mp.input: allow specifying which input request to terminate

This commit adds a new argument to the `input.terminate()` function
which allows specifying the specific input request to cancel.

Previosuly, there was no way to guarantee that the input request being
terminated was the one intended; the asynchronous nature of the API
meant that it was always possible (though unlikely) that another client
may have activated its own input request while the termination request
was in transit.

This commit provides a backwards compatible way to terminate specific
requests. Now `input.get` and `input.select` return an opaque id object
which can be optionally passed into `input.terminate()` to specify which
input request should be terminated.

One advantage of this approach is that it is backwards compatible; a
script passing id values will work without issue on older versions of
mpv as `input.terminate()` previously ignored all of its arguments.

The documentation has been updated to show an example of using these id
values and to promote safe handling of async terminations.

This approach is based on the behaviour of `mp.command_native_async` and
`mp.abort_async_command`.

Author: CogentRedTester

DOCS/man/javascript.rst

@@ -196,11 +196,11 @@ meta-paths like ``~~/foo`` (other JS file functions do expand meta paths).
 ``mp.options.read_options(obj [, identifier [, on_update]])`` (types:
 string/boolean/number)
 
-``mp.input.get(obj)``
+``id = mp.input.get(obj)``
 
-``mp.input.select(obj)``
+``id = mp.input.select(obj)``
 
-``mp.input.terminate()``
+``mp.input.terminate([id])``
 
 ``mp.input.log(message, style)``
 

DOCS/man/lua.rst

@@ -975,8 +975,34 @@ REPL.
         among the ones stored for ``input.get()`` calls. Defaults to the calling
         script name with ``prompt`` appended.
 
-``input.terminate()``
-    Close the console.
+    Returns a table with undefined contents, which can be used as argument for
+    ``input.terminate()``.
+
+``input.terminate([t])``
+    Close the console. If the return value of an ``input.get`` or ``input.select``
+    request is passed in as the first argument then the console will only be
+    closed if it is presenting that specific request.
+
+    Example:
+
+    ::
+        local id, timer
+        id = input.get({
+            prompt = "Open File:\n",
+            history_path = "~~state/open-file-history",
+            opened = function()
+                timer = mp.add_timeout(20, function()
+                    input.terminate(id)
+                end)
+            end,
+            edited = function()
+                timer:kill()
+                timer:resume()
+            end,
+            submit = function(path)
+                mp.commandv("loadfile", path)
+            end
+        })
 
 ``input.log(message, style, terminal_style)``
     Add a line to the log buffer. ``style`` can contain additional ASS tags to
@@ -1027,6 +1053,9 @@ REPL.
     ``keep_open``
         Whether to keep the console open on submit. Defaults to ``false``.
 
+    Returns a table with undefined contents, which can be used as argument for
+    ``input.terminate()``.
+
     Example:
 
         ::

player/javascript/defaults.js

@@ -684,9 +684,16 @@ mp.input = {
 
         mp.commandv("script-message-to", "console", "get-input",
                     mp.script_name, handler_id, JSON.stringify(t));
+
+        return {
+            handler_id: handler_id
+        }
     },
-    terminate: function () {
-        mp.commandv("script-message-to", "console", "disable");
+    terminate: function (t) {
+        mp.commandv("script-message-to", "console", "terminate-input", JSON.stringify({
+            script_name: mp.script_name,
+            handler_id: (t ? t.handler_id : '') || '',
+        }));
     },
     log: function (message, style, terminal_style) {
         mp.commandv("script-message-to", "console", "log", JSON.stringify({

player/lua/console.lua

@@ -1663,6 +1663,15 @@ mp.register_script_message("disable", function()
     set_active(false)
 end)
 
+mp.register_script_message("terminate-input", function(message)
+    message = utils.parse_json(message)
+    if not message.handler_id or message.handler_id == '' then
+        set_active(false)
+    elseif message.script_name == input_caller and message.handler_id == input_caller_handler then
+        set_active(false)
+    end
+end)
+
 mp.register_script_message("get-input", function (script_name, handler_id, args)
     if open then
         mp.commandv("script-message-to", input_caller, input_caller_handler,

player/lua/input.lua

@@ -61,12 +61,19 @@ function input.get(t)
     local handler_id = register_event_handler(t)
     mp.commandv("script-message-to", "console", "get-input",
                 mp.get_script_name(), handler_id, utils.format_json(get_non_callbacks(t)))
+
+    return {
+        handler_id = handler_id
+    }
 end
 
 input.select = input.get
 
-function input.terminate()
-    mp.commandv("script-message-to", "console", "disable")
+function input.terminate(t)
+    mp.commandv("script-message-to", "console", "terminate-input", utils.format_json({
+        script_name = mp.get_script_name(),
+        handler_id = t and t.handler_id or ''
+    }))
 end
 
 function input.log(message, style, terminal_style)