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Pull Statement into its own module

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This commit is contained in:
Steven Fackler 2015-08-15 21:39:46 -07:00
parent dc2f04de96
commit 63e278b9f2
3 changed files with 464 additions and 421 deletions
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440
src/lib.rs
View File

@ -70,10 +70,12 @@ use std::result;
#[cfg(feature = "unix_socket")]
use std::path::PathBuf;
pub use stmt::{Statement, Column};
use error::{Error, ConnectError, SqlState, DbError};
use types::{ToSql, FromSql};
use io::{StreamWrapper, NegotiateSsl};
use types::{IsNull, Kind, Type, SessionInfo, Oid, Other, ReadWithInfo};
use types::{IsNull, Kind, Type, SessionInfo, Oid, Other};
use message::BackendMessage::*;
use message::FrontendMessage::*;
use message::{FrontendMessage, BackendMessage, RowDescriptionEntry};
@ -84,15 +86,16 @@ use rows::{Rows, LazyRows};
#[macro_use]
mod macros;
pub mod error;
pub mod io;
mod md5;
mod message;
mod priv_io;
mod stmt;
mod url;
mod util;
pub mod types;
pub mod error;
pub mod io;
pub mod rows;
mod md5;
pub mod types;
const TYPEINFO_QUERY: &'static str = "t";
@ -663,10 +666,7 @@ impl InnerConnection {
let mut columns = vec![];
for RowDescriptionEntry { name, type_oid, .. } in raw_columns {
columns.push(Column {
name: name,
type_: try!(self.get_type(type_oid)),
});
columns.push(Column::new(name, try!(self.get_type(type_oid))));
}
Ok((param_types, columns))
@ -681,14 +681,7 @@ impl InnerConnection {
fn prepare<'a>(&mut self, query: &str, conn: &'a Connection) -> Result<Statement<'a>> {
let stmt_name = self.make_stmt_name();
let (param_types, columns) = try!(self.raw_prepare(&stmt_name, query));
Ok(Statement {
conn: conn,
name: stmt_name,
param_types: param_types,
columns: columns,
next_portal_id: Cell::new(0),
finished: false,
})
Ok(Statement::new(conn, stmt_name, param_types, columns, Cell::new(0), false))
}
fn prepare_cached<'a>(&mut self, query: &str, conn: &'a Connection) -> Result<Statement<'a>> {
@ -709,14 +702,7 @@ impl InnerConnection {
}
};
Ok(Statement {
conn: conn,
name: name,
param_types: param_types,
columns: columns,
next_portal_id: Cell::new(0),
finished: true, // << !
})
Ok(Statement::new(conn, name, param_types, columns, Cell::new(0), true))
}
fn close_statement(&mut self, name: &str, type_: u8) -> Result<()> {
@ -1082,14 +1068,7 @@ impl Connection {
/// expected.
pub fn execute(&self, query: &str, params: &[&ToSql]) -> Result<u64> {
let (param_types, columns) = try!(self.conn.borrow_mut().raw_prepare("", query));
let stmt = Statement {
conn: self,
name: "".to_owned(),
param_types: param_types,
columns: columns,
next_portal_id: Cell::new(0),
finished: true, // << !!
};
let stmt = Statement::new(self, "".to_owned(), param_types, columns, Cell::new(0), true);
stmt.execute(params)
}
@ -1300,386 +1279,6 @@ impl<'conn> Transaction<'conn> {
}
}
/// A prepared statement.
