Change callback semantics of waitForDataAsync

Also adds a documentation comment to specify the semantics.
This commit is contained in:
Sönke Ludwig 2018-02-26 13:15:24 +01:00 committed by GitHub
parent 99e2873cc0
commit e33cf567ec
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23

View file

@ -586,33 +586,58 @@ mixin(tracer);
return m_context.readBuffer.length > 0;
}
WaitForDataAsyncStatus waitForDataAsync(void delegate(bool) @safe read_callback, Duration timeout = Duration.max)
/** Waits asynchronously for new data to arrive.
This function can be used to detach the `TCPConnection` from a
running task while waiting for data, so that the associated memory
resources are available for other operations.
Note that `read_ready_callback` may be called from outside of a
task, so no blocking operations may be performed. Instead, an existing
task should be notified, or a new one started with `runTask`.
Params:
read_ready_callback = A callback taking a `bool` parameter that
signals the read-readiness of the connection
timeout = Optional timeout to limit the maximum wait time
Returns:
If the read readiness can be determined immediately, it will be
returned as WaitForDataAsyncStatus.sataAvailable` or
`WaitForDataAsyncStatus.noModeData` and the callback will not be
invoked. Otherwise `WaitForDataAsyncStatus.waiting` is returned
and the callback will be invoked once the status can be
determined or the specified timeout is reached.
*/
WaitForDataAsyncStatus waitForDataAsync(CALLABLE)(CALLABLE read_ready_callback, Duration timeout = Duration.max)
if (is(typeof(CALLABLE(true)))
{
mixin(tracer);
import vibe.core.core : runTask, setTimer, createTimer;
import vibe.core.core : setTimer;
if (!m_context) {
runTask(read_callback, false);
if (!m_context)
return WaitForDataAsyncStatus.noMoreData;
}
if (m_context.readBuffer.length > 0) {
runTask(read_callback, true);
if (m_context.readBuffer.length > 0)
return WaitForDataAsyncStatus.dataAvailable;
}
if (timeout <= 0.seconds) {
auto rs = waitForData(0.seconds);
auto mode = rs ? WaitForDataAsyncStatus.dataAvailable : WaitForDataAsyncStatus.noMoreData;
return mode;
return rs ? WaitForDataAsyncStatus.dataAvailable : WaitForDataAsyncStatus.noMoreData;
}
auto tm = setTimer(timeout, { eventDriver.sockets.cancelRead(m_socket);
runTask(read_callback, false); });
auto tm = setTimer(timeout, {
eventDriver.sockets.cancelRead(m_socket);
read_ready_callback(false);
});
eventDriver.sockets.read(m_socket, m_context.readBuffer.peekDst(), IOMode.once,
(sock, st, nb) { tm.stop(); assert(m_context.readBuffer.length == 0);
m_context.readBuffer.putN(nb);
runTask(read_callback, m_context.readBuffer.length > 0);
});
(sock, st, nb) {
tm.stop();
assert(m_context.readBuffer.length == 0);
m_context.readBuffer.putN(nb);
read_ready_callback(m_context.readBuffer.length > 0);
});
return WaitForDataAsyncStatus.waiting;
}