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1 // Copyright 2013 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 EXTENSIONS_BROWSER_PROCESS_MANAGER_H_
6 #define EXTENSIONS_BROWSER_PROCESS_MANAGER_H_
7 
8 #include <map>
9 #include <set>
10 #include <string>
11 
12 #include "base/callback.h"
13 #include "base/compiler_specific.h"
14 #include "base/memory/ref_counted.h"
15 #include "base/memory/weak_ptr.h"
16 #include "base/observer_list.h"
17 #include "base/time/time.h"
18 #include "content/public/browser/notification_observer.h"
19 #include "content/public/browser/notification_registrar.h"
20 #include "extensions/common/view_type.h"
21 
22 class GURL;
23 
24 namespace content {
25 class BrowserContext;
26 class DevToolsAgentHost;
27 class RenderViewHost;
28 class RenderFrameHost;
29 class SiteInstance;
30 };
31 
32 namespace extensions {
33 
34 class Extension;
35 class ExtensionHost;
36 class ExtensionRegistry;
37 class ProcessManagerDelegate;
38 class ProcessManagerObserver;
39 
40 // Manages dynamic state of running Chromium extensions. There is one instance
41 // of this class per Profile. OTR Profiles have a separate instance that keeps
42 // track of split-mode extensions only.
43 class ProcessManager : public content::NotificationObserver {
44  public:
45   typedef std::set<extensions::ExtensionHost*> ExtensionHostSet;
46   typedef ExtensionHostSet::const_iterator const_iterator;
47 
48   static ProcessManager* Create(content::BrowserContext* context);
49   virtual ~ProcessManager();
50 
background_hosts()51   const ExtensionHostSet& background_hosts() const {
52     return background_hosts_;
53   }
54 
55   typedef std::set<content::RenderViewHost*> ViewSet;
56   const ViewSet GetAllViews() const;
57 
58   // The typical observer interface.
59   void AddObserver(ProcessManagerObserver* observer);
60   void RemoveObserver(ProcessManagerObserver* observer);
61 
62   // Creates a new UI-less extension instance.  Like CreateViewHost, but not
63   // displayed anywhere.  Returns false if no background host can be created,
64   // for example for hosted apps and extensions that aren't enabled in
65   // Incognito.
66   virtual bool CreateBackgroundHost(const Extension* extension,
67                                     const GURL& url);
68 
69   // Gets the ExtensionHost for the background page for an extension, or NULL if
70   // the extension isn't running or doesn't have a background page.
71   ExtensionHost* GetBackgroundHostForExtension(const std::string& extension_id);
72 
73   // Returns the SiteInstance that the given URL belongs to.
74   // TODO(aa): This only returns correct results for extensions and packaged
75   // apps, not hosted apps.
76   virtual content::SiteInstance* GetSiteInstanceForURL(const GURL& url);
77 
78   // Unregisters a RenderViewHost as hosting any extension.
79   void UnregisterRenderViewHost(content::RenderViewHost* render_view_host);
80 
81   // Returns all RenderViewHosts that are registered for the specified
82   // extension.
83   std::set<content::RenderViewHost*> GetRenderViewHostsForExtension(
84       const std::string& extension_id);
85 
86   // Returns the extension associated with the specified RenderViewHost, or
87   // NULL.
88   const Extension* GetExtensionForRenderViewHost(
89       content::RenderViewHost* render_view_host);
90 
91   // Returns true if the (lazy) background host for the given extension has
92   // already been sent the unload event and is shutting down.
93   bool IsBackgroundHostClosing(const std::string& extension_id);
94 
95   // Getter and setter for the lazy background page's keepalive count. This is
96   // the count of how many outstanding "things" are keeping the page alive.
97   // When this reaches 0, we will begin the process of shutting down the page.
98   // "Things" include pending events, resource loads, and API calls.
99   int GetLazyKeepaliveCount(const Extension* extension);
100   void IncrementLazyKeepaliveCount(const Extension* extension);
101   void DecrementLazyKeepaliveCount(const Extension* extension);
102 
103   void IncrementLazyKeepaliveCountForView(
104       content::RenderViewHost* render_view_host);
105 
106   // Keeps a background page alive. Unlike IncrementLazyKeepaliveCount, these
107   // impulses will only keep the page alive for a limited amount of time unless
108   // called regularly.
