79 lines
2.2 KiB
Rust
79 lines
2.2 KiB
Rust
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//! Asynchronous notifications.
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use debug_builders::DebugStruct;
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use std::fmt;
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use {Result, Connection, NotificationsNew};
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use message::BackendMessage::NotificationResponse;
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/// An asynchronous notification.
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#[derive(Clone, Debug)]
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pub struct Notification {
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/// The process ID of the notifying backend process.
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pub pid: u32,
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/// The name of the channel that the notify has been raised on.
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pub channel: String,
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/// The "payload" string passed from the notifying process.
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pub payload: String,
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}
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/// An iterator over asynchronous notifications.
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pub struct Notifications<'conn> {
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conn: &'conn Connection
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}
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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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DebugStruct::new(fmt, "Notifications")
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.field("pending", &self.conn.conn.borrow().notifications.len())
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.finish()
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}
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}
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impl<'conn> NotificationsNew<'conn> for Notifications<'conn> {
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fn new(conn: &'conn Connection) -> Notifications<'conn> {
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Notifications {
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conn: conn,
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}
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}
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}
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impl<'conn> Iterator for Notifications<'conn> {
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type Item = Notification;
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/// Returns the oldest pending notification or `None` if there are none.
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///
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/// ## Note
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///
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/// `next` may return `Some` notification after returning `None` if a new
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/// 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()
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}
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}
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impl<'conn> Notifications<'conn> {
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/// Returns the oldest pending notification.
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///
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/// If no notifications are pending, blocks until one arrives.
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pub fn next_block(&mut self) -> Result<Notification> {
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if let Some(notification) = self.next() {
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return Ok(notification);
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}
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let mut conn = self.conn.conn.borrow_mut();
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check_desync!(conn);
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match try!(conn.read_message_with_notification()) {
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NotificationResponse { pid, channel, payload } => {
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Ok(Notification {
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pid: pid,
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channel: channel,
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payload: payload
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})
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}
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_ => unreachable!()
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}
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}
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}
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