src/chrome/browser/web_resource/json_asynchronous_unpacker.cc

   1 // Copyright (c) 2012 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 #include "chrome/browser/web_resource/json_asynchronous_unpacker.h"
   6
   7 #include "base/command_line.h"
   8 #include "chrome/browser/web_resource/web_resource_service.h"
   9 #include "chrome/common/chrome_switches.h"
  10 #include "chrome/common/chrome_utility_messages.h"
  11 #include "content/public/browser/browser_thread.h"
  12 #include "content/public/browser/utility_process_host.h"
  13 #include "content/public/browser/utility_process_host_client.h"
  14
  15 using content::BrowserThread;
  16 using content::UtilityProcessHost;
  17 using content::UtilityProcessHostClient;
  18
  19 // This class coordinates a web resource unpack and parse task which is run in
  20 // a separate process.  Results are sent back to this class and routed to
  21 // the WebResourceService.
  22 class JSONAsynchronousUnpackerImpl
  23     : public UtilityProcessHostClient,
  24       public JSONAsynchronousUnpacker {
  25  public:
  26   explicit JSONAsynchronousUnpackerImpl(
  27       JSONAsynchronousUnpackerDelegate* delegate)
  28     : JSONAsynchronousUnpacker(delegate),
  29       got_response_(false) {
  30   }
  31
  32   virtual void Start(const std::string& json_data) OVERRIDE {
  33     AddRef();  // balanced in Cleanup.
  34
  35     BrowserThread::ID thread_id;
  36     CHECK(BrowserThread::GetCurrentThreadIdentifier(&thread_id));
  37     BrowserThread::PostTask(
  38         BrowserThread::IO, FROM_HERE,
  39         base::Bind(
  40             &JSONAsynchronousUnpackerImpl::StartProcessOnIOThread,
  41             this, thread_id, json_data));
  42   }
  43
  44  private:
  45   virtual ~JSONAsynchronousUnpackerImpl() {}
  46
  47   // UtilityProcessHostClient.
  48   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE {
  49     bool handled = true;
  50     IPC_BEGIN_MESSAGE_MAP(JSONAsynchronousUnpackerImpl, message)
  51       IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_UnpackWebResource_Succeeded,
  52                           OnUnpackWebResourceSucceeded)
  53       IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_UnpackWebResource_Failed,
  54                           OnUnpackWebResourceFailed)
  55       IPC_MESSAGE_UNHANDLED(handled = false)
  56     IPC_END_MESSAGE_MAP()
  57     return handled;
  58   }
  59
  60   virtual void OnProcessCrashed(int exit_code) OVERRIDE {
  61     if (got_response_)
  62       return;
  63
  64     OnUnpackWebResourceFailed(
  65         "Utility process crashed while trying to retrieve web resources.");
  66   }
  67
  68   void OnUnpackWebResourceSucceeded(
  69       const DictionaryValue& parsed_json) {
  70     if (delegate_)
  71       delegate_->OnUnpackFinished(parsed_json);
  72     Cleanup();
  73   }
  74
  75   void OnUnpackWebResourceFailed(const std::string& error_message) {
  76     if (delegate_)
  77       delegate_->OnUnpackError(error_message);
  78     Cleanup();
  79   }
  80
  81   // Release reference and set got_response_.
  82   void Cleanup() {
  83     DCHECK(!got_response_);
  84     got_response_ = true;
  85     Release();
  86   }
  87
  88   void StartProcessOnIOThread(BrowserThread::ID thread_id,
  89                               const std::string& json_data) {
  90     UtilityProcessHost* host = UtilityProcessHost::Create(
  91         this, BrowserThread::GetMessageLoopProxyForThread(thread_id).get());
  92     host->EnableZygote();
  93     // TODO(mrc): get proper file path when we start using web resources
  94     // that need to be unpacked.
  95     host->Send(new ChromeUtilityMsg_UnpackWebResource(json_data));
  96   }
  97
  98   // True if we got a response from the utility process and have cleaned up
  99   // already.
 100   bool got_response_;
 101 };
 102
 103 JSONAsynchronousUnpacker* JSONAsynchronousUnpacker::Create(
 104     JSONAsynchronousUnpackerDelegate* delegate) {
 105   return new JSONAsynchronousUnpackerImpl(delegate);
 106 }
 107