sync]));
}
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_ => {
conn.desynchronized = true;
return Err(Error::BadResponse);
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}
}
}
try!(conn.wait_for_ready());
Ok(more_rows)
}
/// Returns a slice describing the columns of the `Rows`.
pub fn result_descriptions(&self) -> &'stmt [ResultDescription] {
self.stmt.result_descriptions()
}
}
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impl<'stmt> Iterator for Rows<'stmt> {
type Item = Row<'stmt>;
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#[inline]
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fn next(&mut self) -> Option<Row<'stmt>> {
self.data.pop_front().map(|row| Row { stmt: self.stmt, data: row })
}
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#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
(self.data.len(), Some(self.data.len()))
}
}
/// A single result row of a query.
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pub struct Row<'stmt> {
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stmt: &'stmt Statement<'stmt>,
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data: Vec<Option<Vec<u8>>>
}
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impl<'a> fmt::Debug for Row<'a> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt, "Row {{ statement: {:?} }}", self.stmt)
}
}
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impl<'stmt> Row<'stmt> {
/// Returns the number of values in the row
pub fn len(&self) -> usize {
self.data.len()
}
/// Returns a slice describing the columns of the `Row`.
pub fn result_descriptions(&self) -> &'stmt [ResultDescription] {
self.stmt.result_descriptions()
}
/// Retrieves the contents of a field of the row.
///
/// A field can be accessed by the name or index of its column, though
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/// access by index is more efficient. Rows are 0-indexed.
///
/// Returns an `Error` value if the index does not reference a column or
/// the return type is not compatible with the Postgres type.
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pub fn get_opt<I, T>(&self, idx: I) -> Result<T> where I: RowIndex, T: FromSql {
let idx = try!(idx.idx(self.stmt).ok_or(Error::InvalidColumn));
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FromSql::from_sql(&self.stmt.result_desc[idx].ty, self.data[idx].as_ref().map(|e| &**e))
}
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/// Retrieves the contents of a field of the row.
///
/// A field can be accessed by the name or index of its column, though
/// access by index is more efficient. Rows are 0-indexed.
///
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/// ## Panics
///
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/// Panics if the index does not reference a column or the return type is
/// not compatible with the Postgres type.
///
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/// ## Example
///
/// ```rust,no_run
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/// # use postgres::{Connection, SslMode};
/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// # let stmt = conn.prepare("").unwrap();
/// # let mut result = stmt.query(&[]).unwrap();
/// # let row = result.next().unwrap();
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/// let foo: i32 = row.get(0u);
/// let bar: String = row.get("bar");
/// ```
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pub fn get<I, T>(&self, idx: I) -> T where I: RowIndex + fmt::Debug + Clone, T: FromSql {
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match self.get_opt(idx.clone()) {
Ok(ok) => ok,
Err(err) => panic!("error retrieving column {:?}: {:?}", idx, err)
}
}
}
/// A trait implemented by types that can index into columns of a row.
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pub trait RowIndex {
/// Returns the index of the appropriate column, or `None` if no such
/// column exists.
fn idx(&self, stmt: &Statement) -> Option<usize>;
}
impl RowIndex for usize {
#[inline]
fn idx(&self, stmt: &Statement) -> Option<usize> {
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if *self >= stmt.result_desc.len() {
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None
} else {
Some(*self)
}
}
}
impl<'a> RowIndex for &'a str {
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#[inline]
fn idx(&self, stmt: &Statement) -> Option<usize> {
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stmt.result_descriptions().iter().position(|d| d.name == *self)
}
}
/// A lazily-loaded iterator over the resulting rows of a query
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pub struct LazyRows<'trans, 'stmt> {
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result: Rows<'stmt>,
name: String,
row_limit: i32,
more_rows: bool,
finished: bool,
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_trans: &'trans Transaction<'trans>,
}
#[unsafe_destructor]
impl<'a, 'b> Drop for LazyRows<'a, 'b> {
fn drop(&mut self) {
if !self.finished {
let _ = self.finish_inner();
}
}
}
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impl<'a, 'b> fmt::Debug for LazyRows<'a, 'b> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt,
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"LazyRows {{ name: {:?}, row_limit: {:?}, remaining_rows: {:?}, \
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more_rows: {:?} }}",
self.name,
self.row_limit,
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self.result.data.len(),
self.more_rows)
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}
}
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impl<'trans, 'stmt> LazyRows<'trans, 'stmt> {
fn finish_inner(&mut self) -> Result<()> {
let mut conn = self.result.stmt.conn.conn.borrow_mut();
check_desync!(conn);
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conn.close_statement(&self.name, b'P')
}
fn execute(&mut self) -> Result<()> {
try!(self.result.stmt.conn.write_messages(&[
Execute {
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portal: &self.name,
max_rows: self.row_limit
},
Sync]));
self.result.read_rows().map(|more_rows| {
self.more_rows = more_rows;
()
})
}
/// Returns a slice describing the columns of the `Rows`.
pub fn result_descriptions(&self) -> &'stmt [ResultDescription] {
self.result.stmt.result_descriptions()
}
/// Consumes the `LazyRows`, cleaning up associated state.
