Implement AutomationNode.querySelector().

chrome/browser/extensions/api/automation_internal/automation_internal_api.cc

 // Copyright 2014 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 "chrome/browser/extensions/api/automation_internal/automation_internal_api.h"
 
 #include <vector>
 
 #include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/extensions/api/automation_internal/automation_action_adapter.h"
 #include "chrome/browser/extensions/api/automation_internal/automation_util.h"
 #include "chrome/browser/extensions/api/tabs/tabs_constants.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/extensions/api/automation_internal.h"
 #include "chrome/common/extensions/manifest_handlers/automation.h"
 #include "content/public/browser/ax_event_notification_details.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
+#include "extensions/common/extension_messages.h"
 #include "extensions/common/permissions/permissions_data.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/ui/ash/accessibility/automation_manager_ash.h"
 #endif
 
 namespace extensions {
 class AutomationWebContentsObserver;
 }  // namespace extensions
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(extensions::AutomationWebContentsObserver);
 
+namespace extensions {
+
 namespace {
 const int kDesktopProcessID = 0;
 const int kDesktopRoutingID = 0;
 
 const char kCannotRequestAutomationOnPage[] =
     "Cannot request automation tree on url \"*\". "
     "Extension manifest must request permission to access this host.";
-}  // namespace
+const char kRendererDestroyed[] = "The tab was closed.";
 
-namespace extensions {
+// Handles sending and receiving IPCs for a single querySelector request. On
+// creation, sends the request IPC, and is destroyed either when the response is
+// received or the renderer is destroyed.
+class QuerySelectorHandler : public content::WebContentsObserver {
+ public:
+  QuerySelectorHandler(
+      content::WebContents* web_contents,
+      int request_id,
+      int acc_obj_id,
+      const base::string16& query,
+      const extensions::AutomationInternalQuerySelectorFunction::Callback&
+          callback)
+      : content::WebContentsObserver(web_contents),
+        request_id_(request_id),
+        callback_(callback) {
+    content::RenderViewHost* rvh = web_contents->GetRenderViewHost();
+    rvh->Send(new ExtensionMsg_AutomationQuerySelector(
+        rvh->GetRoutingID(), request_id, acc_obj_id, query));
+  }
+
+  ~QuerySelectorHandler() override {}
+
+  bool OnMessageReceived(const IPC::Message& message) override {
+    if (message.type() != ExtensionHostMsg_AutomationQuerySelector_Result::ID)
+      return false;
+
+    // There may be several requests in flight; check this response matches.
+    int message_request_id;

[Devlin, 2014/10/30 23:26:53]

nit: initialize to 0.

[aboxhall, 2014/10/31 20:32:22]

Done, although note that this is not the norm:
https://code.google.com/p/chromium/codesearch#search/&q=ReadInt%5C(&p=3&sq=pa...
- and that the CHECK guarantees that this int will never be read uninitialized
(unless something goes very wrong with ReadInt, in which case we probably have
other problems).

+    PickleIterator iter(message);
+    CHECK(message.ReadInt(&iter, &message_request_id));
+
+    if (message_request_id != request_id_)
+      return false;
+
+    IPC_BEGIN_MESSAGE_MAP(QuerySelectorHandler, message)
+      IPC_MESSAGE_HANDLER(ExtensionHostMsg_AutomationQuerySelector_Result,
+                          OnQueryResponse)
+    IPC_END_MESSAGE_MAP()
+    return true;
+  }
+
+  void WebContentsDestroyed() override {
+    callback_.Run(kRendererDestroyed, 0);
+    delete this;
+  }
+
+ private:
+  void OnQueryResponse(int request_id,
+                       const std::string& error,
+                       int result_acc_obj_id) {
+    callback_.Run(error, result_acc_obj_id);
+    delete this;
+  }
+
+  int request_id_;
+  const extensions::AutomationInternalQuerySelectorFunction::Callback callback_;
+};
 
