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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 WEBKIT_COMMON_BLOB_SHAREABLE_FILE_REFERENCE_H_
      6 #define WEBKIT_COMMON_BLOB_SHAREABLE_FILE_REFERENCE_H_
      7 
      8 #include <vector>
      9 
     10 #include "webkit/common/blob/scoped_file.h"
     11 
     12 namespace webkit_blob {
     13 
     14 // ShareableFileReference allows consumers to share FileReference for the
     15 // same path if it already exists in its internal map.
     16 // This class is non-thread-safe and all methods must be called on a single
     17 // thread.
     18 class WEBKIT_STORAGE_COMMON_EXPORT ShareableFileReference
     19     : public base::RefCounted<ShareableFileReference> {
     20  public:
     21   typedef ScopedFile::ScopeOutCallback FinalReleaseCallback;
     22 
     23   enum FinalReleasePolicy {
     24     DELETE_ON_FINAL_RELEASE = ScopedFile::DELETE_ON_SCOPE_OUT,
     25     DONT_DELETE_ON_FINAL_RELEASE = ScopedFile::DONT_DELETE_ON_SCOPE_OUT,
     26   };
     27 
     28   // Returns a ShareableFileReference for the given path, if no reference
     29   // for this path exists returns NULL.
     30   static scoped_refptr<ShareableFileReference> Get(const base::FilePath& path);
     31 
     32   // Returns a ShareableFileReference for the given path, creating a new
     33   // reference if none yet exists. If there's a pre-existing reference for
     34   // the path, the policy parameter of this method is ignored.
     35   static scoped_refptr<ShareableFileReference> GetOrCreate(
     36       const base::FilePath& path,
     37       FinalReleasePolicy policy,
     38       base::TaskRunner* file_task_runner);
     39 
     40   // Returns a ShareableFileReference for the given path of the |scoped_file|,
     41   // creating a new reference if none yet exists. The ownership of |scoped_file|
     42   // is passed to this reference.
     43   // If there's a pre-existing reference for the path, the scope out policy
     44   // and scope-out-callbacks of the given |scoped_file| is ignored.
     45   // If the given scoped_file has an empty path (e.g. maybe already
     46   // released) this returns NULL reference.
     47   //
     48   // TODO(kinuko): Make sure if this behavior is ok, we could alternatively
     49   // merge callbacks to the existing one.
     50   static scoped_refptr<ShareableFileReference> GetOrCreate(
     51       ScopedFile scoped_file);
     52 
     53   // The full file path.
     54   const base::FilePath& path() const { return scoped_file_.path(); }
     55 
     56   // The |callback| is fired when the final reference of this instance
     57   // is released. If release policy is DELETE_ON_FINAL_RELEASE the
     58   // callback task(s) is/are posted before the deletion is scheduled.
     59   void AddFinalReleaseCallback(const FinalReleaseCallback& callback);
     60 
     61  private:
     62   friend class base::RefCounted<ShareableFileReference>;
     63 
     64   ShareableFileReference(ScopedFile scoped_file);
     65   ~ShareableFileReference();
     66 
     67   ScopedFile scoped_file_;
     68 
     69   DISALLOW_COPY_AND_ASSIGN(ShareableFileReference);
     70 };
     71 
     72 }  // namespace webkit_blob
     73 
     74 #endif  // WEBKIT_COMMON_BLOB_SHAREABLE_FILE_REFERENCE_H_
     75