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 NET_BASE_UPLOAD_ELEMENT_READER_H_ 6#define NET_BASE_UPLOAD_ELEMENT_READER_H_ 7 8#include "base/basictypes.h" 9#include "net/base/completion_callback.h" 10#include "net/base/net_export.h" 11 12namespace net { 13 14class IOBuffer; 15class UploadBytesElementReader; 16class UploadFileElementReader; 17 18// An interface to read an upload data element. 19class NET_EXPORT UploadElementReader { 20 public: 21 UploadElementReader() {} 22 virtual ~UploadElementReader() {} 23 24 // Returns this instance's pointer as UploadBytesElementReader when possible, 25 // otherwise returns NULL. 26 virtual const UploadBytesElementReader* AsBytesReader() const; 27 28 // Returns this instance's pointer as UploadFileElementReader when possible, 29 // otherwise returns NULL. 30 virtual const UploadFileElementReader* AsFileReader() const; 31 32 // Initializes the instance synchronously when possible, otherwise does 33 // initialization aynschronously, returns ERR_IO_PENDING and runs callback. 34 // Calling this method again after a Init() success results in resetting the 35 // state. 36 virtual int Init(const CompletionCallback& callback) = 0; 37 38 // Returns the byte-length of the element. For files that do not exist, 0 39 // is returned. This is done for consistency with Mozilla. 40 virtual uint64 GetContentLength() const = 0; 41 42 // Returns the number of bytes remaining to read. 43 virtual uint64 BytesRemaining() const = 0; 44 45 // Returns true if the upload element is entirely in memory. 46 // The default implementation returns false. 47 virtual bool IsInMemory() const; 48 49 // Reads up to |buf_length| bytes synchronously and returns the number of 50 // bytes read or error code when possible, otherwise, returns ERR_IO_PENDING 51 // and runs |callback| with the result. |buf_length| must be greater than 0. 52 virtual int Read(IOBuffer* buf, 53 int buf_length, 54 const CompletionCallback& callback) = 0; 55 56 private: 57 DISALLOW_COPY_AND_ASSIGN(UploadElementReader); 58}; 59 60} // namespace net 61 62#endif // NET_BASE_UPLOAD_ELEMENT_READER_H_ 63