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

1 files changed, 9 insertions, 2 deletions

diff --git a/src/modules/module-esound-sink.c b/src/modules/module-esound-sink.c
index 6d4a8489..ca1f16ce 100644
--- a/src/modules/module-esound-sink.c
+++ b/src/modules/module-esound-sink.c
@@ -142,18 +142,25 @@ static int do_write(struct userdata *u) {
             u->write_index = u->write_length = 0;
         }
     } else if (u->state == STATE_RUNNING) {
+        void *p;
+        
         pa_module_set_used(u->module, pa_sink_used_by(u->sink));
         
         if (!u->memchunk.length)
             if (pa_sink_render(u->sink, 8192, &u->memchunk) < 0)
                 return 0;
 
-        assert(u->memchunk.memblock && u->memchunk.length);
+        assert(u->memchunk.memblock);
+        assert(u->memchunk.length);
+
+        p = pa_memblock_acquire(u->memchunk.memblock);
         
-        if ((r = pa_iochannel_write(u->io, (uint8_t*) u->memchunk.memblock->data + u->memchunk.index, u->memchunk.length)) < 0) {
+        if ((r = pa_iochannel_write(u->io, (uint8_t*) p + u->memchunk.index, u->memchunk.length)) < 0) {
+            pa_memblock_release(u->memchunk.memblock);
             pa_log("write() failed: %s", pa_cstrerror(errno));
             return -1;
         }
+        pa_memblock_release(u->memchunk.memblock);
 
         u->memchunk.index += r;
         u->memchunk.length -= r;