[PATCH v3 1/2] Wayland: logging

[Martin Minarik]

The core libwayland libraries should not handle logging, only passing
the error messages to subscribed functions.
An application linked to libwayland-server or libwayland-client
will be able to set own functions (one per library) to handle error
messages.

Change in this series: make the wl_log return int, because
of compatibility with printf. It will return the number of bytes logged.
---
 src/wayland-client.c  |    6 ++++++
 src/wayland-client.h  |    2 ++
 src/wayland-private.h |    4 ++++
 src/wayland-server.c  |    6 ++++++
 src/wayland-server.h  |    2 ++
 src/wayland-util.c    |   20 ++++++++++++++++++++
 src/wayland-util.h    |    3 +++
 7 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/src/wayland-client.c b/src/wayland-client.c
index 1a24abf..ecedd99 100644
--- a/src/wayland-client.c
+++ b/src/wayland-client.c
@@ -589,3 +589,9 @@ wl_proxy_get_id(struct wl_proxy *proxy)
 {
 	return proxy->object.id;
 }
+
+WL_EXPORT void
+wl_log_set_handler_client(wl_log_func_t handler)
+{
+	wl_log_handler = handler;
+}
diff --git a/src/wayland-client.h b/src/wayland-client.h
index 5c7fd2f..06dc6fe 100644
--- a/src/wayland-client.h
+++ b/src/wayland-client.h
@@ -96,6 +96,8 @@ uint32_t
 wl_display_get_global(struct wl_display *display,
 		      const char *interface, uint32_t version);
 
+void wl_log_set_handler_client(wl_log_func_t handler);
+
 #ifdef  __cplusplus
 }
 #endif
diff --git a/src/wayland-private.h b/src/wayland-private.h
index 61b07a2..37ef13e 100644
--- a/src/wayland-private.h
+++ b/src/wayland-private.h
@@ -105,4 +105,8 @@ wl_closure_print(struct wl_closure *closure, struct wl_object *target, int send)
 void
 wl_closure_destroy(struct wl_closure *closure);
 
+extern wl_log_func_t wl_log_handler;
+
+int wl_log(const char *fmt, ...);
+
 #endif
diff --git a/src/wayland-server.c b/src/wayland-server.c
index 6ccc097..9f07b88 100644
--- a/src/wayland-server.c
+++ b/src/wayland-server.c
@@ -1178,3 +1178,9 @@ wl_client_new_object(struct wl_client *client,
 				    interface, implementation, id, data);
 
 }
+
+WL_EXPORT void
+wl_log_set_handler_server(wl_log_func_t handler)
+{
+	wl_log_handler = handler;
+}
diff --git a/src/wayland-server.h b/src/wayland-server.h
index 31f6fe5..bf46e0a 100644
--- a/src/wayland-server.h
+++ b/src/wayland-server.h
@@ -417,6 +417,8 @@ wl_buffer_is_shm(struct wl_buffer *buffer);
 int
 wl_display_init_shm(struct wl_display *display);
 
+void wl_log_set_handler_server(wl_log_func_t handler);
+
 #ifdef  __cplusplus
 }
 #endif
diff --git a/src/wayland-util.c b/src/wayland-util.c
index 7bf8924..31c2eeb 100644
--- a/src/wayland-util.c
+++ b/src/wayland-util.c
@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
+#include <stdarg.h>
 
 #include "wayland-util.h"
 #include "wayland-private.h"
@@ -270,3 +271,22 @@ wl_map_for_each(struct wl_map *map, wl_iterator_func_t func, void *data)
 	for_each_helper(&map->client_entries, func, data);
 	for_each_helper(&map->server_entries, func, data);
 }
+
+static int
+wl_log_noop_handler(const char *fmt, va_list arg)
+{
+	return 0;
+}
+
+wl_log_func_t wl_log_handler = wl_log_noop_handler;
+
+int
+wl_log(const char *fmt, ...)
+{
+	int l;
+	va_list argp;
+	va_start(argp, fmt);
+	l = wl_log_handler(fmt, argp);
+	va_end(argp);
+	return l;
+}
diff --git a/src/wayland-util.h b/src/wayland-util.h
index fa5c6c5..9b7466d 100644
--- a/src/wayland-util.h
+++ b/src/wayland-util.h
@@ -30,6 +30,7 @@ extern "C" {
 #include <math.h>
 #include <stddef.h>
 #include <inttypes.h>
+#include <stdarg.h>
 
 /* GCC visibility */
 #if defined(__GNUC__) && __GNUC__ >= 4
@@ -203,6 +204,8 @@ static inline wl_fixed_t wl_fixed_from_int(int i)
 	return i * 256;
 }
 
+typedef int (*wl_log_func_t)(const char *, va_list);
+
 #ifdef  __cplusplus
 }
 #endif
-- 
1.7.5.4