///
/// Functionally identical to the `Drop` implementation on `LazyRows`
/// except that it returns any error to the caller.
pub fn finish(mut self) -> Result<()> {
self.finish_inner()
}
}
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impl<'trans, 'stmt> Iterator for LazyRows<'trans, 'stmt> {
type Item = Result<Row<'stmt>>;
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fn next(&mut self) -> Option<Result<Row<'stmt>>> {
if self.result.data.is_empty() && self.more_rows {
if let Err(err) = self.execute() {
return Some(Err(err));
}
}
self.result.next().map(|r| Ok(r))
}
fn size_hint(&self) -> (usize, Option<usize>) {
let lower = self.result.data.len();
let upper = if self.more_rows {
None
} else {
Some(lower)
};
(lower, upper)
}
}
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/// A prepared COPY FROM STDIN statement
pub struct CopyInStatement<'a> {
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conn: &'a Connection,
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name: String,
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column_types: Vec<Type>,
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finished: bool,
}
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impl<'a> fmt::Debug for CopyInStatement<'a> {
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fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
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write!(fmt, "CopyInStatement {{ name: {:?}, column_types: {:?} }}",
self.name, self.column_types)
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}
}
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#[unsafe_destructor]
impl<'a> Drop for CopyInStatement<'a> {
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fn drop(&mut self) {
if !self.finished {
let _ = self.finish_inner();
}
}
}
/// An `Iterator` variant which returns borrowed values.
pub trait StreamIterator {
/// Returns the next value, or `None` if there is none.
fn next<'a>(&'a mut self) -> Option<&'a (ToSql + 'a)>;
}
/// An adapter type implementing `StreamIterator` for a `Vec<Box<ToSql>>`.
pub struct VecStreamIterator<'a> {
v: Vec<Box<ToSql + 'a>>,
idx: usize,
}
impl<'a> VecStreamIterator<'a> {
/// Creates a new `VecStreamIterator`.
pub fn new(v: Vec<Box<ToSql + 'a>>) -> VecStreamIterator<'a> {
VecStreamIterator {
v: v,
idx: 0,
}
}
/// Returns the underlying `Vec`.
pub fn into_inner(self) -> Vec<Box<ToSql + 'a>> {
self.v
}
}
impl<'a> StreamIterator for VecStreamIterator<'a> {
fn next<'b>(&'b mut self) -> Option<&'b (ToSql + 'b)> {
match self.v.get_mut(self.idx) {
Some(mut e) => {
self.idx += 1;
Some(&mut **e)
},
None => None,
}
}
}
impl<'a> CopyInStatement<'a> {
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fn finish_inner(&mut self) -> Result<()> {
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let mut conn = self.conn.conn.borrow_mut();
check_desync!(conn);
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conn.close_statement(&self.name, b'S')
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}
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/// Returns a slice containing the expected column types.
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pub fn column_types(&self) -> &[Type] {
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&self.column_types
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}
/// Executes the prepared statement.
///
/// The `rows` argument is an `Iterator` returning `StreamIterator` values,
/// each one of which provides values for a row of input. This setup is
/// designed to allow callers to avoid having to maintain the entire row
/// set in memory.
///
/// Returns the number of rows copied.
