w32threads: support for frame multithreading

Replace our incomplete w32threads implementation with x264's pthreads
w32threads wrapper.
Relicensed to LGPL with kind permission by Pegasys Inc.

Signed-off-by: Janne Grunau <janne-libav@jannau.net>

10 files changed, 230 insertions, 190 deletions

diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 04a504be74..4c3eca379b 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -645,7 +645,7 @@ OBJS-$(CONFIG_TEXT2MOVSUB_BSF)            += movsub_bsf.o
 
 # thread libraries
 OBJS-$(HAVE_PTHREADS)                  += pthread.o
-OBJS-$(HAVE_W32THREADS)                += w32thread.o
+OBJS-$(HAVE_W32THREADS)                += pthread.o
 
 OBJS-$(CONFIG_MLIB)                    += mlib/dsputil_mlib.o           \
 
diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index b1204c07b8..1faaaa6802 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -688,7 +688,7 @@ static av_always_inline void hl_motion(H264Context *h, uint8_t *dest_y, uint8_t
 
     assert(IS_INTER(mb_type));
 
-    if(HAVE_PTHREADS && (s->avctx->active_thread_type & FF_THREAD_FRAME))
+    if(HAVE_THREADS && (s->avctx->active_thread_type & FF_THREAD_FRAME))
         await_references(h);
     prefetch_motion(h, 0, pixel_shift, chroma444);
 
diff --git a/libavcodec/h264_direct.c b/libavcodec/h264_direct.c
index 4e05937ab4..a953728a12 100644
--- a/libavcodec/h264_direct.c
+++ b/libavcodec/h264_direct.c
@@ -147,7 +147,7 @@ static void await_reference_mb_row(H264Context * const h, Picture *ref, int mb_y
     int ref_field_picture = ref->field_picture;
     int ref_height = 16*h->s.mb_height >> ref_field_picture;
 
-    if(!HAVE_PTHREADS || !(h->s.avctx->active_thread_type&FF_THREAD_FRAME))
+    if(!HAVE_THREADS || !(h->s.avctx->active_thread_type&FF_THREAD_FRAME))
         return;
 
     //FIXME it can be safe to access mb stuff
diff --git a/libavcodec/mpeg12.c b/libavcodec/mpeg12.c
index 5734ab8674..4e95e02a9b 100644
--- a/libavcodec/mpeg12.c
+++ b/libavcodec/mpeg12.c
@@ -1596,7 +1596,7 @@ static int mpeg_field_start(MpegEncContext *s, const uint8_t *buf, int buf_size)
 
         *s->current_picture_ptr->f.pan_scan = s1->pan_scan;
 
-        if (HAVE_PTHREADS && (avctx->active_thread_type & FF_THREAD_FRAME))
+        if (HAVE_THREADS && (avctx->active_thread_type & FF_THREAD_FRAME))
             ff_thread_finish_setup(avctx);
     } else { // second field
         int i;
diff --git a/libavcodec/mpegvideo.c b/libavcodec/mpegvideo.c
index b8ac2ceb3d..cbc7d99818 100644
--- a/libavcodec/mpegvideo.c
+++ b/libavcodec/mpegvideo.c
@@ -2119,7 +2119,7 @@ void MPV_decode_mb_internal(MpegEncContext *s, DCTELEM block[12][64],
             /* decoding or more than one mb_type (MC was already done otherwise) */
             if(!s->encoding){
 
-                if(HAVE_PTHREADS && s->avctx->active_thread_type&FF_THREAD_FRAME) {
+                if(HAVE_THREADS && s->avctx->active_thread_type&FF_THREAD_FRAME) {
                     if (s->mv_dir & MV_DIR_FORWARD) {
                         ff_thread_await_progress((AVFrame*)s->last_picture_ptr, MPV_lowest_referenced_row(s, 0), 0);
                     }
diff --git a/libavcodec/pthread.c b/libavcodec/pthread.c
index 42f4382e7d..d5129dcc3e 100644
--- a/libavcodec/pthread.c
+++ b/libavcodec/pthread.c
@@ -29,11 +29,16 @@
  * @see doc/multithreading.txt
  */
 
-#include <pthread.h>
-
+#include "config.h"
 #include "avcodec.h"
 #include "thread.h"
 
