ios/web/web_thread_impl.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef IOS_WEB_WEB_THREAD_IMPL_H_
   6 #define IOS_WEB_WEB_THREAD_IMPL_H_
   7
   8 #include "base/threading/thread.h"
   9 #include "ios/web/public/web_thread.h"
  10
  11 namespace web {
  12
  13 class WebThreadDelegate;
  14
  15 class WebThreadImpl : public WebThread, public base::Thread {
  16  public:
  17   // Construct a WebThreadImpl with the supplied identifier.  It is an error
  18   // to construct a WebThreadImpl that already exists.
  19   explicit WebThreadImpl(WebThread::ID identifier);
  20
  21   // Special constructor for the main (UI) thread and unittests. If a
  22   // |message_loop| is provied, we use a dummy thread here since the main
  23   // thread already exists.
  24   WebThreadImpl(WebThread::ID identifier, base::MessageLoop* message_loop);
  25   ~WebThreadImpl() override;
  26
  27   static void ShutdownThreadPool();
  28
  29   // TODO(stuartmorgan): Move this to WebThread (where it belongs) once
  30   // the alternate BrowserThread-backed-WebThread implementation goes away. See
  31   // the note in web_thread_delegate.h.
  32   //
  33   // Sets the delegate for the specified WebThread.
  34   //
  35   // Only one delegate may be registered at a time. Delegates may be
  36   // unregistered by providing a nullptr pointer.
  37   //
  38   // If the caller unregisters a delegate before CleanUp has been
  39   // called, it must perform its own locking to ensure the delegate is
  40   // not deleted while unregistering.
  41   static void SetDelegate(ID identifier, WebThreadDelegate* delegate);
  42
  43  protected:
  44   void Init() override;
  45   void Run(base::MessageLoop* message_loop) override;
  46   void CleanUp() override;
  47
  48  private:
  49   // This class implements all the functionality of the public WebThread
  50   // functions, but state is stored in the WebThreadImpl to keep
  51   // the API cleaner. Therefore make WebThread a friend class.
  52   friend class WebThread;
  53
  54   // The following are unique function names that makes it possible to tell
  55   // the thread id from the callstack alone in crash dumps.
  56   void UIThreadRun(base::MessageLoop* message_loop);
  57   void DBThreadRun(base::MessageLoop* message_loop);
  58   void FileThreadRun(base::MessageLoop* message_loop);
  59   void FileUserBlockingThreadRun(base::MessageLoop* message_loop);
  60   void CacheThreadRun(base::MessageLoop* message_loop);
  61   void IOThreadRun(base::MessageLoop* message_loop);
  62
  63   static bool PostTaskHelper(WebThread::ID identifier,
  64                              const tracked_objects::Location& from_here,
  65                              const base::Closure& task,
  66                              base::TimeDelta delay,
  67                              bool nestable);
  68
  69   // Common initialization code for the constructors.
  70   void Initialize();
  71
  72   // Performs cleanup that needs to happen on the IO thread before calling the
  73   // embedder's CleanUp function.
  74   void IOThreadPreCleanUp();
  75
  76   // For testing.
  77   friend class TestWebThreadBundle;
  78   friend class TestWebThreadBundleImpl;
  79   static void FlushThreadPoolHelperForTesting();
  80
  81   // The identifier of this thread.  Only one thread can exist with a given
  82   // identifier at a given time.
  83   ID identifier_;
  84 };
  85
  86 }  // namespace web
  87
  88 #endif  // IOS_WEB_WEB_THREAD_IMPL_H_