mcpp/src/platform/fs.cppm at main · mcpp-community/mcpp · GitHub

History

259 lines (226 loc) · 8.37 KB

Raw

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

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

// mcpp.platform.fs — platform-specific filesystem operations.

// Consolidates three patterns that were duplicated across the codebase:

// 1. self_exe_path() — current executable path (was in config.cppm &

// ninja_backend.cppm)

// 2. which() — find an executable in PATH (was in config.cppm &

// probe.cppm)

// 3. FileLock — RAII exclusive file lock (was in bmi_cache.cppm)

module;

#include <cstdio>

#include <cstdlib>

#if defined(_WIN32)

#include <io.h>

#include <windows.h>

#define popen _popen

#define pclose _pclose

#elif defined(__APPLE__)

#include <mach-o/dyld.h> // _NSGetExecutablePath

#else

#include <fcntl.h>

#include <sys/file.h>

#include <unistd.h>

#endif

// POSIX file locking (shared between macOS and Linux)

#if !defined(_WIN32)

#include <fcntl.h>

#include <sys/file.h>

#include <unistd.h>

#endif

export module mcpp.platform.fs;

import std;

import mcpp.platform.common;

export namespace mcpp::platform::fs {

// ── self_exe_path ─────────────────────────────────────────────────────────

// Returns the absolute path of the currently running executable.

// Windows: GetModuleFileNameA

// macOS: _NSGetExecutablePath

// Linux: /proc/self/exe

std::filesystem::path self_exe_path();

// ── which ─────────────────────────────────────────────────────────────────

// Find an executable by name in PATH.

// Windows: `where <name>`

// POSIX: `command -v <name>`

std::optional<std::filesystem::path> which(std::string_view binary_name);

// 不先删除目标文件，避免发布失败时丢失最后一份可用的编译数据库。

bool replace_file(const std::filesystem::path& source,

const std::filesystem::path& destination,

std::error_code& ec);

// ── FileLock ──────────────────────────────────────────────────────────────

// RAII exclusive non-blocking file lock.

// Windows: LockFileEx on a HANDLE

// POSIX: flock(2) on a file descriptor

class FileLock {

public:

// Try to acquire an exclusive lock on <dir>/.lock.

// Returns nullopt if another process holds the lock.

static std::optional<FileLock> try_acquire(const std::filesystem::path& dir);

~FileLock();

FileLock(FileLock&& o) noexcept;

FileLock& operator=(FileLock&& o) noexcept;

FileLock(const FileLock&) = delete;

FileLock& operator=(const FileLock&) = delete;

private:

#if defined(_WIN32)

void* handle_ = reinterpret_cast<void*>(static_cast<std::intptr_t>(-1)); // INVALID_HANDLE_VALUE

explicit FileLock(void* h) : handle_(h) {}

#else

int fd_ = -1;

explicit FileLock(int fd) : fd_(fd) {}

#endif

};

} // namespace mcpp::platform::fs

// ─── Implementation ──────────────────────────────────────────────────────

namespace mcpp::platform::fs {

std::filesystem::path self_exe_path() {

std::error_code ec;

#if defined(_WIN32)

char buf[MAX_PATH];

DWORD len = GetModuleFileNameA(NULL, buf, MAX_PATH);

if (len > 0 && len < MAX_PATH) {

auto p = std::filesystem::canonical(buf, ec);

if (!ec) return p;

}

#elif defined(__APPLE__)

char buf[4096];

uint32_t size = sizeof(buf);

if (_NSGetExecutablePath(buf, &size) == 0) {

auto p = std::filesystem::canonical(buf, ec);

if (!ec) return p;

}

#else

auto p = std::filesystem::read_symlink("/proc/self/exe", ec);

if (!ec) return p;

#endif

// Fallback: hope the binary is in PATH

return "mcpp";

}

std::optional<std::filesystem::path> which(std::string_view binary_name) {

std::string name(binary_name);

#if defined(_WIN32)

std::string cmd = "where " + name + " 2>nul";

#else

std::string cmd = "command -v '" + name + "' 2>/dev/null </dev/null";

#endif

std::array<char, 4096> buf{};

std::string out;

std::FILE* fp = ::popen(cmd.c_str(), "r");

if (!fp) return std::nullopt;

while (std::fgets(buf.data(), static_cast<int>(buf.size()), fp) != nullptr)

out += buf.data();

int rc = ::pclose(fp);

