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Remove pthread code for Windows older than Vista

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Assume the CONDITION_VARIABLE added in Windows Vista is available.

Remove an unneeded WaitForSingleObject() macro that converts
WaitForSingleObject() calls to WaitForSingleObjectEx() calls with
bAlertable=FALSE. The WaitForSingleObject() function does not enter an
alertable wait state, so it is equivalent to WaitForSingleObjectEx()
with bAlertable=FALSE.

Remove code for Windows older than Vista in src/dsp/cpu.h.

Change-Id: I7df95557713923e05a7bfb62e095ec6172cfd708
This commit is contained in:
Wan-Teh Chang
2025-08-02 08:09:14 -07:00
parent c41d168d25
commit ac2795e904
2 changed files with 10 additions and 79 deletions
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19
src/dsp/cpu.h
View File

@@ -193,7 +193,9 @@
#if defined(_WIN32)
#include <windows.h>
#if _WIN32_WINNT >= 0x0600
#if _WIN32_WINNT < 0x0600
#error _WIN32_WINNT must target Windows Vista / Server 2008 or newer.
#endif
// clang-format off
#define WEBP_DSP_INIT_VARS(func) \
static VP8CPUInfo func##_last_cpuinfo_used = \
@@ -207,20 +209,7 @@
ReleaseSRWLockExclusive(&func##_lock); \
} while (0)
// clang-format on
#else // _WIN32_WINNT < 0x0600
// clang-format off
#define WEBP_DSP_INIT_VARS(func) \
static volatile VP8CPUInfo func##_last_cpuinfo_used = \
(VP8CPUInfo)&func##_last_cpuinfo_used
#define WEBP_DSP_INIT(func) \
do { \
if (func##_last_cpuinfo_used == VP8GetCPUInfo) break; \
func(); \
func##_last_cpuinfo_used = VP8GetCPUInfo; \
} while (0)
// clang-format on
#endif // _WIN32_WINNT >= 0x0600
#else // !defined(_WIN32)
#else // !defined(_WIN32)
// NOLINTNEXTLINE
#include <pthread.h>

70
src/utils/thread_utils.c
View File

@@ -29,16 +29,10 @@ WEBP_ASSUME_UNSAFE_INDEXABLE_ABI
typedef HANDLE pthread_t;
typedef CRITICAL_SECTION pthread_mutex_t;
#if _WIN32_WINNT >= 0x0600 // Windows Vista / Server 2008 or greater
#define USE_WINDOWS_CONDITION_VARIABLE
#if _WIN32_WINNT < 0x0600
#error _WIN32_WINNT must target Windows Vista / Server 2008 or newer.
#endif
typedef CONDITION_VARIABLE pthread_cond_t;
#else
typedef struct {
HANDLE waiting_sem;
HANDLE received_sem;
HANDLE signal_event;
} pthread_cond_t;
#endif // _WIN32_WINNT >= 0x600
#ifndef WINAPI_FAMILY_PARTITION
#define WINAPI_PARTITION_DESKTOP 1
@@ -72,11 +66,6 @@ typedef struct {
#define THREADFN unsigned int __stdcall
#define THREAD_RETURN(val) (unsigned int)((DWORD_PTR)val)
#if _WIN32_WINNT >= 0x0501 // Windows XP or greater
#define WaitForSingleObject(obj, timeout) \
WaitForSingleObjectEx(obj, timeout, /*bAlertable=*/FALSE)
#endif
static int pthread_create(pthread_t* const thread, const void* attr,
unsigned int(__stdcall* start)(void*), void* arg) {
(void)attr;
@@ -104,11 +93,7 @@ static int pthread_join(pthread_t thread, void** value_ptr) {
// Mutex
static int pthread_mutex_init(pthread_mutex_t* const mutex, void* mutexattr) {
(void)mutexattr;
#if _WIN32_WINNT >= 0x0600 // Windows Vista / Server 2008 or greater
InitializeCriticalSectionEx(mutex, /*dwSpinCount=*/0, /*Flags=*/0);
#else
InitializeCriticalSection(mutex);
#endif
return 0;
}
@@ -129,67 +114,24 @@ static int pthread_mutex_destroy(pthread_mutex_t* const mutex) {
// Condition
static int pthread_cond_destroy(pthread_cond_t* const condition) {
int ok = 1;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
(void)condition;
#else
ok &= (CloseHandle(condition->waiting_sem) != 0);
ok &= (CloseHandle(condition->received_sem) != 0);
ok &= (CloseHandle(condition->signal_event) != 0);
#endif
return !ok;
return 0;
}
static int pthread_cond_init(pthread_cond_t* const condition, void* cond_attr) {
(void)cond_attr;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
InitializeConditionVariable(condition);
#else
condition->waiting_sem = CreateSemaphore(NULL, 0, 1, NULL);
condition->received_sem = CreateSemaphore(NULL, 0, 1, NULL);
condition->signal_event = CreateEvent(NULL, FALSE, FALSE, NULL);
if (condition->waiting_sem == NULL || condition->received_sem == NULL ||
condition->signal_event == NULL) {
pthread_cond_destroy(condition);
return 1;
}
#endif
return 0;
}
static int pthread_cond_signal(pthread_cond_t* const condition) {
int ok = 1;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
WakeConditionVariable(condition);
#else
if (WaitForSingleObject(condition->waiting_sem, 0) == WAIT_OBJECT_0) {
// a thread is waiting in pthread_cond_wait: allow it to be notified
ok = SetEvent(condition->signal_event);
// wait until the event is consumed so the signaler cannot consume
// the event via its own pthread_cond_wait.
ok &= (WaitForSingleObject(condition->received_sem, INFINITE) !=
WAIT_OBJECT_0);
}
#endif
return !ok;
return 0;
}
static int pthread_cond_wait(pthread_cond_t* const condition,
pthread_mutex_t* const mutex) {
int ok;
#ifdef USE_WINDOWS_CONDITION_VARIABLE
ok = SleepConditionVariableCS(condition, mutex, INFINITE);
#else
// note that there is a consumer available so the signal isn't dropped in
// pthread_cond_signal
if (!ReleaseSemaphore(condition->waiting_sem, 1, NULL)) return 1;
// now unlock the mutex so pthread_cond_signal may be issued
pthread_mutex_unlock(mutex);
ok =
(WaitForSingleObject(condition->signal_event, INFINITE) == WAIT_OBJECT_0);
ok &= ReleaseSemaphore(condition->received_sem, 1, NULL);
pthread_mutex_lock(mutex);
#endif
const int ok = SleepConditionVariableCS(condition, mutex, INFINITE);
return !ok;
}