chrome/browser/chromeos/extensions/external_cache.h

   1 // Copyright (c) 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 CHROME_BROWSER_CHROMEOS_EXTENSIONS_EXTERNAL_CACHE_H_
   6 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_EXTERNAL_CACHE_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/callback_forward.h"
  12 #include "base/files/file_path.h"
  13 #include "base/gtest_prod_util.h"
  14 #include "base/memory/ref_counted.h"
  15 #include "base/memory/scoped_ptr.h"
  16 #include "base/memory/weak_ptr.h"
  17 #include "base/sequenced_task_runner.h"
  18 #include "chrome/browser/extensions/updater/extension_downloader_delegate.h"
  19 #include "chrome/browser/extensions/updater/local_extension_cache.h"
  20 #include "content/public/browser/notification_observer.h"
  21 #include "content/public/browser/notification_registrar.h"
  22
  23 namespace base {
  24 class DictionaryValue;
  25 }
  26
  27 namespace extensions {
  28 class ExtensionDownloader;
  29 }
  30
  31 namespace net {
  32 class URLRequestContextGetter;
  33 }
  34
  35 namespace chromeos {
  36
  37 // The ExternalCache manages a cache for external extensions.
  38 class ExternalCache : public content::NotificationObserver,
  39                       public extensions::ExtensionDownloaderDelegate {
  40  public:
  41   class Delegate {
  42    public:
  43     virtual ~Delegate() {}
  44     // Caller owns |prefs|.
  45     virtual void OnExtensionListsUpdated(
  46         const base::DictionaryValue* prefs) = 0;
  47
  48     // Cache needs to provide already installed extensions otherwise they
  49     // will be removed. Cache calls this function to get version of installed
  50     // extension or empty string if not installed.
  51     virtual std::string GetInstalledExtensionVersion(const std::string& id);
  52   };
  53
  54   // The |request_context| is used for update checks. All file I/O is done via
  55   // the |backend_task_runner|. If |always_check_updates| is |false|, update
  56   // checks are performed for extensions that have an |external_update_url|
  57   // only. If |wait_for_cache_initialization| is |true|, the cache contents will
  58   // not be read until a flag file appears in the cache directory, signaling
  59   // that the cache is ready.
  60   ExternalCache(const base::FilePath& cache_dir,
  61                 net::URLRequestContextGetter* request_context,
  62                 const scoped_refptr<base::SequencedTaskRunner>&
  63                     backend_task_runner,
  64                 Delegate* delegate,
  65                 bool always_check_updates,
  66                 bool wait_for_cache_initialization);
  67   virtual ~ExternalCache();
  68
  69   // Returns already cached extensions.
  70   const base::DictionaryValue* cached_extensions() {
  71     return cached_extensions_.get();
  72   }
  73
  74   // Implementation of content::NotificationObserver:
  75   virtual void Observe(int type,
  76                        const content::NotificationSource& source,
  77                        const content::NotificationDetails& details) OVERRIDE;
  78
  79   // Implementation of ExtensionDownloaderDelegate:
  80   virtual void OnExtensionDownloadFailed(
  81       const std::string& id,
  82       Error error,
  83       const PingResult& ping_result,
  84       const std::set<int>& request_ids) OVERRIDE;
  85
  86   virtual void OnExtensionDownloadFinished(
  87       const std::string& id,
  88       const base::FilePath& path,
  89       const GURL& download_url,
  90       const std::string& version,
  91       const PingResult& ping_result,
  92       const std::set<int>& request_ids) OVERRIDE;
  93
  94   virtual bool IsExtensionPending(const std::string& id) OVERRIDE;
  95
  96   virtual bool GetExtensionExistingVersion(const std::string& id,
  97                                            std::string* version) OVERRIDE;
  98
  99   // Shut down the cache. The |callback| will be invoked when the cache has shut
 100   // down completely and there are no more pending file I/O operations.
 101   void Shutdown(const base::Closure& callback);
 102
 103   // Replace the list of extensions to cache with |prefs| and perform update
 104   // checks for these.
 105   void UpdateExtensionsList(scoped_ptr<base::DictionaryValue> prefs);
 106
 107   // If a user of one of the ExternalCache's extensions detects that
 108   // the extension is damaged then this method can be used to remove it from
 109   // the cache and retry to download it after a restart.
 110   void OnDamagedFileDetected(const base::FilePath& path);
 111
 112  private:
 113   // Notifies the that the cache has been updated, providing
 114   // extensions loader with an updated list of extensions.
 115   void UpdateExtensionLoader();
 116
 117   // Checks the cache contents and initiate download if needed.
 118   void CheckCache();
 119
 120   // Invoked on the UI thread when a new entry has been installed in the cache.
 121   void CacheEntryInstalled(const std::string& id);
 122
 123   extensions::LocalExtensionCache local_cache_;
 124
 125   // Request context used by the |downloader_|.
 126   scoped_refptr<net::URLRequestContextGetter> request_context_;
 127
 128   // Delegate that would like to get notifications about cache updates.
 129   Delegate* delegate_;
 130
 131   // Updates needs to be check for the extensions with external_crx too.
 132   bool always_check_updates_;
 133
 134   // Set to true if cache should wait for initialization flag file.
 135   bool wait_for_cache_initialization_;
 136
 137   // This is the list of extensions currently configured.
 138   scoped_ptr<base::DictionaryValue> extensions_;
 139
 140   // This contains extensions that are both currently configured
 141   // and that have a valid crx in the cache.
 142   scoped_ptr<base::DictionaryValue> cached_extensions_;
 143
 144   // Used to download the extensions and to check for updates.
 145   scoped_ptr<extensions::ExtensionDownloader> downloader_;
 146
 147   // Observes failures to install CRX files.
 148   content::NotificationRegistrar notification_registrar_;
 149
 150   // Weak factory for callbacks.
 151   base::WeakPtrFactory<ExternalCache> weak_ptr_factory_;
 152
 153   DISALLOW_COPY_AND_ASSIGN(ExternalCache);
 154 };
 155
 156 }  // namespace chromeos
 157
 158 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_EXTERNAL_CACHE_H_