// Trim and take first line

while (!out.empty() && (out.back() == '\n' || out.back() == '\r'))

out.pop_back();

auto nl = out.find('\n');

if (nl != std::string::npos) out.resize(nl);

if (rc != 0 || out.empty()) return std::nullopt;

if (!std::filesystem::exists(out)) return std::nullopt;

return std::filesystem::path(out);

}

bool replace_file(const std::filesystem::path& source,

const std::filesystem::path& destination,

std::error_code& ec) {

#if defined(_WIN32)

// 直接替换已有文件，不能先删除 last-known-good CDB。编辑器或杀毒软件

// 可能短暂占用目标文件，sharing violation 仅做有限退避后再报告失败。

auto delay = std::chrono::milliseconds{50};

for (int attempt = 0; attempt < 4; ++attempt) {

if (MoveFileExW(source.wstring().c_str(), destination.wstring().c_str(),

MOVEFILE_REPLACE_EXISTING)) {

ec.clear();

return true;

}

const auto error = GetLastError();

if (error != ERROR_SHARING_VIOLATION || attempt == 3) {

ec = std::error_code(static_cast<int>(error), std::system_category());

return false;

}

std::this_thread::sleep_for(delay);

delay *= 3;

}

return false;

#else

// 临时文件与目标文件位于同一文件系统时，rename 提供原子替换。

std::filesystem::rename(source, destination, ec);

return !ec;

#endif

}

#if defined(_WIN32)

std::optional<FileLock> FileLock::try_acquire(const std::filesystem::path& dir) {

std::error_code ec;

std::filesystem::create_directories(dir, ec);

auto lockPath = dir / ".lock";

HANDLE h = CreateFileW(lockPath.wstring().c_str(),

GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE,

NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

if (h == INVALID_HANDLE_VALUE) return std::nullopt;

OVERLAPPED ov = {};

if (!LockFileEx(h, LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY,

0, 1, 0, &ov)) {

CloseHandle(h);

return std::nullopt;

}

return FileLock{h};

}

FileLock::~FileLock() {

if (handle_ != INVALID_HANDLE_VALUE) {

OVERLAPPED ov = {};

UnlockFileEx(static_cast<HANDLE>(handle_), 0, 1, 0, &ov);

CloseHandle(static_cast<HANDLE>(handle_));

}

FileLock::FileLock(FileLock&& o) noexcept : handle_(o.handle_) {

o.handle_ = INVALID_HANDLE_VALUE;

}

FileLock& FileLock::operator=(FileLock&& o) noexcept {

if (this != &o) {

if (handle_ != INVALID_HANDLE_VALUE) {

OVERLAPPED ov = {};

UnlockFileEx(static_cast<HANDLE>(handle_), 0, 1, 0, &ov);

CloseHandle(static_cast<HANDLE>(handle_));

}

handle_ = o.handle_;

o.handle_ = INVALID_HANDLE_VALUE;

}

return *this;

}

#else // POSIX

std::optional<FileLock> FileLock::try_acquire(const std::filesystem::path& dir) {

std::error_code ec;

std::filesystem::create_directories(dir, ec);

auto lockPath = dir / ".lock";

int fd = ::open(lockPath.c_str(), O_CREAT | O_RDWR | O_CLOEXEC, 0644);

if (fd < 0) return std::nullopt;

if (::flock(fd, LOCK_EX | LOCK_NB) != 0) {

::close(fd);

return std::nullopt;

}

return FileLock{fd};

}

FileLock::~FileLock() {

if (fd_ >= 0) {

::flock(fd_, LOCK_UN);

::close(fd_);

}

FileLock::FileLock(FileLock&& o) noexcept : fd_(o.fd_) {

o.fd_ = -1;

}

FileLock& FileLock::operator=(FileLock&& o) noexcept {

if (this != &o) {

if (fd_ >= 0) {

::flock(fd_, LOCK_UN);

::close(fd_);

}

fd_ = o.fd_;

o.fd_ = -1;

}

return *this;

}

#endif

} // namespace mcpp::platform::fs

mcpp/src/platform/fs.cppm at main · mcpp-community/mcpp · GitHub

Uh oh!

Expand file tree

Breadcrumbs

fs.cppm

Latest commit

History

Breadcrumbs

fs.cppm

File metadata and controls