pub struct Statement<'conn> {
conn: &'conn Connection,
name: String,
param_types: Vec<Type>,
columns: Vec<Column>,
next_portal_id: Cell<u32>,
finished: bool,
}
impl<'a> fmt::Debug for Statement<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
DebugStruct::new(fmt, "Statement")
.field("name", &self.name)
.field("parameter_types", &self.param_types)
.field("columns", &self.columns)
.finish()
}
}
impl<'conn> Drop for Statement<'conn> {
fn drop(&mut self) {
let _ = self.finish_inner();
}
}
impl<'conn> Statement<'conn> {
fn finish_inner(&mut self) -> Result<()> {
if !self.finished {
self.finished = true;
let mut conn = self.conn.conn.borrow_mut();
check_desync!(conn);
conn.close_statement(&self.name, b'S')
} else {
Ok(())
}
}
fn inner_execute(&self, portal_name: &str, row_limit: i32, params: &[&ToSql]) -> Result<()> {
let mut conn = self.conn.conn.borrow_mut();
assert!(self.param_types().len() == params.len(),
"expected {} parameters but got {}",
self.param_types.len(),
params.len());
debug!("executing statement {} with parameters: {:?}", self.name, params);
let mut values = vec![];
for (param, ty) in params.iter().zip(self.param_types.iter()) {
let mut buf = vec![];
match try!(param.to_sql_checked(ty, &mut buf, &SessionInfo::new(&*conn))) {
IsNull::Yes => values.push(None),
IsNull::No => values.push(Some(buf)),
}
};
try!(conn.write_messages(&[
Bind {
portal: portal_name,
statement: &self.name,
formats: &[1],
values: &values,
result_formats: &[1]
},
Execute {
portal: portal_name,
max_rows: row_limit
},
Sync]));
match try!(conn.read_message()) {
BindComplete => Ok(()),
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
DbError::new(fields)
}
_ => {
conn.desynchronized = true;
Err(Error::IoError(bad_response()))
}
}
}
fn inner_query<'a>(&'a self, portal_name: &str, row_limit: i32, params: &[&ToSql])
-> Result<(VecDeque<Vec<Option<Vec<u8>>>>, bool)> {
try!(self.inner_execute(portal_name, row_limit, params));
let mut buf = VecDeque::new();
let more_rows = try!(read_rows(&mut self.conn.conn.borrow_mut(), &mut buf));
Ok((buf, more_rows))
}
/// Returns a slice containing the expected parameter types.
pub fn param_types(&self) -> &[Type] {
&self.param_types
}
/// Returns a slice describing the columns of the result of the query.
pub fn columns(&self) -> &[Column] {
&self.columns
}
/// Executes the prepared statement, returning the number of rows modified.
///
/// If the statement does not modify any rows (e.g. SELECT), 0 is returned.
///
/// ## Panics
///
/// Panics if the number of parameters provided does not match the number
/// expected.
///
/// ## Example
///
/// ```rust,no_run
/// # 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),
/// Err(err) => println!("Error executing query: {:?}", err)
/// }
/// ```
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 {
match try!(conn.read_message()) {
DataRow { .. } => {}
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
return DbError::new(fields);
}
CommandComplete { tag } => {
num = util::parse_update_count(tag);
break;
}
EmptyQueryResponse => {
num = 0;
break;
}
CopyInResponse { .. } => {
try!(conn.write_messages(&[
CopyFail {
message: "COPY queries cannot be directly executed",
},
Sync]));
}
CopyOutResponse { .. } => {
loop {
match try!(conn.read_message()) {
BCopyDone => break,
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
return DbError::new(fields);
}
_ => {}
}
}
num = 0;
break;
}
_ => {
conn.desynchronized = true;
return Err(Error::IoError(bad_response()));
}
}
}
try!(conn.wait_for_ready());
Ok(num)
}
/// Executes the prepared statement, returning the resulting rows.
///
/// ## Panics
///
/// Panics if the number of parameters provided does not match the number
/// expected.
///
/// ## Example
///
/// ```rust,no_run
/// # 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 rows = match stmt.query(&[&baz]) {
/// Ok(rows) => rows,
/// Err(err) => panic!("Error running query: {:?}", err)
/// };
/// for row in &rows {
/// let foo: i32 = row.get("foo");
/// println!("foo: {}", foo);
/// }
/// ```
pub fn query<'a>(&'a self, params: &[&ToSql]) -> Result<Rows<'a>> {
check_desync!(self.conn);
self.inner_query("", 0, params).map(|(buf, _)| {
Rows::new(self, buf.into_iter().collect())
})
}
/// 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
/// `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>> {
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);
assert!(conn.trans_depth == trans.depth,
"`lazy_query` must be passed 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);
self.inner_query(&portal_name, row_limit, params).map(move |(data, more_rows)| {
LazyRows::new(self, data, portal_name, row_limit, more_rows, false, trans)
})
}
/// Executes a `COPY FROM STDIN` statement, returning the number of rows
/// added.