+#if HAVE_PTHREADS
+#include <pthread.h>
+#elif HAVE_W32THREADS
+#include "w32pthreads.h"
+#endif
+
 typedef int (action_func)(AVCodecContext *c, void *arg);
 typedef int (action_func2)(AVCodecContext *c, void *arg, int jobnr, int threadnr);
 
@@ -898,6 +903,10 @@ int ff_thread_init(AVCodecContext *avctx)
         return -1;
     }
 
+#if HAVE_W32THREADS
+    w32thread_init();
+#endif
+
     if (avctx->codec) {
         validate_thread_parameters(avctx);
 
diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 1c95fa1236..ac4de7da4a 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -723,7 +723,7 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
     avctx->pkt = avpkt;
 
     if((avctx->codec->capabilities & CODEC_CAP_DELAY) || avpkt->size || (avctx->active_thread_type&FF_THREAD_FRAME)){
-        if (HAVE_PTHREADS && avctx->active_thread_type&FF_THREAD_FRAME)
+        if (HAVE_THREADS && avctx->active_thread_type&FF_THREAD_FRAME)
              ret = ff_thread_decode_frame(avctx, picture, got_picture_ptr,
                                           avpkt);
         else {
@@ -1089,7 +1089,7 @@ const char *avcodec_license(void)
 
 void avcodec_flush_buffers(AVCodecContext *avctx)
 {
-    if(HAVE_PTHREADS && avctx->active_thread_type&FF_THREAD_FRAME)
+    if(HAVE_THREADS && avctx->active_thread_type&FF_THREAD_FRAME)
         ff_thread_flush(avctx);
     else if(avctx->codec->flush)
         avctx->codec->flush(avctx);
@@ -1277,7 +1277,7 @@ unsigned int ff_toupper4(unsigned int x)
             + (toupper((x>>24)&0xFF)<<24);
 }
 
-#if !HAVE_PTHREADS
+#if !HAVE_THREADS
 
 int ff_thread_get_buffer(AVCodecContext *avctx, AVFrame *f)
 {
diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
index 462a482f42..9262c27f05 100644
--- a/libavcodec/vp3.c
+++ b/libavcodec/vp3.c
@@ -1316,7 +1316,7 @@ static void vp3_draw_horiz_band(Vp3DecodeContext *s, int y)
     int h, cy;
     int offset[4];
 
-    if (HAVE_PTHREADS && s->avctx->active_thread_type&FF_THREAD_FRAME) {
+    if (HAVE_THREADS && s->avctx->active_thread_type&FF_THREAD_FRAME) {
         int y_flipped = s->flipped_image ? s->avctx->height-y : y;
 
         // At the end of the frame, report INT_MAX instead of the height of the frame.
@@ -1400,7 +1400,7 @@ static void render_slice(Vp3DecodeContext *s, int slice)
         int fragment_width    = s->fragment_width[!!plane];
         int fragment_height   = s->fragment_height[!!plane];
         int fragment_start    = s->fragment_start[plane];
-        int do_await          = !plane && HAVE_PTHREADS && (s->avctx->active_thread_type&FF_THREAD_FRAME);
+        int do_await          = !plane && HAVE_THREADS && (s->avctx->active_thread_type&FF_THREAD_FRAME);
 
         if (!s->flipped_image) stride = -stride;
         if (CONFIG_GRAY && plane && (s->avctx->flags & CODEC_FLAG_GRAY))
@@ -1965,7 +1965,7 @@ static int vp3_decode_frame(AVCodecContext *avctx,
     *data_size=sizeof(AVFrame);
     *(AVFrame*)data= s->current_frame;
 
-    if (!HAVE_PTHREADS || !(s->avctx->active_thread_type&FF_THREAD_FRAME))
+    if (!HAVE_THREADS || !(s->avctx->active_thread_type&FF_THREAD_FRAME))
         update_frames(avctx);
 
     return buf_size;
@@ -1973,7 +1973,7 @@ static int vp3_decode_frame(AVCodecContext *avctx,
 error:
     ff_thread_report_progress(&s->current_frame, INT_MAX, 0);
 
