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+//////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright Ion Gaztanaga 2009-2012. Distributed under the Boost
+// Software License, Version 1.0. (See accompanying file
+// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/interprocess for documentation.
+//
+//////////////////////////////////////////////////////////////////////////////
+
+#ifndef BOOST_INTERPROCESS_FILE_LOCKING_HELPERS_HPP
+#define BOOST_INTERPROCESS_FILE_LOCKING_HELPERS_HPP
+
+#if defined(_MSC_VER)&&(_MSC_VER>=1200)
+#pragma once
+#endif
+
+#include <boost/interprocess/detail/config_begin.hpp>
+#include <boost/interprocess/detail/workaround.hpp>
+
+#include <sstream>
+#include <string>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+#include <cstddef>
+#include <boost/interprocess/detail/os_file_functions.hpp>
+
+#include <boost/interprocess/detail/tmp_dir_helpers.hpp>
+
+#if defined(BOOST_INTERPROCESS_WINDOWS)
+
+#include <fcntl.h>
+#include <io.h>
+#include <sys/locking.h>
+
+#else //defined(BOOST_INTERPROCESS_WINDOWS)
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#endif //defined(BOOST_INTERPROCESS_WINDOWS)
+
+namespace boost{
+namespace interprocess{
+namespace ipcdetail{
+
+#if defined(BOOST_INTERPROCESS_WINDOWS)
+
+struct locking_file_serial_id
+{
+ int fd;
+ unsigned long dwVolumeSerialNumber;
+ unsigned long nFileIndexHigh;
+ unsigned long nFileIndexLow;
+ //This reference count counts the number of modules attached
+ //to the shared memory and lock file. This serves to unlink
+ //the locking file and shared memory when all modules are
+ //done with the global memory (shared memory)
+ volatile boost::uint32_t modules_attached_to_gmem_count;
+};
+
+inline bool lock_locking_file(int fd)
+{
+ int ret = 0;
+ while(ret != 0 && errno == EDEADLK){
+ ret = _locking(fd, _LK_LOCK, 1/*lock_file_contents_length()*/);
+ }
+ return 0 == ret;
+}
+
+inline bool try_lock_locking_file(int fd)
+{
+ return 0 == _locking(fd, _LK_NBLCK , 1);
+}
+
+inline int open_or_create_and_lock_file(const char *name)
+{
+ permissions p;
+ p.set_unrestricted();
+ while(1){
+ file_handle_t handle = create_or_open_file(name, read_write, p);
+ int fd = _open_osfhandle((intptr_t)handle, _O_TEXT);
+ if(fd < 0){
+ close_file(handle);
+ return fd;
+ }
+ if(!try_lock_locking_file(fd)){
+ _close(fd);
+ return -1;
+ }
+ struct _stat s;
+ if(0 == _stat(name, &s)){
+ return fd;
+ }
+ else{
+ _close(fd);
+ }
+ }
+}
+
+inline int try_open_and_lock_file(const char *name)
+{
+ file_handle_t handle = open_existing_file(name, read_write);
+ int fd = _open_osfhandle((intptr_t)handle, _O_TEXT);
+ if(fd < 0){
+ close_file(handle);
+ return fd;
+ }
+ if(!try_lock_locking_file(fd)){
+ _close(fd);
+ return -1;
+ }
+ return fd;
+}
+
+inline void close_lock_file(int fd)
+{ _close(fd); }
+
+inline bool is_valid_fd(int fd)
+{
+ struct _stat s;
+ return EBADF != _fstat(fd, &s);
+}
+
+inline bool is_normal_file(int fd)
+{
+ if(_isatty(fd))
+ return false;
+ struct _stat s;
+ if(0 != _fstat(fd, &s))
+ return false;
+ return 0 != (s.st_mode & _S_IFREG);
+}
+
+inline std::size_t get_size(int fd)
+{
+ struct _stat s;
+ if(0 != _fstat(fd, &s))
+ return 0u;
+ return (std::size_t)s.st_size;
+}
+
+inline bool fill_file_serial_id(int fd, locking_file_serial_id &id)
+{
+ winapi::interprocess_by_handle_file_information info;
