uclient: add function for getting the amount of pending read/write data

This can be used to throttle writes when doing large POST requests

Signed-off-by: Felix Fietkau <nbd@nbd.name>

4 files changed, 19 insertions, 0 deletions

diff --git a/uclient-backend.h b/uclient-backend.h
index b013cde..1b808ac 100644
--- a/uclient-backend.h
+++ b/uclient-backend.h
@@ -34,6 +34,7 @@ struct uclient_backend {
 
 	int (*read)(struct uclient *cl, char *buf, unsigned int len);
 	int (*write)(struct uclient *cl, const char *buf, unsigned int len);
+	int (*pending_bytes)(struct uclient *cl, bool write);
 };
 
 void uclient_backend_set_error(struct uclient *cl, int code);
diff --git a/uclient-http.c b/uclient-http.c
index 33f6513..d6e9dcf 100644
--- a/uclient-http.c
+++ b/uclient-http.c
@@ -1229,6 +1229,14 @@ int uclient_http_set_address_family(struct uclient *cl, int af)
 	return 0;
 }
 
+static int
+uclient_http_pending_bytes(struct uclient *cl, bool write)
+{
+	struct uclient_http *uh = container_of(cl, struct uclient_http, uc);
+
+	return ustream_pending_data(uh->us, write);
+}
+
 const struct uclient_backend uclient_backend_http = {
 	.prefix = uclient_http_prefix,
 
@@ -1242,4 +1250,5 @@ const struct uclient_backend uclient_backend_http = {
 	.read = uclient_http_read,
 	.write = uclient_http_send_data,
 	.request = uclient_http_request_done,
+	.pending_bytes = uclient_http_pending_bytes,
 };
diff --git a/uclient.c b/uclient.c
index a309de8..0fb92b8 100644
--- a/uclient.c
+++ b/uclient.c
@@ -406,6 +406,14 @@ int uclient_read(struct uclient *cl, char *buf, int len)
 	return cl->backend->read(cl, buf, len);
 }
 
+int uclient_pending_bytes(struct uclient *cl, bool write)
+{
+	if (!cl->backend->pending_bytes)
+		return -1;
+
+	return cl->backend->pending_bytes(cl, write);
+}
+
 void uclient_disconnect(struct uclient *cl)
 {
 	uloop_timeout_cancel(&cl->connection_timeout);
diff --git a/uclient.h b/uclient.h
index 29563b3..5ccda74 100644
--- a/uclient.h
+++ b/uclient.h
@@ -113,6 +113,7 @@ void uclient_disconnect(struct uclient *cl);
 
 int uclient_read(struct uclient *cl, char *buf, int len);
 int uclient_write(struct uclient *cl, const char *buf, int len);
+int uclient_pending_bytes(struct uclient *cl, bool write);
 int uclient_request(struct uclient *cl);
 
 char *uclient_get_addr(char *dest, int *port, union uclient_addr *a);