Implementation of beginning of Declarative Web Request API backend

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"
+
+namespace extensions {
+namespace declarative_webrequest {
+
+namespace {
+// Constants from the JavaScript API.
+const char kInstanceType[] = "instanceType";
+const char kInstanceCancel[] = "experimental.webRequest.CancelRequest";
+
+// Error messages.
+const char kExpectedDictionary[] = "Expected a dictionary as action.";
+const char kInvalidInstanceTypeError[] =
+    "An action has an invalid instanceType: %s";
+}  // namespace
+
+//
+// WebRequestAction
+//
+
+WebRequestAction::WebRequestAction() {}
+
+WebRequestAction::~WebRequestAction() {}
+
+
+//
+// WebRequestActionCollection
+//
+
+WebRequestActionCollection::WebRequestActionCollection(const Actions& actions)
+    : actions_(actions) {}
+
+WebRequestActionCollection::~WebRequestActionCollection() {}
+
+
+//
+// WebRequestActionFactory
+//
+
+// static
+bool WebRequestActionFactory::IsHandledByThisFactory(
+    const std::string& action_name) {
+  return action_name == kInstanceCancel;
+}
+
+// static
+scoped_ptr<WebRequestAction> WebRequestActionFactory::CreateAction(
+    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(kInstanceType, &instance_type)) {
+    *error = base::StringPrintf(kInvalidInstanceTypeError,
+                                instance_type.c_str());
+    return scoped_ptr<WebRequestAction>(NULL);
+  }
+
+  if (instance_type == kInstanceCancel) {

[Matt Perry, 2012/03/22 23:07:25]

Take a look at ExtensionFunctionRegistry for a way to do this without a long
list of if statements. It probably applies to conditions and condition
attributes as well.

[battre, 2012/03/26 18:35:51]

Yes, I had that in mind. I will change this code once we have >1 action. ;-)

+    *error = "";
+    return scoped_ptr<WebRequestAction>(new WebRequestCancelAction);
+  }
+
+  *error = base::StringPrintf(kInvalidInstanceTypeError, instance_type.c_str());
+  return scoped_ptr<WebRequestAction>();
+}
+
+// static
+scoped_ptr<WebRequestActionCollection>
+WebRequestActionFactory::CreateActionCollection(
+    const WebRequestActionFactory::AnyVector& actions,
+    std::string* error) {
+  WebRequestActionCollection::Actions result;
+
+  for (AnyVector::const_iterator i = actions.begin();
+      i != actions.end(); ++i) {
+    CHECK(i->get());
+    scoped_ptr<WebRequestAction> action = CreateAction((*i)->value(), error);
+    if (!error->empty())
+      return scoped_ptr<WebRequestActionCollection>(NULL);
+    result.push_back(make_linked_ptr(action.release()));
+  }
+
+  return scoped_ptr<WebRequestActionCollection>(
+      new WebRequestActionCollection(result));
+}
+
+//
+// WebRequestCancelAction
+//
+
+WebRequestCancelAction::WebRequestCancelAction() {}
+
+WebRequestCancelAction::~WebRequestCancelAction() {}
+
+int WebRequestCancelAction::GetStages() const {
+  return ON_BEFORE_REQUEST | ON_BEFORE_SEND_HEADERS | ON_HEADERS_RECEIVED |
+      ON_AUTH_REQUIRED;
+}
+
+}  // namespace declarative_webrequest
+}  // namespace extensions