Adds trunk/talk folder of revision 359 from libjingles google code to
trunk/talk
git-svn-id: http://webrtc.googlecode.com/svn/trunk@4318 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/talk/base/taskrunner.cc b/talk/base/taskrunner.cc
new file mode 100644
index 0000000..0c0816c
--- /dev/null
+++ b/talk/base/taskrunner.cc
@@ -0,0 +1,241 @@
+/*
+ * libjingle
+ * Copyright 2004--2006, Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <algorithm>
+
+#include "talk/base/taskrunner.h"
+
+#include "talk/base/common.h"
+#include "talk/base/scoped_ptr.h"
+#include "talk/base/task.h"
+#include "talk/base/logging.h"
+
+namespace talk_base {
+
+TaskRunner::TaskRunner()
+ : TaskParent(this),
+ next_timeout_task_(NULL),
+ tasks_running_(false)
+#ifdef _DEBUG
+ , abort_count_(0),
+ deleting_task_(NULL)
+#endif
+{
+}
+
+TaskRunner::~TaskRunner() {
+ // this kills and deletes children silently!
+ AbortAllChildren();
+ InternalRunTasks(true);
+}
+
+void TaskRunner::StartTask(Task * task) {
+ tasks_.push_back(task);
+
+ // the task we just started could be about to timeout --
+ // make sure our "next timeout task" is correct
+ UpdateTaskTimeout(task, 0);
+
+ WakeTasks();
+}
+
+void TaskRunner::RunTasks() {
+ InternalRunTasks(false);
+}
+
+void TaskRunner::InternalRunTasks(bool in_destructor) {
+ // This shouldn't run while an abort is happening.
+ // If that occurs, then tasks may be deleted in this method,
+ // but pointers to them will still be in the
+ // "ChildSet copy" in TaskParent::AbortAllChildren.
+ // Subsequent use of those task may cause data corruption or crashes.
+ ASSERT(!abort_count_);
+ // Running continues until all tasks are Blocked (ok for a small # of tasks)
+ if (tasks_running_) {
+ return; // don't reenter
+ }
+
+ tasks_running_ = true;
+
+ int64 previous_timeout_time = next_task_timeout();
+
+ int did_run = true;
+ while (did_run) {
+ did_run = false;
+ // use indexing instead of iterators because tasks_ may grow
+ for (size_t i = 0; i < tasks_.size(); ++i) {
+ while (!tasks_[i]->Blocked()) {
+ tasks_[i]->Step();
+ did_run = true;
+ }
+ }
+ }
+ // Tasks are deleted when running has paused
+ bool need_timeout_recalc = false;
+ for (size_t i = 0; i < tasks_.size(); ++i) {
+ if (tasks_[i]->IsDone()) {
+ Task* task = tasks_[i];
+ if (next_timeout_task_ &&
+ task->unique_id() == next_timeout_task_->unique_id()) {
+ next_timeout_task_ = NULL;
+ need_timeout_recalc = true;
+ }
+
+#ifdef _DEBUG
+ deleting_task_ = task;
+#endif
+ delete task;
+#ifdef _DEBUG
+ deleting_task_ = NULL;
+#endif
+ tasks_[i] = NULL;
+ }
+ }
+ // Finally, remove nulls
+ std::vector<Task *>::iterator it;
+ it = std::remove(tasks_.begin(),
+ tasks_.end(),
+ reinterpret_cast<Task *>(NULL));
+
+ tasks_.erase(it, tasks_.end());
+
+ if (need_timeout_recalc)
+ RecalcNextTimeout(NULL);
+
+ // Make sure that adjustments are done to account
+ // for any timeout changes (but don't call this
+ // while being destroyed since it calls a pure virtual function).
+ if (!in_destructor)
+ CheckForTimeoutChange(previous_timeout_time);
+
+ tasks_running_ = false;
+}
+
+void TaskRunner::PollTasks() {
+ // see if our "next potentially timed-out task" has indeed timed out.