+ if(!winapi::get_file_information_by_handle((void*)_get_osfhandle(fd), &info))
+ return false;
+ id.fd = fd;
+ id.dwVolumeSerialNumber = info.dwVolumeSerialNumber;
+ id.nFileIndexHigh = info.nFileIndexHigh;
+ id.nFileIndexLow = info.nFileIndexLow;
+ id.modules_attached_to_gmem_count = 1; //Initialize attached count
+ return true;
+}
+
+inline bool compare_file_serial(int fd, const locking_file_serial_id &id)
+{
+ winapi::interprocess_by_handle_file_information info;
+ if(!winapi::get_file_information_by_handle((void*)_get_osfhandle(fd), &info))
+ return false;
+
+ return id.dwVolumeSerialNumber == info.dwVolumeSerialNumber &&
+ id.nFileIndexHigh == info.nFileIndexHigh &&
+ id.nFileIndexLow == info.nFileIndexLow;
+}
+
+#else //UNIX
+
+struct locking_file_serial_id
+{
+ int fd;
+ dev_t st_dev;
+ ino_t st_ino;
+ //This reference count counts the number of modules attached
+ //to the shared memory and lock file. This serves to unlink
+ //the locking file and shared memory when all modules are
+ //done with the global memory (shared memory)
+ volatile boost::uint32_t modules_attached_to_gmem_count;
+};
+
+inline bool lock_locking_file(int fd)
+{
+ int ret = 0;
+ while(ret != 0 && errno != EINTR){
+ struct flock lock;
+ lock.l_type = F_WRLCK;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = 0;
+ lock.l_len = 1;
+ ret = fcntl (fd, F_SETLKW, &lock);
+ }
+ return 0 == ret;
+}
+
+inline bool try_lock_locking_file(int fd)
+{
+ struct flock lock;
+ lock.l_type = F_WRLCK;
+ lock.l_whence = SEEK_SET;
+ lock.l_start = 0;
+ lock.l_len = 1;
+ return 0 == fcntl (fd, F_SETLK, &lock);
+}
+
+inline int open_or_create_and_lock_file(const char *name)
+{
+ permissions p;
+ p.set_unrestricted();
+ while(1){
+ int fd = create_or_open_file(name, read_write, p);
+ if(fd < 0){
+ return fd;
+ }
+ if(!try_lock_locking_file(fd)){
+ close(fd);
+ return -1;
+ }
+ struct stat s;
+ if(0 == stat(name, &s)){
+ return fd;
+ }
+ else{
+ close(fd);
+ }
+ }
+}
+
+inline int try_open_and_lock_file(const char *name)
+{
+ int fd = open_existing_file(name, read_write);
+ if(fd < 0){
+ return fd;
+ }
+ if(!try_lock_locking_file(fd)){
+ close(fd);
+ return -1;
+ }
+ return fd;
+}
+
+inline void close_lock_file(int fd)
+{ close(fd); }
+
+inline bool is_valid_fd(int fd)
+{
+ struct stat s;
+ return EBADF != fstat(fd, &s);
+}
+
+inline bool is_normal_file(int fd)
+{
+ struct stat s;
+ if(0 != fstat(fd, &s))
+ return false;
+ return 0 != (s.st_mode & S_IFREG);
+}
+
+inline std::size_t get_size(int fd)
+{
+ struct stat s;
+ if(0 != fstat(fd, &s))
+ return 0u;
+ return (std::size_t)s.st_size;
+}
+
+inline bool fill_file_serial_id(int fd, locking_file_serial_id &id)
+{
+ struct stat s;
+ if(0 != fstat(fd, &s))
+ return false;
+ id.fd = fd;
+ id.st_dev = s.st_dev;
+ id.st_ino = s.st_ino;
+ id.modules_attached_to_gmem_count = 1; //Initialize attached count
+ return true;
+}
+
+inline bool compare_file_serial(int fd, const locking_file_serial_id &id)
+{
+ struct stat info;
+ if(0 != fstat(fd, &info))
+ return false;
+
+ return id.st_dev == info.st_dev &&
+ id.st_ino == info.st_ino;
+}
+
+#endif
+
+} //namespace ipcdetail{
+} //namespace interprocess{
+} //namespace boost{
+
+#include <boost/interprocess/detail/config_end.hpp>
+
+#endif //BOOST_INTERPROCESS_FILE_LOCKING_HELPERS_HPP
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