command: add keypress, keydown, and keyup commands.

These commands are used to simulate keypresses using the key names from
input.conf.

DOCS/interface-changes.rst

@@ -20,6 +20,7 @@ Interface changes
 ::
 
  --- mpv 0.10.0 will be released ---
+    - add "keypress", "keydown", and "keyup" commands
     - deprecate --ad-spdif-dtshd and enabling passthrough via --ad
       add --audio-spdif as replacement
     - remove "get_property" command

DOCS/man/input.rst

@@ -395,6 +395,23 @@ List of Input Commands
     <double>
         The mouse event represents double-click.
 
+``keypress <key_name>``
+    Send a key event through mpv's input handler, triggering whatever
+    behavior is configured to that key. ``key_name`` uses the ``input.conf``
+    naming scheme for keys and modifiers. Useful for the client API: key events
+    can be sent to libmpv to handle internally.
+
+``keydown <key_name>``
+    Similar to ``keypress``, but sets the ``KEYDOWN`` flag so that if the key is
+    bound to a repeatable command, it will be run repeatedly with mpv's key
+    repeat timing until the ``keyup`` command is called.
+
+``keyup [<key_name>]``
+    Set the ``KEYUP`` flag, stopping any repeated behavior that had been
+    triggered. ``key_name`` is optional. If ``key_name`` is not given or is an
+    empty string, ``KEYUP`` will be set on all keys. Otherwise, ``KEYUP`` will
+    only be set on the key specified by ``key_name``.
+
 ``audio-add "<file>" [<flags> [<title> [<lang>]]]``
     Load the given audio file. See ``sub-add`` command.
 

input/cmd_list.c

@@ -203,6 +203,9 @@ const struct mp_cmd_def mp_cmds[] = {
       OARG_CHOICE(0, ({"single", 0},
                       {"double", 1})),
   }},
+  { MP_CMD_KEYPRESS, "keypress", { ARG_STRING } },
+  { MP_CMD_KEYDOWN, "keydown", { ARG_STRING } },
+  { MP_CMD_KEYUP, "keyup", { OARG_STRING("") } },
 
   { MP_CMD_AUDIO_ADD, "audio-add", { ARG_STRING,
       OARG_CHOICE(0, ({"select", 0}, {"auto", 1}, {"cached", 2})),

input/cmd_list.h

@@ -87,6 +87,9 @@ enum mp_command_type {
     MP_CMD_DROP_BUFFERS,
 
     MP_CMD_MOUSE,
+    MP_CMD_KEYPRESS,
+    MP_CMD_KEYDOWN,
+    MP_CMD_KEYUP,
 
     /// Audio Filter commands
     MP_CMD_AF,

player/command.c

@@ -4846,6 +4846,36 @@ int run_command(struct MPContext *mpctx, struct mp_cmd *cmd, struct mpv_node *re
         break;
     }
 
+    case MP_CMD_KEYPRESS:
+    case MP_CMD_KEYDOWN: {
+        const char *key_name = cmd->args[0].v.s;
+        int code = mp_input_get_key_from_name(key_name);
+        if (code < 0) {
+            MP_ERR(mpctx, "%s is not a valid input name.\n", key_name);
+            return -1;
+        }
+        if (cmd->id == MP_CMD_KEYDOWN)
+            code |= MP_KEY_STATE_DOWN;
+
+        mp_input_put_key(mpctx->input, code);
+        break;
+    }
+
+    case MP_CMD_KEYUP: {
+        const char *key_name = cmd->args[0].v.s;
+        if (key_name[0] == '\0') {
+            mp_input_put_key(mpctx->input, MP_INPUT_RELEASE_ALL);
+        } else {
+            int code = mp_input_get_key_from_name(key_name);
+            if (code < 0) {
+                MP_ERR(mpctx, "%s is not a valid input name.\n", key_name);
+                return -1;
+            }
+            mp_input_put_key(mpctx->input, code | MP_KEY_STATE_UP);
+        }
+        break;
+    }
+
     default:
         MP_VERBOSE(mpctx, "Received unknown cmd %s\n", cmd->name);
         return -1;