Implemented declarative redirects to transparent image and empty document.

chrome/browser/extensions/api/declarative_webrequest/webrequest_action.cc

 // Copyright (c) 2012 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/declarative_webrequest/webrequest_action.h"
 
 #include "base/logging.h"
 #include "base/stringprintf.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/api/declarative_webrequest/request_stages.h"
 #include "chrome/browser/extensions/api/declarative_webrequest/webrequest_constants.h"
 #include "chrome/browser/extensions/api/web_request/web_request_api_helpers.h"
 #include "net/url_request/url_request.h"
 
 namespace extensions {
 
 namespace keys = declarative_webrequest_constants;
 
 namespace {
 // Error messages.
 const char kExpectedDictionary[] = "Expected a dictionary as action.";
 const char kInvalidInstanceTypeError[] =
     "An action has an invalid instanceType: %s";
 const char kMissingRedirectUrl[] = "No redirection target specified.";
+
+const char kTransparentImageUrl[] = "data:image/png;base64,iVBORw0KGgoAAAANSUh"
+    "EUgAAAAEAAAABCAYAAAAfFcSJAAAACklEQVR4nGMAAQAABQABDQottAAAAABJRU5ErkJggg==";
+const char kEmptyDocumentUrl[] = "data:text/html,";
 }  // namespace
 
 //
 // WebRequestAction
 //
 
 WebRequestAction::WebRequestAction() {}
 
 WebRequestAction::~WebRequestAction() {}
 
 // static
 scoped_ptr<WebRequestAction> WebRequestAction::Create(
     const base::Value& json_action,
     std::string* error) {
   const base::DictionaryValue* action_dict = NULL;
   if (!json_action.GetAsDictionary(&action_dict)) {
     *error = kExpectedDictionary;
     return scoped_ptr<WebRequestAction>(NULL);
   }
 
   std::string instance_type = "No instanceType";
   if (!action_dict->GetString(keys::kInstanceTypeKey, &instance_type)) {
     *error = base::StringPrintf(kInvalidInstanceTypeError,
                                 instance_type.c_str());
     return scoped_ptr<WebRequestAction>(NULL);
   }
 
   // TODO(battre): Change this into a proper factory.
+  *error = "";
   if (instance_type == keys::kCancelRequestType) {
-    *error = "";
     return scoped_ptr<WebRequestAction>(new WebRequestCancelAction);
   } else if (instance_type == keys::kRedirectRequestType) {
     std::string redirect_url_string;
     if (!action_dict->GetString(keys::kRedirectUrlKey, &redirect_url_string)) {
       *error = kMissingRedirectUrl;
       return scoped_ptr<WebRequestAction>(NULL);
     }
-    *error = "";
     GURL redirect_url(redirect_url_string);
     return scoped_ptr<WebRequestAction>(
         new WebRequestRedirectAction(redirect_url));
+  } else if (instance_type == keys::kRedirectToTransparentImageType) {
+    return scoped_ptr<WebRequestAction>(
+        new WebRequestRedirectToTransparentImageAction);
+  } else if (instance_type == keys::kRedirectToEmptyDocumentType) {
+    return scoped_ptr<WebRequestAction>(
+        new WebRequestRedirectToEmptyDocumentAction);
   }
 
   *error = base::StringPrintf(kInvalidInstanceTypeError, instance_type.c_str());
   return scoped_ptr<WebRequestAction>();
 }
 
 
 //
 // WebRequestActionSet
 //
@@ skipping 96 matching lines @@
     return LinkedPtrEventResponseDelta(NULL);
   if (request->url() == redirect_url_)
     return LinkedPtrEventResponseDelta(NULL);
   LinkedPtrEventResponseDelta result(
       new extension_web_request_api_helpers::EventResponseDelta(
           extension_id, extension_install_time));
   result->new_url = redirect_url_;
   return result;
 }
 
+//
+// WebRequestRedirectToTransparentImageAction
+//
+
+WebRequestRedirectToTransparentImageAction::
+WebRequestRedirectToTransparentImageAction() {}
+
+WebRequestRedirectToTransparentImageAction::
+~WebRequestRedirectToTransparentImageAction() {}
+
+int WebRequestRedirectToTransparentImageAction::GetStages() const {
+  return ON_BEFORE_REQUEST;
+}
+
+WebRequestAction::Type
+WebRequestRedirectToTransparentImageAction::GetType() const {
+  return WebRequestAction::ACTION_REDIRECT_TO_TRANSPARENT_IMAGE;
+}
+
+LinkedPtrEventResponseDelta
+WebRequestRedirectToTransparentImageAction::CreateDelta(
+    net::URLRequest* request,
+    RequestStages request_stage,
+    const std::string& extension_id,
+    const base::Time& extension_install_time) const {
+  if (!(request_stage & GetStages()))

[Matt Perry, 2012/05/16 23:54:12]

seems like all the CreateDeltas have this check. Can it be moved to a shared
location (i.e. the calling code)?

[battre, 2012/05/18 10:29:38]

I do this at the caller already. I have replaced these checks with CHECK()s.

+    return LinkedPtrEventResponseDelta(NULL);
+  LinkedPtrEventResponseDelta result(
+      new extension_web_request_api_helpers::EventResponseDelta(
+          extension_id, extension_install_time));
+  result->new_url = GURL(kTransparentImageUrl);
+  return result;
+}
+
+//
+// WebRequestRedirectToEmptyDocumentAction
+//
+
+WebRequestRedirectToEmptyDocumentAction::
+WebRequestRedirectToEmptyDocumentAction() {}
+
+WebRequestRedirectToEmptyDocumentAction::
+~WebRequestRedirectToEmptyDocumentAction() {}
+
+int WebRequestRedirectToEmptyDocumentAction::GetStages() const {
+  return ON_BEFORE_REQUEST;
+}
+
+WebRequestAction::Type
+WebRequestRedirectToEmptyDocumentAction::GetType() const {
+  return WebRequestAction::ACTION_REDIRECT_TO_EMPTY_DOCUMENT;
+}
+
+LinkedPtrEventResponseDelta
+WebRequestRedirectToEmptyDocumentAction::CreateDelta(
+    net::URLRequest* request,
+    RequestStages request_stage,
+    const std::string& extension_id,
+    const base::Time& extension_install_time) const {
+  if (!(request_stage & GetStages()))
+    return LinkedPtrEventResponseDelta(NULL);
+  LinkedPtrEventResponseDelta result(
+      new extension_web_request_api_helpers::EventResponseDelta(
+          extension_id, extension_install_time));
+  result->new_url = GURL(kEmptyDocumentUrl);
+  return result;
+}
+
 }  // namespace extensions