songvec: add songvec_for_each iterator

This is so we can more consistently deal with locking
needed for thread-safety in iterator functions.

2 files changed, 15 insertions, 0 deletions

diff --git a/src/songvec.c b/src/songvec.c
index 969e67220..50694c68a 100644
--- a/src/songvec.c
+++ b/src/songvec.c
@@ -68,6 +68,19 @@ void songvec_destroy(struct songvec *sv)
 	sv->nr = 0;
 }
 
+int songvec_for_each(struct songvec *sv, int (*fn)(Song *, void *), void *arg)
+{
+	int i;
+	Song **sp = sv->base;
+
+	for (i = sv->nr; --i >= 0; ) {
+		if (fn(*sp++, arg) < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
 int songvec_write(struct songvec *sv, int fd, int extra)
 {
 	int i;
diff --git a/src/songvec.h b/src/songvec.h
index fb5c38c8b..adfdeccfb 100644
--- a/src/songvec.h
+++ b/src/songvec.h
@@ -19,6 +19,8 @@ void songvec_add(struct songvec *sv, Song *add);
 
 void songvec_destroy(struct songvec *sv);
 
+int songvec_for_each(struct songvec *sv, int (*fn)(Song *, void *), void *arg);
+
 int songvec_write(struct songvec *sv, int fd, int extra);
 
 #endif /* SONGVEC_H */