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-rw-r--r--compat/win32/pthread.c188
-rw-r--r--compat/win32/pthread.h68
2 files changed, 256 insertions, 0 deletions
diff --git a/compat/win32/pthread.c b/compat/win32/pthread.c
new file mode 100644
index 0000000..0f949fc
--- /dev/null
+++ b/compat/win32/pthread.c
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2009 Andrzej K. Haczewski <ahaczewski@gmail.com>
+ *
+ * DISCLAIMER: The implementation is Git-specific, it is subset of original
+ * Pthreads API, without lots of other features that Git doesn't use.
+ * Git also makes sure that the passed arguments are valid, so there's
+ * no need for double-checking.
+ */
+
+#include "../../git-compat-util.h"
+#include "pthread.h"
+
+#include <errno.h>
+#include <limits.h>
+
+static unsigned __stdcall win32_start_routine(void *arg)
+{
+ pthread_t *thread = arg;
+ thread->arg = thread->start_routine(thread->arg);
+ return 0;
+}
+
+int pthread_create(pthread_t *thread, const void *unused,
+ void *(*start_routine)(void*), void *arg)
+{
+ thread->arg = arg;
+ thread->start_routine = start_routine;
+ thread->handle = (HANDLE)
+ _beginthreadex(NULL, 0, win32_start_routine, thread, 0, NULL);
+
+ if (!thread->handle)
+ return errno;
+ else
+ return 0;
+}
+
+int win32_pthread_join(pthread_t *thread, void **value_ptr)
+{
+ DWORD result = WaitForSingleObject(thread->handle, INFINITE);
+ switch (result) {
+ case WAIT_OBJECT_0:
+ if (value_ptr)
+ *value_ptr = thread->arg;
+ return 0;
+ case WAIT_ABANDONED:
+ return EINVAL;
+ default:
+ return err_win_to_posix(GetLastError());
+ }
+}
+
+int pthread_cond_init(pthread_cond_t *cond, const void *unused)
+{
+ cond->waiters = 0;
+ cond->was_broadcast = 0;
+ InitializeCriticalSection(&cond->waiters_lock);
+
+ cond->sema = CreateSemaphore(NULL, 0, LONG_MAX, NULL);
+ if (!cond->sema)
+ die("CreateSemaphore() failed");
+
+ cond->continue_broadcast = CreateEvent(NULL, /* security */
+ FALSE, /* auto-reset */
+ FALSE, /* not signaled */
+ NULL); /* name */
+ if (!cond->continue_broadcast)
+ die("CreateEvent() failed");
+
+ return 0;
+}
+
+int pthread_cond_destroy(pthread_cond_t *cond)
+{
+ CloseHandle(cond->sema);
+ CloseHandle(cond->continue_broadcast);
+ DeleteCriticalSection(&cond->waiters_lock);
+ return 0;
+}
+
+int pthread_cond_wait(pthread_cond_t *cond, CRITICAL_SECTION *mutex)
+{
+ int last_waiter;
+
+ EnterCriticalSection(&cond->waiters_lock);
+ cond->waiters++;
+ LeaveCriticalSection(&cond->waiters_lock);
+
+ /*
+ * Unlock external mutex and wait for signal.
+ * NOTE: we've held mutex locked long enough to increment
+ * waiters count above, so there's no problem with
+ * leaving mutex unlocked before we wait on semaphore.
+ */
+ LeaveCriticalSection(mutex);
+
+ /* let's wait - ignore return value */
+ WaitForSingleObject(cond->sema, INFINITE);
+
+ /*
+ * Decrease waiters count. If we are the last waiter, then we must
+ * notify the broadcasting thread that it can continue.
+ * But if we continued due to cond_signal, we do not have to do that
+ * because the signaling thread knows that only one waiter continued.
+ */
+ EnterCriticalSection(&cond->waiters_lock);
+ cond->waiters--;
+ last_waiter = cond->was_broadcast && cond->waiters == 0;
+ LeaveCriticalSection(&cond->waiters_lock);
+
+ if (last_waiter) {
+ /*
+ * cond_broadcast was issued while mutex was held. This means
+ * that all other waiters have continued, but are contending
+ * for the mutex at the end of this function because the
+ * broadcasting thread did not leave cond_broadcast, yet.
+ * (This is so that it can be sure that each waiter has
+ * consumed exactly one slice of the semaphor.)
+ * The last waiter must tell the broadcasting thread that it
+ * can go on.
+ */
+ SetEvent(cond->continue_broadcast);
+ /*
+ * Now we go on to contend with all other waiters for
+ * the mutex. Auf in den Kampf!
