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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/base/serial_runner.h"
#include "base/bind.h"
#include "base/callback_helpers.h"
#include "base/location.h"
#include "base/message_loop/message_loop_proxy.h"
#include "base/single_thread_task_runner.h"
namespace media {
// Converts a bound function accepting a Closure into a bound function
// accepting a PipelineStatusCB. Since closures have no way of reporting a
// status |status_cb| is executed with PIPELINE_OK.
static void RunBoundClosure(
const SerialRunner::BoundClosure& bound_closure,
const PipelineStatusCB& status_cb) {
bound_closure.Run(base::Bind(status_cb, PIPELINE_OK));
}
// Runs |status_cb| with |last_status| on |task_runner|.
static void RunOnTaskRunner(
const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
const PipelineStatusCB& status_cb,
PipelineStatus last_status) {
// Force post to permit cancellation of a series in the scenario where all
// bound functions run on the same thread.
task_runner->PostTask(FROM_HERE, base::Bind(status_cb, last_status));
}
SerialRunner::Queue::Queue() {}
SerialRunner::Queue::~Queue() {}
void SerialRunner::Queue::Push(
const BoundClosure& bound_closure) {
bound_fns_.push(base::Bind(&RunBoundClosure, bound_closure));
}
void SerialRunner::Queue::Push(
const BoundPipelineStatusCB& bound_status_cb) {
bound_fns_.push(bound_status_cb);
}
SerialRunner::BoundPipelineStatusCB SerialRunner::Queue::Pop() {
BoundPipelineStatusCB bound_fn = bound_fns_.front();
bound_fns_.pop();
return bound_fn;
}
bool SerialRunner::Queue::empty() {
return bound_fns_.empty();
}
SerialRunner::SerialRunner(const Queue& bound_fns,
const PipelineStatusCB& done_cb)
: task_runner_(base::MessageLoopProxy::current()),
bound_fns_(bound_fns),
done_cb_(done_cb),
weak_factory_(this) {
// Respect both cancellation and calling stack guarantees for |done_cb|
// when empty.
if (bound_fns_.empty()) {
task_runner_->PostTask(FROM_HERE,
base::Bind(&SerialRunner::RunNextInSeries,
weak_factory_.GetWeakPtr(),
PIPELINE_OK));
return;
}
RunNextInSeries(PIPELINE_OK);
}
SerialRunner::~SerialRunner() {}
scoped_ptr<SerialRunner> SerialRunner::Run(
const Queue& bound_fns, const PipelineStatusCB& done_cb) {
scoped_ptr<SerialRunner> callback_series(
new SerialRunner(bound_fns, done_cb));
return callback_series.Pass();
}
void SerialRunner::RunNextInSeries(PipelineStatus last_status) {
DCHECK(task_runner_->BelongsToCurrentThread());
DCHECK(!done_cb_.is_null());
if (bound_fns_.empty() || last_status != PIPELINE_OK) {
base::ResetAndReturn(&done_cb_).Run(last_status);
return;
}
BoundPipelineStatusCB bound_fn = bound_fns_.Pop();
bound_fn.Run(base::Bind(
&RunOnTaskRunner,
task_runner_,
base::Bind(&SerialRunner::RunNextInSeries, weak_factory_.GetWeakPtr())));
}
} // namespace media
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