From d210ebbb09daddb2c8c8e8e77243e088b0b19c4d Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 26 Sep 2006 23:50:56 +0000
Subject: rework memory block management to be thread-safe and mostly
 lock-free.

pa_memblock is now an opaque structure. Access to its fields is now done
through various accessor functions in a thread-safe manner.

pa_memblock_acquire() and pa_memblock_release() are now used to access the
attached audio data. Why? To allow safe manipulation of the memory pointer
maintained by the memory block. Internally _acquire() and _release() maintain a
reference counter. Please do not confuse this reference counter whith the one
maintained by pa_memblock_ref()/_unref()!

As a side effect this patch removes all direct usages of AO_t and replaces it
with pa_atomic_xxx based code.

This stuff needs some serious testing love. Especially if threads are actively
used.



git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@1404 fefdeb5f-60dc-0310-8127-8f9354f1896f
---
 src/pulsecore/sink.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

(limited to 'src/pulsecore/sink.c')

diff --git a/src/pulsecore/sink.c b/src/pulsecore/sink.c
index 05695254..04795e39 100644
--- a/src/pulsecore/sink.c
+++ b/src/pulsecore/sink.c
@@ -237,7 +237,6 @@ static unsigned fill_mix_info(pa_sink *s, pa_mix_info *info, unsigned maxinfo) {
         info->userdata = i;
         
         assert(info->chunk.memblock);
-        assert(info->chunk.memblock->data);
         assert(info->chunk.length);
         
         info++;
@@ -305,13 +304,16 @@ int pa_sink_render(pa_sink*s, size_t length, pa_memchunk *result) {
                 pa_volume_memchunk(result, &s->sample_spec, &volume);
         }
     } else {
+        void *ptr;
         result->memblock = pa_memblock_new(s->core->mempool, length);
         assert(result->memblock);
 
 /*          pa_log("mixing %i", n);  */
 
-        result->length = pa_mix(info, n, result->memblock->data, length,
-            &s->sample_spec, &s->sw_volume, s->sw_muted);
+        ptr = pa_memblock_acquire(result->memblock);
+        result->length = pa_mix(info, n, ptr, length, &s->sample_spec, &s->sw_volume, s->sw_muted);
+        pa_memblock_release(result->memblock);
+        
         result->index = 0;
     }
 
@@ -332,13 +334,13 @@ int pa_sink_render_into(pa_sink*s, pa_memchunk *target) {
     pa_mix_info info[MAX_MIX_CHANNELS];
     unsigned n;
     int r = -1;
+    void *ptr;
     
     assert(s);
     assert(s->ref >= 1);
     assert(target);
     assert(target->memblock);
     assert(target->length);
-    assert(target->memblock->data);
 
     pa_sink_ref(s);
     
@@ -347,16 +349,23 @@ int pa_sink_render_into(pa_sink*s, pa_memchunk *target) {
     if (n <= 0)
         goto finish;
 
+    ptr = pa_memblock_acquire(target->memblock);
+    
     if (n == 1) {
+        void *src;
         pa_cvolume volume;
 
         if (target->length > info[0].chunk.length)
             target->length = info[0].chunk.length;
+
+        src = pa_memblock_acquire(info[0].chunk.memblock);
         
-        memcpy((uint8_t*) target->memblock->data + target->index,
-               (uint8_t*) info[0].chunk.memblock->data + info[0].chunk.index,
+        memcpy((uint8_t*) ptr + target->index,
+               (uint8_t*) src + info[0].chunk.index,
                target->length);
 
+        pa_memblock_release(info[0].chunk.memblock);
+
         pa_sw_cvolume_multiply(&volume, &s->sw_volume, &info[0].volume);
 
         if (s->sw_muted)
@@ -365,11 +374,13 @@ int pa_sink_render_into(pa_sink*s, pa_memchunk *target) {
             pa_volume_memchunk(target, &s->sample_spec, &volume);
     } else
         target->length = pa_mix(info, n,
-                                (uint8_t*) target->memblock->data + target->index,
+                                (uint8_t*) ptr + target->index,
                                 target->length,
                                 &s->sample_spec,
                                 &s->sw_volume,
                                 s->sw_muted);
+
+    pa_memblock_release(target->memblock);
     
     inputs_drop(s, info, n, target->length);
 
@@ -393,7 +404,6 @@ void pa_sink_render_into_full(pa_sink *s, pa_memchunk *target) {
     assert(target);
     assert(target->memblock);
     assert(target->length);
-    assert(target->memblock->data);
 
     pa_sink_ref(s);
     
-- 
cgit