extensions/browser/serial_extension_host_queue.h

   1 // Copyright 2015 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 EXTENSIONS_BROWSER_SERIAL_EXTENSION_HOST_QUEUE_H_
   6 #define EXTENSIONS_BROWSER_SERIAL_EXTENSION_HOST_QUEUE_H_
   7
   8 #include <list>
   9
  10 #include "base/macros.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "extensions/browser/extension_host_queue.h"
  13
  14 namespace extensions {
  15
  16 class DeferredStartRenderHost;
  17
  18 // An ExtensionHostQueue which initializes DeferredStartRenderHosts in the order
  19 // they're Add()ed, with simple rate limiting logic that re-posts each task to
  20 // the UI thread, to avoid clogging it for a long period of time.
  21 class SerialExtensionHostQueue : public ExtensionHostQueue {
  22  public:
  23   SerialExtensionHostQueue();
  24   ~SerialExtensionHostQueue() override;
  25
  26  private:
  27   // ExtensionHostQueue:
  28   void Add(DeferredStartRenderHost* host) override;
  29   void Remove(DeferredStartRenderHost* host) override;
  30
  31   // Queues up a delayed task to process the next DeferredStartRenderHost in
  32   // the queue.
  33   void PostTask();
  34
  35   // Creates the RenderView for the next host in the queue.
  36   void ProcessOneHost();
  37
  38   // True if this queue is currently in the process of starting an
  39   // DeferredStartRenderHost.
  40   bool pending_create_;
  41
  42   // The list of DeferredStartRenderHosts waiting to be started.
  43   std::list<DeferredStartRenderHost*> queue_;
  44
  45   base::WeakPtrFactory<SerialExtensionHostQueue> ptr_factory_;
  46
  47   DISALLOW_COPY_AND_ASSIGN(SerialExtensionHostQueue);
  48 };
  49
  50 }  // namespace extensions
  51
  52 #endif  // EXTENSIONS_BROWSER_SERIAL_EXTENSION_HOST_QUEUE_H_