Have content/ create and destroy its own threads.

content/browser/browser_main_loop.cc

 // Copyright (c) 2011 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 "content/browser/browser_main_loop.h"
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/threading/thread_restrictions.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/trace_controller.h"
 #include "content/common/hi_res_timer_manager.h"
 #include "content/common/sandbox_policy.h"
 #include "content/public/browser/browser_main_parts.h"
+#include "content/public/browser/browser_shutdown.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "content/public/common/result_codes.h"
 #include "crypto/nss_util.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/ssl_config_service.h"
 #include "net/socket/client_socket_factory.h"
 #include "net/socket/tcp_client_socket.h"
 
@@ skipping 109 matching lines @@
                       GLibLogHandler,
                       NULL);
   }
 }
 #endif
 
 }  // namespace
 
 namespace content {
 
+// The currently-running BrowserMainLoop.  There can be one or zero.
+// This is stored to enable immediate shutdown when needed.
+BrowserMainLoop* current_browser_main_loop = NULL;
+
+// This is just to be able to keep ShutdownThreadsAndCleanUp out of
+// the public interface of BrowserMainLoop.
+class BrowserShutdownImpl {
+ public:
+  static void ImmediateShutdownAndExitProcess() {
+    DCHECK(current_browser_main_loop);
+    current_browser_main_loop->ShutdownThreadsAndCleanUp();
+
+#if defined(OS_WIN)
+    // At this point the message loop is still running yet we've shut everything
+    // down. If any messages are processed we'll likely crash. Exit now.
+    ExitProcess(content::RESULT_CODE_NORMAL_EXIT);
+#elif defined(OS_POSIX) && !defined(OS_MACOSX)
+    _exit(content::RESULT_CODE_NORMAL_EXIT);
+#else
+    NOTIMPLEMENTED();
+#endif
+  }
+};
+
+void ImmediateShutdownAndExitProcess() {
+  BrowserShutdownImpl::ImmediateShutdownAndExitProcess();
+}
 
 // BrowserMainLoop construction / destructione =============================
 
 BrowserMainLoop::BrowserMainLoop(const content::MainFunctionParams& parameters)
     : parameters_(parameters),
       parsed_command_line_(parameters.command_line),
       result_code_(content::RESULT_CODE_NORMAL_EXIT) {
+  DCHECK(!current_browser_main_loop);
+  current_browser_main_loop = this;
 #if defined(OS_WIN)
   OleInitialize(NULL);
 #endif
 }
 
 BrowserMainLoop::~BrowserMainLoop() {
+  DCHECK_EQ(this, current_browser_main_loop);
+  current_browser_main_loop = NULL;
 #if defined(OS_WIN)
   OleUninitialize();
 #endif
 }
 
 void BrowserMainLoop::Init() {
   parts_.reset(
       GetContentClient()->browser()->CreateBrowserMainParts(parameters_));
 }
 
@@ skipping 84 matching lines @@
   system_message_window_.reset(new SystemMessageWindowWin);
 #endif
 
   if (parts_.get())
     parts_->PostMainMessageLoopStart();
 }
 
 void BrowserMainLoop::RunMainMessageLoopParts(
     bool* completed_main_message_loop) {
   if (parts_.get())
+    parts_->PreCreateThreads();
+
+  base::Thread::Options default_options;
+  base::Thread::Options io_message_loop_options;
+  io_message_loop_options.message_loop_type = MessageLoop::TYPE_IO;
+  base::Thread::Options ui_message_loop_options;
+  ui_message_loop_options.message_loop_type = MessageLoop::TYPE_UI;
+
+  // Start threads in the order they occur in the BrowserThread::ID
+  // enumeration, except for BrowserThread::UI which is the main
+  // thread.
+  //
+  // Must be size_t so we can increment it.
+  for (size_t thread_id = BrowserThread::UI + 1;
+       thread_id < BrowserThread::ID_COUNT;
+       ++thread_id) {
+    scoped_ptr<BrowserProcessSubThread>* thread_to_start = NULL;
+    base::Thread::Options* options = &default_options;
+
+    switch (thread_id) {
+      case BrowserThread::DB:
+        thread_to_start = &db_thread_;
+        break;
+      case BrowserThread::WEBKIT:
+        // For now, the WebKit thread in the browser is owned by
+        // ResourceDispatcherHost, not by the content framework. Until
+        // this is fixed, we don't start the thread but still call
+        // Pre/PostStartThread for the ID.
+        break;
+      case BrowserThread::FILE:
+        thread_to_start = &file_thread_;
+#if defined(OS_WIN)
+        // On Windows, the FILE thread needs to be have a UI message loop
+        // which pumps messages in such a way that Google Update can
+        // communicate back to us.
+        options = &ui_message_loop_options;
+#else
+        options = &io_message_loop_options;
+#endif
+        break;
+      case BrowserThread::PROCESS_LAUNCHER:
+        thread_to_start = &process_launcher_thread_;
+        break;
+      case BrowserThread::CACHE:
+        thread_to_start = &cache_thread_;
+        options = &io_message_loop_options;
+        break;
+      case BrowserThread::IO:
+        thread_to_start = &io_thread_;
+        options = &io_message_loop_options;
+        break;
+#if defined(OS_CHROMEOS)
+      case BrowserThread::WEB_SOCKET_PROXY:
+        thread_to_start = &web_socket_proxy_thread_;
+        options = &io_message_loop_options;
+        break;
+#endif
+      case BrowserThread::UI:
+      case BrowserThread::ID_COUNT:
+      default:
+        NOTREACHED();
+        break;
+    }
+
+    BrowserThread::ID id = static_cast<BrowserThread::ID>(thread_id);
+
+    if (parts_.get())
+      parts_->PreStartThread(id);
+
+    if (thread_to_start) {
+      (*thread_to_start).reset(new BrowserProcessSubThread(id));
+      (*thread_to_start)->StartWithOptions(*options);
+    }
+
+    if (parts_.get())
+      parts_->PostStartThread(id);
+  }
+
+  if (parts_.get())
     parts_->PreMainMessageLoopRun();
 
