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"
@@ skipping 244 matching lines @@
   hi_res_timer_manager_.reset(new HighResolutionTimerManager);
 
   network_change_notifier_.reset(net::NetworkChangeNotifier::Create());
 
   for (size_t i = 0; i < parts_list_.size(); ++i)
     parts_list_[i]->PostMainMessageLoopStart();
 }
 
 void BrowserMainLoop::RunMainMessageLoopParts(
     bool* completed_main_message_loop) {
+  IOThreadDelegate* io_thread_delegate = NULL;
+  for (size_t i = 0; i < parts_list_.size(); ++i) {
+    IOThreadDelegate* current_delegate =
+        parts_list_[i]->PreMainMessageLoopRun();
+    if (current_delegate) {
+      DCHECK(!io_thread_delegate) << "Only one delegate allowed.";
+      io_thread_delegate = current_delegate;
+    }
+  }
+
+  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;
+
+  db_thread_.reset(new BrowserProcessSubThread(BrowserThread::DB));
+  db_thread_->Start();
+
+  file_thread_.reset(new BrowserProcessSubThread(BrowserThread::FILE));
+#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.
+  file_thread_->StartWithOptions(ui_message_loop_options);
+#else
+  file_thread_->StartWithOptions(io_message_loop_options);
+#endif
+
+  process_launcher_thread_.reset(
+      new BrowserProcessSubThread(BrowserThread::PROCESS_LAUNCHER));
+  process_launcher_thread_->Start();
+
+  cache_thread_.reset(new BrowserProcessSubThread(BrowserThread::CACHE));
+  cache_thread_->StartWithOptions(io_message_loop_options);
+  io_thread_.reset(new BrowserProcessIOThread(io_thread_delegate));
+  io_thread_->StartWithOptions(io_message_loop_options);
+#if defined(OS_CHROMEOS)
+  web_socket_proxy_thread_.reset(
+      new BrowserProcessSubThread(BrowserThread::WEB_SOCKET_PROXY));
+  web_socket_proxy_thread_->StartWithOptions(io_message_loop_options);
+#endif
+
   for (size_t i = 0; i < parts_list_.size(); ++i)
-    parts_list_[i]->PreMainMessageLoopRun();
+    parts_list_[i]->PreMainMessageLoopRunThreadsCreated();
 
   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);
 
   // Iterate through each of the parts. If any of them ran the main
   // message loop then they should return |true|. Otherwise
   // BrowserMainLoop::MainMessageLoopRun loop will be run.
   bool ran_main_loop = false;
   for (size_t i = 0; i < parts_list_.size(); ++i) {
     int result_code = result_code_;
     if (parts_list_[i]->MainMessageLoopRun(&result_code)) {
       ran_main_loop = true;
       result_code_ = 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;
 
+  // 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));
+
   for (size_t i = 0; i < parts_list_.size(); ++i)
     parts_list_[i]->PostMainMessageLoopRun();
+
+  // Must be size_t so we can subtract from it.
+  for (size_t thread_id = BrowserThread::ID_COUNT - 1;
+       thread_id >= BrowserThread::DB;
+       --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::UI:
+      case BrowserThread::ID_COUNT:
+        NOTREACHED();
+        break;
+      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
+    }
+
+    BrowserThread::ID id = static_cast<BrowserThread::ID>(thread_id);
+
+    for (size_t i = 0; i < parts_list_.size(); ++i)
+      parts_list_[i]->PreStopThread(id);
+    if (thread_to_stop)
+      thread_to_stop->reset();
+    for (size_t i = 0; i < parts_list_.size(); ++i)
+      parts_list_[i]->PostStopThread(id);
+  }
+
+  for (size_t i = 0; i < parts_list_.size(); ++i)
+    parts_list_[i]->FinalCleanup();
 }
 
 void BrowserMainLoop::InitializeMainThread() {
   const char* kThreadName = "CrBrowserMain";
   base::PlatformThread::SetName(kThreadName);
   main_message_loop_->set_thread_name(kThreadName);
   tracked_objects::ThreadData::InitializeThreadContext(kThreadName);
 
   // Register the main thread by instantiating it, but don't call any methods.
   main_thread_.reset(new BrowserThreadImpl(BrowserThread::UI,
@@ skipping 45 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