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feat(util/file_lock): add support for Windows

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Remark: the lock are not being erased on Windows.
I tried different solutions based on MoveFileEx and DeleteFile.
None of them worked. The one based on MoveFileEx

        MoveFileEx(m_fname.c_str(), NULL, MOVEFILE_DELAY_UNTIL_REBOOT);

seems to delete the file after REBOOT.
But, this is not very useful.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2015-12-14 10:03:33 -08:00
parent 95fba3dba6
commit 31c9a76777
2 changed files with 58 additions and 7 deletions
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1
.gitignore vendored
View file

@ -7,6 +7,7 @@
*.clean
*.ilean
*.d
*.lock
a.out
build
GPATH

64
src/util/file_lock.cpp
View file

@ -8,17 +8,68 @@ Author: Leonardo de Moura
#include "util/exception.h"
#include "util/sstream.h"
#include "util/file_lock.h"
#ifdef _WINDOWS
namespace lean {
file_lock::file_lock(char const *, bool) {
// TODO(Leo):
#include <sys/file.h>
#ifdef LEAN_WINDOWS
#include <windows.h>
#include <io.h>
#define LOCK_SH 1 /* shared lock */
#define LOCK_EX 2 /* exclusive lock */
#define LOCK_NB 4 /* don't block when locking */
#define LOCK_UN 8 /* unlock */
static BOOL lock(HANDLE h, int non_blocking, int exclusive) {
DWORD lower, upper;
OVERLAPPED ovlp;
int flags = 0;
lower = GetFileSize(h, &upper);
memset (&ovlp, 0, sizeof(ovlp));
if (non_blocking)
flags |= LOCKFILE_FAIL_IMMEDIATELY;
if (exclusive)
flags |= LOCKFILE_EXCLUSIVE_LOCK;
return LockFileEx(h, flags, 0, lower, upper, &ovlp);
}
file_lock::~file_lock() {
static BOOL unlock(HANDLE h) {
DWORD lower, upper;
lower = GetFileSize(h, &upper);
return UnlockFile(h, 0, 0, lower, upper);
}
int flock(int fd, int op) {
HANDLE h = (HANDLE)_get_osfhandle(fd);
DWORD res;
int non_blocking;
if (h == INVALID_HANDLE_VALUE)
return -1;
non_blocking = op & LOCK_NB;
op &= ~LOCK_NB;
switch (op) {
case LOCK_SH:
res = lock(h, non_blocking, 0);
break;
case LOCK_EX:
res = lock(h, non_blocking, 1);
break;
case LOCK_UN:
res = unlock(h);
break;
default:
return -1;
}
return !res ? -1 : 0;
}
#else
#include <unistd.h>
#include <sys/file.h>
#endif
namespace lean {
file_lock::file_lock(char const * fname, bool exclusive):
m_fname(fname), m_fd(-1) {
@ -39,4 +90,3 @@ file_lock::~file_lock() {
}
}
}
#endif