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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 NET_BASE_UPLOAD_ELEMENT_READER_H_
- #define NET_BASE_UPLOAD_ELEMENT_READER_H_
- #include <stdint.h>
- #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_
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