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1 // Copyright (c) 2013 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef STORAGE_BROWSER_BLOB_BLOB_DATA_HANDLE_H_ | 5 #ifndef STORAGE_BROWSER_BLOB_BLOB_DATA_HANDLE_H_ |
6 #define STORAGE_BROWSER_BLOB_BLOB_DATA_HANDLE_H_ | 6 #define STORAGE_BROWSER_BLOB_BLOB_DATA_HANDLE_H_ |
7 | 7 |
8 #include <string> | 8 #include <string> |
9 | 9 |
10 #include "base/memory/ref_counted.h" | 10 #include "base/memory/ref_counted.h" |
11 #include "base/memory/weak_ptr.h" | 11 #include "base/memory/weak_ptr.h" |
12 #include "base/supports_user_data.h" | 12 #include "base/supports_user_data.h" |
13 #include "storage/browser/storage_browser_export.h" | 13 #include "storage/browser/storage_browser_export.h" |
14 | 14 |
15 namespace base { | 15 namespace base { |
16 class SequencedTaskRunner; | 16 class SequencedTaskRunner; |
17 } | 17 } |
18 | 18 |
19 namespace storage { | 19 namespace storage { |
20 | 20 |
21 class BlobData; | 21 class BlobDataSnapshot; |
22 class BlobStorageContext; | 22 class BlobStorageContext; |
23 | 23 |
24 // A scoper object for use in chrome's main browser process, ensures | 24 // BlobDataHandle ensures that the underlying blob (keyed by the uuid) remains |
25 // the underlying BlobData and its uuid remain in BlobStorageContext's | 25 // in the BlobStorageContext's collection while this object is alive. Anything |
26 // collection for the duration. This object has delete semantics and | 26 // that needs to keep a blob alive needs to store this handle. |
27 // maybe deleted on any thread. | 27 // When the blob data itself is needed, clients must call the CreateSnapshot() |
| 28 // method on the IO thread to create a snapshot of the blob data. This snapshot |
| 29 // is not intended to be persisted, and serves to ensure that the backing |
| 30 // resources remain around for the duration of reading the blob. This snapshot |
| 31 // can be read on any thread. |
| 32 // This object has delete semantics and may be deleted on any thread. |
28 class STORAGE_EXPORT BlobDataHandle | 33 class STORAGE_EXPORT BlobDataHandle |
29 : public base::SupportsUserData::Data { | 34 : public base::SupportsUserData::Data { |
30 public: | 35 public: |
31 BlobDataHandle(const BlobDataHandle& other); // May be copied on any thread. | 36 BlobDataHandle(const BlobDataHandle& other); // May be copied on any thread. |
32 ~BlobDataHandle() override; // Maybe be deleted on any thread. | 37 ~BlobDataHandle() override; // May be deleted on any thread. |
33 BlobData* data() const; // May only be accessed on the IO thread. | |
34 | 38 |
35 std::string uuid() const; // May be accessed on any thread. | 39 // This must be called on the IO thread, but the snapshot can be accessed |
| 40 // from any thread. |
| 41 scoped_ptr<BlobDataSnapshot> CreateSnapshot() const; |
| 42 |
| 43 const std::string& uuid() const; // May be accessed on any thread. |
36 | 44 |
37 private: | 45 private: |
| 46 // Internal class whose destructor is guarenteed to be called on the IO |
| 47 // thread. |
38 class BlobDataHandleShared | 48 class BlobDataHandleShared |
39 : public base::RefCountedThreadSafe<BlobDataHandleShared> { | 49 : public base::RefCountedThreadSafe<BlobDataHandleShared> { |
40 public: | 50 public: |
41 BlobDataHandleShared(BlobData* blob_data, | 51 BlobDataHandleShared(const std::string& uuid, |
42 BlobStorageContext* context, | 52 BlobStorageContext* context, |
43 base::SequencedTaskRunner* task_runner); | 53 base::SequencedTaskRunner* task_runner); |
44 | 54 |
45 BlobData* data() const; | 55 scoped_ptr<BlobDataSnapshot> CreateSnapshot() const; |
46 const std::string& uuid() const; | 56 const std::string& uuid() const; |
47 | 57 |
48 private: | 58 private: |
49 friend class base::DeleteHelper<BlobDataHandleShared>; | 59 friend class base::DeleteHelper<BlobDataHandleShared>; |
50 friend class base::RefCountedThreadSafe<BlobDataHandleShared>; | 60 friend class base::RefCountedThreadSafe<BlobDataHandleShared>; |
51 friend class BlobDataHandle; | 61 friend class BlobDataHandle; |
52 | 62 |
53 virtual ~BlobDataHandleShared(); | 63 virtual ~BlobDataHandleShared(); |
54 | 64 |
55 scoped_refptr<BlobData> blob_data_; | 65 const std::string uuid_; |
56 base::WeakPtr<BlobStorageContext> context_; | 66 base::WeakPtr<BlobStorageContext> context_; |
57 | 67 |
58 DISALLOW_COPY_AND_ASSIGN(BlobDataHandleShared); | 68 DISALLOW_COPY_AND_ASSIGN(BlobDataHandleShared); |
59 }; | 69 }; |
60 | 70 |
61 friend class BlobStorageContext; | 71 friend class BlobStorageContext; |
62 BlobDataHandle(BlobData* blob_data, BlobStorageContext* context, | 72 BlobDataHandle(const std::string& uuid, |
| 73 BlobStorageContext* context, |
63 base::SequencedTaskRunner* task_runner); | 74 base::SequencedTaskRunner* task_runner); |
64 | 75 |
65 scoped_refptr<base::SequencedTaskRunner> io_task_runner_; | 76 scoped_refptr<base::SequencedTaskRunner> io_task_runner_; |
66 scoped_refptr<BlobDataHandleShared> shared_; | 77 scoped_refptr<BlobDataHandleShared> shared_; |
67 }; | 78 }; |
68 | 79 |
69 } // namespace storage | 80 } // namespace storage |
70 | 81 |
71 #endif // STORAGE_BROWSER_BLOB_BLOB_DATA_HANDLE_H_ | 82 #endif // STORAGE_BROWSER_BLOB_BLOB_DATA_HANDLE_H_ |
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