jens@0: /*
jens@0: * File.cpp
jens@0: * Ottoman
jens@0: *
jens@0: * Created by Jens Alfke on 8/20/09.
jens@0: * Copyright 2009 Jens Alfke. All rights reserved.
jens@0: * BSD-Licensed: See the file "LICENSE.txt" for details.
jens@0: */
jens@0:
jens@0: #include "File.h"
jens@0: #include "MemoryMap.h"
jens@0:
jens@0: #include <assert.h>
jens@0: #include <errno.h>
jens@0: #include <fcntl.h>
jens@0: #include <stdio.h>
jens@0: #include <sys/stat.h>
jens@0: #include <sys/uio.h>
jens@0: #include <unistd.h>
jens@0:
jens@0: namespace Mooseyard {
jens@0:
jens@0: File::File (const char *filename, bool writeable, bool create) throw(Error)
jens@0: :_fd(_check( ::open(filename, writeable ?(create ?O_RDWR|O_CREAT :O_RDWR) :O_RDONLY, 0644) )),
jens@0: _memoryMap(NULL),
jens@0: _locked(0)
jens@0: { }
jens@0:
jens@0: File::File (const char *filename, int oflag) throw(Error)
jens@0: :_fd(_check( ::open(filename, oflag, 0644) )),
jens@0: _memoryMap(NULL),
jens@0: _locked( (oflag | O_EXLOCK) ?1 :0)
jens@0: { }
jens@0:
jens@0: File::~File() {
jens@0: delete _memoryMap;
jens@0: _unlock();
jens@0: ::close(_fd);
jens@0: }
jens@0:
jens@0:
jens@0: off_t File::length() const throw(Error) {
jens@0: struct stat s;
jens@0: _check( ::fstat(_fd,&s) );
jens@0: return s.st_size;
jens@0: }
jens@0:
jens@0: void File::setLength (off_t length) throw(Error) {
jens@0: _check( ftruncate(_fd,length) );
jens@0: }
jens@0:
jens@0: off_t File::position() const throw(Error) {
jens@0: return _check( lseek(_fd,0,SEEK_CUR) );
jens@0: }
jens@0:
jens@0: void File::setPosition (off_t pos) throw(Error) {
jens@0: _check( lseek(_fd,pos,SEEK_SET) );
jens@0: }
jens@0:
jens@0: off_t File::setPositionToEnd (off_t bytesBefore) throw(Error) {
jens@0: return _check( lseek(_fd,-bytesBefore,SEEK_END) );
jens@0: }
jens@0:
jens@0: void File::read (void *dst, size_t size) throw(Error) {
jens@0: _checkRead( ::read(_fd, dst, size), size );
jens@0: }
jens@0:
jens@0: size_t File::write (const void *src, size_t size) throw(Error) {
jens@0: return _check( ::write(_fd, src, size) );
jens@0: }
jens@0:
jens@0:
jens@0: void File::readFrom (off_t where, void *dst, size_t size) throw(Error) {
jens@0: _checkRead( ::pread(_fd, dst, size, where), size );
jens@0: }
jens@0:
jens@0: void File::writeTo (off_t where, const void *src, size_t size) throw(Error) {
jens@0: _check( ::pwrite(_fd, src, size, where) );
jens@0: }
jens@0:
jens@0: size_t File::writeMultiple (Blob blobs[], int count) throw(Error) {
jens@0: struct iovec vec[count];
jens@0: for (int i=0; i<count; i++) {
jens@0: vec[i].iov_base = (void*) blobs[i].bytes;
jens@0: vec[i].iov_len = blobs[i].length;
jens@0: }
jens@0: return _check( ::writev(_fd, vec, count) );
jens@0: }
jens@0:
jens@0: size_t File::writePadding (int alignment) {
jens@2: int pad = alignment - (int)(position() & (alignment-1));
jens@0: if (pad == alignment)
jens@0: return 0;
jens@0: uint8_t zero[pad];
jens@0: memset(zero, 0, pad);
jens@0: return write(zero, pad);
jens@0: }
jens@0:
jens@0:
jens@0: void File::flush() throw(Error) {
