// 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 NET_BASE_UPLOAD_ELEMENT_READER_H_ #define NET_BASE_UPLOAD_ELEMENT_READER_H_ #include #include "net/base/completion_once_callback.h" #include "net/base/net_export.h" namespace net { class IOBuffer; class UploadBytesElementReader; class UploadFileElementReader; // An interface to read an upload data element. class NET_EXPORT UploadElementReader { public: UploadElementReader() = default; UploadElementReader(const UploadElementReader&) = delete; UploadElementReader& operator=(const UploadElementReader&) = delete; virtual ~UploadElementReader() = default; // Returns this instance's pointer as UploadBytesElementReader when possible, // otherwise returns NULL. virtual const UploadBytesElementReader* AsBytesReader() const; // Returns this instance's pointer as UploadFileElementReader when possible, // otherwise returns NULL. virtual const UploadFileElementReader* AsFileReader() const; // This function must be called before calling any other method. It is not // valid to call any method (other than the destructor) if Init() fails. // This method can be called multiple times. Calling this results in resetting // the state (i.e. the stream is rewound), and any previously pending Init() // or Read() calls are aborted. // // Initializes the instance synchronously when possible, otherwise does // initialization aynschronously, returns ERR_IO_PENDING and runs callback. // Calling this method again after a Init() success results in resetting the // state. virtual int Init(CompletionOnceCallback callback) = 0; // Returns the byte-length of the element. For files that do not exist, 0 // is returned. This is done for consistency with Mozilla. virtual uint64_t GetContentLength() const = 0; // Returns the number of bytes remaining to read. virtual uint64_t BytesRemaining() const = 0; // Returns true if the upload element is entirely in memory. // The default implementation returns false. virtual bool IsInMemory() const; // Reads up to |buf_length| bytes synchronously and returns the number of // bytes read or error code when possible, otherwise, returns ERR_IO_PENDING // and runs |callback| with the result. |buf_length| must be greater than 0. virtual int Read(IOBuffer* buf, int buf_length, CompletionOnceCallback callback) = 0; }; } // namespace net #endif // NET_BASE_UPLOAD_ELEMENT_READER_H_