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be7c937 | 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 | #include "wayy_db/mmap_file.hpp"
#include "wayy_db/types.hpp"
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <cstring>
namespace wayy_db {
MmapFile::MmapFile(const std::string& path, Mode mode, size_t size) {
open(path, mode, size);
}
MmapFile::MmapFile(MmapFile&& other) noexcept
: path_(std::move(other.path_))
, data_(other.data_)
, size_(other.size_)
, mode_(other.mode_)
, fd_(other.fd_) {
other.data_ = nullptr;
other.size_ = 0;
other.fd_ = -1;
}
MmapFile& MmapFile::operator=(MmapFile&& other) noexcept {
if (this != &other) {
close();
path_ = std::move(other.path_);
data_ = other.data_;
size_ = other.size_;
mode_ = other.mode_;
fd_ = other.fd_;
other.data_ = nullptr;
other.size_ = 0;
other.fd_ = -1;
}
return *this;
}
MmapFile::~MmapFile() {
close();
}
void MmapFile::open(const std::string& path, Mode mode, size_t size) {
close();
path_ = path;
mode_ = mode;
int flags = 0;
int prot = 0;
switch (mode) {
case Mode::ReadOnly:
flags = O_RDONLY;
prot = PROT_READ;
break;
case Mode::ReadWrite:
flags = O_RDWR;
prot = PROT_READ | PROT_WRITE;
break;
case Mode::Create:
flags = O_RDWR | O_CREAT | O_TRUNC;
prot = PROT_READ | PROT_WRITE;
break;
}
fd_ = ::open(path.c_str(), flags, 0644);
if (fd_ < 0) {
throw WayyException("Failed to open file: " + path + " (" + strerror(errno) + ")");
}
if (mode == Mode::Create && size > 0) {
// Extend file to requested size
if (ftruncate(fd_, size) < 0) {
::close(fd_);
fd_ = -1;
throw WayyException("Failed to resize file: " + path);
}
size_ = size;
} else {
// Get file size
struct stat st;
if (fstat(fd_, &st) < 0) {
::close(fd_);
fd_ = -1;
throw WayyException("Failed to stat file: " + path);
}
size_ = st.st_size;
}
if (size_ == 0) {
// Can't mmap empty file
return;
}
data_ = mmap(nullptr, size_, prot, MAP_SHARED, fd_, 0);
if (data_ == MAP_FAILED) {
data_ = nullptr;
::close(fd_);
fd_ = -1;
throw WayyException("Failed to mmap file: " + path + " (" + strerror(errno) + ")");
}
}
void MmapFile::close() {
if (data_ != nullptr) {
munmap(data_, size_);
data_ = nullptr;
}
if (fd_ >= 0) {
::close(fd_);
fd_ = -1;
}
size_ = 0;
path_.clear();
}
void MmapFile::sync() {
if (data_ != nullptr && mode_ != Mode::ReadOnly) {
msync(data_, size_, MS_SYNC);
}
}
void MmapFile::resize(size_t new_size) {
if (mode_ != Mode::Create && mode_ != Mode::ReadWrite) {
throw InvalidOperation("Cannot resize read-only mmap");
}
if (data_ != nullptr) {
munmap(data_, size_);
data_ = nullptr;
}
if (ftruncate(fd_, new_size) < 0) {
throw WayyException("Failed to resize file: " + path_);
}
size_ = new_size;
if (size_ > 0) {
int prot = PROT_READ | PROT_WRITE;
data_ = mmap(nullptr, size_, prot, MAP_SHARED, fd_, 0);
if (data_ == MAP_FAILED) {
data_ = nullptr;
throw WayyException("Failed to remap file: " + path_);
}
}
}
} // namespace wayy_db
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