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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_BROWSER_BLOB_BLOB_READER_H_ |
| 6 #define WEBKIT_BROWSER_BLOB_BLOB_READER_H_ |
| 7 |
| 8 #include <map> |
| 9 |
| 10 #include "base/memory/scoped_ptr.h" |
| 11 #include "base/memory/weak_ptr.h" |
| 12 #include "webkit/browser/blob/file_stream_reader.h" |
| 13 #include "webkit/browser/webkit_storage_browser_export.h" |
| 14 #include "webkit/common/blob/blob_data.h" |
| 15 |
| 16 namespace base { |
| 17 class SequencedTaskRunner; |
| 18 } |
| 19 |
| 20 namespace fileapi { |
| 21 class FileSystemContext; |
| 22 } |
| 23 |
| 24 namespace net { |
| 25 class DrainableIOBuffer; |
| 26 } |
| 27 |
| 28 namespace webkit_blob { |
| 29 |
| 30 // A reader implementation that will read the contents of a BlobData. |
| 31 // Should only be used on the IO thread. Delete semantics so delete |
| 32 // whenever you like. If deleted with a pending call, the callback |
| 33 // will not be called (per the FileStreamReader interface design). |
| 34 class WEBKIT_STORAGE_BROWSER_EXPORT BlobReader : public FileStreamReader { |
| 35 public: |
| 36 // Constructs a reader that will start reading from |blob_data|. |
| 37 // The filesystem context is needed to support reading file and |
| 38 // filesystem backed blobs. |
| 39 BlobReader(BlobData* blob_data, |
| 40 fileapi::FileSystemContext* file_system_context); |
| 41 virtual ~BlobReader(); |
| 42 |
| 43 // Must be called prior to making the first call to Read(). |
| 44 void SetInitialOffset(int64 position); |
| 45 |
| 46 // FileStreamReader impl, GetLength returns the full size of |
| 47 // the BlobData without subtracting the initial offset. |
| 48 virtual int Read(net::IOBuffer* buf, int buf_len, |
| 49 const net::CompletionCallback& callback) OVERRIDE; |
| 50 virtual int64 GetLength(const net::Int64CompletionCallback& callback) OVERRIDE
; |
| 51 |
| 52 private: |
| 53 typedef std::map<size_t, FileStreamReader*> IndexToReaderMap; |
| 54 |
| 55 // For size computations. |
| 56 void CountSize(); |
| 57 void DidGetFileItemLength(size_t index, int64 result); |
| 58 bool AddItemLength(size_t index, int64 item_length); |
| 59 void OnSizeCounted(); |
| 60 |
| 61 // For reading the blob. |
| 62 int DoRead(); |
| 63 void PerformInitialSeek(); |
| 64 int ReadLoop(); |
| 65 bool ReadItem(); |
| 66 void AdvanceItem(); |
| 67 void AdvanceBytesRead(int result); |
| 68 bool ReadBytesItem(const BlobData::Item& item, int bytes_to_read); |
| 69 bool ReadFileItem(FileStreamReader* reader, int bytes_to_read); |
| 70 void DidReadFile(int result); |
| 71 int ComputeBytesToRead() const; |
| 72 int OnReadComplete(); |
| 73 |
| 74 // Called upon an error of any kind. |
| 75 void OnError(int error_code); |
| 76 |
| 77 FileStreamReader* GetFileStreamReader(size_t index); |
| 78 void CreateFileStreamReader(size_t index, int64 additional_offset); |
| 79 void DeleteCurrentFileReader(); |
| 80 |
| 81 base::WeakPtrFactory<BlobReader> weak_factory_; |
| 82 scoped_refptr<BlobData> blob_data_; |
| 83 net::CompletionCallback pending_read_callback_; |
| 84 scoped_refptr<net::IOBuffer> pending_read_buf_; |
| 85 int pending_read_length_; |
| 86 net::Int64CompletionCallback pending_size_callback_; |
| 87 int64 initial_offset_; |
| 88 bool is_counting_size_; |
| 89 bool has_total_size_; |
| 90 bool has_started_reading_; |
| 91 |
| 92 // Variables for controlling read from |blob_data_|. |
| 93 scoped_refptr<fileapi::FileSystemContext> file_system_context_; |
| 94 scoped_refptr<base::SequencedTaskRunner> file_task_runner_; |
| 95 std::vector<int64> item_length_list_; |
| 96 int64 total_size_; |
| 97 int64 remaining_bytes_; |
| 98 int pending_get_file_info_count_; |
| 99 IndexToReaderMap index_to_reader_; |
| 100 size_t current_item_index_; |
| 101 int64 current_item_offset_; |
| 102 |
| 103 // Holds the buffer for read data with the IOBuffer interface. |
| 104 scoped_refptr<net::DrainableIOBuffer> read_buf_; |
| 105 |
| 106 // Is set when OnError() is called. |
| 107 int error_; |
| 108 |
| 109 DISALLOW_COPY_AND_ASSIGN(BlobReader); |
| 110 }; |
| 111 |
| 112 } // namespace webkit_blob |
| 113 |
| 114 #endif // WEBKIT_BROWSER_BLOB_BLOB_READER_H_ |
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