///
/// The contents of the provided reader are passed to the Postgres server
/// verbatim; it is the caller's responsibility to ensure it uses the
/// proper format. See the
/// [Postgres documentation](http://www.postgresql.org/docs/9.4/static/sql-copy.html)
/// for details.
///
/// If the statement is not a `COPY FROM STDIN` statement it will still be
/// executed and this method will return an error.
///
/// # Examples
///
/// ```rust,no_run
/// # use postgres::{Connection, SslMode};
/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// conn.batch_execute("CREATE TABLE people (id INT PRIMARY KEY, name VARCHAR)").unwrap();
/// let stmt = conn.prepare("COPY people FROM STDIN").unwrap();
/// stmt.copy_in(&[], &mut "1\tjohn\n2\tjane\n".as_bytes()).unwrap();
/// ```
pub fn copy_in<R: ReadWithInfo>(&self, params: &[&ToSql], r: &mut R) -> Result<u64> {
try!(self.inner_execute("", 0, params));
let mut conn = self.conn.conn.borrow_mut();
match try!(conn.read_message()) {
CopyInResponse { .. } => {}
_ => {
loop {
match try!(conn.read_message()) {
ReadyForQuery { .. } => {
return Err(Error::IoError(std_io::Error::new(
std_io::ErrorKind::InvalidInput,
"called `copy_in` on a non-`COPY FROM STDIN` statement")));
}
_ => {}
}
}
}
}
let mut buf = [0; 16 * 1024];
loop {
match fill_copy_buf(&mut buf, r, &SessionInfo::new(&conn)) {
Ok(0) => break,
Ok(len) => {
try_desync!(conn, conn.stream.write_message(
&CopyData {
data: &buf[..len],
}));
}
Err(err) => {
try!(conn.write_messages(&[
CopyFail {
message: "",
},
CopyDone,
Sync]));
match try!(conn.read_message()) {
ErrorResponse { .. } => { /* expected from the CopyFail */ }
_ => {
conn.desynchronized = true;
return Err(Error::IoError(bad_response()));
}
}
try!(conn.wait_for_ready());
return Err(Error::IoError(err));
}
}
}
try!(conn.write_messages(&[CopyDone, Sync]));
let num = match try!(conn.read_message()) {
CommandComplete { tag } => util::parse_update_count(tag),
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
return DbError::new(fields);
}
_ => {
conn.desynchronized = true;
return Err(Error::IoError(bad_response()));
}
};
try!(conn.wait_for_ready());
Ok(num)
}
/// Consumes the statement, clearing it from the Postgres session.
///
/// If this statement was created via the `prepare_cached` method, `finish`
/// does nothing.
///
/// Functionally identical to the `Drop` implementation of the
/// `Statement` except that it returns any error to the caller.
pub fn finish(mut self) -> Result<()> {
self.finish_inner()
}
}
fn fill_copy_buf<R: ReadWithInfo>(buf: &mut [u8], r: &mut R, info: &SessionInfo)
-> std_io::Result<usize> {
let mut nread = 0;
while nread < buf.len() {
match r.read_with_info(&mut buf[nread..], info) {
Ok(0) => break,
Ok(n) => nread += n,
Err(ref e) if e.kind() == std_io::ErrorKind::Interrupted => {}
Err(e) => return Err(e),
}
}
Ok(nread)
}
/// Information about a column of the result of a query.
#[derive(PartialEq, Eq, Clone, Debug)]
pub struct Column {
name: String,
type_: Type
}
impl Column {
/// The name of the column.
pub fn name(&self) -> &str {
&self.name
}
/// The type of the data in the column.
pub fn type_(&self) -> &Type {
&self.type_
}
}
fn read_rows(conn: &mut InnerConnection, buf: &mut VecDeque<Vec<Option<Vec<u8>>>>) -> Result<bool> {
let more_rows;
loop {
@ -1829,3 +1428,18 @@ trait LazyRowsNew<'trans, 'stmt> {
trait SessionInfoNew<'a> {
fn new(conn: &'a InnerConnection) -> SessionInfo<'a>;
}
trait StatementInternals<'conn> {
fn new(conn: &'conn Connection,
name: String,
param_types: Vec<Type>,
columns: Vec<Column>,
next_portal_id: Cell<u32>,
finished: bool) -> Statement<'conn>;
fn conn(&self) -> &'conn Connection;
}
trait ColumnNew {
fn new(name: String, type_: Type) -> Column;
}

17
src/rows.rs
View File

@ -16,7 +16,8 @@ use {Statement,
DbErrorNew,
SessionInfoNew,
RowsNew,
LazyRowsNew};
LazyRowsNew,
StatementInternals};
use types::{FromSql, SessionInfo};
use error::Error;
use message::FrontendMessage::*;
@ -204,11 +205,11 @@ impl<'a> Row<'a> {
/// the return type is not compatible with the Postgres type.
