command: add protocol-list property

Fixes #1972.

DOCS/interface-changes.rst

@@ -20,6 +20,7 @@ Interface changes
 ::
 
  --- mpv 0.10.0 will be released ---
+    - add protocol-list property
     - deprecate audio-samplerate and audio-channels properties
       (audio-params sub-properties are the replacement)
     - add audio-params and audio-out-params properties

DOCS/man/input.rst

@@ -1778,6 +1778,12 @@ Property list
     Return the working directory of the mpv process. Can be useful for JSON IPC
     users, because the command line player usually works with relative paths.
 
+``protocol-list``
+    List of protocol prefixes potentially recognized by the player. They are
+    returned without trailing ``://`` suffix (which is still always required).
+    In some cases, the protocol will not actually be supported (consider
+    ``https`` if ffmpeg is not compiled with TLS support).
+
 ``mpv-version``
     Return the mpv version/copyright string. Depending on how the binary was
     built, it might contain either a release version, or just a git hash.

player/command.c

@@ -3063,6 +3063,20 @@ static int mp_property_cwd(void *ctx, struct m_property *prop,
     return M_PROPERTY_NOT_IMPLEMENTED;
 }
 
+static int mp_property_protocols(void *ctx, struct m_property *prop,
+                                 int action, void *arg)
+{
+    switch (action) {
+    case M_PROPERTY_GET:
+        *(char ***)arg = stream_get_proto_list();
+        return M_PROPERTY_OK;
+    case M_PROPERTY_GET_TYPE:
+        *(struct m_option *)arg = (struct m_option){.type = CONF_TYPE_STRING_LIST};
+        return M_PROPERTY_OK;
+    }
+    return M_PROPERTY_NOT_IMPLEMENTED;
+}
+
 static int mp_property_version(void *ctx, struct m_property *prop,
                                int action, void *arg)
 {
@@ -3465,6 +3479,8 @@ static const struct m_property mp_properties[] = {
 
     {"working-directory", mp_property_cwd},
 
+    {"protocol-list", mp_property_protocols},
+
     {"mpv-version", mp_property_version},
     {"mpv-configuration", mp_property_configuration},
 

stream/stream.c

@@ -1024,11 +1024,10 @@ int mp_cancel_get_fd(struct mp_cancel *c)
     return c->wakeup_pipe[0];
 }
 
-void stream_print_proto_list(struct mp_log *log)
+char **stream_get_proto_list(void)
 {
-    int count = 0;
+    char **list = NULL;
-
+    int num = 0;
-    mp_info(log, "Protocols:\n\n");
     for (int i = 0; stream_list[i]; i++) {
         const stream_info_t *stream_info = stream_list[i];
 
@@ -1039,9 +1038,25 @@ void stream_print_proto_list(struct mp_log *log)
             if (*stream_info->protocols[j] == '\0')
                continue;
 
-            mp_info(log, " %s://\n", stream_info->protocols[j]);
+            MP_TARRAY_APPEND(NULL, list, num,
-            count++;
+                                talloc_strdup(NULL, stream_info->protocols[j]));
         }
     }
+    MP_TARRAY_APPEND(NULL, list, num, NULL);
+    return list;
+}
+
+void stream_print_proto_list(struct mp_log *log)
+{
+    int count = 0;
+
+    mp_info(log, "Protocols:\n\n");
+    char **list = stream_get_proto_list();
+    for (int i = 0; list[i]; i++) {
+        mp_info(log, " %s://\n", list[i]);
+        count++;
+        talloc_free(list[i]);
+    }
+    talloc_free(list);
     mp_info(log, "\nTotal: %d protocols\n", count);
 }

stream/stream.h

@@ -289,5 +289,6 @@ void mp_setup_av_network_options(struct AVDictionary **dict,
                                  struct MPOpts *opts);
 
 void stream_print_proto_list(struct mp_log *log);
+char **stream_get_proto_list(void);
 
 #endif /* MPLAYER_STREAM_H */