(svn r8508) -Codechange (r5762): [win32] Use an atomic operation to query and set the value of _global_dir_is_in_use for opendir etc to guarantee concurrency.

This commit is contained in:
Darkvater 2007-02-01 13:01:05 +00:00
parent 3c2cb4871e
commit 50909e272b

View File

@ -625,20 +625,19 @@ static void Win32InitializeExceptions(void)
/* suballocator - satisfies most requests with a reusable static instance.
* this avoids hundreds of alloc/free which would fragment the heap.
* To guarantee reentrancy, we fall back to malloc if the instance is
* To guarantee concurrency, we fall back to malloc if the instance is
* already in use (it's important to avoid suprises since this is such a
* low-level routine). */
static DIR _global_dir;
static bool _global_dir_is_in_use = false;
static LONG _global_dir_is_in_use = false;
static inline DIR *dir_calloc(void)
{
DIR *d;
if (_global_dir_is_in_use) {
if (InterlockedExchange(&_global_dir_is_in_use, true) == (LONG)true) {
d = CallocT<DIR>(1);
} else {
_global_dir_is_in_use = true;
d = &_global_dir;
memset(d, 0, sizeof(*d));
}
@ -648,7 +647,7 @@ static inline DIR *dir_calloc(void)
static inline void dir_free(DIR *d)
{
if (d == &_global_dir) {
_global_dir_is_in_use = false;
_global_dir_is_in_use = (LONG)false;
} else {
free(d);
}