109   void KeepaliveImpulse(const Extension* extension);
110 
111   // Triggers a keepalive impulse for a plug-in (e.g NaCl).
112   static void OnKeepaliveFromPlugin(int render_process_id,
113                                     int render_frame_id,
114                                     const std::string& extension_id);
115 
116   // Handles a response to the ShouldSuspend message, used for lazy background
117   // pages.
118   void OnShouldSuspendAck(const std::string& extension_id, uint64 sequence_id);
119 
120   // Same as above, for the Suspend message.
121   void OnSuspendAck(const std::string& extension_id);
122 
123   // Tracks network requests for a given RenderFrameHost, used to know
124   // when network activity is idle for lazy background pages.
125   void OnNetworkRequestStarted(content::RenderFrameHost* render_frame_host);
126   void OnNetworkRequestDone(content::RenderFrameHost* render_frame_host);
127 
128   // Prevents |extension|'s background page from being closed and sends the
129   // onSuspendCanceled() event to it.
130   void CancelSuspend(const Extension* extension);
131 
132   // Creates background hosts if the embedder is ready and they are not already
133   // loaded.
134   void MaybeCreateStartupBackgroundHosts();
135 
136   // Called on shutdown to close our extension hosts.
137   void CloseBackgroundHosts();
138 
139   // Gets the BrowserContext associated with site_instance_ and all other
140   // related SiteInstances.
141   content::BrowserContext* GetBrowserContext() const;
142 
143   // Sets callbacks for testing keepalive impulse behavior.
144   typedef base::Callback<void(const std::string& extension_id)>
145       ImpulseCallbackForTesting;
146   void SetKeepaliveImpulseCallbackForTesting(
147       const ImpulseCallbackForTesting& callback);
148   void SetKeepaliveImpulseDecrementCallbackForTesting(
149       const ImpulseCallbackForTesting& callback);
150 
151   // Sets the time in milliseconds that an extension event page can
152   // be idle before it is shut down; must be > 0.
153   static void SetEventPageIdleTimeForTesting(unsigned idle_time_msec);
154 
155   // Sets the time in milliseconds that an extension event page has
156   // between being notified of its impending unload and that unload
157   // happening.
158   static void SetEventPageSuspendingTimeForTesting(
159       unsigned suspending_time_msec);
160 
161   // Creates a non-incognito instance for tests. |registry| allows unit tests
162   // to inject an ExtensionRegistry that is not managed by the usual
163   // BrowserContextKeyedServiceFactory system.
164   static ProcessManager* CreateForTesting(content::BrowserContext* context,
165                                           ExtensionRegistry* registry);
166 
167   // Creates an incognito-context instance for tests.
168   static ProcessManager* CreateIncognitoForTesting(
169       content::BrowserContext* incognito_context,
170       content::BrowserContext* original_context,
171       ProcessManager* original_manager,
172       ExtensionRegistry* registry);
173 
startup_background_hosts_created_for_test()174   bool startup_background_hosts_created_for_test() const {
175     return startup_background_hosts_created_;
176   }
177 
178  protected:
179   // If |context| is incognito pass the master context as |original_context|.
180   // Otherwise pass the same context for both. Pass the ExtensionRegistry for
181   // |context| as |registry|, or override it for testing.
182   ProcessManager(content::BrowserContext* context,
183                  content::BrowserContext* original_context,
184                  ExtensionRegistry* registry);
185 
186   // content::NotificationObserver:
187   virtual void Observe(int type,
188                        const content::NotificationSource& source,
189                        const content::NotificationDetails& details) OVERRIDE;
190 
191   content::NotificationRegistrar registrar_;
192 
193   // The set of ExtensionHosts running viewless background extensions.
194   ExtensionHostSet background_hosts_;
195 
196   // A SiteInstance related to the SiteInstance for all extensions in
197   // this profile.  We create it in such a way that a new
198   // browsing instance is created.  This controls process grouping.
199   scoped_refptr<content::SiteInstance> site_instance_;
200 
201   // Not owned. Also used by IncognitoProcessManager.
