win32: add native wrappers for pthread functions

Off by default, use --enable-win32-internal-pthreads .

This probably still needs a lot more testing. It also won't work on
Windows XP.

osdep/win32/include/pthread.h

@@ -0,0 +1,82 @@
+#ifndef MP_WRAP_PTHREAD_H_
+#define MP_WRAP_PTHREAD_H_
+
+#include <windows.h>
+
+#include <sys/types.h>
+
+// Note: all pthread functions are mangled to make static linking easier.
+#define pthread_once m_pthread_once
+#define pthread_mutex_destroy m_pthread_mutex_destroy
+#define pthread_mutex_init m_pthread_mutex_init
+#define pthread_mutex_lock m_pthread_mutex_lock
+#define pthread_mutex_unlock m_pthread_mutex_unlock
+#define pthread_cond_timedwait m_pthread_cond_timedwait
+#define pthread_cond_wait m_pthread_cond_wait
+#define pthread_self m_pthread_self
+#define pthread_exit m_pthread_exit
+#define pthread_join m_pthread_join
+#define pthread_detach m_pthread_detach
+#define pthread_create m_pthread_create
+
+#define pthread_once_t INIT_ONCE
+#define PTHREAD_ONCE_INIT INIT_ONCE_STATIC_INIT
+
+int pthread_once(pthread_once_t *once_control, void (*init_routine)(void));
+
+typedef struct {
+    volatile LONG requires_init;
+    CRITICAL_SECTION cs;
+} pthread_mutex_t;
+
+#define PTHREAD_MUTEX_INITIALIZER {1}
+
+#define pthread_mutexattr_t int
+#define pthread_mutexattr_destroy(attr) (void)0
+#define pthread_mutexattr_init(attr) (*(attr) = 0)
+#define pthread_mutexattr_settype(attr, type) (void)0
+// CRITICAL_SECTION is always recursive
+#define PTHREAD_MUTEX_RECURSIVE 0
+
+int pthread_mutex_destroy(pthread_mutex_t *mutex);
+int pthread_mutex_init(pthread_mutex_t *restrict mutex,
+                       const pthread_mutexattr_t *restrict attr);
+
+int pthread_mutex_lock(pthread_mutex_t *mutex);
+int pthread_mutex_unlock(pthread_mutex_t *mutex);
+
+#define pthread_cond_t CONDITION_VARIABLE
+#define pthread_condattr_t int
+
+#define PTHREAD_COND_INITIALIZER CONDITION_VARIABLE_INIT
+
+#define pthread_cond_init(cond, attr) InitializeConditionVariable(cond)
+#define pthread_cond_destroy(c) (void)0
+#define pthread_cond_broadcast(cond) WakeAllConditionVariable(cond)
+#define pthread_cond_signal(cond) WakeConditionVariable(cond)
+
+int pthread_cond_timedwait(pthread_cond_t *restrict cond,
+                           pthread_mutex_t *restrict mutex,
+                           const struct timespec *restrict abstime);
+int pthread_cond_wait(pthread_cond_t *restrict cond,
+                      pthread_mutex_t *restrict mutex);
+
+// Unusual, but allowed by POSIX.
+typedef struct {
+    DWORD id;
+    struct m_thread_info *info;
+} pthread_t;
+
+#define pthread_equal(a, b) ((a).id == (b).id)
+
+pthread_t pthread_self(void);
+void pthread_exit(void *retval);
+int pthread_join(pthread_t thread, void **retval);
+int pthread_detach(pthread_t thread);
+
+#define pthread_attr_t int
+
+int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
+                   void *(*start_routine) (void *), void *arg);
+
+#endif

osdep/win32/include/semaphore.h

@@ -0,0 +1,29 @@
+#ifndef MP_WRAP_SEMAPHORE_H_
+#define MP_WRAP_SEMAPHORE_H_
+
+#include <pthread.h>
+
+// See pthread.h for rationale.
+#define sem_init m_sem_init
+#define sem_destroy m_sem_destroy
+#define sem_wait m_sem_wait
+#define sem_trywait m_sem_trywait
+#define sem_timedwait m_sem_timedwait
+#define sem_post m_sem_post
+
+#define SEM_VALUE_MAX 100
+
+typedef struct {
+    pthread_mutex_t lock;
+    pthread_cond_t wakeup;
+    unsigned int value;
+} sem_t;
+
+int sem_init(sem_t *sem, int pshared, unsigned int value);
+int sem_destroy(sem_t *sem);
+int sem_wait(sem_t *sem);
+int sem_trywait(sem_t *sem);
+int sem_timedwait(sem_t *sem, const struct timespec *abs_timeout);
+int sem_post(sem_t *sem);
+
+#endif

