content/renderer/dom_automation_controller.h

   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 #ifndef CONTENT_RENDERER_DOM_AUTOMATION_CONTROLLER_H_
   6 #define CONTENT_RENDERER_DOM_AUTOMATION_CONTROLLER_H_
   7
   8 #include "ipc/ipc_sender.h"
   9 #include "webkit/renderer/cpp_bound_class.h"
  10
  11 /* DomAutomationController class:
  12    Bound to Javascript window.domAutomationController object.
  13    At the very basic, this object makes any native value (string, numbers,
  14    boolean) from javascript available to the automation host in Cpp.
  15    Any renderer implementation that is built with this binding will allow the
  16    above facility.
  17    The intended use of this object is to expose the DOM Objects and their
  18    attributes to the automation host.
  19
  20    A typical usage would be like following (JS code):
  21
  22    var object = document.getElementById('some_id');
  23    window.domAutomationController.send(object.nodeName); // get the tag name
  24
  25    For the exact mode of usage,
  26    refer AutomationProxyTest.*DomAutomationController tests.
  27
  28    The class provides a single send method that can send variety of native
  29    javascript values. (NPString, Number(double), Boolean)
  30
  31    The actual communication occurs in the following manner:
  32
  33     TEST            MASTER          RENDERER
  34               (1)             (3)
  35    |AProxy| ----->|AProvider|----->|RenderView|------|
  36       /\                |               |            |
  37       |                 |               |            |
  38       |(6)              |(2)            |(0)         |(4)
  39       |                 |               \/           |
  40       |                 |-------->|DAController|<----|
  41       |                                 |
  42       |                                 |(5)
  43       |-------|WebContentsImpl|<--------|
  44
  45
  46    Legends:
  47    - AProxy = AutomationProxy
  48    - AProvider = AutomationProvider
  49    - DAController = DomAutomationController
  50
  51    (0) Initialization step where DAController is bound to the renderer
  52        and the view_id of the renderer is supplied to the DAController for
  53        routing message in (5). (routing_id_)
  54    (1) A 'javascript:' url is sent from the test process to master as an IPC
  55        message. A unique routing id is generated at this stage (automation_id_)
  56    (2) The automation_id_ of step (1) is supplied to DAController by calling
  57        the bound method setAutomationId(). This is required for routing message
  58        in (6).
  59    (3) The 'javascript:' url is sent for execution by calling into
  60        Browser::LoadURL()
  61    (4) A callback is generated as a result of domAutomationController.send()
  62        into Cpp. The supplied value is received as a result of this callback.
  63    (5) The value received in (4) is sent to the master along with the
  64        stored automation_id_ as an IPC message. routing_id_ is used to route
  65        the message. (IPC messages, ViewHostMsg_*DomAutomation* )
  66    (6) The value and the automation_id_ is extracted out of the message received
  67        in (5). This value is relayed to AProxy using another IPC message.
  68        automation_id_ is used to route the message.
  69        (IPC messages, AutomationMsg_Dom*Response)
  70
  71 */
  72
  73 namespace content {
  74
  75 // TODO(vibhor): Add another method-pair like sendLater() and sendNow()
  76 // sendLater() should keep building a json serializer
  77 // sendNow() should send the above serializer as a string.
  78 class DomAutomationController : public webkit_glue::CppBoundClass {
  79  public:
  80   DomAutomationController();
  81
  82   // Makes the renderer send a javascript value to the app.
  83   // The value to be sent can be either of type NPString,
  84   // Number (double casted to int32) or boolean.
  85   // The function returns true/false based on the result of actual send over
  86   // IPC. It sets the return value to null on unexpected errors or arguments.
  87   void Send(const webkit_glue::CppArgumentList& args,
  88             webkit_glue::CppVariant* result);
  89
  90   // Makes the renderer send a javascript value to the app.
  91   // The value must be a NPString and should be properly formed JSON.
  92   // This function does not modify/escape the returned string in any way.
  93   void SendJSON(const webkit_glue::CppArgumentList& args,
  94                 webkit_glue::CppVariant* result);
  95
  96   // Sends a string with a provided Automation Id.
  97   // Expects two javascript values; the first must be a number type and will be
  98   // used as the Automation Id, the second must be of type NPString.
  99   // The function returns true/false to the javascript based on the success
 100   // of the send over IPC. It sets the javascript return value to null on
 101   // unexpected errors or arguments.
 102   void SendWithId(const webkit_glue::CppArgumentList& args,
 103                   webkit_glue::CppVariant* result);
 104
 105   void SetAutomationId(const webkit_glue::CppArgumentList& args,
 106                        webkit_glue::CppVariant* result);
 107
 108   // TODO(vibhor): Implement later
 109   // static CppBindingObjectMethod sendLater;
 110   // static CppBindingObjectMethod sendNow;
 111
 112   void set_routing_id(int routing_id) { routing_id_ = routing_id; }
 113
 114   void set_message_sender(IPC::Sender* sender) {
 115     sender_ = sender;
 116   }
 117
 118  private:
 119   IPC::Sender* sender_;
 120
 121   // Refer to the comments at the top of the file for more details.
 122   int routing_id_;  // routing id to be used by first channel.
 123   int automation_id_;  // routing id to be used by the next channel.
 124 };
 125
 126 }  // namespace content
 127
 128 #endif  // CONTENT_RENDERER_DOM_AUTOMATION_CONTROLLER_H_