+ */
+ }
+ /* lock external mutex again */
+ EnterCriticalSection(mutex);
+
+ return 0;
+}
+
+/*
+ * IMPORTANT: This implementation requires that pthread_cond_signal
+ * is called while the mutex is held that is used in the corresponding
+ * pthread_cond_wait calls!
+ */
+int pthread_cond_signal(pthread_cond_t *cond)
+{
+ int have_waiters;
+
+ EnterCriticalSection(&cond->waiters_lock);
+ have_waiters = cond->waiters > 0;
+ LeaveCriticalSection(&cond->waiters_lock);
+
+ /*
+ * Signal only when there are waiters
+ */
+ if (have_waiters)
+ return ReleaseSemaphore(cond->sema, 1, NULL) ?
+ 0 : err_win_to_posix(GetLastError());
+ else
+ return 0;
+}
+
+/*
+ * DOUBLY IMPORTANT: This implementation requires that pthread_cond_broadcast
+ * is called while the mutex is held that is used in the corresponding
+ * pthread_cond_wait calls!
+ */
+int pthread_cond_broadcast(pthread_cond_t *cond)
+{
+ EnterCriticalSection(&cond->waiters_lock);
+
+ if ((cond->was_broadcast = cond->waiters > 0)) {
+ /* wake up all waiters */
+ ReleaseSemaphore(cond->sema, cond->waiters, NULL);
+ LeaveCriticalSection(&cond->waiters_lock);
+ /*
+ * At this point all waiters continue. Each one takes its
+ * slice of the semaphor. Now it's our turn to wait: Since
+ * the external mutex is held, no thread can leave cond_wait,
+ * yet. For this reason, we can be sure that no thread gets
+ * a chance to eat *more* than one slice. OTOH, it means
+ * that the last waiter must send us a wake-up.
+ */
+ WaitForSingleObject(cond->continue_broadcast, INFINITE);
+ /*
+ * Since the external mutex is held, no thread can enter
+ * cond_wait, and, hence, it is safe to reset this flag
+ * without cond->waiters_lock held.
+ */
+ cond->was_broadcast = 0;
+ } else {
+ LeaveCriticalSection(&cond->waiters_lock);
+ }
+ return 0;
+}
diff --git a/compat/win32/pthread.h b/compat/win32/pthread.h
new file mode 100644
index 0000000..c72f100
--- /dev/null
+++ b/compat/win32/pthread.h
@@ -0,0 +1,68 @@
+/*
+ * Header used to adapt pthread-based POSIX code to Windows API threads.
+ *
+ * Copyright (C) 2009 Andrzej K. Haczewski <ahaczewski@gmail.com>
+ */
+
+#ifndef PTHREAD_H
+#define PTHREAD_H
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>
+
+/*
+ * Defines that adapt Windows API threads to pthreads API
+ */
+#define pthread_mutex_t CRITICAL_SECTION
+
+#define pthread_mutex_init(a,b) InitializeCriticalSection((a))
+#define pthread_mutex_destroy(a) DeleteCriticalSection((a))
+#define pthread_mutex_lock EnterCriticalSection
+#define pthread_mutex_unlock LeaveCriticalSection
+
+/*
+ * Implement simple condition variable for Windows threads, based on ACE
+ * implementation.
+ *
+ * See original implementation: http://bit.ly/1vkDjo
+ * ACE homepage: http://www.cse.wustl.edu/~schmidt/ACE.html
+ * See also: http://www.cse.wustl.edu/~schmidt/win32-cv-1.html
+ */
+typedef struct {
+ LONG waiters;
+ int was_broadcast;
+ CRITICAL_SECTION waiters_lock;
+ HANDLE sema;
+ HANDLE continue_broadcast;
+} pthread_cond_t;
+
+extern int pthread_cond_init(pthread_cond_t *cond, const void *unused);
+extern int pthread_cond_destroy(pthread_cond_t *cond);
+extern int pthread_cond_wait(pthread_cond_t *cond, CRITICAL_SECTION *mutex);
+extern int pthread_cond_signal(pthread_cond_t *cond);
+extern int pthread_cond_broadcast(pthread_cond_t *cond);
+
+/*
+ * Simple thread creation implementation using pthread API
+ */
+typedef struct {
+ HANDLE handle;
+ void *(*start_routine)(void*);
+ void *arg;
+} pthread_t;
+
+extern int pthread_create(pthread_t *thread, const void *unused,
+ void *(*start_routine)(void*), void *arg);
+
+/*
+ * To avoid the need of copying a struct, we use small macro wrapper to pass
+ * pointer to win32_pthread_join instead.
+ */
+#define pthread_join(a, b) win32_pthread_join(&(a), (b))
+
+extern int win32_pthread_join(pthread_t *thread, void **value_ptr);
+
+#endif /* PTHREAD_H */