command: add a change-list command

Requested. See manpage additions.

The main reason why this goes through the trouble to keep the
action/operation parameter separate is so that we don't expose some
option parser implementation details to the command (although that is a
relatively weak reason), and also to make it more different from the
"set" command, which can't support this type of option as it goes
through the property layer.

Fixes #5435.

DOCS/man/input.rst

@@ -732,6 +732,23 @@ Input Commands that are Possibly Subject to Change
 ``load-script "<path>"``
     Load a script, similar to the ``--script`` option.
 
+``change-list "<option>" "<operation>" "<value>"``
+    This command changes list options as described in `List Options`_. The
+    ``<option>`` parameter is the normal option name, while ``<operation>`` is
+    the suffix or action used on the option.
+
+    Some operations take no value, but the command still requires the value
+    parameter. In these cases, the value must be an empty string.
+
+    .. admonition:: Example
+
+        ``change-list glsl-shaders append file.glsl``
+
+        Add a filename to the ``glsl-shaders`` list. The command line
+        equivalent is ``--glsl-shaders-append=file.glsl`` or alternatively
+        ``--glsl-shader=file.glsl``.
+
+
 Undocumented commands: ``tv-last-channel`` (TV/DVB only),
 ``ao-reload`` (experimental/internal).
 

DOCS/man/mpv.rst

@@ -448,6 +448,9 @@ aliases for the proper option with ``-append`` action. For example,
 
 Some options only support a subset of the above.
 
+Options of this type can be changed at runtime using the ``change-list``
+command, which takes the suffix as separate operation parameter.
+
 Playing DVDs
 ------------
 

input/cmd_list.c

@@ -150,6 +150,7 @@ const struct mp_cmd_def mp_cmds[] = {
   { MP_CMD_RUN, "run", { ARG_STRING, ARG_STRING }, .vararg = true },
 
   { MP_CMD_SET, "set", { ARG_STRING,  ARG_STRING } },
+  { MP_CMD_CHANGE_LIST, "change-list", { ARG_STRING, ARG_STRING, ARG_STRING } },
   { MP_CMD_ADD, "add", { ARG_STRING, OARG_DOUBLE(1) },
     .allow_auto_repeat = true,
     .scalable = true,

input/cmd_list.h

@@ -65,6 +65,7 @@ enum mp_command_type {
     MP_CMD_SUB_REMOVE,
     MP_CMD_SUB_RELOAD,
     MP_CMD_SET,
+    MP_CMD_CHANGE_LIST,
     MP_CMD_PRINT_TEXT,
     MP_CMD_SHOW_TEXT,
     MP_CMD_EXPAND_TEXT,

player/command.c

@@ -4918,6 +4918,37 @@ int run_command(struct MPContext *mpctx, struct mp_cmd *cmd, struct mpv_node *re
         break;
     }
 
+    case MP_CMD_CHANGE_LIST: {
+        char *name = cmd->args[0].v.s;
+        char *op = cmd->args[1].v.s;
+        char *value = cmd->args[2].v.s;
+        struct m_config_option *co = m_config_get_co(mpctx->mconfig, bstr0(name));
+        if (!co) {
+            set_osd_msg(mpctx, osdl, osd_duration, "Unknown option: '%s'", name);
+            return -1;
+        }
+        const struct m_option_type *type = co->opt->type;
+        bool found = false;
+        for (int i = 0; type->actions && type->actions[i].name; i++) {
+            const struct m_option_action *action = &type->actions[i];
+            if (strcmp(action->name, op) == 0)
+                found = true;
+        }
+        if (!found) {
+            set_osd_msg(mpctx, osdl, osd_duration, "Unknown action: '%s'", op);
+            return -1;
+        }
+        char *optname = mp_tprintf(80, "%s-%s", name, op); // the dirty truth
+        int r = m_config_set_option_cli(mpctx->mconfig, bstr0(optname),
+                                        bstr0(value), M_SETOPT_RUNTIME);
+        if (r < 0) {
+            set_osd_msg(mpctx, osdl, osd_duration,
+                        "Failed setting option: '%s'", name);
+            return -1;
+        }
+        break;
+    }
+
     case MP_CMD_ADD:
     case MP_CMD_CYCLE:
     {