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, 7 deletions

diff --git a/src/tests/mcalign-test.c b/src/tests/mcalign-test.c
index 35691698..1584256c 100644
--- a/src/tests/mcalign-test.c
+++ b/src/tests/mcalign-test.c
@@ -59,24 +59,27 @@ int main(PA_GCC_UNUSED int argc, PA_GCC_UNUSED char *argv[]) {
             c.index = c.length = 0;
         }
 
-        assert(c.index < c.memblock->length);
+        assert(c.index < pa_memblock_get_length(c.memblock));
 
-        l = c.memblock->length - c.index;
+        l = pa_memblock_get_length(c.memblock) - c.index;
 
         l = l <= 1 ? l : rand() % (l-1) +1 ;
-        
-        if ((r = read(STDIN_FILENO, (uint8_t*) c.memblock->data + c.index, l)) <= 0) {
+
+        p = pa_memblock_acquire(c.memblock);
+        if ((r = read(STDIN_FILENO, (uint8_t*) p + c.index, l)) <= 0) {
+            pa_memblock_release(c.memblock);
             fprintf(stderr, "read() failed: %s\n", r < 0 ? strerror(errno) : "EOF");
             break;
         }
-
+        pa_memblock_release(c.memblock);
+            
         c.length = r;
         pa_mcalign_push(a, &c);
         fprintf(stderr, "Read %ld bytes\n", (long)r);
 
         c.index += r;
 
-        if (c.index >= c.memblock->length) {
+        if (c.index >= pa_memblock_get_length(c.memblock)) {
             pa_memblock_unref(c.memblock);
             pa_memchunk_reset(&c);
         }
@@ -87,7 +90,9 @@ int main(PA_GCC_UNUSED int argc, PA_GCC_UNUSED char *argv[]) {
             if (pa_mcalign_pop(a, &t) < 0)
                 break;
 
-            pa_loop_write(STDOUT_FILENO, (uint8_t*) t.memblock->data + t.index, t.length, NULL);
+            p = pa_memblock_acquire(t.memblock);
+            pa_loop_write(STDOUT_FILENO, (uint8_t*) p + t.index, t.length, NULL);
+            pa_memblock_release(t.memblock);
             fprintf(stderr, "Wrote %lu bytes.\n", (unsigned long) t.length);
 
             pa_memblock_unref(t.memblock);