202   ExtensionRegistry* extension_registry_;
203 
204  private:
205   friend class ProcessManagerTest;
206 
207   // Extra information we keep for each extension's background page.
208   struct BackgroundPageData;
209   typedef std::string ExtensionId;
210   typedef std::map<ExtensionId, BackgroundPageData> BackgroundPageDataMap;
211   typedef std::map<content::RenderViewHost*,
212       extensions::ViewType> ExtensionRenderViews;
213 
214   // Load all background pages once the profile data is ready and the pages
215   // should be loaded.
216   void CreateStartupBackgroundHosts();
217 
218   // Called just after |host| is created so it can be registered in our lists.
219   void OnBackgroundHostCreated(ExtensionHost* host);
220 
221   // Close the given |host| iff it's a background page.
222   void CloseBackgroundHost(ExtensionHost* host);
223 
224   // Internal implementation of DecrementLazyKeepaliveCount with an
225   // |extension_id| known to have a lazy background page.
226   void DecrementLazyKeepaliveCount(const std::string& extension_id);
227 
228   // Checks if keepalive impulses have occured, and adjusts keep alive count.
229   void OnKeepaliveImpulseCheck();
230 
231   // These are called when the extension transitions between idle and active.
232   // They control the process of closing the background page when idle.
233   void OnLazyBackgroundPageIdle(const std::string& extension_id,
234                                 uint64 sequence_id);
235   void OnLazyBackgroundPageActive(const std::string& extension_id);
236   void CloseLazyBackgroundPageNow(const std::string& extension_id,
237                                   uint64 sequence_id);
238 
239   // Potentially registers a RenderViewHost, if it is associated with an
240   // extension. Does nothing if this is not an extension renderer.
241   // Returns true, if render_view_host was registered (it is associated
242   // with an extension).
243   bool RegisterRenderViewHost(content::RenderViewHost* render_view_host);
244 
245   // Unregister RenderViewHosts and clear background page data for an extension
246   // which has been unloaded.
247   void UnregisterExtension(const std::string& extension_id);
248 
249   // Clears background page data for this extension.
250   void ClearBackgroundPageData(const std::string& extension_id);
251 
252   void OnDevToolsStateChanged(content::DevToolsAgentHost*, bool attached);
253 
254   // Contains all active extension-related RenderViewHost instances for all
255   // extensions. We also keep a cache of the host's view type, because that
256   // information is not accessible at registration/deregistration time.
257   ExtensionRenderViews all_extension_views_;
258 
259   BackgroundPageDataMap background_page_data_;
260 
261   // True if we have created the startup set of background hosts.
262   bool startup_background_hosts_created_;
263 
264   base::Callback<void(content::DevToolsAgentHost*, bool)> devtools_callback_;
265 
266   ImpulseCallbackForTesting keepalive_impulse_callback_for_testing_;
267   ImpulseCallbackForTesting keepalive_impulse_decrement_callback_for_testing_;
268 
269   ObserverList<ProcessManagerObserver> observer_list_;
270 
271   // ID Counter used to set ProcessManager::BackgroundPageData close_sequence_id
272   // members. These IDs are tracked per extension in background_page_data_ and
273   // are used to verify that nothing has interrupted the process of closing a
274   // lazy background process.
275   //
276   // Any interruption obtains a new ID by incrementing
277   // last_background_close_sequence_id_ and storing it in background_page_data_
278   // for a particular extension. Callbacks and round-trip IPC messages store the
279   // value of the extension's close_sequence_id at the beginning of the process.
280   // Thus comparisons can be done to halt when IDs no longer match.
281   //
282   // This counter provides unique IDs even when BackgroundPageData objects are
283   // reset.
284   uint64 last_background_close_sequence_id_;
285 
286   // Must be last member, see doc on WeakPtrFactory.
287   base::WeakPtrFactory<ProcessManager> weak_ptr_factory_;
288 
289   DISALLOW_COPY_AND_ASSIGN(ProcessManager);
290 };
291 
292 }  // namespace extensions
293 
294 #endif  // EXTENSIONS_BROWSER_PROCESS_MANAGER_H_
295