Allow platform apps to respond to Web Intents

chrome/browser/extensions/web_intent_callbacks.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 "base/stringprintf.h"
+#include "chrome/browser/extensions/web_intent_callbacks.h"
+#include "chrome/browser/profiles/profile_dependency_manager.h"
+#include "chrome/common/extensions/extension.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_intents_dispatcher.h"
+
+namespace {
+
+// Get the key for use inside the internal pending WebIntentCallbacks map.
+std::string GetKey(const extensions::Extension* extension, int id) {
+  return StringPrintf("%s/%d", extension->id().c_str(), id);
+}
+
+}  // namespace
+
+namespace extensions {
+
+// SourceObserver is a subclass of WebContentsObserver that is instantiated
+// on RegisterCallback to wait for the source WebContents to be destroyed.
+// If it is destroyed, this automatically clears the callback from pending_.
+class WebIntentCallbacks::SourceObserver : content::WebContentsObserver {
+ public:
+  SourceObserver(content::WebContents* web_contents,
+                 WebIntentCallbacks* callbacks,
+                 const std::string key)
+      : content::WebContentsObserver(web_contents),
+        callbacks_(callbacks),
+        key_(key) {}
+  virtual ~SourceObserver() {}
+
+  // Implement WebContentsObserver
+  virtual void WebContentsDestroyed(content::WebContents* web_contents)
+      OVERRIDE {
+    content::WebIntentsDispatcher* dispatcher =
+        callbacks_->GetAndClear(key_);
+    if (dispatcher)
+      delete dispatcher;
+
+    delete this;
+  }
+
+ private:
+  WebIntentCallbacks* callbacks_;
+  const std::string key_;
+};
+
+WebIntentCallbacks::WebIntentCallbacks() : last_id_(0) {}
+
+WebIntentCallbacks::~WebIntentCallbacks() {}
+
+// static
+WebIntentCallbacks* WebIntentCallbacks::Get(Profile* profile) {
+  return Factory::GetForProfile(profile);
+}
+
+int WebIntentCallbacks::RegisterCallback(
+    const Extension* extension,
+    content::WebIntentsDispatcher* dispatcher,
+    content::WebContents* source) {
+  int id = ++last_id_;
+  std::string key = GetKey(extension, id);
+  pending_[key] = dispatcher;
+
+  // TODO(thorogood): We should also listen for extension suspend events, and
+  // clear the relevant callback (i.e., the handler of this intent)
+
+  // TODO(thorogood): The source window may actually be a ShellWindow of a
+  // platform app. In this case, we should not wait for its destruction:
+  // rather, we should be listening to platform app suspend events.
+
+  // Listen to when the source WebContent is destroyed. This object is self-
+  // deleting on this event.
+  DCHECK(source);
+  new SourceObserver(source, this, key);
+
+  return id;
+}
+
+content::WebIntentsDispatcher* WebIntentCallbacks::RetrieveCallback(
+    const Extension* extension, int id) {
+  std::string key = GetKey(extension, id);
+  return GetAndClear(key);
+}
+
+content::WebIntentsDispatcher* WebIntentCallbacks::GetAndClear(
+    std::string key) {
+  if (!pending_.count(key))
+    return NULL;
+
+  content::WebIntentsDispatcher* dispatcher = pending_[key];
+  pending_.erase(key);
+  return dispatcher;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+// Factory boilerplate
+
+// static
+WebIntentCallbacks* WebIntentCallbacks::Factory::GetForProfile(
+    Profile* profile) {
+  return static_cast<WebIntentCallbacks*>(
+      GetInstance()->GetServiceForProfile(profile, true));
+}
+
+WebIntentCallbacks::Factory* WebIntentCallbacks::Factory::GetInstance() {
+  return Singleton<WebIntentCallbacks::Factory>::get();
+}
+
+WebIntentCallbacks::Factory::Factory()
+    : ProfileKeyedServiceFactory("WebIntentCallbacks",
+                                 ProfileDependencyManager::GetInstance()) {
+}
+
+WebIntentCallbacks::Factory::~Factory() {
+}
+
+ProfileKeyedService* WebIntentCallbacks::Factory::BuildServiceInstanceFor(
+    Profile* profile) const {
+  return new WebIntentCallbacks();
+}
+
+}  // namespace extensions