   TRACE_EVENT_BEGIN_ETW("BrowserMain:MESSAGE_LOOP", 0, "");
   // If the UI thread blocks, the whole UI is unresponsive.
   // Do not allow disk IO from the UI thread.
   base::ThreadRestrictions::SetIOAllowed(false);
 
   bool ran_main_loop = false;
   if (parts_.get())
     ran_main_loop = parts_->MainMessageLoopRun(&result_code_);
 
   if (!ran_main_loop)
     MainMessageLoopRun();
 
   TRACE_EVENT_END_ETW("BrowserMain:MESSAGE_LOOP", 0, "");
 
   if (completed_main_message_loop)
     *completed_main_message_loop = true;
 
+  ShutdownThreadsAndCleanUp();
+}
+
+void BrowserMainLoop::ShutdownThreadsAndCleanUp() {
+  // Teardown may start in PostMainMessageLoopRun, and during teardown we
+  // need to be able to perform IO.
+  base::ThreadRestrictions::SetIOAllowed(true);
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      NewRunnableFunction(&base::ThreadRestrictions::SetIOAllowed, true));
+
   if (parts_.get())
     parts_->PostMainMessageLoopRun();
+
+  // Must be size_t so we can subtract from it.
+  for (size_t thread_id = BrowserThread::ID_COUNT - 1;
+       thread_id >= (BrowserThread::UI + 1);
+       --thread_id) {
+    // Find the thread object we want to stop. Looping over all valid
+    // BrowserThread IDs and DCHECKing on a missing case in the switch
+    // statement helps avoid a mismatch between this code and the
+    // BrowserThread::ID enumeration.
+    //
+    // The destruction order is the reverse order of occurrence in the
+    // BrowserThread::ID list. The rationale for the order is as
+    // follows (need to be filled in a bit):
+    //
+    // - (Not sure why the WEB_SOCKET_PROXY thread is stopped first.)
+    //
+    // - The IO thread is the only user of the CACHE thread.
+    //
+    // - The PROCESS_LAUNCHER thread must be stopped after IO in case
+    //   the IO thread posted a task to terminate a process on the
+    //   process launcher thread.
+    //
+    // - (Not sure why FILE needs to stop before WEBKIT.)
+    //
+    // - The WEBKIT thread (which currently is the responsibility of
+    //   the embedder to stop, by destroying ResourceDispatcherHost
+    //   before the DB thread is stopped)
+    //
+    // - (Not sure why DB stops last.)
+    scoped_ptr<BrowserProcessSubThread>* thread_to_stop = NULL;
+    switch (thread_id) {
+      case BrowserThread::DB:
+        thread_to_stop = &db_thread_;
+        break;
+      case BrowserThread::WEBKIT:
+        // For now, the WebKit thread in the browser is owned by
+        // ResourceDispatcherHost, not by the content framework. Until
+        // this is fixed, we don't stop the thread but still call
+        // Pre/PostStopThread for the ID.
+        break;
+      case BrowserThread::FILE:
+        thread_to_stop = &file_thread_;
+        break;
+      case BrowserThread::PROCESS_LAUNCHER:
+        thread_to_stop = &process_launcher_thread_;
+        break;
+      case BrowserThread::CACHE:
+        thread_to_stop = &cache_thread_;
+        break;
+      case BrowserThread::IO:
+        thread_to_stop = &io_thread_;
+        break;
+#if defined(OS_CHROMEOS)
+      case BrowserThread::WEB_SOCKET_PROXY:
+        thread_to_stop = &web_socket_proxy_thread_;
+        break;
+#endif
+      case BrowserThread::UI:
+      case BrowserThread::ID_COUNT:
+      default:
+        NOTREACHED();
+        break;
+    }
+
+    BrowserThread::ID id = static_cast<BrowserThread::ID>(thread_id);
+
+    if (parts_.get())
+      parts_->PreStopThread(id);
+    if (thread_to_stop)
+      thread_to_stop->reset();
+    if (parts_.get())
+      parts_->PostStopThread(id);
+  }
+
+  if (parts_.get())
+    parts_->PostDestroyThreads();
 }
 
 void BrowserMainLoop::InitializeMainThread() {
   const char* kThreadName = "CrBrowserMain";
   base::PlatformThread::SetName(kThreadName);
   main_message_loop_->set_thread_name(kThreadName);
 
   // Register the main thread by instantiating it, but don't call any methods.
   main_thread_.reset(new BrowserThreadImpl(BrowserThread::UI,
                                            MessageLoop::current()));
@@ skipping 44 matching lines @@
     MessageLoopForUI::current()->PostTask(FROM_HERE, parameters_.ui_task);
 
 #if defined(OS_MACOSX)
   MessageLoopForUI::current()->Run();
 #else
   MessageLoopForUI::current()->RunWithDispatcher(NULL);
 #endif
 }
 
 }  // namespace content