 bool CanRequestAutomation(const Extension* extension,
                           const AutomationInfo* automation_info,
                           const content::WebContents* contents) {
   if (automation_info->desktop)
     return true;
 
   const GURL& url = contents->GetURL();
   // TODO(aboxhall): check for webstore URL
   if (automation_info->matches.MatchesURL(url))
     return true;
 
   int tab_id = ExtensionTabUtil::GetTabId(contents);
   content::RenderProcessHost* process = contents->GetRenderProcessHost();
   int process_id = process ? process->GetID() : -1;
   std::string unused_error;
   return extension->permissions_data()->CanAccessPage(
       extension, url, url, tab_id, process_id, &unused_error);
 }
 
+// Helper class that implements an action adapter for a |RenderFrameHost|.
+class RenderFrameHostActionAdapter : public AutomationActionAdapter {
+ public:
+  explicit RenderFrameHostActionAdapter(content::RenderFrameHost* rfh)
+      : rfh_(rfh) {}
+
+  virtual ~RenderFrameHostActionAdapter() {}
+
+  // AutomationActionAdapter implementation.
+  void DoDefault(int32 id) override { rfh_->AccessibilityDoDefaultAction(id); }

[Devlin, 2014/10/30 23:26:53]

use int32_t and include stdint.h

[aboxhall, 2014/10/31 20:32:21]

This isn't new code.

+
+  void Focus(int32 id) override { rfh_->AccessibilitySetFocus(id); }
+
+  void MakeVisible(int32 id) override {
+    rfh_->AccessibilityScrollToMakeVisible(id, gfx::Rect());
+  }
+
+  void SetSelection(int32 id, int32 start, int32 end) override {
+    rfh_->AccessibilitySetTextSelection(id, start, end);
+  }
+
+ private:
+  content::RenderFrameHost* rfh_;
+
+  DISALLOW_COPY_AND_ASSIGN(RenderFrameHostActionAdapter);
+};

[Devlin, 2014/10/30 23:26:53]

nit: newline

[aboxhall, 2014/10/31 20:32:22]

Done.

+}  // anonymous namespace

[Devlin, 2014/10/30 23:26:53]

nit: typically just "namespace" is enough.

[aboxhall, 2014/10/31 20:32:22]

Done.

+
+

[Devlin, 2014/10/30 23:26:53]

nit: just one newline. :)

[aboxhall, 2014/10/31 20:32:22]

Done.

 // Helper class that receives accessibility data from |WebContents|.
 class AutomationWebContentsObserver
     : public content::WebContentsObserver,
       public content::WebContentsUserData<AutomationWebContentsObserver> {
  public:
   ~AutomationWebContentsObserver() override {}
 
   // content::WebContentsObserver overrides.
   void AccessibilityEventReceived(
       const std::vector<content::AXEventNotificationDetails>& details)
@@ skipping 17 matching lines @@
   AutomationWebContentsObserver(
       content::WebContents* web_contents)
       : content::WebContentsObserver(web_contents),
         browser_context_(web_contents->GetBrowserContext()) {}
 
   content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(AutomationWebContentsObserver);
 };
 
-// Helper class that implements an action adapter for a |RenderFrameHost|.
-class RenderFrameHostActionAdapter : public AutomationActionAdapter {
- public:
-  explicit RenderFrameHostActionAdapter(content::RenderFrameHost* rfh)
-      : rfh_(rfh) {}
-
-  virtual ~RenderFrameHostActionAdapter() {}
-
-  // AutomationActionAdapter implementation.
-  void DoDefault(int32 id) override { rfh_->AccessibilityDoDefaultAction(id); }
-
-  void Focus(int32 id) override { rfh_->AccessibilitySetFocus(id); }
-
-  void MakeVisible(int32 id) override {
-    rfh_->AccessibilityScrollToMakeVisible(id, gfx::Rect());
-  }
-
-  void SetSelection(int32 id, int32 start, int32 end) override {
-    rfh_->AccessibilitySetTextSelection(id, start, end);
-  }
-
- private:
-  content::RenderFrameHost* rfh_;
-
-  DISALLOW_COPY_AND_ASSIGN(RenderFrameHostActionAdapter);
-};
-
 ExtensionFunction::ResponseAction
 AutomationInternalEnableTabFunction::Run() {
   const AutomationInfo* automation_info = AutomationInfo::Get(extension());
   EXTENSION_FUNCTION_VALIDATE(automation_info);
 
