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authorEric Wong <normalperson@yhbt.net>2008-10-07 22:07:34 +0200
committerMax Kellermann <max@duempel.org>2008-10-07 22:07:34 +0200
commit45334a23e18da4928f53ccb9ecc7afd5f7eca28e (patch)
treedba88e561ff5e5989a5aa3e51720f2c273f5f6ab
parentbb04c6342e692b39d04126940570a5ade9ca371a (diff)
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songvec: lock traversals for thread-safe updates/reads
Only one lock is used for all songvec traversals since they're rarely changed. Also, minimize lock time and release it before calling iterator functions since they may block (updateSongInfo => stat/open/seek/read). This lock only protects songvecs (and all of them) during traversals; not the individual song structures themselves.
-rw-r--r--src/songvec.c44
1 files changed, 34 insertions, 10 deletions
diff --git a/src/songvec.c b/src/songvec.c
index dd188f46c..b22ac4c1b 100644
--- a/src/songvec.c
+++ b/src/songvec.c
@@ -1,6 +1,8 @@
#include "songvec.h"
#include "utils.h"
+static pthread_mutex_t nr_lock = PTHREAD_MUTEX_INITIALIZER;
+
/* Only used for sorting/searchin a songvec, not general purpose compares */
static int songvec_cmp(const void *s1, const void *s2)
{
@@ -16,23 +18,32 @@ static size_t sv_size(struct songvec *sv)
void songvec_sort(struct songvec *sv)
{
+ pthread_mutex_lock(&nr_lock);
qsort(sv->base, sv->nr, sizeof(Song *), songvec_cmp);
+ pthread_mutex_unlock(&nr_lock);
}
Song *songvec_find(struct songvec *sv, const char *url)
{
int i;
+ Song *ret = NULL;
- for (i = sv->nr; --i >= 0; )
- if (!strcmp(sv->base[i]->url, url))
- return sv->base[i];
- return NULL;
+ pthread_mutex_lock(&nr_lock);
+ for (i = sv->nr; --i >= 0; ) {
+ if (strcmp(sv->base[i]->url, url))
+ continue;
+ ret = sv->base[i];
+ break;
+ }
+ pthread_mutex_unlock(&nr_lock);
+ return ret;
}
int songvec_delete(struct songvec *sv, const Song *del)
{
int i;
+ pthread_mutex_lock(&nr_lock);
for (i = sv->nr; --i >= 0; ) {
if (sv->base[i] != del)
continue;
@@ -45,37 +56,50 @@ int songvec_delete(struct songvec *sv, const Song *del)
(sv->nr - i + 1) * sizeof(Song *));
sv->base = xrealloc(sv->base, sv_size(sv));
}
- return i;
+ break;
}
+ pthread_mutex_unlock(&nr_lock);
- return -1; /* not found */
+ return i;
}
void songvec_add(struct songvec *sv, Song *add)
{
+ pthread_mutex_lock(&nr_lock);
++sv->nr;
sv->base = xrealloc(sv->base, sv_size(sv));
sv->base[sv->nr - 1] = add;
+ pthread_mutex_unlock(&nr_lock);
}
void songvec_destroy(struct songvec *sv)
{
+ pthread_mutex_lock(&nr_lock);
if (sv->base) {
free(sv->base);
sv->base = NULL;
}
sv->nr = 0;
+ pthread_mutex_unlock(&nr_lock);
}
int songvec_for_each(struct songvec *sv, int (*fn)(Song *, void *), void *arg)
{
- int i;
- Song **sp = sv->base;
+ size_t i;
- for (i = sv->nr; --i >= 0; ) {
- if (fn(*sp++, arg) < 0)
+ pthread_mutex_lock(&nr_lock);
+ for (i = 0; i < sv->nr; ++i) {
+ Song *song = sv->base[i];
+
+ assert(song);
+ assert(*song->url);
+
+ pthread_mutex_unlock(&nr_lock); /* fn() may block */
+ if (fn(song, arg) < 0)
return -1;
+ pthread_mutex_lock(&nr_lock); /* sv->nr may change in fn() */
}
+ pthread_mutex_unlock(&nr_lock);
return 0;
}