input/curl: per-request mutex/cond

The global data structures are now lock-free, because they are
accessed only from the I/O thread.  By using per-request locks, we
have finer grained locking, preparing for locks shared with the
client.

1 files changed, 35 insertions, 33 deletions

diff --git a/src/input/curl_input_plugin.c b/src/input/curl_input_plugin.c
index c377b642..d4c11613 100644
--- a/src/input/curl_input_plugin.c
+++ b/src/input/curl_input_plugin.c
@@ -76,6 +76,9 @@ struct input_curl {
 	/** the curl handles */
 	CURL *easy;
 
+	GMutex *mutex;
+	GCond *cond;
+
 	/** the GMainLoop source used to poll all CURL file
 	    descriptors */
 	GSource *source;
@@ -123,8 +126,6 @@ static const char *proxy, *proxy_user, *proxy_password;
 static unsigned proxy_port;
 
 static struct {
-	GStaticMutex mutex;
-	GCond *cond;
 	CURLM *multi;
 
 	/**
@@ -165,9 +166,7 @@ static struct {
 	 */
 	GTimeVal absolute_timeout;
 #endif
-} curl = {
-	.mutex = G_STATIC_MUTEX_INIT,
-};
+} curl;
 
 static inline GQuark
 curl_quark(void)
@@ -460,21 +459,21 @@ input_curl_abort_all_requests(GError *error)
 	assert(io_thread_inside());
 	assert(error != NULL);
 
-	g_static_mutex_lock(&curl.mutex);
-
 	while (curl.requests != NULL) {
 		struct input_curl *c = curl.requests->data;
 		assert(c->postponed_error == NULL);
 
 		input_curl_easy_free(c);
+
+		g_mutex_lock(c->mutex);
 		c->postponed_error = g_error_copy(error);
 		c->base.ready = true;
+		g_cond_broadcast(c->cond);
+		g_mutex_unlock(c->mutex);
 	}
 
 	g_error_free(error);
 
-	g_cond_broadcast(curl.cond);
-	g_static_mutex_unlock(&curl.mutex);
 }
 
 /**
@@ -490,7 +489,7 @@ input_curl_request_done(struct input_curl *c, CURLcode result, long status)
 	assert(c->easy == NULL);
 	assert(c->postponed_error == NULL);
 
-	g_static_mutex_lock(&curl.mutex);
+	g_mutex_lock(c->mutex);
 
 	if (result != CURLE_OK) {
 		c->postponed_error = g_error_new(curl_quark(), result,
@@ -503,8 +502,8 @@ input_curl_request_done(struct input_curl *c, CURLcode result, long status)
 	}
 
 	c->base.ready = true;
-	g_cond_broadcast(curl.cond);
-	g_static_mutex_unlock(&curl.mutex);
+	g_cond_broadcast(c->cond);
+	g_mutex_unlock(c->mutex);
 }
 
 static void
@@ -711,8 +710,6 @@ input_curl_init(const struct config_param *param,
 		return false;
 	}
 
-	curl.cond = g_cond_new();
-
 	curl.source = g_source_new(&curl_source_funcs, sizeof(*curl.source));
 	curl.source_id = g_source_attach(curl.source, io_thread_context());
 
@@ -745,7 +742,6 @@ input_curl_finish(void)
 	io_thread_call(curl_destroy_sources, NULL);
 
 	curl_multi_cleanup(curl.multi);
-	g_cond_free(curl.cond);
 
 	curl_slist_free_all(http_200_aliases);
 
@@ -809,6 +805,9 @@ input_curl_free(struct input_curl *c)
 
 	g_queue_free(c->buffers);
 
+	g_mutex_free(c->mutex);
+	g_cond_free(c->cond);
+
 	g_free(c->url);
 	input_stream_deinit(&c->base);
 	g_free(c);
@@ -828,7 +827,7 @@ static bool
 fill_buffer(struct input_curl *c, GError **error_r)
 {
 	while (c->easy != NULL && g_queue_is_empty(c->buffers))
-		g_cond_wait(curl.cond, g_static_mutex_get_mutex(&curl.mutex));
+		g_cond_wait(c->cond, c->mutex);
 
 	if (c->postponed_error != NULL) {
 		g_propagate_error(error_r, c->postponed_error);
@@ -938,14 +937,14 @@ input_curl_read(struct input_stream *is, void *ptr, size_t size,
 	size_t nbytes = 0;
 	char *dest = ptr;
 
-	g_static_mutex_lock(&curl.mutex);
+	g_mutex_lock(c->mutex);
 
 	do {
 		/* fill the buffer */
 
 		success = fill_buffer(c, error_r);
 		if (!success) {
-			g_static_mutex_unlock(&curl.mutex);
+			g_mutex_unlock(c->mutex);
 			return 0;
 		}
 
