diff options
Diffstat (limited to 'zen/file_io.cpp')
| -rw-r--r-- | zen/file_io.cpp | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/zen/file_io.cpp b/zen/file_io.cpp index e081335d..f575a366 100644 --- a/zen/file_io.cpp +++ b/zen/file_io.cpp @@ -41,7 +41,7 @@ namespace FileBase::FileHandle openHandleForRead(const Zstring& filePath) //throw FileError, ErrorFileLocked { //caveat: check for file types that block during open(): character device, block device, named pipe - struct ::stat fileInfo = {}; + struct stat fileInfo = {}; if (::stat(filePath.c_str(), &fileInfo) == 0) //follows symlinks { if (!S_ISREG(fileInfo.st_mode) && @@ -74,11 +74,11 @@ FileBase::FileHandle openHandleForRead(const Zstring& filePath) //throw FileErro } -FileInput::FileInput(FileHandle handle, const Zstring& filePath, const IOCallback& notifyUnbufferedIO) : +FileInput::FileInput(FileHandle handle, const Zstring& filePath, const IoCallback& notifyUnbufferedIO) : FileBase(handle, filePath), notifyUnbufferedIO_(notifyUnbufferedIO) {} -FileInput::FileInput(const Zstring& filePath, const IOCallback& notifyUnbufferedIO) : +FileInput::FileInput(const Zstring& filePath, const IoCallback& notifyUnbufferedIO) : FileBase(openHandleForRead(filePath), filePath), //throw FileError, ErrorFileLocked notifyUnbufferedIO_(notifyUnbufferedIO) { @@ -166,8 +166,13 @@ FileBase::FileHandle openHandleForWrite(const Zstring& filePath) //throw FileErr { //checkForUnsupportedType(filePath); -> not needed, open() + O_WRONLY should fail fast - const int fdFile = ::open(filePath.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC | /*access == FileOutput::ACC_OVERWRITE ? O_TRUNC : */ O_EXCL, - S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH); //0666 => umask will be applied implicitly! + const mode_t lockFileMode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH; //0666 => umask will be applied implicitly! + + //O_EXCL contains a race condition on NFS file systems: https://linux.die.net/man/2/open + const int fdFile = ::open(filePath.c_str(), //const char* pathname + O_CREAT | //int flags + /*access == FileOutput::ACC_OVERWRITE ? O_TRUNC : */ O_EXCL | O_WRONLY | O_CLOEXEC, + lockFileMode); //mode_t mode if (fdFile == -1) { const int ec = errno; //copy before making other system calls! @@ -185,13 +190,13 @@ FileBase::FileHandle openHandleForWrite(const Zstring& filePath) //throw FileErr } -FileOutput::FileOutput(FileHandle handle, const Zstring& filePath, const IOCallback& notifyUnbufferedIO) : +FileOutput::FileOutput(FileHandle handle, const Zstring& filePath, const IoCallback& notifyUnbufferedIO) : FileBase(handle, filePath), notifyUnbufferedIO_(notifyUnbufferedIO) { } -FileOutput::FileOutput(const Zstring& filePath, const IOCallback& notifyUnbufferedIO) : +FileOutput::FileOutput(const Zstring& filePath, const IoCallback& notifyUnbufferedIO) : FileBase(openHandleForWrite(filePath), filePath), notifyUnbufferedIO_(notifyUnbufferedIO) {} //throw FileError, ErrorTargetExisting @@ -298,8 +303,8 @@ void FileOutput::reserveSpace(uint64_t expectedSize) //throw FileError //don't use ::posix_fallocate which uses horribly inefficient fallback if FS doesn't support it (EOPNOTSUPP) and changes files size! //FALLOC_FL_KEEP_SIZE => allocate only, file size is NOT changed! - if (::fallocate(getHandle(), //int fd, - FALLOC_FL_KEEP_SIZE, //int mode, + if (::fallocate(getHandle(), //int fd + FALLOC_FL_KEEP_SIZE, //int mode 0, //off_t offset expectedSize) != 0) //off_t len if (errno != EOPNOTSUPP) //possible, unlike with posix_fallocate() @@ -308,19 +313,19 @@ void FileOutput::reserveSpace(uint64_t expectedSize) //throw FileError } -std::string zen::getFileContent(const Zstring& filePath, const IOCallback& notifyUnbufferedIO /*throw X*/) //throw FileError, X +std::string zen::getFileContent(const Zstring& filePath, const IoCallback& notifyUnbufferedIO /*throw X*/) //throw FileError, X { FileInput streamIn(filePath, notifyUnbufferedIO); //throw FileError, ErrorFileLocked return bufferedLoad<std::string>(streamIn); //throw FileError, X } -void zen::setFileContent(const Zstring& filePath, const std::string& byteStream, const IOCallback& notifyUnbufferedIO /*throw X*/) //throw FileError, X +void zen::setFileContent(const Zstring& filePath, const std::string& byteStream, const IoCallback& notifyUnbufferedIO /*throw X*/) //throw FileError, X { TempFileOutput fileOut(filePath, notifyUnbufferedIO); //throw FileError if (!byteStream.empty()) { - //preallocate disk space + reduce fragmentation + //preallocate disk space & reduce fragmentation fileOut.reserveSpace(byteStream.size()); //throw FileError fileOut.write(&byteStream[0], byteStream.size()); //throw FileError, X } |