jens@0: _check( ::fsync(_fd) );
jens@0: }
jens@0:
jens@0: void File::flushDisk() throw(Error) {
jens@0: _check( ::fcntl(_fd,F_FULLFSYNC) );
jens@0: }
jens@0:
jens@0: bool File::hasPath (const char *path) const throw(Error) {
jens@0: struct stat myStat, pathStat;
jens@0: _check( ::fstat(_fd, &myStat) );
jens@0: if ( ::stat(path, &pathStat) != 0 ) {
jens@0: if (errno == ENOENT)
jens@0: return false;
jens@0: _check(errno);
jens@0: }
jens@0: // Compare my inode number with that of the file at path:
jens@0: return myStat.st_ino == pathStat.st_ino;
jens@0: }
jens@0:
jens@0:
jens@0: void File::unlink (const char *filename) throw(Error) {
jens@0: _check( ::unlink(filename) );
jens@0: }
jens@0:
jens@0: void File::rename (const char *srcFilename, const char *dstFilename) throw(Error) {
jens@0: _check( ::rename(srcFilename, dstFilename) );
jens@0: }
jens@0:
jens@0:
jens@0: #pragma mark -
jens@0: #pragma mark UTILITIES:
jens@0:
jens@0: int File::_check (int result) throw(Error) {
jens@0: if (result >= 0)
jens@0: return result;
jens@0: //printf("*** File::_check: Error %i: %s\n", errno, strerror(errno));
jens@0: throw Error(errno, strerror(errno));
jens@0: }
jens@0:
jens@0: void File::_checkRead (ssize_t result, size_t expectedSize) throw(Error) {
jens@0: if ((size_t)result < expectedSize) {
jens@0: if (result < 0)
jens@0: throw Error(errno, strerror(errno));
jens@0: else
jens@0: throw Error(kEOF, "unexpected EOF");
jens@0: }
jens@0: }
jens@0:
jens@0: File::Error::Error(const char *m)
jens@0: :code(ERANGE),
jens@0: message(m)
jens@0: { }
jens@0:
jens@0:
jens@0: #pragma mark -
jens@0: #pragma mark LOCKS:
jens@0:
jens@0: bool File::_lock (bool block) {
jens@0: if (_locked) {
jens@0: _locked++;
jens@0: } else {
jens@0: int mode = LOCK_EX;
jens@0: if (block)
jens@0: mode |= LOCK_NB;
jens@0: if (::flock(_fd, mode) == 0)
jens@0: _locked = 1;
jens@0: else if (errno != EWOULDBLOCK) // may be returned in LOCK_UN mode
jens@0: _check(-1);
jens@0: }
jens@0: return _locked > 0;
jens@0: }
jens@0:
jens@0: void File::_unlock() {
jens@0: if (_locked > 0) {
jens@0: _locked--;
jens@0: ::flock(_fd, LOCK_UN);
jens@0: }
jens@0: }
jens@0:
jens@0: File::Lock::Lock (File *file, bool block) throw(Error)
jens@0: :_file(file),
jens@0: _locked( _file->_lock(block) )
jens@0: { }
jens@0:
jens@0: File::Lock::~Lock() {
jens@0: if (_locked)
jens@0: _file->_unlock();
jens@0: }
jens@0:
jens@0: bool File::Lock::retry() {
jens@0: if (!_locked)
jens@0: _locked = _file->_lock(false);
jens@0: return _locked;
jens@0: }
jens@0:
jens@0:
jens@0: #pragma mark -
jens@0: #pragma mark MEMORY MAP:
jens@0:
jens@0: MemoryMap* File::map() {
jens@0: if (!_memoryMap)
jens@0: _memoryMap = new MemoryMap(this);
jens@0: return _memoryMap;
jens@0: }
jens@0:
jens@0: void File::mapRegion (off_t position, size_t length) {
jens@0: return map()->mapRegion(position,length);
jens@0: }
jens@0:
jens@0: const void* File::mappedPosition (off_t position) const {
jens@0: return map()->mappedPosition(position);
jens@0: }
jens@0:
jens@0: }