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      1 // Copyright (c) 2012 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 CONTENT_BROWSER_WEBUI_URL_DATA_MANAGER_H_
      6 #define CONTENT_BROWSER_WEBUI_URL_DATA_MANAGER_H_
      7 
      8 #include <string>
      9 #include <vector>
     10 
     11 #include "base/memory/ref_counted.h"
     12 #include "base/supports_user_data.h"
     13 #include "content/common/content_export.h"
     14 
     15 namespace content {
     16 class BrowserContext;
     17 class URLDataSource;
     18 class URLDataSourceImpl;
     19 class WebUIDataSource;
     20 
     21 // To serve dynamic data off of chrome: URLs, implement the
     22 // URLDataManager::DataSource interface and register your handler
     23 // with AddDataSource. DataSources must be added on the UI thread (they are also
     24 // deleted on the UI thread). Internally the DataSources are maintained by
     25 // URLDataManagerBackend, see it for details.
     26 class CONTENT_EXPORT URLDataManager : public base::SupportsUserData::Data {
     27  public:
     28   explicit URLDataManager(BrowserContext* browser_context);
     29   virtual ~URLDataManager();
     30 
     31   // Adds a DataSource to the collection of data sources. This *must* be invoked
     32   // on the UI thread.
     33   //
     34   // If |AddDataSource| is called more than once for a particular name it will
     35   // release the old |DataSource|, most likely resulting in it getting deleted
     36   // as there are no other references to it. |DataSource| uses the
     37   // |DeleteOnUIThread| trait to insure that the destructor is called on the UI
     38   // thread. This is necessary as some |DataSource|s notably |FileIconSource|
     39   // and |FaviconSource|, have members that will DCHECK if they are not
     40   // destructed in the same thread as they are constructed (the UI thread).
     41   void AddDataSource(URLDataSourceImpl* source);
     42 
     43   // Deletes any data sources no longer referenced. This is normally invoked
     44   // for you, but can be invoked to force deletion (such as during shutdown).
     45   static void DeleteDataSources();
     46 
     47   // Convenience wrapper function to add |source| to |browser_context|'s
     48   // |URLDataManager|. Creates a URLDataSourceImpl to wrap the given
     49   // source.
     50   static void AddDataSource(BrowserContext* browser_context,
     51                             URLDataSource* source);
     52 
     53   // Adds a WebUI data source to |browser_context|'s |URLDataManager|.
     54   static void AddWebUIDataSource(BrowserContext* browser_context,
     55                                  WebUIDataSource* source);
     56 
     57  private:
     58   friend class URLDataSourceImpl;
     59   friend struct DeleteURLDataSource;
     60   typedef std::vector<const URLDataSourceImpl*> URLDataSources;
     61 
     62   // If invoked on the UI thread the DataSource is deleted immediatlye,
     63   // otherwise it is added to |data_sources_| and a task is scheduled to handle
     64   // deletion on the UI thread. See note abouve DeleteDataSource for more info.
     65   static void DeleteDataSource(const URLDataSourceImpl* data_source);
     66 
     67   // Returns true if |data_source| is scheduled for deletion (|DeleteDataSource|
     68   // was invoked).
     69   static bool IsScheduledForDeletion(const URLDataSourceImpl* data_source);
     70 
     71   BrowserContext* browser_context_;
     72 
     73   // |data_sources_| that are no longer referenced and scheduled for deletion.
     74   // Protected by g_delete_lock in the .cc file.
     75   static URLDataSources* data_sources_;
     76 
     77   DISALLOW_COPY_AND_ASSIGN(URLDataManager);
     78 };
     79 
     80 }  // namespace content
     81 
     82 #endif  // CONTENT_BROWSER_WEBUI_URL_DATA_MANAGER_H_
     83