debian-packages/vibe-core
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

Add yieldLock(), which enables enforcing no task switches within a scope.

Browse source 
runTask() was altered to delay the task switch in case it gets called within an active yieldLock(), so that running tasks is still possible.
This commit is contained in:
Sönke Ludwig 2017-06-11 01:35:57 +02:00
parent 698824e811
commit bc689489a8
No known key found for this signature in database
GPG key ID: D95E8DB493EE314C
2 changed files with 66 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

23
source/vibe/core/task.d
View file

@ -302,6 +302,7 @@ final package class TaskFiber : Fiber {
void[] m_fls;
bool m_interrupt; // Task.interrupt() is progress
package int m_yieldLockCount;
static TaskFiber ms_globalDummyFiber;
static FLSInfo[] ms_flsInfo;
@ -325,7 +326,7 @@ final package class TaskFiber : Fiber {
auto f = () @trusted nothrow {
return Fiber.getThis();
} ();
if (f) return cast(TaskFiber)f;
if (auto tf = cast(TaskFiber)f) return tf;
if (!ms_globalDummyFiber) ms_globalDummyFiber = new TaskFiber;
return ms_globalDummyFiber;
}
@ -637,6 +638,8 @@ package struct TaskScheduler {
*/
ExitReason process()
{
assert(TaskFiber.getThis().m_yieldLockCount == 0, "May not process events within an active yieldLock()!");
bool any_events = false;
while (true) {
// process pending tasks
@ -742,7 +745,7 @@ package struct TaskScheduler {
This forces immediate execution of the specified task. After the tasks finishes or yields,
the calling task will continue execution.
*/
void switchTo(Task t)
void switchTo(Task t, Flag!"defer" defer = No.defer)
{
auto thist = Task.getThis();
@ -750,14 +753,15 @@ package struct TaskScheduler {
auto thisthr = thist ? thist.thread : () @trusted { return Thread.getThis(); } ();
assert(t.thread is thisthr, "Cannot switch to a task that lives in a different thread.");
if (thist == Task.init) {
if (thist == Task.init && defer == No.defer) {
assert(TaskFiber.getThis().m_yieldLockCount == 0, "Cannot yield within an active yieldLock()!");
logTrace("switch to task from global context");
resumeTask(t);
logTrace("task yielded control back to global context");
} else {
auto tf = () @trusted { return t.taskFiber; } ();
auto thistf = () @trusted { return thist.taskFiber; } ();
assert(!thistf.m_queue, "Calling task is running, but scheduled to be resumed!?");
assert(!thistf || !thistf.m_queue, "Calling task is running, but scheduled to be resumed!?");
if (tf.m_queue) {
logTrace("Task to switch to is already scheduled. Moving to front of queue.");
assert(tf.m_queue is &m_taskQueue, "Task is already enqueued, but not in the main task queue.");
@ -766,9 +770,13 @@ package struct TaskScheduler {
}
logDebugV("Switching tasks (%s already in queue)", m_taskQueue.length);
m_taskQueue.insertFront(thistf);
m_taskQueue.insertFront(tf);
doYield(thist);
if (defer) {
m_taskQueue.insertFront(tf);
} else {
m_taskQueue.insertFront(thistf);
m_taskQueue.insertFront(tf);
doYield(thist);
}
}
}
@ -840,6 +848,7 @@ package struct TaskScheduler {
private void doYield(Task task)
{
assert(() @trusted { return task.taskFiber; } ().m_yieldLockCount == 0, "May not yield while in an active yieldLock()!");
debug if (TaskFiber.ms_taskEventCallback) () @trusted { TaskFiber.ms_taskEventCallback(TaskEvent.yield, task); } ();
() @trusted { Fiber.yield(); } ();
debug if (TaskFiber.ms_taskEventCallback) () @trusted { TaskFiber.ms_taskEventCallback(TaskEvent.resume, task); } ();