[FFmpeg-devel] [PATCH 1/2] avutil/executor: Allowing thread_count be zero

[Zhao Zhili]

From: Zhao Zhili <zhilizhao at tencent.com>

When thread_count be zero, it will be run on current thread like
!HAVE_THREADS.
---
 libavutil/executor.c | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/libavutil/executor.c b/libavutil/executor.c
index 26691fe157..fb20104b58 100644
--- a/libavutil/executor.c
+++ b/libavutil/executor.c
@@ -82,9 +82,11 @@ static int run_one_task(AVExecutor *e, void *lc)
         /* nothing */;
     if (*prev) {
         AVTask *t = remove_task(prev, *prev);
-        ff_mutex_unlock(&e->lock);
+        if (e->thread_count > 0)
+            ff_mutex_unlock(&e->lock);
         cb->run(t, lc, cb->user_data);
-        ff_mutex_lock(&e->lock);
+        if (e->thread_count > 0)
+            ff_mutex_lock(&e->lock);
         return 1;
     }
     return 0;
@@ -146,14 +148,17 @@ AVExecutor* av_executor_alloc(const AVTaskCallbacks *cb, int thread_count)
         return NULL;
     e->cb = *cb;
 
-    e->local_contexts = av_calloc(thread_count, e->cb.local_context_size);
+    e->local_contexts = av_calloc(FFMAX(thread_count, 1), e->cb.local_context_size);
     if (!e->local_contexts)
         goto free_executor;
 
-    e->threads = av_calloc(thread_count, sizeof(*e->threads));
+    e->threads = av_calloc(FFMAX(thread_count, 1), sizeof(*e->threads));
     if (!e->threads)
         goto free_executor;
 
+    if (!thread_count)
+        return e;
+
     has_lock = !ff_mutex_init(&e->lock, NULL);
     has_cond = !ff_cond_init(&e->cond, NULL);
 
@@ -175,9 +180,12 @@ free_executor:
 
 void av_executor_free(AVExecutor **executor)
 {
+    int thread_count;
+
     if (!executor || !*executor)
         return;
-    executor_free(*executor, 1, 1);
+    thread_count = (*executor)->thread_count;
+    executor_free(*executor, thread_count, thread_count);
     *executor = NULL;
 }
 
@@ -195,9 +203,9 @@ void av_executor_execute(AVExecutor *e, AVTask *t)
     ff_cond_signal(&e->cond);
     ff_mutex_unlock(&e->lock);
 
-#if !HAVE_THREADS
-    // We are running in a single-threaded environment, so we must handle all tasks ourselves
-    while (run_one_task(e, e->local_contexts))
-        /* nothing */;
-#endif
+    if (!e->thread_count || !HAVE_THREADS) {
+        // We are running in a single-threaded environment, so we must handle all tasks ourselves
+        while (run_one_task(e, e->local_contexts))
+            /* nothing */;
+    }
 }
-- 
2.25.1