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added comments to describe refcounting of multicase chains

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This commit is contained in:
Joachim Bauch 2011-10-17 21:46:12 +02:00
parent 26041a8ed8
commit ba24f616e5
1 changed files with 11 additions and 2 deletions
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13
buffer.c
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@ -192,7 +192,9 @@ evbuffer_chain_free(struct evbuffer_chain *chain)
// chain is still referenced by other chains // chain is still referenced by other chains
return; return;
} }
// save to release chain, it's either a referencing
// chain or all references to it have been freed
if (chain->flags & EVBUFFER_REFERENCE) { if (chain->flags & EVBUFFER_REFERENCE) {
struct evbuffer_chain_reference *info = struct evbuffer_chain_reference *info =
EVBUFFER_CHAIN_EXTRA( EVBUFFER_CHAIN_EXTRA(
@ -221,6 +223,10 @@ evbuffer_chain_free(struct evbuffer_chain *chain)
EVBUFFER_CHAIN_EXTRA( EVBUFFER_CHAIN_EXTRA(
struct evbuffer_multicast_parent, struct evbuffer_multicast_parent,
chain); chain);
// referencing chain is being freed, decrease
// refcounts of source chain and associated
// evbuffer (which get freed once both reach
// zero)
EVUTIL_ASSERT(info->source != NULL); EVUTIL_ASSERT(info->source != NULL);
EVUTIL_ASSERT(info->parent != NULL); EVUTIL_ASSERT(info->parent != NULL);
EVBUFFER_LOCK(info->source); EVBUFFER_LOCK(info->source);
@ -835,9 +841,12 @@ APPEND_CHAIN_MULTICAST(struct evbuffer *dst, struct evbuffer *src)
return; return;
} }
extra = EVBUFFER_CHAIN_EXTRA(struct evbuffer_multicast_parent, tmp); extra = EVBUFFER_CHAIN_EXTRA(struct evbuffer_multicast_parent, tmp);
// reference source chain which now becomes immutable // reference evbuffer containing source chain so it
// doesn't get released while the chain is still
// being referenced to
_evbuffer_incref(src); _evbuffer_incref(src);
extra->source = src; extra->source = src;
// reference source chain which now becomes immutable
evbuffer_chain_incref(chain); evbuffer_chain_incref(chain);
extra->parent = chain; extra->parent = chain;
chain->flags |= EVBUFFER_IMMUTABLE; chain->flags |= EVBUFFER_IMMUTABLE;