pub fn execute<I, J>(&self, rows: I) -> Result<u64>
where I: Iterator<Item=J>, J: StreamIterator {
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let mut conn = self.conn.conn.borrow_mut();
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try!(conn.write_messages(&[
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Bind {
portal: "",
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statement: &self.name,
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formats: &[],
values: &[],
result_formats: &[]
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},
Execute {
portal: "",
max_rows: 0,
},
Sync]));
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match try!(conn.read_message()) {
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BindComplete => {},
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
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return DbError::new(fields);
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}
_ => {
conn.desynchronized = true;
return Err(Error::BadResponse);
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}
}
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match try!(conn.read_message()) {
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CopyInResponse { .. } => {}
_ => {
conn.desynchronized = true;
return Err(Error::BadResponse);
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}
}
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let mut buf = vec![];
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let _ = buf.write_all(b"PGCOPY\n\xff\r\n\x00");
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let _ = buf.write_be_i32(0);
let _ = buf.write_be_i32(0);
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'l: for mut row in rows {
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let _ = buf.write_be_i16(self.column_types.len() as i16);
let mut types = self.column_types.iter();
loop {
match (row.next(), types.next()) {
(Some(val), Some(ty)) => {
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match val.to_sql(ty) {
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Ok(None) => {
let _ = buf.write_be_i32(-1);
}
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Ok(Some(val)) => {
let _ = buf.write_be_i32(val.len() as i32);
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let _ = buf.write_all(&val);
}
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Err(err) => {
// FIXME this is not the right way to handle this
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try_desync!(conn, conn.stream.write_message(
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&CopyFail {
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message: &err.to_string(),
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}));
break 'l;
}
}
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}
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(Some(_), None) | (None, Some(_)) => {
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try_desync!(conn, conn.stream.write_message(
&CopyFail {
message: "Invalid column count",
}));
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break 'l;
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}
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(None, None) => break
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}
}
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try_desync!(conn, conn.stream.write_message(
&CopyData {
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data: &buf
}));
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buf.clear();
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}
let _ = buf.write_be_i16(-1);
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try!(conn.write_messages(&[
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CopyData {
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data: &buf,
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},
CopyDone,
Sync]));
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let num = match try!(conn.read_message()) {
CommandComplete { tag } => util::parse_update_count(tag),
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ErrorResponse { fields } => {
try!(conn.wait_for_ready());
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return DbError::new(fields);
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}
_ => {
conn.desynchronized = true;
return Err(Error::BadResponse);
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}
};
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try!(conn.wait_for_ready());
Ok(num)
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}
/// Consumes the statement, clearing it from the Postgres session.
///
/// Functionally identical to the `Drop` implementation of the
/// `CopyInStatement` except that it returns any error to the
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/// caller.
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pub fn finish(mut self) -> Result<()> {
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self.finished = true;
self.finish_inner()
}
}
/// A trait allowing abstraction over connections and transactions
pub trait GenericConnection {
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/// Like `Connection::prepare`.
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fn prepare<'a>(&'a self, query: &str) -> Result<Statement<'a>>;
/// Like `Connection::prepare_cached`.
fn prepare_cached<'a>(&'a self, query: &str) -> Result<Statement<'a>>;
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/// Like `Connection::execute`.
fn execute(&self, query: &str, params: &[&ToSql]) -> Result<u64>;
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/// Like `Connection::prepare_copy_in`.
fn prepare_copy_in<'a>(&'a self, table: &str, columns: &[&str])
-> Result<CopyInStatement<'a>>;
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/// Like `Connection::transaction`.
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fn transaction<'a>(&'a self) -> Result<Transaction<'a>>;
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/// Like `Connection::batch_execute`.
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fn batch_execute(&self, query: &str) -> Result<()>;
/// Like `Connection::is_active`.
fn is_active(&self) -> bool;
}
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impl GenericConnection for Connection {
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fn prepare<'a>(&'a self, query: &str) -> Result<Statement<'a>> {
self.prepare(query)
}
fn prepare_cached<'a>(&'a self, query: &str) -> Result<Statement<'a>> {
self.prepare_cached(query)
}
fn execute(&self, query: &str, params: &[&ToSql]) -> Result<u64> {
self.execute(query, params)
}
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fn transaction<'a>(&'a self) -> Result<Transaction<'a>> {
self.transaction()
}
fn prepare_copy_in<'a>(&'a self, table: &str, columns: &[&str])
-> Result<CopyInStatement<'a>> {
self.prepare_copy_in(table, columns)
}
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fn batch_execute(&self, query: &str) -> Result<()> {
self.batch_execute(query)
}
fn is_active(&self) -> bool {
self.is_active()
}
}
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impl<'a> GenericConnection for Transaction<'a> {
fn prepare<'b>(&'b self, query: &str) -> Result<Statement<'b>> {
self.prepare(query)
}
fn prepare_cached<'b>(&'b self, query: &str) -> Result<Statement<'b>> {
self.prepare_cached(query)
}
fn execute(&self, query: &str, params: &[&ToSql]) -> Result<u64> {
self.execute(query, params)
}
fn transaction<'b>(&'b self) -> Result<Transaction<'b>> {
self.transaction()
}
fn prepare_copy_in<'b>(&'b self, table: &str, columns: &[&str])
-> Result<CopyInStatement<'b>> {
self.prepare_copy_in(table, columns)
}
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fn batch_execute(&self, query: &str) -> Result<()> {
self.batch_execute(query)
}
fn is_active(&self) -> bool {
self.is_active()
}
}