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1 // Copyright 2015 The Chromium Authors. All rights reserved. | 1 // Copyright 2015 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_SHAREABLE_BLOB_DATA_ITEM_H_ | 5 #ifndef STORAGE_BROWSER_BLOB_SHAREABLE_BLOB_DATA_ITEM_H_ |
6 #define STORAGE_BROWSER_BLOB_SHAREABLE_BLOB_DATA_ITEM_H_ | 6 #define STORAGE_BROWSER_BLOB_SHAREABLE_BLOB_DATA_ITEM_H_ |
7 | 7 |
8 #include <string> | 8 #include <string> |
9 | 9 |
10 #include "base/containers/hash_tables.h" | 10 #include "base/containers/hash_tables.h" |
11 #include "base/hash.h" | 11 #include "base/hash.h" |
12 #include "base/macros.h" | 12 #include "base/macros.h" |
13 #include "base/memory/ref_counted.h" | 13 #include "base/memory/ref_counted.h" |
14 #include "storage/common/data_element.h" | 14 #include "storage/common/data_element.h" |
15 | 15 |
16 namespace storage { | 16 namespace storage { |
17 class BlobDataItem; | 17 class BlobDataItem; |
18 class InternalBlobData; | 18 class InternalBlobData; |
19 | 19 |
20 // This class allows blob items to be shared between blobs, and is only used by | 20 // This class allows blob items to be shared between blobs, and is only used by |
21 // BlobStorageContext. This class contains both the blob data item and the uuids | 21 // BlobStorageContext. This class contains both the blob data item and the uuids |
22 // of all the blobs using this item. | 22 // of all the blobs using this item. |
23 // The data in this class (the item) is immutable, but the item itself can be | 23 // The data in this class (the item) is immutable, but the item itself can be |
24 // swapped out with an item with the same data but a different backing (think | 24 // swapped out with an item with the same data but a different backing (think |
25 // RAM vs file backed). | 25 // RAM vs file backed). |
26 class ShareableBlobDataItem : public base::RefCounted<ShareableBlobDataItem> { | 26 class ShareableBlobDataItem |
27 : public base::RefCountedThreadSafe<ShareableBlobDataItem> { | |
michaeln
2016/07/14 01:44:43
Why does this need to be a threadsafe refcount? If
dmurph
2016/07/15 20:18:15
We pass this to a file thread in the BlobMemoryCon
michaeln
2016/08/15 22:44:42
But if the Shareable item can be deref'd on the ba
| |
27 public: | 28 public: |
28 ShareableBlobDataItem(const std::string& blob_uuid, | 29 ShareableBlobDataItem(scoped_refptr<BlobDataItem> item); |
29 const scoped_refptr<BlobDataItem>& item); | |
30 | 30 |
31 const scoped_refptr<BlobDataItem>& item(); | 31 const scoped_refptr<BlobDataItem>& item(); |
32 | 32 |
33 // This is a unique auto-incrementing id assigned to this item on | |
34 // construction. It is used to keep track of this item in an LRU data | |
35 // structure for eviction to disk. | |
36 uint64_t item_id() const { return item_id_; } | |
37 | |
33 base::hash_set<std::string>& referencing_blobs() { | 38 base::hash_set<std::string>& referencing_blobs() { |
34 return referencing_blobs_; | 39 return referencing_blobs_; |
35 } | 40 } |
36 | 41 |
37 private: | 42 private: |
38 friend class base::RefCounted<ShareableBlobDataItem>; | 43 friend class base::RefCountedThreadSafe<ShareableBlobDataItem>; |
39 friend class InternalBlobData; | 44 friend class InternalBlobData; |
45 friend class BlobMemoryController; | |
46 friend class BlobStorageContext; | |
40 ~ShareableBlobDataItem(); | 47 ~ShareableBlobDataItem(); |
41 | 48 |
49 // This is a unique identifier for this ShareableBlobDataItem. | |
50 uint64_t item_id_; | |
42 scoped_refptr<BlobDataItem> item_; | 51 scoped_refptr<BlobDataItem> item_; |
43 | 52 |
44 base::hash_set<std::string> referencing_blobs_; | 53 base::hash_set<std::string> referencing_blobs_; |
45 | 54 |
46 DISALLOW_COPY_AND_ASSIGN(ShareableBlobDataItem); | 55 DISALLOW_COPY_AND_ASSIGN(ShareableBlobDataItem); |
47 }; | 56 }; |
48 | 57 |
49 } // namespace storage | 58 } // namespace storage |
50 #endif // STORAGE_BROWSER_BLOB_SHAREABLE_BLOB_DATA_ITEM_H_ | 59 #endif // STORAGE_BROWSER_BLOB_SHAREABLE_BLOB_DATA_ITEM_H_ |
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