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rework memory block management to be thread-safe and mostly lock-free.

Browse source 
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
This commit is contained in:
Lennart Poettering 2006-09-26 23:50:56 +00:00
parent 5ad143b3ab
commit d210ebbb09
36 changed files with 991 additions and 500 deletions
Download patch file Download diff file Expand all files Collapse all files

15
src/pulsecore/memchunk.c
View file

@ -35,22 +35,25 @@
void pa_memchunk_make_writable(pa_memchunk *c, size_t min) {
pa_memblock *n;
size_t l;
void *tdata, *sdata;
assert(c);
assert(c->memblock);
assert(PA_REFCNT_VALUE(c->memblock) > 0);
if (PA_REFCNT_VALUE(c->memblock) == 1 &&
!c->memblock->read_only &&
c->memblock->length >= c->index+min)
if (pa_memblock_is_read_only(c->memblock) &&
pa_memblock_get_length(c->memblock) >= c->index+min)
return;
l = c->length;
if (l < min)
l = min;
n = pa_memblock_new(c->memblock->pool, l);
memcpy(n->data, (uint8_t*) c->memblock->data + c->index, c->length);
n = pa_memblock_new(pa_memblock_get_pool(c->memblock), l);
tdata = pa_memblock_acquire(n);
sdata = pa_memblock_acquire(c->memblock);
memcpy(tdata, (uint8_t*) sdata + c->index, c->length);
pa_memblock_release(n);
pa_memblock_release(c->memblock);
pa_memblock_unref(c->memblock);
c->memblock = n;
c->index = 0;