osdep/win32/pthread.c

@@ -0,0 +1,269 @@
+/* Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <pthread.h>
+#include <semaphore.h>
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+#include <sys/time.h>
+
+// We keep this around to avoid active waiting while handling static
+// initializers.
+static pthread_once_t init_cs_once = PTHREAD_ONCE_INIT;
+static CRITICAL_SECTION init_cs;
+
+static void init_init_cs(void)
+{
+    InitializeCriticalSection(&init_cs);
+}
+
+static void init_lock(void)
+{
+    pthread_once(&init_cs_once, init_init_cs);
+    EnterCriticalSection(&init_cs);
+}
+
+static void init_unlock(void)
+{
+    LeaveCriticalSection(&init_cs);
+}
+
+int pthread_once(pthread_once_t *once_control, void (*init_routine)(void))
+{
+    BOOL pending;
+    if (!InitOnceBeginInitialize(once_control, 0, &pending, NULL))
+        abort();
+    if (pending) {
+        init_routine();
+        InitOnceComplete(once_control, 0, NULL);
+    }
+    return 0;
+}
+
+int pthread_mutex_destroy(pthread_mutex_t *mutex)
+{
+    DeleteCriticalSection(&mutex->cs);
+    return 0;
+}
+
+int pthread_mutex_init(pthread_mutex_t *restrict mutex,
+                       const pthread_mutexattr_t *restrict attr)
+{
+    InitializeCriticalSection(&mutex->cs);
+    return 0;
+}
+
+int pthread_mutex_lock(pthread_mutex_t *mutex)
+{
+    if (mutex->requires_init) {
+        init_lock();
+        if (mutex->requires_init)
+            InitializeCriticalSection(&mutex->cs);
+        _InterlockedAnd(&mutex->requires_init, 0);
+        init_unlock();
+    }
+    EnterCriticalSection(&mutex->cs);
+    return 0;
+}
+
+int pthread_mutex_unlock(pthread_mutex_t *mutex)
+{
+    LeaveCriticalSection(&mutex->cs);
+    return 0;
+}
+
+static int cond_wait(pthread_cond_t *restrict cond,
+                     pthread_mutex_t *restrict mutex,
+                     DWORD ms)
+{
+    return SleepConditionVariableCS(cond, &mutex->cs, ms) ? 0 : ETIMEDOUT;
+}
+
+int pthread_cond_timedwait(pthread_cond_t *restrict cond,
+                           pthread_mutex_t *restrict mutex,
+                           const struct timespec *restrict abstime)
+{
+    // mpv uses mingw's gettimeofday() as time source too.
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    DWORD timeout_ms = 0;
+    if (abstime->tv_sec >= INT64_MAX / 10000) {
+        timeout_ms = INFINITE;
+    } else if (abstime->tv_sec >= tv.tv_sec) {
+        long long msec = (abstime->tv_sec - tv.tv_sec) * 1000LL +
+            abstime->tv_nsec / 1000LL / 1000LL - tv.tv_usec / 1000LL;
+        if (msec > INT_MAX) {
+            timeout_ms = INFINITE;
+        } else if (msec > 0) {
+            timeout_ms = msec;
+        }
+    }
+    return cond_wait(cond, mutex, timeout_ms);
+}
+
+int pthread_cond_wait(pthread_cond_t *restrict cond,
+                      pthread_mutex_t *restrict mutex)
+{
+    return cond_wait(cond, mutex, INFINITE);
+}
+
+struct m_thread_info {
+    HANDLE handle;
+    void *(*user_fn)(void *);
+    void *user_arg;
+    void *res;
+};
+
+// Assuming __thread maps to __declspec(thread)
+static __thread struct m_thread_info *self;
+
+pthread_t pthread_self(void)
+{
+    return (pthread_t){GetCurrentThreadId(), self};
+}
+
+void pthread_exit(void *retval)
+{
+    if (!self)
+        abort(); // not started with pthread_create
+    self->res = retval;
+    if (!self->handle) {
+        // detached case
+        free(self);
+        self = NULL;
+    }
+    ExitThread(0);
+}
+
+int pthread_join(pthread_t thread, void **retval)
+{
+    if (!thread.info)
+        abort(); // not started with pthread_create
+    HANDLE h = thread.info->handle;
+    if (!h)
+        abort(); // thread was detached
+    WaitForSingleObject(h, INFINITE);
+    CloseHandle(h);
+    if (retval)
+        *retval = thread.info->res;
+    free(thread.info);
+    return 0;
+}
+
+int pthread_detach(pthread_t thread)
+{
+    if (!pthread_equal(thread, pthread_self()))
+        abort(); // restriction of this wrapper
+    if (!thread.info)
+        abort(); // not started with pthread_create
+    if (!thread.info->handle)
+        abort(); // already deatched
+    CloseHandle(thread.info->handle);
+    thread.info->handle = NULL;
+    return 0;
+}
+
+static DWORD WINAPI run_thread(LPVOID lpParameter)
+{
+    struct m_thread_info *info = lpParameter;
+    self = info;
+    pthread_exit(info->user_fn(info->user_arg));
+    abort(); // not reached
+}
+
+int pthread_create(pthread_t *thread, const pthread_attr_t *attr,
+                   void *(*start_routine) (void *), void *arg)
+{
+    struct m_thread_info *info = calloc(1, sizeof(*info));
+    if (!info)
+        return EAGAIN;
+    info->user_fn = start_routine;
+    info->user_arg = arg;
+    HANDLE h = CreateThread(NULL, 0, run_thread, info, CREATE_SUSPENDED, NULL);
+    if (!h) {
+        free(info);
+        return EAGAIN;
+    }
+    info->handle = h;
+    *thread = (pthread_t){GetThreadId(h), info};
+    ResumeThread(h);
+    return 0;
+}
+
+int sem_init(sem_t *sem, int pshared, unsigned int value)
+{
+    if (pshared)
+        abort(); // unsupported
+    pthread_mutex_init(&sem->lock, NULL);
+    pthread_cond_init(&sem->wakeup, NULL);
+    sem->value = value;
+    return 0;
+}
+
+int sem_destroy(sem_t *sem)
+{
+    pthread_mutex_destroy(&sem->lock);
+    pthread_cond_destroy(&sem->wakeup);
+    return 0;
+}
+
+int sem_wait(sem_t *sem)
+{
+    pthread_mutex_lock(&sem->lock);
+    while (!sem->value)
+        pthread_cond_wait(&sem->wakeup, &sem->lock);
+    sem->value -= 1;
+    pthread_mutex_unlock(&sem->lock);
+    return 0;
+}
+
+int sem_trywait(sem_t *sem)
+{
+    pthread_mutex_lock(&sem->lock);
+    int r;
+    if (sem->value > 0) {
+        sem->value -= 1;
+        r = 0;
+    } else {
+        errno = EAGAIN;
+        r = -1;
+    }
+    pthread_mutex_unlock(&sem->lock);
+    return r;
+}
+
+int sem_timedwait(sem_t *sem, const struct timespec *abs_timeout)
+{
+    pthread_mutex_lock(&sem->lock);
+    while (!sem->value) {
+        int err = pthread_cond_timedwait(&sem->wakeup, &sem->lock, abs_timeout);
+        if (err) {
+            pthread_mutex_unlock(&sem->lock);
+            errno = err;
+            return -1;
+        }
+    }
+    sem->value -= 1;
+    pthread_mutex_unlock(&sem->lock);
+    return 0;
+}
+
+int sem_post(sem_t *sem)
+{
+    pthread_mutex_lock(&sem->lock);
+    sem->value += 1;
+    pthread_cond_broadcast(&sem->wakeup);
+    pthread_mutex_unlock(&sem->lock);
+    return 0;
+}

