1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
// *****************************************************************************
// * This file is part of the FreeFileSync project. It is distributed under *
// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0 *
// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
// *****************************************************************************
#ifndef FILE_IO_H_89578342758342572345
#define FILE_IO_H_89578342758342572345
#include "file_access.h"
//#include "serialize.h"
#include "crc.h"
#include "guid.h"
namespace zen
{
const char LINE_BREAK[] = "\n"; //since OS X Apple uses newline, too
/* OS-buffered file IO optimized for
- sequential read/write accesses
- better error reporting
- long path support
- follows symlinks */
class FileBase
{
public:
using FileHandle = int;
static const int invalidFileHandle = -1;
FileHandle getHandle() { return hFile_; }
//Windows: use 64kB ?? https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-2000-server/cc938632%28v=technet.10%29
//macOS, Linux: use st_blksize?
static size_t getBlockSize() { return 128 * 1024; };
const Zstring& getFilePath() const { return filePath_; }
protected:
FileBase(FileHandle handle, const Zstring& filePath) : hFile_(handle), filePath_(filePath) {}
~FileBase();
void close(); //throw FileError -> optional, but good place to catch errors when closing stream!
private:
FileBase (const FileBase&) = delete;
FileBase& operator=(const FileBase&) = delete;
FileHandle hFile_ = invalidFileHandle;
const Zstring filePath_;
};
//-----------------------------------------------------------------------------------------------
class FileInput : public FileBase
{
public:
FileInput( const Zstring& filePath, const IoCallback& notifyUnbufferedIO /*throw X*/); //throw FileError, ErrorFileLocked
FileInput(FileHandle handle, const Zstring& filePath, const IoCallback& notifyUnbufferedIO /*throw X*/); //takes ownership!
size_t read(void* buffer, size_t bytesToRead); //throw FileError, ErrorFileLocked, X; return "bytesToRead" bytes unless end of stream!
private:
size_t tryRead(void* buffer, size_t bytesToRead); //throw FileError, ErrorFileLocked; may return short, only 0 means EOF! => CONTRACT: bytesToRead > 0!
const IoCallback notifyUnbufferedIO_; //throw X
std::vector<std::byte> memBuf_ = std::vector<std::byte>(getBlockSize());
size_t bufPos_ = 0;
size_t bufPosEnd_= 0;
};
class FileOutput : public FileBase
{
public:
FileOutput( const Zstring& filePath, const IoCallback& notifyUnbufferedIO /*throw X*/); //throw FileError, ErrorTargetExisting
FileOutput(FileHandle handle, const Zstring& filePath, const IoCallback& notifyUnbufferedIO /*throw X*/); //takes ownership!
~FileOutput();
void reserveSpace(uint64_t expectedSize); //throw FileError
void write(const void* buffer, size_t bytesToWrite); //throw FileError, X
void flushBuffers(); //throw FileError, X
//caveat: does NOT flush OS or hard disk buffers like e.g. FlushFileBuffers()!
void finalize(); /*= flushBuffers() + close()*/ //throw FileError, X
private:
size_t tryWrite(const void* buffer, size_t bytesToWrite); //throw FileError; may return short! CONTRACT: bytesToWrite > 0
IoCallback notifyUnbufferedIO_; //throw X
std::vector<std::byte> memBuf_ = std::vector<std::byte>(getBlockSize());
size_t bufPos_ = 0;
size_t bufPosEnd_ = 0;
};
//-----------------------------------------------------------------------------------------------
//native stream I/O convenience functions:
class TempFileOutput
{
public:
TempFileOutput( const Zstring& filePath, const IoCallback& notifyUnbufferedIO /*throw X*/) : //throw FileError
filePath_(filePath),
tmpFile_(tmpFilePath_, notifyUnbufferedIO) {} //throw FileError, (ErrorTargetExisting)
void reserveSpace(uint64_t expectedSize) { tmpFile_.reserveSpace(expectedSize); } //throw FileError
void write(const void* buffer, size_t bytesToWrite) { tmpFile_.write(buffer, bytesToWrite); } //throw FileError, X
FileOutput& refTempFile() { return tmpFile_; }
void commit() //throw FileError, X
{
tmpFile_.finalize(); //throw FileError, X
//take ownership:
ZEN_ON_SCOPE_FAIL( try { removeFilePlain(tmpFilePath_); /*throw FileError*/ }
catch (FileError&) {});
//operation finished: move temp file transactionally
moveAndRenameItem(tmpFilePath_, filePath_, true /*replaceExisting*/); //throw FileError, (ErrorMoveUnsupported), (ErrorTargetExisting)
}
private:
//generate (hopefully) unique file name to avoid clashing with unrelated tmp file
const Zstring filePath_;
const Zstring shortGuid_ = printNumber<Zstring>(Zstr("%04x"), static_cast<unsigned int>(getCrc16(generateGUID())));
const Zstring tmpFilePath_ = filePath_ + Zstr('.') + shortGuid_ + Zstr(".tmp");
FileOutput tmpFile_;
};
[[nodiscard]] std::string getFileContent(const Zstring& filePath, const IoCallback& notifyUnbufferedIO /*throw X*/); //throw FileError, X
//overwrites if existing + transactional! :)
void setFileContent(const Zstring& filePath, const std::string& bytes, const IoCallback& notifyUnbufferedIO /*throw X*/); //throw FileError, X
}
#endif //FILE_IO_H_89578342758342572345
|