-    if (!HAVE_PTHREADS || !(s->avctx->active_thread_type&FF_THREAD_FRAME))
+    if (!HAVE_THREADS || !(s->avctx->active_thread_type&FF_THREAD_FRAME))
         avctx->release_buffer(avctx, &s->current_frame);
 
     return -1;
diff --git a/libavcodec/w32pthreads.h b/libavcodec/w32pthreads.h
new file mode 100644
index 0000000000..7774817518
--- /dev/null
+++ b/libavcodec/w32pthreads.h
@@ -0,0 +1,207 @@
+/*
+ * Copyright (C) 2010-2011 x264 project
+ *
+ * Authors: Steven Walters <kemuri9@gmail.com>
+ *          Pegasys Inc. <http://www.pegasys-inc.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * w32threads to pthreads wrapper
+ */
+
+#ifndef AVCODEC_W32PTHREADS_H
+#define AVCODEC_W32PTHREADS_H
+
+/* Build up a pthread-like API using underlying Windows API. Have only static
+ * methods so as to not conflict with a potentially linked in pthread-win32
+ * library.
+ * As most functions here are used without checking return values,
+ * only implement return values as necessary. */
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <process.h>
+
+typedef struct {
+    void *handle;
+    void *(*func)(void* arg);
+    void *arg;
+    void *ret;
+} pthread_t;
+
+/* the conditional variable api for windows 6.0+ uses critical sections and
+ * not mutexes */
+typedef CRITICAL_SECTION pthread_mutex_t;
+
+/* This is the CONDITIONAL_VARIABLE typedef for using Window's native
+ * conditional variables on kernels 6.0+.
+ * MinGW does not currently have this typedef. */
+typedef struct {
+    void *ptr;
+} pthread_cond_t;
+
+/* function pointers to conditional variable API on windows 6.0+ kernels */
+static void (WINAPI *cond_broadcast)(pthread_cond_t *cond);
+static void (WINAPI *cond_init)(pthread_cond_t *cond);
+static void (WINAPI *cond_signal)(pthread_cond_t *cond);
+static BOOL (WINAPI *cond_wait)(pthread_cond_t *cond, pthread_mutex_t *mutex,
+                                DWORD milliseconds);
+
+static unsigned __stdcall attribute_align_arg win32thread_worker(void *arg)
+{
+    pthread_t *h = arg;
+    h->ret = h->func(h->arg);
+    return 0;
+}
+
+static int pthread_create(pthread_t *thread, const void *unused_attr,
+                          void *(*start_routine)(void*), void *arg)
+{
+    thread->func   = start_routine;
+    thread->arg    = arg;
+    thread->handle = (void*)_beginthreadex(NULL, 0, win32thread_worker, thread,
+                                           0, NULL);
+    return !thread->handle;
+}
+
+static void pthread_join(pthread_t thread, void **value_ptr)
+{
+    DWORD ret = WaitForSingleObject(thread.handle, INFINITE);
+    if (ret != WAIT_OBJECT_0)
+        return;
+    if (value_ptr)
+        *value_ptr = thread.ret;
+    CloseHandle(thread.handle);
+}
+
+#define pthread_mutex_init(m, a) InitializeCriticalSection(m)
+#define pthread_mutex_destroy(m) DeleteCriticalSection(m)
+#define pthread_mutex_lock(m)    EnterCriticalSection(m)
+#define pthread_mutex_unlock(m)  LeaveCriticalSection(m)
+
+/* for pre-Windows 6.0 platforms we need to define and use our own condition
+ * variable and api */
+typedef struct {
+    pthread_mutex_t mtx_waiter_count;
+    volatile int waiter_count;
+    HANDLE semaphore;
+} win32_cond_t;
+
+static void pthread_cond_init(pthread_cond_t *cond, const void *unused_attr)
+{
+    win32_cond_t *win32_cond = NULL;
+    if (cond_init) {
+        cond_init(cond);
+        return;
+    }
+
+    /* non native condition variables */
+    win32_cond = av_mallocz(sizeof(win32_cond_t));
+    if (!win32_cond)
+        return;
+    cond->ptr = win32_cond;
+    win32_cond->semaphore = CreateSemaphore(NULL, 0, 0x7fffffff, NULL);
+    if (!win32_cond->semaphore)
+        return;
+
+    pthread_mutex_init(&win32_cond->mtx_waiter_count, NULL);
+}
+
+static void pthread_cond_destroy(pthread_cond_t *cond)