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));
let ty = &self.stmt.columns[idx].type_;
let ty = self.stmt.columns()[idx].type_();
if !<T as FromSql>::accepts(ty) {
return Err(Error::WrongType(ty.clone()));
}
let conn = self.stmt.conn.conn.borrow();
let conn = self.stmt.conn().conn.borrow();
FromSql::from_sql_nullable(ty, self.data[idx].as_ref().map(|e| &**e).as_mut(),
&SessionInfo::new(&*conn))
}
@ -264,7 +265,7 @@ pub trait RowIndex {
impl RowIndex for usize {
#[inline]
fn idx(&self, stmt: &Statement) -> Option<usize> {
if *self >= stmt.columns.len() {
if *self >= stmt.columns().len() {
None
} else {
Some(*self)
@ -275,14 +276,14 @@ impl RowIndex for usize {
impl<'a> RowIndex for &'a str {
#[inline]
fn idx(&self, stmt: &Statement) -> Option<usize> {
if let Some(idx) = stmt.columns().iter().position(|d| d.name == *self) {
if let Some(idx) = stmt.columns().iter().position(|d| d.name() == *self) {
return Some(idx);
};
// FIXME ASCII-only case insensitivity isn't really the right thing to
// do. Postgres itself uses a dubious wrapper around tolower and JDBC
// uses the US locale.
stmt.columns().iter().position(|d| d.name.eq_ignore_ascii_case(*self))
stmt.columns().iter().position(|d| d.name().eq_ignore_ascii_case(*self))
}
}
@ -338,13 +339,13 @@ impl<'a, 'b> fmt::Debug for LazyRows<'a, 'b> {
impl<'trans, 'stmt> LazyRows<'trans, 'stmt> {
fn finish_inner(&mut self) -> Result<()> {
let mut conn = self.stmt.conn.conn.borrow_mut();
let mut conn = self.stmt.conn().conn.borrow_mut();
check_desync!(conn);
conn.close_statement(&self.name, b'P')
}
fn execute(&mut self) -> Result<()> {
let mut conn = self.stmt.conn.conn.borrow_mut();
let mut conn = self.stmt.conn().conn.borrow_mut();
try!(conn.write_messages(&[
Execute {

428
src/stmt.rs Normal file
View File

@ -0,0 +1,428 @@
use debug_builders::DebugStruct;
use std::cell::Cell;
use std::collections::VecDeque;
use std::fmt;
use std::io;
use error::{Error, DbError};
use types::{ReadWithInfo, SessionInfo, Type, ToSql, IsNull};
use message::FrontendMessage::*;
use message::BackendMessage::*;
use message::WriteMessage;
use util;
use rows::{Rows, LazyRows};
use {read_rows, bad_response, Connection, Transaction, StatementInternals, Result, RowsNew};
use {SessionInfoNew, LazyRowsNew, DbErrorNew, ColumnNew};
/// A prepared statement.
