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, 12 insertions, 3 deletions

diff --git a/src/pulsecore/sound-file.c b/src/pulsecore/sound-file.c
index 1bf650e2..c74a1586 100644
--- a/src/pulsecore/sound-file.c
+++ b/src/pulsecore/sound-file.c
@@ -40,7 +40,11 @@ int pa_sound_file_load(pa_mempool *pool, const char *fname, pa_sample_spec *ss,
     int ret = -1;
     size_t l;
     sf_count_t (*readf_function)(SNDFILE *sndfile, void *ptr, sf_count_t frames) = NULL;
-    assert(fname && ss && chunk);
+    void *ptr = NULL;
+    
+    assert(fname);
+    assert(ss);
+    assert(chunk);
 
     chunk->memblock = NULL;
     chunk->index = chunk->length = 0;
@@ -97,8 +101,10 @@ int pa_sound_file_load(pa_mempool *pool, const char *fname, pa_sample_spec *ss,
     chunk->index = 0;
     chunk->length = l;
 
-    if ((readf_function && readf_function(sf, chunk->memblock->data, sfinfo.frames) != sfinfo.frames) ||
-        (!readf_function && sf_read_raw(sf, chunk->memblock->data, l) != l)) {
+    ptr = pa_memblock_acquire(chunk->memblock);
+    
+    if ((readf_function && readf_function(sf, ptr, sfinfo.frames) != sfinfo.frames) ||
+        (!readf_function && sf_read_raw(sf, ptr, l) != l)) {
         pa_log("Premature file end");
         goto finish;
     }
@@ -110,6 +116,9 @@ finish:
     if (sf)
         sf_close(sf);
 
+    if (ptr)
+        pa_memblock_release(chunk->memblock);
+    
     if (ret != 0 && chunk->memblock)
         pa_memblock_unref(chunk->memblock);