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 <stdint.h> 9 10 #include "net/base/completion_once_callback.h" 11 #include "net/base/net_export.h" 12 13 namespace net { 14 15 class IOBuffer; 16 class UploadBytesElementReader; 17 class UploadFileElementReader; 18 19 // An interface to read an upload data element. 20 class NET_EXPORT UploadElementReader { 21 public: 22 UploadElementReader() = default; 23 UploadElementReader(const UploadElementReader&) = delete; 24 UploadElementReader& operator=(const UploadElementReader&) = delete; 25 virtual ~UploadElementReader() = default; 26 27 // Returns this instance's pointer as UploadBytesElementReader when possible, 28 // otherwise returns NULL. 29 virtual const UploadBytesElementReader* AsBytesReader() const; 30 31 // Returns this instance's pointer as UploadFileElementReader when possible, 32 // otherwise returns NULL. 33 virtual const UploadFileElementReader* AsFileReader() const; 34 35 // This function must be called before calling any other method. It is not 36 // valid to call any method (other than the destructor) if Init() fails. 37 // This method can be called multiple times. Calling this results in resetting 38 // the state (i.e. the stream is rewound), and any previously pending Init() 39 // or Read() calls are aborted. 40 // 41 // Initializes the instance synchronously when possible, otherwise does 42 // initialization aynschronously, returns ERR_IO_PENDING and runs callback. 43 // Calling this method again after a Init() success results in resetting the 44 // state. 45 virtual int Init(CompletionOnceCallback callback) = 0; 46 47 // Returns the byte-length of the element. For files that do not exist, 0 48 // is returned. This is done for consistency with Mozilla. 49 virtual uint64_t GetContentLength() const = 0; 50 51 // Returns the number of bytes remaining to read. 52 virtual uint64_t BytesRemaining() const = 0; 53 54 // Returns true if the upload element is entirely in memory. 55 // The default implementation returns false. 56 virtual bool IsInMemory() const; 57 58 // Reads up to |buf_length| bytes synchronously and returns the number of 59 // bytes read or error code when possible, otherwise, returns ERR_IO_PENDING 60 // and runs |callback| with the result. |buf_length| must be greater than 0. 61 virtual int Read(IOBuffer* buf, 62 int buf_length, 63 CompletionOnceCallback callback) = 0; 64 }; 65 66 } // namespace net 67 68 #endif // NET_BASE_UPLOAD_ELEMENT_READER_H_ 69