waftools/checks/custom.py

@@ -20,6 +20,12 @@ def check_pthread_flag(ctx, dependency_identifier):
     return False
 
 def check_pthreads(ctx, dependency_identifier):
+    if ctx.dependency_satisfied('win32-internal-pthreads'):
+        h = ctx.path.find_node('osdep/win32/include').abspath()
+        # define IN_WINPTHREAD to workaround mingw stupidity (we never want it
+        # to define features specific to its own pthread stuff)
+        ctx.env.CFLAGS += ['-isystem', h, '-I', h, '-D_WIN32_WINNT=0x600', '-DIN_WINPTHREAD']
+        return True
     if check_pthread_flag(ctx, dependency_identifier):
         return True
     platform_cflags = {

wscript

@@ -124,6 +124,13 @@ main_dependencies = [
         'req': True,
         'fmsg': 'Unable to find either POSIX or MinGW-w64 environment, ' \
                 'or compiler does not work.',
+    }, {
+        'name': '--win32-internal-pthreads',
+        'desc': 'internal pthread wrapper for win32 (Vista+)',
+        'deps_neg': [ 'posix' ],
+        'deps': [ 'mingw' ],
+        'func': check_true,
+        'default': 'disable',
     }, {
         'name': 'pthreads',
         'desc': 'POSIX threads',

wscript_build.py

@@ -392,6 +392,7 @@ def build(ctx):
         ( "osdep/w32_keyboard.c",                "os-win32" ),
         ( "osdep/w32_keyboard.c",                "os-cygwin" ),
         ( "osdep/mpv.rc",                        "win32-executable" ),
+        ( "osdep/win32/pthread.c",               "win32-internal-pthreads"),
 
         ## tree_allocator
         "ta/ta.c", "ta/ta_talloc.c", "ta/ta_utils.c"