+{
+    win32_cond_t *win32_cond = cond->ptr;
+    /* native condition variables do not destroy */
+    if (cond_init)
+        return;
+
+    /* non native condition variables */
+    CloseHandle(win32_cond->semaphore);
+    pthread_mutex_destroy(&win32_cond->mtx_waiter_count);
+    av_freep(&win32_cond);
+    cond->ptr = NULL;
+}
+
+static void pthread_cond_broadcast(pthread_cond_t *cond)
+{
+    win32_cond_t *win32_cond = cond->ptr;
+    if (cond_broadcast) {
+        cond_broadcast(cond);
+        return;
+    }
+
+    /* non native condition variables */
+    pthread_mutex_lock(&win32_cond->mtx_waiter_count);
+    if (win32_cond->waiter_count) {
+        ReleaseSemaphore(win32_cond->semaphore, win32_cond->waiter_count, NULL);
+        win32_cond->waiter_count = 0;
+    }
+    pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
+}
+
+static void pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
+{
+    win32_cond_t *win32_cond = cond->ptr;
+    if (cond_wait) {
+        cond_wait(cond, mutex, INFINITE);
+        return;
+    }
+
+    /* non native condition variables */
+    pthread_mutex_lock(&win32_cond->mtx_waiter_count);
+    win32_cond->waiter_count++;
+    pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
+
+    pthread_mutex_unlock(mutex);
+    WaitForSingleObject(win32_cond->semaphore, INFINITE);
+    pthread_mutex_lock(mutex);
+}
+
+static void pthread_cond_signal(pthread_cond_t *cond)
+{
+    win32_cond_t *win32_cond = cond->ptr;
+    if (cond_signal) {
+        cond_signal(cond);
+        return;
+    }
+
+    /* non-native condition variables */
+    pthread_mutex_lock(&win32_cond->mtx_waiter_count);
+    if (win32_cond->waiter_count) {
+        ReleaseSemaphore(win32_cond->semaphore, 1, NULL);
+        win32_cond->waiter_count--;
+    }
+    pthread_mutex_unlock(&win32_cond->mtx_waiter_count);
+}
+
+static void w32thread_init(void)
+{
+    HANDLE kernel_dll = GetModuleHandle(TEXT("kernel32.dll"));
+    /* if one is available, then they should all be available */
+    cond_init      =
+        (void*)GetProcAddress(kernel_dll, "InitializeConditionVariable");
+    cond_broadcast =
+        (void*)GetProcAddress(kernel_dll, "WakeAllConditionVariable");
+    cond_signal    =
+        (void*)GetProcAddress(kernel_dll, "WakeConditionVariable");
+    cond_wait      =
+        (void*)GetProcAddress(kernel_dll, "SleepConditionVariableCS");
+}
+
+#endif /* AVCODEC_W32PTHREADS_H */
diff --git a/libavcodec/w32thread.c b/libavcodec/w32thread.c
deleted file mode 100644
index ceaafebc80..0000000000
--- a/libavcodec/w32thread.c
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
- *
- * This file is part of Libav.
- *
- * Libav is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * Libav is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with Libav; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-//#define DEBUG
-
-#include "avcodec.h"
-#include "thread.h"
-
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#include <process.h>
-
-typedef struct ThreadContext{
-    AVCodecContext *avctx;
-    HANDLE thread;
-    HANDLE work_sem;
-    HANDLE job_sem;
-    HANDLE done_sem;
-    int (*func)(AVCodecContext *c, void *arg);
-    int (*func2)(AVCodecContext *c, void *arg, int, int);
-    void *arg;
-    int argsize;
-    int *jobnr;
-    int *ret;
-    int threadnr;
-}ThreadContext;
-
-
-static unsigned WINAPI attribute_align_arg thread_func(void *v){
-    ThreadContext *c= v;
-
-    for(;;){
-        int ret, jobnr;
-//printf("thread_func %X enter wait\n", (int)v); fflush(stdout);
-        WaitForSingleObject(c->work_sem, INFINITE);
-        // avoid trying to access jobnr if we should quit
-        if (!c->func && !c->func2)
-            break;
-        WaitForSingleObject(c->job_sem, INFINITE);
