1 // Copyright 2015 The Chromium OS 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 _BSDIFF_FILE_INTERFACE_H_ 6 #define _BSDIFF_FILE_INTERFACE_H_ 7 8 #include <sys/types.h> 9 10 #include <stddef.h> 11 #include <stdint.h> 12 13 #include "bsdiff/common.h" 14 15 static_assert(sizeof(off_t) == sizeof(int64_t), 16 "off_t must be a 64-bit number, use -D_FILE_OFFSET_BITS=64"); 17 18 namespace bsdiff { 19 20 class BSDIFF_EXPORT FileInterface { 21 public: 22 virtual ~FileInterface() = default; 23 24 // Reads synchronously from the current file position up to |count| bytes into 25 // the passed |buf| buffer. On success, stores in |bytes_read| how many bytes 26 // were actually read from the file. In case of error returns false. This 27 // method may read less than |count| bytes even if there's no error. If the 28 // end of file is reached, 0 bytes will be read and this methods returns true. 29 virtual bool Read(void* buf, size_t count, size_t* bytes_read) = 0; 30 31 // Writes synchronously up to |count| bytes from to passed |buf| buffer to 32 // the file. On success, stores in |bytes_written| how many bytes 33 // were actually written to the file. This method may write less than |count| 34 // bytes and return successfully, or even write 0 bytes if there's no more 35 // space left on the device. Returns whether the write succeeded. 36 virtual bool Write(const void* buf, size_t count, size_t* bytes_written) = 0; 37 38 // Change the current file position to |pos| bytes from the beginning of the 39 // file. Return whether the seek succeeded. 40 virtual bool Seek(off_t pos) = 0; 41 42 // Closes the file and flushes any cached data. Returns whether the close 43 // succeeded. 44 virtual bool Close() = 0; 45 46 // Compute the size of the file and store it in |size|. Returns whether it 47 // computed the size successfully. 48 virtual bool GetSize(uint64_t* size) = 0; 49 50 protected: 51 FileInterface() = default; 52 }; 53 54 } // namespace bsdiff 55 56 #endif // _BSDIFF_FILE_INTERFACE_H_ 57
