Replace RunInSeries() and RunInParallel() with CallbackSeries helper class.

media/base/serial_runner.cc

+// 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/message_loop.h"
+#include "base/message_loop_proxy.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 |message_loop|, trampolining if
+// necessary.
+static void RunOnMessageLoop(
+    const scoped_refptr<base::MessageLoopProxy>& message_loop,
+    const PipelineStatusCB& status_cb,
+    PipelineStatus last_status) {
+  if (!message_loop->BelongsToCurrentThread()) {
+    message_loop->PostTask(FROM_HERE, base::Bind(
+        &RunOnMessageLoop, message_loop, status_cb, last_status));
+    return;
+  }
+  status_cb.Run(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;
+}
+
+SerialRunner::SerialRunner(
+    const Queue& bound_fns, const PipelineStatusCB& done_cb)
+    : weak_this_(this),
+      message_loop_(base::MessageLoopProxy::current()),
+      bound_fns_(bound_fns),
+      done_cb_(done_cb) {
+  message_loop_->PostTask(FROM_HERE, base::Bind(
+      &SerialRunner::RunNextInSeries, weak_this_.GetWeakPtr(),
+      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(message_loop_->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(&RunOnMessageLoop, message_loop_, base::Bind(
+      &SerialRunner::RunNextInSeries, weak_this_.GetWeakPtr())));
+}
+
+}  // namespace media