   using api::automation_internal::EnableTab::Params;
   scoped_ptr<Params> params(Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
   content::WebContents* contents = NULL;
   if (params->tab_id.get()) {
@@ skipping 19 matching lines @@
 
   if (!CanRequestAutomation(extension(), automation_info, contents)) {
     return RespondNow(
         Error(kCannotRequestAutomationOnPage, contents->GetURL().spec()));
   }
   AutomationWebContentsObserver::CreateForWebContents(contents);
   contents->EnableTreeOnlyAccessibilityMode();
   return RespondNow(
       ArgumentList(api::automation_internal::EnableTab::Results::Create(
           rfh->GetProcess()->GetID(), rfh->GetRoutingID())));
-  }
+}
 
 ExtensionFunction::ResponseAction
 AutomationInternalPerformActionFunction::Run() {
   const AutomationInfo* automation_info = AutomationInfo::Get(extension());
   EXTENSION_FUNCTION_VALIDATE(automation_info && automation_info->interact);
 
   using api::automation_internal::PerformAction::Params;
   scoped_ptr<Params> params(Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
 
@@ skipping 63 matching lines @@
   if (!automation_info || !automation_info->desktop)
     return RespondNow(Error("desktop permission must be requested"));
 
   AutomationManagerAsh::GetInstance()->Enable(browser_context());
   return RespondNow(NoArguments());
 #else
   return RespondNow(Error("getDesktop is unsupported by this platform"));
 #endif  // defined(OS_CHROMEOS)
 }
 
+// static
+int AutomationInternalQuerySelectorFunction::query_request_id_counter_ = 0;
+
+ExtensionFunction::ResponseAction
+AutomationInternalQuerySelectorFunction::Run() {
+  const AutomationInfo* automation_info = AutomationInfo::Get(extension());
+  EXTENSION_FUNCTION_VALIDATE(automation_info);
+
+  using api::automation_internal::QuerySelector::Params;
+  scoped_ptr<Params> params(Params::Create(*args_));
+  EXTENSION_FUNCTION_VALIDATE(params.get());
+
+  if (params->args.process_id == kDesktopProcessID &&
+      params->args.routing_id == kDesktopRoutingID) {
+    return RespondNow(
+        Error("querySelector queries may not be used on the desktop."));
+  }
+  content::RenderFrameHost* rfh = content::RenderFrameHost::FromID(
+      params->args.process_id, params->args.routing_id);
+  if (!rfh)
+    return RespondNow(Error("querySelector query sent on destroyed node"));

[dmazzoni, 2014/10/30 23:32:42]

nit: this is really "destroyed tree" or "destroyed web contents" or something
like that

[aboxhall, 2014/10/31 20:32:22]

Good point, fixed.

+
+  content::WebContents* contents =
+      content::WebContents::FromRenderFrameHost(rfh);
+
+  int request_id = query_request_id_counter_++;
+  base::string16 selector = base::UTF8ToUTF16(params->args.selector);
+
+  // QuerySelectorHandler handles IPCs and deletes itself on completion.
+  new QuerySelectorHandler(
+      contents, request_id, params->args.automation_node_id, selector,
+      base::Bind(&AutomationInternalQuerySelectorFunction::OnResponse, this));
+
+  return RespondLater();
+}
+
+void AutomationInternalQuerySelectorFunction::OnResponse(
+    const std::string& error,
+    int result_acc_obj_id) {
+  if (!error.empty()) {
+    Respond(Error(error));
+    return;
+  }
+
+  Respond(OneArgument(new base::FundamentalValue(result_acc_obj_id)));
+}
+
 }  // namespace extensions