pub struct Statement<'conn> {
conn: &'conn Connection,
name: String,
param_types: Vec<Type>,
columns: Vec<Column>,
next_portal_id: Cell<u32>,
finished: bool,
}
impl<'a> fmt::Debug for Statement<'a> {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
DebugStruct::new(fmt, "Statement")
.field("name", &self.name)
.field("parameter_types", &self.param_types)
.field("columns", &self.columns)
.finish()
}
}
impl<'conn> Drop for Statement<'conn> {
fn drop(&mut self) {
let _ = self.finish_inner();
}
}
impl<'conn> StatementInternals<'conn> for Statement<'conn> {
fn new(conn: &'conn Connection,
name: String,
param_types: Vec<Type>,
columns: Vec<Column>,
next_portal_id: Cell<u32>,
finished: bool) -> Statement<'conn> {
Statement {
conn: conn,
name: name,
param_types: param_types,
columns: columns,
next_portal_id: next_portal_id,
finished: finished,
}
}
fn conn(&self) -> &'conn Connection {
self.conn
}
}
impl<'conn> Statement<'conn> {
fn finish_inner(&mut self) -> Result<()> {
if !self.finished {
self.finished = true;
let mut conn = self.conn.conn.borrow_mut();
check_desync!(conn);
conn.close_statement(&self.name, b'S')
} else {
Ok(())
}
}
fn inner_execute(&self, portal_name: &str, row_limit: i32, params: &[&ToSql]) -> Result<()> {
let mut conn = self.conn.conn.borrow_mut();
assert!(self.param_types().len() == params.len(),
"expected {} parameters but got {}",
self.param_types.len(),
params.len());
debug!("executing statement {} with parameters: {:?}", self.name, params);
let mut values = vec![];
for (param, ty) in params.iter().zip(self.param_types.iter()) {
let mut buf = vec![];
match try!(param.to_sql_checked(ty, &mut buf, &SessionInfo::new(&*conn))) {
IsNull::Yes => values.push(None),
IsNull::No => values.push(Some(buf)),
}
};
try!(conn.write_messages(&[
Bind {
portal: portal_name,
statement: &self.name,
formats: &[1],
values: &values,
result_formats: &[1]
},
Execute {
portal: portal_name,
max_rows: row_limit
},
Sync]));
match try!(conn.read_message()) {
BindComplete => Ok(()),
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
DbError::new(fields)
}
_ => {
conn.desynchronized = true;
Err(Error::IoError(bad_response()))
}
}
}
fn inner_query<'a>(&'a self, portal_name: &str, row_limit: i32, params: &[&ToSql])
-> Result<(VecDeque<Vec<Option<Vec<u8>>>>, bool)> {
try!(self.inner_execute(portal_name, row_limit, params));
let mut buf = VecDeque::new();
let more_rows = try!(read_rows(&mut self.conn.conn.borrow_mut(), &mut buf));
Ok((buf, more_rows))
}
/// Returns a slice containing the expected parameter types.
pub fn param_types(&self) -> &[Type] {
&self.param_types
}
/// Returns a slice describing the columns of the result of the query.
pub fn columns(&self) -> &[Column] {
&self.columns
}
/// Executes the prepared statement, returning the number of rows modified.
///
/// If the statement does not modify any rows (e.g. SELECT), 0 is returned.
///
/// ## Panics
///
/// Panics if the number of parameters provided does not match the number
/// expected.
///
/// ## Example
///
/// ```rust,no_run
/// # 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),
/// Err(err) => println!("Error executing query: {:?}", err)
/// }
/// ```
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 {
match try!(conn.read_message()) {
DataRow { .. } => {}
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
return DbError::new(fields);
}
CommandComplete { tag } => {
num = util::parse_update_count(tag);
break;
}
EmptyQueryResponse => {
num = 0;
break;
}
CopyInResponse { .. } => {
try!(conn.write_messages(&[
CopyFail {
message: "COPY queries cannot be directly executed",
},
Sync]));
}
CopyOutResponse { .. } => {
loop {
match try!(conn.read_message()) {
BCopyDone => break,
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
return DbError::new(fields);
}
_ => {}
}
}
num = 0;
break;
}
_ => {
conn.desynchronized = true;
return Err(Error::IoError(bad_response()));
}
}
}
try!(conn.wait_for_ready());
Ok(num)
}
/// Executes the prepared statement, returning the resulting rows.
///
/// ## Panics
///
/// Panics if the number of parameters provided does not match the number
/// expected.
///
/// ## Example
///
/// ```rust,no_run
/// # 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 rows = match stmt.query(&[&baz]) {
/// Ok(rows) => rows,
/// Err(err) => panic!("Error running query: {:?}", err)
/// };
/// for row in &rows {
/// let foo: i32 = row.get("foo");
/// println!("foo: {}", foo);
/// }
/// ```
pub fn query<'a>(&'a self, params: &[&ToSql]) -> Result<Rows<'a>> {
check_desync!(self.conn);
self.inner_query("", 0, params).map(|(buf, _)| {
Rows::new(self, buf.into_iter().collect())
})
}
/// 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
/// `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>> {
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);
assert!(conn.trans_depth == trans.depth,
"`lazy_query` must be passed 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);
self.inner_query(&portal_name, row_limit, params).map(move |(data, more_rows)| {
LazyRows::new(self, data, portal_name, row_limit, more_rows, false, trans)
})
}
/// Executes a `COPY FROM STDIN` statement, returning the number of rows
/// added.
