mojo: allow BackgroundServiceLoader-loaded apps to Quit themselves.

mojo/service_manager/background_shell_service_loader.cc

 // Copyright 2014 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 "mojo/service_manager/background_service_loader.h"
+#include "mojo/service_manager/background_shell_service_loader.h"
 
 #include "base/bind.h"
+#include "base/run_loop.h"
 #include "mojo/service_manager/service_manager.h"
 
 namespace mojo {
 
-class BackgroundServiceLoader::BackgroundLoader {
+class BackgroundShellServiceLoader::BackgroundLoader {
  public:
   explicit BackgroundLoader(ServiceLoader* loader) : loader_(loader) {}
   ~BackgroundLoader() {}
 
   void LoadService(ServiceManager* manager,
                    const GURL& url,
                    ScopedMessagePipeHandle shell_handle) {
     loader_->LoadService(manager, url, shell_handle.Pass());
   }
 
   void OnServiceError(ServiceManager* manager, const GURL& url) {
     loader_->OnServiceError(manager, url);
   }
 
  private:
-  base::MessageLoop::Type message_loop_type_;
-  ServiceLoader* loader_;  // Owned by BackgroundServiceLoader
+  ServiceLoader* loader_;  // Owned by BackgroundShellServiceLoader
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundLoader);
 };
 
-BackgroundServiceLoader::BackgroundServiceLoader(
+BackgroundShellServiceLoader::BackgroundShellServiceLoader(
     scoped_ptr<ServiceLoader> real_loader,
-    const char* thread_name,
+    const std::string& thread_name,
     base::MessageLoop::Type message_loop_type)
-    : loader_(real_loader.Pass()),
-      thread_(thread_name),
+    : quit_on_shutdown_(false),
+      loader_(real_loader.Pass()),
       message_loop_type_(message_loop_type),
+      thread_name_(thread_name),
+      message_loop_created_(true, false),
       background_loader_(NULL) {
 }
 
-BackgroundServiceLoader::~BackgroundServiceLoader() {
-  if (thread_.IsRunning()) {
-    thread_.message_loop()->PostTask(
-        FROM_HERE,
-        base::Bind(&BackgroundServiceLoader::ShutdownOnBackgroundThread,
-                   base::Unretained(this)));
+BackgroundShellServiceLoader::~BackgroundShellServiceLoader() {
+  if (thread_) {
+    if (quit_on_shutdown_)
+      task_runner_->PostTask(FROM_HERE, quit_closure_);
+    thread_->Join();
   }
-  thread_.Stop();
 }
 
-void BackgroundServiceLoader::LoadService(
+void BackgroundShellServiceLoader::LoadService(
     ServiceManager* manager,
     const GURL& url,
     ScopedMessagePipeHandle shell_handle) {
-  const int kDefaultStackSize = 0;
-  if (!thread_.IsRunning()) {
-    thread_.StartWithOptions(
-        base::Thread::Options(message_loop_type_, kDefaultStackSize));
+  if (!thread_) {
+    // TODO(tim): It'd be nice if we could just have each LoadService call
+    // result in a new thread like DynamicService{Loader, Runner}. But some
+    // loaders are creating multiple ApplicationImpls (NetworkServiceLoader)
+    // sharing a delegate (etc). So we have to keep it single threaded, wait
+    // for the thread to initialize, and post to the TaskRunner for subsequent
+    // LoadService calls for now.
+    thread_.reset(new base::DelegateSimpleThread(this, thread_name_));
+    thread_->Start();
+    message_loop_created_.Wait();
+    DCHECK(task_runner_);
   }
-  thread_.message_loop()->PostTask(
-      FROM_HERE,
-      base::Bind(&BackgroundServiceLoader::LoadServiceOnBackgroundThread,
+
+  task_runner_->PostTask(FROM_HERE,
+      base::Bind(&BackgroundShellServiceLoader::LoadServiceOnBackgroundThread,
                  base::Unretained(this), manager, url,
                  base::Owned(
                     new ScopedMessagePipeHandle(shell_handle.Pass()))));
 }
 
-void BackgroundServiceLoader::OnServiceError(ServiceManager* manager,
-                                             const GURL& url) {
-  if (!thread_.IsRunning())
-    thread_.Start();
-  thread_.message_loop()->PostTask(
-      FROM_HERE,
-      base::Bind(&BackgroundServiceLoader::OnServiceErrorOnBackgroundThread,
-                 base::Unretained(this), manager, url));
+void BackgroundShellServiceLoader::OnServiceError(
+    ServiceManager* manager, const GURL& url) {
+  task_runner_->PostTask(FROM_HERE,
+      base::Bind(
+          &BackgroundShellServiceLoader::OnServiceErrorOnBackgroundThread,
+          base::Unretained(this), manager, url));
 }
 
-void BackgroundServiceLoader::LoadServiceOnBackgroundThread(
-    ServiceManager* manager,
-    const GURL& url,
-    ScopedMessagePipeHandle* shell_handle) {
+void BackgroundShellServiceLoader::Run() {
+  base::MessageLoop message_loop(message_loop_type_);
+  base::RunLoop loop;
+  task_runner_ = message_loop.task_runner();
+  quit_closure_ = loop.QuitClosure();
+  message_loop_created_.Signal();
+  loop.Run();
+
+  delete background_loader_;
+  background_loader_ = NULL;
+  // Destroy |loader_| on the thread it's actually used on.
+  loader_.reset();
+}
+
+void BackgroundShellServiceLoader::LoadServiceOnBackgroundThread(
+      ServiceManager* manager,
+      const GURL& url,
+      ScopedMessagePipeHandle* shell_handle) {
+  DCHECK(task_runner_->RunsTasksOnCurrentThread());
   if (!background_loader_)
     background_loader_ = new BackgroundLoader(loader_.get());
-  background_loader_->LoadService(
-      manager, url, shell_handle->Pass());
+  background_loader_->LoadService(manager, url, shell_handle->Pass());
 }
 
-void BackgroundServiceLoader::OnServiceErrorOnBackgroundThread(
-    ServiceManager* manager,
-    const GURL& url) {
+void BackgroundShellServiceLoader::OnServiceErrorOnBackgroundThread(
+    ServiceManager* manager, const GURL& url) {
+  DCHECK(task_runner_->RunsTasksOnCurrentThread());
   if (!background_loader_)
     background_loader_ = new BackgroundLoader(loader_.get());
   background_loader_->OnServiceError(manager, url);
 }
 
-void BackgroundServiceLoader::ShutdownOnBackgroundThread() {
-  delete background_loader_;
-  // Destroy |loader_| on the thread it's actually used on.
-  loader_.reset();
-}
-
 }  // namespace mojo