-        jobnr = (*c->jobnr)++;
-        ReleaseSemaphore(c->job_sem, 1, 0);
-//printf("thread_func %X after wait (func=%X)\n", (int)v, (int)c->func); fflush(stdout);
-        if(c->func)
-            ret= c->func(c->avctx, (uint8_t *)c->arg + jobnr*c->argsize);
-        else
-            ret= c->func2(c->avctx, c->arg, jobnr, c->threadnr);
-        if (c->ret)
-            c->ret[jobnr] = ret;
-//printf("thread_func %X signal complete\n", (int)v); fflush(stdout);
-        ReleaseSemaphore(c->done_sem, 1, 0);
-    }
-
-    return 0;
-}
-
-/**
- * Free what has been allocated by ff_thread_init().
- * Must be called after decoding has finished, especially do not call while avcodec_thread_execute() is running.
- */
-void ff_thread_free(AVCodecContext *s){
-    ThreadContext *c= s->thread_opaque;
-    int i;
-
-    for(i=0; i<s->thread_count; i++){
-
-        c[i].func= NULL;
-        c[i].func2= NULL;
-    }
-    ReleaseSemaphore(c[0].work_sem, s->thread_count, 0);
-    for(i=0; i<s->thread_count; i++){
-        WaitForSingleObject(c[i].thread, INFINITE);
-        if(c[i].thread)   CloseHandle(c[i].thread);
-    }
-    if(c[0].work_sem) CloseHandle(c[0].work_sem);
-    if(c[0].job_sem)  CloseHandle(c[0].job_sem);
-    if(c[0].done_sem) CloseHandle(c[0].done_sem);
-
-    av_freep(&s->thread_opaque);
-}
-
-static int avcodec_thread_execute(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2),void *arg, int *ret, int count, int size){
-    ThreadContext *c= s->thread_opaque;
-    int i;
-    int jobnr = 0;
-
-    assert(s == c->avctx);
-
-    /* note, we can be certain that this is not called with the same AVCodecContext by different threads at the same time */
-
-    for(i=0; i<s->thread_count; i++){
-        c[i].arg= arg;
-        c[i].argsize= size;
-        c[i].func= func;
-        c[i].ret= ret;
-        c[i].jobnr = &jobnr;
-    }
-    ReleaseSemaphore(c[0].work_sem, count, 0);
-    for(i=0; i<count; i++)
-        WaitForSingleObject(c[0].done_sem, INFINITE);
-
-    return 0;
-}
-
-static int avcodec_thread_execute2(AVCodecContext *s, int (*func)(AVCodecContext *c2, void *arg2, int, int),void *arg, int *ret, int count){
-    ThreadContext *c= s->thread_opaque;
-    int i;
-    for(i=0; i<s->thread_count; i++)
-        c[i].func2 = func;
-    avcodec_thread_execute(s, NULL, arg, ret, count, 0);
-}
-
-int ff_thread_init(AVCodecContext *s){
-    int i;
-    ThreadContext *c;
-    uint32_t threadid;
-
-    if (s->thread_type && !(s->thread_type & FF_THREAD_SLICE)) {
-        av_log(s, AV_LOG_WARNING,
-            "This thread library only supports FF_THREAD_SLICE"
-            " threading algorithm.\n");
-        return 0;
-    }
-
-    s->active_thread_type= FF_THREAD_SLICE;
-
-    if (s->thread_count <= 1)
-        return 0;
-
-    assert(!s->thread_opaque);
-    c= av_mallocz(sizeof(ThreadContext)*s->thread_count);
-    s->thread_opaque= c;
-    if(!(c[0].work_sem = CreateSemaphore(NULL, 0, INT_MAX, NULL)))
-        goto fail;
-    if(!(c[0].job_sem  = CreateSemaphore(NULL, 1, 1, NULL)))
-        goto fail;
-    if(!(c[0].done_sem = CreateSemaphore(NULL, 0, INT_MAX, NULL)))
-        goto fail;
-
-    for(i=0; i<s->thread_count; i++){
-//printf("init semaphors %d\n", i); fflush(stdout);
-        c[i].avctx= s;
-        c[i].work_sem = c[0].work_sem;
-        c[i].job_sem  = c[0].job_sem;
-        c[i].done_sem = c[0].done_sem;
-        c[i].threadnr = i;
-
-//printf("create thread %d\n", i); fflush(stdout);
-        c[i].thread = (HANDLE)_beginthreadex(NULL, 0, thread_func, &c[i], 0, &threadid );
-        if( !c[i].thread ) goto fail;
-    }
-//printf("init done\n"); fflush(stdout);
-
-    s->execute= avcodec_thread_execute;
-    s->execute2= avcodec_thread_execute2;
-
-    return 0;
-fail:
-    ff_thread_free(s);
-    return -1;
-}