add sync live preview back

Author: Danny McClanahan

markdown-mode.el

@@ -1096,7 +1096,7 @@ update the buffer containing the preview and return the buffer."
   :type 'function)
 
 (defcustom markdown-live-preview-delete-export 'delete-on-destroy
-  "Delete exported html file when using `markdown-live-preview-export' on every
+  "Delete exported html file when using `markdown-live-preview-sync-export' on every
 export by setting to 'delete-on-export, when quitting
 `markdown-live-preview-mode' by setting to 'delete-on-destroy, or not at all
 when nil."
@@ -1108,6 +1108,12 @@ when nil."
   :group 'markdown
   :type 'integer)
 
+(defcustom markdown-live-preview-do-sync nil
+  "Whether to do live preview exports synchronously on save, or asynchronously
+with an idle timer."
+  :group 'markdown
+  :type 'boolean)
+
 (defcustom markdown-list-indent-width 4
   "Depth of indentation for markdown lists. Used in `markdown-demote-list-item'
 and `markdown-promote-list-item'."
@@ -5871,7 +5877,8 @@ current filename, but with the extension removed and replaced with .html."
 ;;; Live Preview ===============================================================
 
 (defvar markdown-live-preview-view-buffer nil
-  "Buffer used to preview markdown output in `markdown-live-preview-export'.")
+  "Buffer used to preview markdown output in
+`markdown-live-preview-sync-export' and `markdown-live-preview-async-export'.")
 (make-variable-buffer-local 'markdown-live-preview-view-buffer)
 
 (defvar markdown-live-preview-source-buffer nil
@@ -5889,6 +5896,10 @@ buffer. Inverse of `markdown-live-preview-view-buffer'.")
 `markdown-live-preview-async-export'.")
 (make-variable-buffer-local 'markdown-live-preview-idle-timer)
 
+(defvar markdown-live-preview-current-buffer-sync-async nil
+  "Status of sync or async live preview in current buffer.")
+(make-variable-buffer-local 'markdown-live-preview-current-buffer-sync-async)
+
 (defun markdown-live-preview-window-eww (file)
   "A `markdown-live-preview-window-function' for previewing with `eww'."
   (if (require 'eww nil t)
@@ -5928,14 +5939,14 @@ alive."
       (set-window-point win pt)
       (set-window-start win start))))
 
-(defun markdown-live-preview-cleanup-export (buf msg)
+(defun markdown-live-preview-async-cleanup-export (buf msg)
   (with-current-buffer buf
     (when (eq markdown-live-preview-delete-export 'delete-on-export)
       (markdown-live-preview-delete-export))
     (setq markdown-live-preview-currently-exporting-process nil))
   (message msg))
 
-(defun markdown-live-preview-create-view-display (src-buf out-file msg)
+(defun markdown-live-preview-async-create-view-display (src-buf out-file msg)
   (unwind-protect
       (let (had-view-buffer window-data-list)
         (with-current-buffer src-buf
@@ -5957,7 +5968,7 @@ alive."
                          do (markdown-live-preview-window-deserialize
                              window-data view-buf))
               (markdown-display-buffer-other-window view-buf)))))
-    (markdown-live-preview-cleanup-export src-buf msg)))
+    (markdown-live-preview-async-cleanup-export src-buf msg)))
 
 (defmacro markdown-silence-messages (&rest body)
   `(cl-letf (((symbol-function #'message) (lambda (&rest _)))) ,@body))
@@ -5968,10 +5979,11 @@ alive."
     (let ((cur-msg (current-message))
           (proc-buf (process-buffer proc)))
       (kill-buffer proc-buf)
-      (markdown-live-preview-create-view-display src-buf out-file cur-msg))))
+      (markdown-live-preview-async-create-view-display
+       src-buf out-file cur-msg))))
 
-(defun markdown-live-preview-make-sentinel (src-buf out-file)
-  (lambda (proc msg)
+(defun markdown-live-preview-make-async-sentinel (src-buf out-file)
+  (lambda (proc _)
     (markdown-live-preview-do-sentinel src-buf out-file proc)))
 
