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Diffstat (limited to 'tools/emacs-pkgs/niri/niri.el')
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diff --git a/tools/emacs-pkgs/niri/niri.el b/tools/emacs-pkgs/niri/niri.el new file mode 100644 index 000000000000..32b65efdfcaa --- /dev/null +++ b/tools/emacs-pkgs/niri/niri.el @@ -0,0 +1,181 @@ +;;; niri.el --- seamless niri/emacs integration. -*- lexical-binding: t; -*- +;; +;; Copyright (C) 2024 The TVL Contributors +;; +;; Author: Vincent Ambo <tazjin@tvl.su> +;; Version: 1.0 +;; Package-Requires: ((emacs "27.1")) +;; +;;; Commentary: +;; +;; After having used EXWM for many years (7 or so?) it's become second nature +;; that there is no difference between windows and Emacs buffers. This means +;; that from any Emacs buffer (or, in the case of EXWM, from any X window) it's +;; possible to switch to any of the others. +;; +;; This implements similar logic for Emacs running in Niri, consisting of two +;; sides of the integration: +;; +;; # In Emacs +;; +;; Inside of Emacs, when switching buffers, populate the buffer-switching menu +;; additionally with all open Niri windows. Selecting a Niri window moves the +;; screen to that window. +;; +;; # Outside of Emacs +;; +;; Provides an interface for the same core functionality that can be used from +;; shell scripts, and bound to selectors like dmenu or rofi. +;; +;; # Switching to Emacs buffers +;; +;; Some special logic exists for handling the case of switching to an Emacs +;; buffer. There are several conditions that we can be in, that each have a +;; predictable result: +;; +;; In a non-Emacs window, selecting an Emacs buffer will either switch to an +;; Emacs frame already displaying this buffer, or launch a new frame for it. +;; +;; Inside of Emacs, if *another* frame is already displaying the buffer, switch +;; to it. Otherwise the behaviour is the same as standard buffer switching. + +(require 'seq) +(require 'map) + +(defun niri-list-windows () + "List all currently open Niri windows." + (json-parse-string + (shell-command-to-string "niri msg -j windows") + :false-object nil)) + +(defun niri--window-is-emacs (window) + (equal (map-elt window "app_id") "emacs")) + +(defun niri--list-selectables () + "Lists all currently selectable things in a format that can work +with completing-read. Selectable means all open Niri +windows (except Emacs windows) and all Emacs buffers. + +Emacs windows are returned separately, as they are required for +frame navigation." + (let* (;; all niri windows, with emacs/non-emacs windows split up + (all-windows (niri-list-windows)) + (windows (seq-filter (lambda (w) (not (niri--window-is-emacs w))) + all-windows)) + (emacs-windows (seq-filter #'niri--window-is-emacs all-windows)) + + ;; all non-hidden buffers + (buffers (seq-filter (lambda (b) (not (string-prefix-p " " (buffer-name b)))) + (buffer-list))) + (selectables (make-hash-table :test 'equal :size (+ (length windows) + (length buffers))))) + (seq-do (lambda (window) + (map-put! selectables (map-elt window "title") + (cons :niri window))) + windows) + + (seq-do (lambda (buf) + (map-put! selectables (buffer-name buf) + (cons :emacs buf))) + buffers) + (cons selectables emacs-windows))) + +(defun niri--focus-window (window) + (shell-command (format "niri msg action focus-window --id %d" + (map-elt window "id")))) + +(defun niri--target-action-internal (target) + "Focus the given TARGET (a Niri window or Emacs buffer). This is +used when called from inside of Emacs. It will NOT correctly +switch Niri windows when called from outside of Emacs." + (pcase (car target) + (:emacs (pop-to-buffer (cdr target) '((display-buffer-reuse-window + display-buffer-same-window) + (reusable-frames . 0)))) + (:niri (niri--focus-window (cdr target))))) + +(defun niri-go-anywhere () + "Interactively select and switch to an open Niri window, or an + Emacs buffer." + (interactive) + (let* ((selectables (car (niri--list-selectables))) + ;; Annotate buffers that display remote files. I frequently + ;; want to see it, because I might have identically named + ;; files open locally and remotely at the same time, and it + ;; helps with differentiating them. + (completion-extra-properties + '(:annotation-function + (lambda (name) + (let ((elt (map-elt selectables name))) + (pcase (car elt) + (:emacs + (if-let* ((file (buffer-file-name (cdr elt))) + (remote (file-remote-p file))) + (format " [%s]" remote))) + (:niri (format " [%s]" (map-elt (cdr elt) "app_id")))))))) + + (target-key (completing-read "Switch to: " (map-keys selectables))) + (target (map-elt selectables target-key))) + (if target + (niri--target-action-internal target) + (switch-to-buffer target-key nil t)))) + + +(defun niri--target-action-external (target frames) + "Focus the given TARGET (a Niri window or Emacs buffer). This +always behaves correctly, but does more work than the -internal +variant. It should only be called when invoking the switcher from +outside of Emacs (i.e. through `emacsclient'). + +FRAMES is the exact list of Emacs frames that existed at the time +the switcher was invoked." + (pcase (car target) + (:niri (niri--focus-window (cdr target))) + + ;; When switching to an Emacs buffer from outside of Emacs, we run into the + ;; additional complication that Wayland does not allow arbitrary + ;; applications to change the focused window. Calling e.g. + ;; `select-frame-set-input-focus' has no effect on Wayland when not called + ;; from within a focused Emacs frame. + ;; + ;; However, due to concurrency, frames may change between the moment when we + ;; start the switcher (and potentially wait for user input), and when the + ;; final selection happens. + ;; + ;; To get around this we try to match the target Emacs frame (if present) to + ;; a Niri window, switch to it optimistically, and *then* execute the final + ;; buffer switching command. + (:emacs + (if-let ((window (get-buffer-window (cdr target) t)) + (frame (window-frame window)) + (frame-name (frame-parameter frame 'name)) + (niri-window (seq-find (lambda (w) + (equal (map-elt w "title") frame-name)) + frames))) + ;; Target frame found and could be matched to a Niri window: Go there! + (progn (select-window window) ;; ensure the right window in the frame has focus + (niri--focus-window niri-window) + (message "Switched to existing window for \"%s\"" (buffer-name (cdr target)))) + + ;; Target frame not found; is Emacs the focused program? + (if (seq-find (lambda (w) (map-elt w "is_focused")) frames) + (switch-to-buffer (cdr target)) + ;; if not, just make a new frame + (display-buffer (cdr target) '(display-buffer-pop-up-frame))))))) + +(defun niri-go-anywhere-external () + "Use a dmenu-compatible launcher like `fuzzel' to achieve the same +effect as `niri-go-anywhere', but from outside of Emacs through +Emacsclient." + (interactive) ;; TODO no? + (let* ((all (niri--list-selectables)) + (selectables (car all)) + (target (with-temp-buffer + (dolist (key (map-keys selectables)) + (insert key "\n")) + (call-process-region nil nil "fuzzel" t t nil "-d") + (string-trim (buffer-string))))) + (when-let ((selectable (map-elt selectables target))) + (niri--target-action-external selectable (cdr all))))) + +(provide 'niri) |