add persistent org-roam-buffer

org-roam-completion.el

@@ -112,6 +112,13 @@ This is a `completion-at-point' function, and is active when
                                 str))
                 (forward-char 2)))))))
 
+(defun org-roam--register-completion-functions ()
+  "."
+  (dolist (fn org-roam-completion-functions)
+    (add-hook 'completion-at-point-functions fn nil t)))
+
+(add-hook 'org-roam-find-file-hook #'org-roam--register-completion-functions)
+
 (provide 'org-roam-completion)
 
 ;;; org-roam-completion.el ends here

org-roam-db.el

@@ -44,6 +44,7 @@
 (require 'org-roam-structs)
 
 (defvar org-roam-directory)
+(defvar org-roam-find-file-hook)
 (defvar org-roam-verbose)
 (defvar org-agenda-files)
 
@@ -463,6 +464,12 @@ If the file exists, update the cache with information."
           (org-roam-db-map-links
            (list #'org-roam-db-insert-link)))))))
 
+(defun org-roam-db--update-on-save-h ()
+  "."
+  (add-hook 'after-save-hook #'org-roam-db-update-file nil t))
+
+(add-to-list 'org-roam-find-file-hook #'org-roam-db--update-on-save-h)
+
 ;; Diagnostic Interactives
 (defun org-roam-db-diagnose-node ()
   "Print information about node at point."

org-roam-mode.el

@@ -35,6 +35,7 @@
 (require 'org-roam-utils)
 
 (defvar org-roam-directory)
+(defvar org-roam-find-file-hook)
 
 (declare-function org-roam--org-file-p "org-roam")
 (declare-function org-roam-node-at-point "org-roam-node")
@@ -120,10 +121,6 @@ and `:slant'."
   :group 'org-roam-faces)
 
 ;;; Variables
-;; TODO: make defcustom
-(defvar org-roam-last-window nil
-  "Last window `org-roam' was called from.")
-
 (defvar org-roam-mode-sections nil
   "List of functions that insert sections for Org-roam.")
 
@@ -169,5 +166,67 @@ which visits the thing at point."
           (switch-to-buffer-other-window buffer)))
     (user-error "No node at point")))
 
+;;; Persistent buffer
+(defvar org-roam-current-node nil
+  "The current node at point.")
+
+(defvar org-roam-buffer "*org-roam*"
+  "The persistent Org-roam buffer name.")
+
+(defun org-roam-buffer--post-command-h ()
+  "Reconstructs `org-roam-buffer'.
+This needs to be quick or infrequent, because this is run at
+`post-command-hook'.  If REDISPLAY, force an update of
+`org-roam-buffer'."
+  (when (get-buffer-window org-roam-buffer)
+    (when-let ((node (org-roam-node-at-point)))
+      (unless (equal node org-roam-current-node)
+        (setq org-roam-current-node node)
+        (org-roam-buffer-persistent-redisplay)))))
+
+(define-inline org-roam-buffer--visibility ()
+  "Return whether the current visibility state of the org-roam buffer.
+Valid states are 'visible, 'exists and 'none."
+  (declare (side-effect-free t))
+  (inline-quote
+   (cond
+    ((get-buffer-window org-roam-buffer) 'visible)
+    ((get-buffer org-roam-buffer) 'exists)
+    (t 'none))))
+
+(defun org-roam-buffer-toggle ()
+  "Toggle display of the `org-roam-buffer'."
+  (interactive)
+  (pcase (org-roam-buffer--visibility)
+    ('visible
+     (progn
+       (delete-window (get-buffer-window org-roam-buffer))
+       (remove-hook 'post-command-hook #'org-roam-buffer--post-command-h)))
+    ((or 'exists 'none)
+     (progn
+       (display-buffer (get-buffer-create org-roam-buffer))
+       (setq org-roam-current-node (org-roam-node-at-point))
+       (org-roam-buffer-persistent-redisplay)))))
+
+(defun org-roam-buffer-persistent-redisplay ()
+  "Recompute contents of the persistent Org-roam buffer.
+Has no effect when `org-roam-current-node' is nil."
+  (when org-roam-current-node
+    (with-current-buffer (get-buffer-create org-roam-buffer)
+      (let ((inhibit-read-only t))
+        (erase-buffer)
+        (org-roam-mode)
+        (org-roam-set-header-line-format (org-roam-node-title org-roam-current-node))
+        (magit-insert-section (org-roam)
+          (magit-insert-heading)
+          (dolist (fn org-roam-mode-sections)
+            (funcall fn org-roam-current-node)))))))
+
+(defun org-roam-buffer--redisplay ()
+  "."
+  (add-hook 'post-command-hook #'org-roam-buffer--post-command-h nil t))
+
+(add-hook 'org-roam-find-file-hook #'org-roam-buffer--redisplay)
+
 (provide 'org-roam-mode)
 ;;; org-roam-mode.el ends here

org-roam.el

@@ -372,6 +372,9 @@ Use external shell commands if defined in `org-roam-list-files-commands'."
     completions))
 
 ;;; Org-roam setup and teardown
+(defvar org-roam-find-file-hook nil
+  "Hook run when an Org-roam file is visited.")
+
 (defun org-roam-setup ()
   "Setup Org-roam."
   (interactive)
@@ -381,7 +384,7 @@ Use external shell commands if defined in `org-roam-list-files-commands'."
     (lwarn '(org-roam) :error "Cannot find executable 'sqlite3'. \
 Ensure it is installed and can be found within `exec-path'. \
 M-x info for more information at Org-roam > Installation > Post-Installation Tasks."))
-  (add-hook 'find-file-hook #'org-roam--find-file-hook-function)
+  (add-hook 'find-file-hook #'org-roam--file-setup)
   (add-hook 'kill-emacs-hook #'org-roam-db--close-all)
   (advice-add 'rename-file :after #'org-roam--rename-file-advice)
   (advice-add 'delete-file :before #'org-roam--delete-file-advice)
@@ -390,7 +393,7 @@ M-x info for more information at Org-roam > Installation > Post-Installation Tas
 (defun org-roam-teardown ()
   "Teardown Org-roam."
   (interactive)
-  (remove-hook 'find-file-hook #'org-roam--find-file-hook-function)
+  (remove-hook 'find-file-hook #'org-roam--file-setup)
   (remove-hook 'kill-emacs-hook #'org-roam-db--close-all)
   (advice-remove 'rename-file #'org-roam--rename-file-advice)
   (advice-remove 'delete-file #'org-roam--delete-file-advice)
@@ -401,14 +404,10 @@ M-x info for more information at Org-roam > Installation > Post-Installation Tas
       (remove-hook 'after-save-hook #'org-roam-db-update-file t))))
 
 ;;; Hooks and advices
-(defun org-roam--find-file-hook-function ()
-  "Setup automatic database update."
+(defun org-roam--file-setup ()
+  "Setup an Org-roam file."
   (when (org-roam--org-roam-file-p)
-    (setq org-roam-last-window (get-buffer-window))
-    (run-hooks 'org-roam-file-setup-hook) ; Run user hooks
-    (add-hook 'after-save-hook #'org-roam-db-update-file nil t)
-    (dolist (fn org-roam-completion-functions)
-      (add-hook 'completion-at-point-functions fn nil t))))
+    (run-hooks 'org-roam-find-file-hook)))
 
 (defun org-roam--delete-file-advice (file &optional _trash)
   "Maintain cache consistency when file deletes.