NavigationController prototype

webkit/browser/blob/blob_reader.h

Index: webkit/browser/blob/blob_reader.h
diff --git a/webkit/browser/blob/blob_reader.h b/webkit/browser/blob/blob_reader.h
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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WEBKIT_BROWSER_BLOB_BLOB_READER_H_
+#define WEBKIT_BROWSER_BLOB_BLOB_READER_H_
+
+#include <map>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "webkit/browser/blob/file_stream_reader.h"
+#include "webkit/browser/webkit_storage_browser_export.h"
+#include "webkit/common/blob/blob_data.h"
+
+namespace base {
+class SequencedTaskRunner;
+}
+
+namespace fileapi {
+class FileSystemContext;
+}
+
+namespace net {
+class DrainableIOBuffer;
+}
+
+namespace webkit_blob {
+
+// A reader implementation that will read the contents of a BlobData.
+// Should only be used on the IO thread. Delete semantics so delete
+// whenever you like. If deleted with a pending call, the callback
+// will not be called (per the FileStreamReader interface design).
+class WEBKIT_STORAGE_BROWSER_EXPORT BlobReader : public FileStreamReader {
+ public:
+  // Constructs a reader that will start reading from |blob_data|.
+  // The filesystem context is needed to support reading file and
+  // filesystem backed blobs.
+  BlobReader(BlobData* blob_data,
+             fileapi::FileSystemContext* file_system_context);
+  virtual ~BlobReader();
+
+  // Must be called prior to making the first call to Read().
+  void SetInitialOffset(int64 position);
+
+  // FileStreamReader impl, GetLength returns the full size of
+  // the BlobData without subtracting the initial offset.
+  virtual int Read(net::IOBuffer* buf, int buf_len,
+                   const net::CompletionCallback& callback) OVERRIDE;
+  virtual int64 GetLength(const net::Int64CompletionCallback& callback) OVERRIDE;
+
+ private:
+  typedef std::map<size_t, FileStreamReader*> IndexToReaderMap;
+
+  // For size computations.
+  void CountSize();
+  void DidGetFileItemLength(size_t index, int64 result);
+  bool AddItemLength(size_t index, int64 item_length);
+  void OnSizeCounted();
+
+  // For reading the blob.
+  int DoRead();
+  void PerformInitialSeek();
+  int ReadLoop();
+  bool ReadItem();
+  void AdvanceItem();
+  void AdvanceBytesRead(int result);
+  bool ReadBytesItem(const BlobData::Item& item, int bytes_to_read);
+  bool ReadFileItem(FileStreamReader* reader, int bytes_to_read);
+  void DidReadFile(int result);
+  int ComputeBytesToRead() const;
+  int OnReadComplete();
+
+  // Called upon an error of any kind.
+  void OnError(int error_code);
+
+  FileStreamReader* GetFileStreamReader(size_t index);
+  void CreateFileStreamReader(size_t index, int64 additional_offset);
+  void DeleteCurrentFileReader();
+
+  base::WeakPtrFactory<BlobReader> weak_factory_;
+  scoped_refptr<BlobData> blob_data_;
+  net::CompletionCallback pending_read_callback_;
+  scoped_refptr<net::IOBuffer> pending_read_buf_;
+  int pending_read_length_;
+  net::Int64CompletionCallback pending_size_callback_;
+  int64 initial_offset_;
+  bool is_counting_size_;
+  bool has_total_size_;
+  bool has_started_reading_;
+
+  // Variables for controlling read from |blob_data_|.
+  scoped_refptr<fileapi::FileSystemContext> file_system_context_;
+  scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
+  std::vector<int64> item_length_list_;
+  int64 total_size_;
+  int64 remaining_bytes_;
+  int pending_get_file_info_count_;
+  IndexToReaderMap index_to_reader_;
+  size_t current_item_index_;
+  int64 current_item_offset_;
+
+  // Holds the buffer for read data with the IOBuffer interface.
+  scoped_refptr<net::DrainableIOBuffer> read_buf_;
+
+  // Is set when OnError() is called.
+  int error_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlobReader);
+};
+
+}  // namespace webkit_blob
+
+#endif  // WEBKIT_BROWSER_BLOB_BLOB_READER_H_