buffer: Pass timeout parameter

This is a preparation to check the buffer contents without waiting.
deep-observability-lab · Sep 29, 2021 · b15240d · b15240d
1 parent 9b8438c
commit b15240d
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Showing 3 changed files with 10 additions and 5 deletions.
diff --git a/include/ply/buffer.h b/include/ply/buffer.h
@@ -36,6 +36,6 @@ struct buffer;
 
 struct buffer *buffer_new(int mapfd);
 
-struct ply_return buffer_loop(struct buffer *buf);
+struct ply_return buffer_loop(struct buffer *buf, int timeout);
 
 #endif	/* _PLY_BUFFER_H */
diff --git a/src/libply/built-in/buffer.c b/src/libply/built-in/buffer.c
@@ -153,21 +153,26 @@ struct ply_return buffer_q_drain(struct buffer_q *q)
 	return ret;
 }
 
-struct ply_return buffer_loop(struct buffer *buf)
+struct ply_return buffer_loop(struct buffer *buf, int timeout)
 {
 	struct ply_return ret;
 	uint32_t cpu;
 	int ready;
 
 	for (;;) {
-		ready = poll(buf->poll, buf->ncpus, -1);
+		ready = poll(buf->poll, buf->ncpus, timeout);
 		if (ready < 0) {
 			ret.err = 1;
 			ret.val = errno;
 			return ret;
 		}
 
-		assert(ready);
+		if (timeout == -1) {
+			assert(ready);
+		} else if (ready == 0) {
+			ret.err = 0;
+			return ret;
+		}
 
 		for (cpu = 0; ready && (cpu < buf->ncpus); cpu++) {
 			if (!(buf->poll[cpu].revents & POLLIN))

diff --git a/src/libply/libply.c b/src/libply/libply.c
@@ -374,7 +374,7 @@ struct ply_return ply_loop(struct ply *ply)
 		return (struct ply_return){ .err = 1, .val = EINTR };
 	}
 
-	return buffer_loop((struct buffer *)ply->stdbuf->priv);
+	return buffer_loop((struct buffer *)ply->stdbuf->priv, -1);
 }
 
 int ply_stop(struct ply *ply)