command: add a mechanism to allow scripts to intercept file loads

A vague idea to get something similar what libquvi did.

Undocumented because it might change a lot, or even be removed. To give
an idea what it does, a Lua script could do the following:

--                      type       ID priority
mp.commandv("hook_add", "on_load", 0, 0)
mp.register_script_message("hook_run", function(param, param2)
    -- param is "0", the user-chosen ID from the hook_add command
    -- param2 is the magic value that has to be passed to finish
    -- the hook
    mp.resume_all()
    -- do something, maybe set options that are reset on end:
    mp.set_property("file-local-options/name", "value")
    -- or change the URL that's being opened:
    local url = mp.get_property("stream-open-filename")
    mp.set_property("stream-open-filename", url .. ".png")
    -- let the player (or the next script) continue
    mp.commandv("hook_ack", param2)
end)

1 files changed, 4 insertions, 0 deletions

diff --git a/player/client.c b/player/client.c
index 38b0898f86..2166255c2c 100644
--- a/player/client.c
+++ b/player/client.c
@@ -871,6 +871,8 @@ static int run_client_command(mpv_handle *ctx, struct mp_cmd *cmd)
     if (mp_input_is_abort_cmd(cmd))
         mp_cancel_trigger(ctx->mpctx->playback_abort);
 
+    cmd->sender = ctx->name;
+
     struct cmd_request req = {
         .mpctx = ctx->mpctx,
         .cmd = cmd,
@@ -905,6 +907,8 @@ static int run_cmd_async(mpv_handle *ctx, uint64_t ud, struct mp_cmd *cmd)
     if (!cmd)
         return MPV_ERROR_INVALID_PARAMETER;
 
+    cmd->sender = ctx->name;
+
     struct cmd_request *req = talloc_ptrtype(NULL, req);
     *req = (struct cmd_request){
         .mpctx = ctx->mpctx,