///
/// The contents of the provided reader are passed to the Postgres server
/// verbatim; it is the caller's responsibility to ensure it uses the
/// proper format. See the
/// [Postgres documentation](http://www.postgresql.org/docs/9.4/static/sql-copy.html)
/// for details.
///
/// If the statement is not a `COPY FROM STDIN` statement it will still be
/// executed and this method will return an error.
///
/// # Examples
///
/// ```rust,no_run
/// # use postgres::{Connection, SslMode};
/// # let conn = Connection::connect("", &SslMode::None).unwrap();
/// conn.batch_execute("CREATE TABLE people (id INT PRIMARY KEY, name VARCHAR)").unwrap();
/// let stmt = conn.prepare("COPY people FROM STDIN").unwrap();
/// stmt.copy_in(&[], &mut "1\tjohn\n2\tjane\n".as_bytes()).unwrap();
/// ```
pub fn copy_in<R: ReadWithInfo>(&self, params: &[&ToSql], r: &mut R) -> Result<u64> {
try!(self.inner_execute("", 0, params));
let mut conn = self.conn.conn.borrow_mut();
match try!(conn.read_message()) {
CopyInResponse { .. } => {}
_ => {
loop {
match try!(conn.read_message()) {
ReadyForQuery { .. } => {
return Err(Error::IoError(io::Error::new(
io::ErrorKind::InvalidInput,
"called `copy_in` on a non-`COPY FROM STDIN` statement")));
}
_ => {}
}
}
}
}
let mut buf = [0; 16 * 1024];
loop {
match fill_copy_buf(&mut buf, r, &SessionInfo::new(&conn)) {
Ok(0) => break,
Ok(len) => {
try_desync!(conn, conn.stream.write_message(
&CopyData {
data: &buf[..len],
}));
}
Err(err) => {
try!(conn.write_messages(&[
CopyFail {
message: "",
},
CopyDone,
Sync]));
match try!(conn.read_message()) {
ErrorResponse { .. } => { /* expected from the CopyFail */ }
_ => {
conn.desynchronized = true;
return Err(Error::IoError(bad_response()));
}
}
try!(conn.wait_for_ready());
return Err(Error::IoError(err));
}
}
}
try!(conn.write_messages(&[CopyDone, Sync]));
let num = match try!(conn.read_message()) {
CommandComplete { tag } => util::parse_update_count(tag),
ErrorResponse { fields } => {
try!(conn.wait_for_ready());
return DbError::new(fields);
}
_ => {
conn.desynchronized = true;
return Err(Error::IoError(bad_response()));
}
};
try!(conn.wait_for_ready());
Ok(num)
}
/// Consumes the statement, clearing it from the Postgres session.
///
/// If this statement was created via the `prepare_cached` method, `finish`
/// does nothing.
///
/// Functionally identical to the `Drop` implementation of the
/// `Statement` except that it returns any error to the caller.
pub fn finish(mut self) -> Result<()> {
self.finish_inner()
}
}
fn fill_copy_buf<R: ReadWithInfo>(buf: &mut [u8], r: &mut R, info: &SessionInfo)
-> io::Result<usize> {
let mut nread = 0;
while nread < buf.len() {
match r.read_with_info(&mut buf[nread..], info) {
Ok(0) => break,
Ok(n) => nread += n,
Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
Err(e) => return Err(e),
}
}
Ok(nread)
}
/// Information about a column of the result of a query.
#[derive(PartialEq, Eq, Clone, Debug)]
pub struct Column {
name: String,
type_: Type
}
impl ColumnNew for Column {
fn new(name: String, type_: Type) -> Column {
Column {
name: name,
type_: type_,
}
}
}
impl Column {
/// The name of the column.
pub fn name(&self) -> &str {
&self.name
}
/// The type of the data in the column.
pub fn type_(&self) -> &Type {
&self.type_
}
}