@@ -970,7 +969,7 @@ input_curl_read(struct input_stream *is, void *ptr, size_t size,
 		io_thread_call(input_curl_resume, c);
 #endif
 
-	g_static_mutex_unlock(&curl.mutex);
+	g_mutex_unlock(c->mutex);
 
 	return nbytes;
 }
@@ -988,9 +987,9 @@ input_curl_eof(G_GNUC_UNUSED struct input_stream *is)
 {
 	struct input_curl *c = (struct input_curl *)is;
 
-	g_static_mutex_lock(&curl.mutex);
+	g_mutex_lock(c->mutex);
 	bool eof = c->easy == NULL && g_queue_is_empty(c->buffers);
-	g_static_mutex_unlock(&curl.mutex);
+	g_mutex_unlock(c->mutex);
 
 	return eof;
 }
@@ -1000,7 +999,7 @@ input_curl_buffer(struct input_stream *is, GError **error_r)
 {
 	struct input_curl *c = (struct input_curl *)is;
 
-	g_static_mutex_lock(&curl.mutex);
+	g_mutex_lock(c->mutex);
 
 	int result;
 	if (c->postponed_error != NULL) {
@@ -1012,7 +1011,7 @@ input_curl_buffer(struct input_stream *is, GError **error_r)
 	else
 		result = 1;
 
-	g_static_mutex_unlock(&curl.mutex);
+	g_mutex_unlock(c->mutex);
 
 	return result;
 }
@@ -1112,12 +1111,12 @@ input_curl_writefunction(void *ptr, size_t size, size_t nmemb, void *stream)
 	if (size == 0)
 		return 0;
 
-	g_static_mutex_lock(&curl.mutex);
+	g_mutex_lock(c->mutex);
 
 #if LIBCURL_VERSION_NUM >= 0x071200
 	if (curl_total_buffer_size(c) + size >= CURL_MAX_BUFFERED) {
 		c->paused = true;
-		g_static_mutex_unlock(&curl.mutex);
+		g_mutex_unlock(c->mutex);
 		return CURL_WRITEFUNC_PAUSE;
 	}
 #endif
@@ -1131,8 +1130,8 @@ input_curl_writefunction(void *ptr, size_t size, size_t nmemb, void *stream)
 
 	c->base.ready = true;
 
-	g_cond_broadcast(curl.cond);
-	g_static_mutex_unlock(&curl.mutex);
+	g_cond_broadcast(c->cond);
+	g_mutex_unlock(c->mutex);
 
 	return size;
 }
@@ -1239,7 +1238,7 @@ input_curl_seek(struct input_stream *is, goffset offset, int whence,
 
 	/* check if we can fast-forward the buffer */
 
-	g_static_mutex_lock(&curl.mutex);
+	g_mutex_lock(c->mutex);
 
 	while (offset > is->offset && !g_queue_is_empty(c->buffers)) {
 		struct buffer *buffer;
@@ -1258,7 +1257,7 @@ input_curl_seek(struct input_stream *is, goffset offset, int whence,
 		is->offset += length;
 	}
 
-	g_static_mutex_unlock(&curl.mutex);
+	g_mutex_unlock(c->mutex);
 
 	if (offset == is->offset)
 		return true;
@@ -1292,19 +1291,19 @@ input_curl_seek(struct input_stream *is, goffset offset, int whence,
 	if (!input_curl_easy_add_indirect(c, error_r))
 		return false;
 
-	g_static_mutex_lock(&curl.mutex);
+	g_mutex_lock(c->mutex);
 
 	while (!c->base.ready)
-		g_cond_wait(curl.cond, g_static_mutex_get_mutex(&curl.mutex));
+		g_cond_wait(c->cond, c->mutex);
 
 	if (c->postponed_error != NULL) {
 		g_propagate_error(error_r, c->postponed_error);
 		c->postponed_error = NULL;
-		g_static_mutex_unlock(&curl.mutex);
+		g_mutex_unlock(c->mutex);
 		return false;
 	}
 
-	g_static_mutex_unlock(&curl.mutex);
+	g_mutex_unlock(c->mutex);
 
 	return true;
 }
@@ -1320,6 +1319,9 @@ input_curl_open(const char *url, GError **error_r)
 	c = g_new0(struct input_curl, 1);
 	input_stream_init(&c->base, &input_plugin_curl, url);
 
+	c->mutex = g_mutex_new();
+	c->cond = g_cond_new();
+
 	c->url = g_strdup(url);
 	c->buffers = g_queue_new();