+ // If it has, wake it up, then queue up the next task in line
+ // Repeat while we have new timed-out tasks.
+ // TODO: We need to guard against WakeTasks not updating
+ // next_timeout_task_. Maybe also add documentation in the header file once
+ // we understand this code better.
+ Task* old_timeout_task = NULL;
+ while (next_timeout_task_ &&
+ old_timeout_task != next_timeout_task_ &&
+ next_timeout_task_->TimedOut()) {
+ old_timeout_task = next_timeout_task_;
+ next_timeout_task_->Wake();
+ WakeTasks();
+ }
+}
+
+int64 TaskRunner::next_task_timeout() const {
+ if (next_timeout_task_) {
+ return next_timeout_task_->timeout_time();
+ }
+ return 0;
+}
+
+// this function gets called frequently -- when each task changes
+// state to something other than DONE, ERROR or BLOCKED, it calls
+// ResetTimeout(), which will call this function to make sure that
+// the next timeout-able task hasn't changed. The logic in this function
+// prevents RecalcNextTimeout() from getting called in most cases,
+// effectively making the task scheduler O-1 instead of O-N
+
+void TaskRunner::UpdateTaskTimeout(Task* task,
+ int64 previous_task_timeout_time) {
+ ASSERT(task != NULL);
+ int64 previous_timeout_time = next_task_timeout();
+ bool task_is_timeout_task = next_timeout_task_ != NULL &&
+ task->unique_id() == next_timeout_task_->unique_id();
+ if (task_is_timeout_task) {
+ previous_timeout_time = previous_task_timeout_time;
+ }
+
+ // if the relevant task has a timeout, then
+ // check to see if it's closer than the current
+ // "about to timeout" task
+ if (task->timeout_time()) {
+ if (next_timeout_task_ == NULL ||
+ (task->timeout_time() <= next_timeout_task_->timeout_time())) {
+ next_timeout_task_ = task;
+ }
+ } else if (task_is_timeout_task) {
+ // otherwise, if the task doesn't have a timeout,
+ // and it used to be our "about to timeout" task,
+ // walk through all the tasks looking for the real
+ // "about to timeout" task
+ RecalcNextTimeout(task);
+ }
+
+ // Note when task_running_, then the running routine
+ // (TaskRunner::InternalRunTasks) is responsible for calling
+ // CheckForTimeoutChange.
+ if (!tasks_running_) {
+ CheckForTimeoutChange(previous_timeout_time);
+ }
+}
+
+void TaskRunner::RecalcNextTimeout(Task *exclude_task) {
+ // walk through all the tasks looking for the one
+ // which satisfies the following:
+ // it's not finished already
+ // we're not excluding it
+ // it has the closest timeout time
+
+ int64 next_timeout_time = 0;
+ next_timeout_task_ = NULL;
+
+ for (size_t i = 0; i < tasks_.size(); ++i) {
+ Task *task = tasks_[i];
+ // if the task isn't complete, and it actually has a timeout time
+ if (!task->IsDone() && (task->timeout_time() > 0))
+ // if it doesn't match our "exclude" task
+ if (exclude_task == NULL ||
+ exclude_task->unique_id() != task->unique_id())
+ // if its timeout time is sooner than our current timeout time
+ if (next_timeout_time == 0 ||
+ task->timeout_time() <= next_timeout_time) {
+ // set this task as our next-to-timeout
+ next_timeout_time = task->timeout_time();
+ next_timeout_task_ = task;
+ }
+ }
+}
+
+void TaskRunner::CheckForTimeoutChange(int64 previous_timeout_time) {
+ int64 next_timeout = next_task_timeout();
+ bool timeout_change = (previous_timeout_time == 0 && next_timeout != 0) ||
+ next_timeout < previous_timeout_time ||
+ (previous_timeout_time <= CurrentTime() &&
+ previous_timeout_time != next_timeout);
+ if (timeout_change) {
+ OnTimeoutChange();
+ }
+}
+
+} // namespace talk_base