reds: Add ability to query the video-codecs currently enabled

spice_server_get_video_codecs: new public function to query the video
encoders/codecs currently enabled in the spice server. It returns a
string that can be fed to the setter counter
(spice_server_set_video_codecs). The string returned by this function
should be released with spice_server_free_video_codecs.

spice_server_free_video_codecs: new public function to free the the
video codec list returned by spice_server_get_video_codecs.

video_codecs_to_string: new private function to transform an array of
RedVideoCodec into a string.

Signed-off-by: Kevin Pouget <kpouget@redhat.com>
Acked-by: Frediano Ziglio <fziglio@redhat.com>

server/dcc.c

@@ -1120,9 +1120,8 @@ static gint sort_video_codecs_by_client_preference(gconstpointer a_pointer,
 
 static void dcc_update_preferred_video_codecs(DisplayChannelClient *dcc)
 {
-    guint i;
     GArray *video_codecs, *server_codecs;
-    GString *msg;
+    char *codecs_str;
 
     server_codecs = display_channel_get_video_codecs(DCC_TO_DC(dcc));
     spice_return_if_fail(server_codecs != NULL);
@@ -1137,13 +1136,9 @@ static void dcc_update_preferred_video_codecs(DisplayChannelClient *dcc)
     g_clear_pointer(&dcc->priv->preferred_video_codecs, g_array_unref);
     dcc->priv->preferred_video_codecs = video_codecs;
 
-    msg = g_string_new("Preferred video-codecs:");
-    for (i = 0; i < video_codecs->len; i++) {
-        RedVideoCodec codec = g_array_index(video_codecs, RedVideoCodec, i);
-        g_string_append_printf(msg, " %d", codec.type);
-    }
-    spice_debug("%s", msg->str);
-    g_string_free(msg, TRUE);
+    codecs_str = video_codecs_to_string(video_codecs, " ");
+    spice_debug("Preferred video-codecs: %s", codecs_str);
+    g_free(codecs_str);
 }
 
 static void on_display_video_codecs_update(GObject *gobject, GParamSpec *pspec, gpointer user_data)

server/reds.c

@@ -3708,6 +3708,16 @@ static gboolean get_name_index(const EnumNames names[], const char *name, uint32
     return FALSE;
 }
 
+/* returns NULL if index is invalid. */
+static const char *get_index_name(const EnumNames names[], uint32_t index)
+{
+    while (names->name != NULL && names->id != index) {
+        names++;
+    }
+
+    return names->name;
+}
+
 static const EnumNames renderer_names[] = {
     {RED_RENDERER_SW, "sw"},
     {RED_RENDERER_INVALID, NULL},
@@ -3755,6 +3765,24 @@ static const int video_codec_caps[] = {
     SPICE_DISPLAY_CAP_CODEC_VP9,
 };
 
+char *reds_get_video_codec_fullname(RedVideoCodec *codec)
+{
+    int i;
+    const char *encoder_name = NULL;
+    const char *codec_name = get_index_name(video_codec_names, codec->type);
+
+    spice_assert(codec_name);
+
+    for (i = 0; i < G_N_ELEMENTS(video_encoder_procs); i++) {
+        if (video_encoder_procs[i] == codec->create) {
+            encoder_name = get_index_name(video_encoder_names, i);
+            break;
+        }
+    }
+    spice_assert(encoder_name);
+
+    return g_strdup_printf("%s:%s", encoder_name, codec_name);
+}
 
 /* Parses the given codec string and returns newly-allocated strings describing
  * the next encoder and codec in the list. These strings must be freed by the
@@ -4196,6 +4224,16 @@ SPICE_GNUC_VISIBLE int spice_server_set_video_codecs(SpiceServer *reds, const ch
     return 0;
 }
 
+SPICE_GNUC_VISIBLE const char *spice_server_get_video_codecs(SpiceServer *reds)
+{
+    return video_codecs_to_string(reds_get_video_codecs(reds), ";");
+}
+
+SPICE_GNUC_VISIBLE void spice_server_free_video_codecs(SpiceServer *reds, const char *video_codecs)
+{
+    g_free((char *) video_codecs);
+}
+
 GArray* reds_get_video_codecs(const RedsState *reds)
 {
     return reds->config->video_codecs;

server/reds.h

@@ -27,6 +27,7 @@
 #include "char-device.h"
 #include "spice.h"
 #include "red-channel.h"
+#include "video-encoder.h"
 #include "main-dispatcher.h"
 #include "migration-protocol.h"
 
@@ -54,6 +55,7 @@ void reds_send_device_display_info(RedsState *reds);
 void reds_handle_agent_mouse_event(RedsState *reds, const VDAgentMouseState *mouse_state); // used by inputs_channel
 
 GArray* reds_get_renderers(RedsState *reds);
+char *reds_get_video_codec_fullname(RedVideoCodec *codec);
 
 enum {
     RED_RENDERER_INVALID,

server/spice-server.h

@@ -136,6 +136,22 @@ enum {
 };
 
 int spice_server_set_video_codecs(SpiceServer *s, const char* video_codecs);
+
+/**
+ * Returns a newly allocated string describing video encoders/codecs
+ * currently allowed in @s Spice server. The string returned by
+ * this function must be released with spice_server_free_video_codecs.
+ *
+ * @s: the Spice server to query
+ * @return the string describing the video encoders/codecs currently enabled
+ */
+const char *spice_server_get_video_codecs(SpiceServer *s);
+
+/**
+ * Releases the memory of the video-codec string returned by
+ * spice_server_get_video_codecs.
+ */
+void spice_server_free_video_codecs(SpiceServer *s, const char *video_codecs);
 int spice_server_set_playback_compression(SpiceServer *s, int enable);
 int spice_server_set_agent_mouse(SpiceServer *s, int enable);
 int spice_server_set_agent_copypaste(SpiceServer *s, int enable);

server/spice-server.syms

@@ -178,3 +178,9 @@ SPICE_SERVER_0.14.2 {
 global:
     spice_qxl_set_device_info;
 } SPICE_SERVER_0.13.2;
+
+SPICE_SERVER_0.14.3 {
+global:
+    spice_server_get_video_codecs;
+    spice_server_free_video_codecs;
+} SPICE_SERVER_0.14.2;

server/video-encoder.h

@@ -213,4 +213,6 @@ typedef struct RedVideoCodec {
     uint32_t cap;
 } RedVideoCodec;
 
+char *video_codecs_to_string(GArray *video_codecs, const char *sep);
+
 #endif /* VIDEO_ENCODER_H_ */

server/video-stream.c

@@ -970,3 +970,26 @@ void video_stream_trace_add_drawable(DisplayChannel *display,
     trace->height = src_area->bottom - src_area->top;
     trace->dest_area = item->red_drawable->bbox;
 }
+
+/*
+ * video_codecs: an array of RedVideoCodec
+ * sep: a string for separating the list elements
+ *
+ * returns a string of "enc:codec<sep>"* that must be released
+ *         with g_free.
+ */
+char *video_codecs_to_string(GArray *video_codecs, const char *sep)
+{
+    int i;
+    GString *msg = g_string_new("");
+
+    for (i = 0; i < video_codecs->len; i++) {
+        RedVideoCodec codec = g_array_index(video_codecs, RedVideoCodec, i);
+        char *codec_name = reds_get_video_codec_fullname(&codec);
+
+        g_string_append_printf(msg, "%s%s", i ? sep : "", codec_name);
+        g_free(codec_name);
+    }
+
+    return g_string_free(msg, FALSE);
+}