 (defconst markdown-live-preview-proc-name "*markdown-live-preview*")
@@ -5984,7 +5996,8 @@ alive."
      (let* ((cur-buf (current-buffer))
             (mode major-mode)
             (out-file (markdown-live-preview-get-filename))
-            (sentinel (markdown-live-preview-make-sentinel cur-buf out-file))
+            (sentinel (markdown-live-preview-make-async-sentinel
+                       cur-buf out-file))
             (proc
              (start-process-shell-command
               markdown-live-preview-proc-name markdown-live-preview-buf-name
@@ -6004,23 +6017,64 @@ alive."
          (run-hooks 'markdown-after-export-hook)
          proc)))))
 
+(defvar markdown-live-preview-currently-exporting nil)
+
+(defun markdown-live-preview-sync-export ()
+  "Export to XHTML using `markdown-export' and browse the resulting file within
+Emacs using `markdown-live-preview-window-function' Return the buffer displaying
+the rendered output."
+  (interactive)
+  (let* ((markdown-live-preview-currently-exporting t)
+         (src-buf (current-buffer))
+         (export-file (markdown-export (markdown-live-preview-get-filename)))
+         ;; get positions in all windows currently displaying output buffer
+         (window-data
+          (markdown-live-preview-window-serialize
+           markdown-live-preview-view-buffer)))
+    (save-window-excursion
+      (let ((view-buf
+             (funcall markdown-live-preview-window-function export-file)))
+        (markdown-live-preview-link-source-view-buffers src-buf view-buf)
+        (with-current-buffer view-buf
+          (add-hook 'kill-buffer-hook
+                    #'markdown-live-preview-teardown-view t t))))
+    (with-current-buffer src-buf
+      ;; reset all windows displaying output buffer to where they were,
+      ;; now with the new output
+      (mapc #'markdown-live-preview-window-deserialize window-data)
+      ;; delete html editing buffer
+      (let ((buf (get-file-buffer export-file))) (when buf (kill-buffer buf)))
+      (when (and export-file (file-exists-p export-file)
+                 (eq markdown-live-preview-delete-export
+                     'delete-on-export))
+        (delete-file export-file))
+      markdown-live-preview-view-buffer)))
+
 (defun markdown-live-preview-update (buf)
   (lexical-let ((buf buf))
     (lambda () (with-current-buffer buf (markdown-live-preview-async-export)))))
 
 (defun markdown-live-preview-setup ()
+  (setq markdown-live-preview-current-buffer-sync-async
+        markdown-live-preview-do-sync)
   (add-hook 'kill-buffer-hook #'markdown-live-preview-teardown-source t t)
-  (markdown-live-preview-async-export)
-  (setq markdown-live-preview-idle-timer
-        (run-with-idle-timer
-         markdown-live-preview-idle-delay t
-         (markdown-live-preview-update (current-buffer)))))
+  (if markdown-live-preview-current-buffer-sync-async
+      (progn
+        (add-hook
+         'after-save-hook #'markdown-live-preview-do-sync-preview t t)
+        (markdown-live-preview-sync-export))
+    (setq markdown-live-preview-idle-timer
+          (run-with-idle-timer
+           markdown-live-preview-idle-delay t
+           (markdown-live-preview-update (current-buffer))))
+    (markdown-live-preview-async-export)))
 
 (defun markdown-live-preview-teardown-view ()
   (with-current-buffer markdown-live-preview-source-buffer
-    (setq markdown-live-preview-view-buffer nil)))
+    (setq markdown-live-preview-view-buffer nil))
+  (setq markdown-live-preview-source-buffer nil))
 
-(defun markdown-live-preview-teardown-source ()
+(defun markdown-live-preview-teardown-async ()
   (when (buffer-live-p markdown-live-preview-view-buffer)
     ;; calls `kill-buffer-hook' within `markdown-live-preview-view-buffer'
     (kill-buffer markdown-live-preview-view-buffer))
@@ -6036,6 +6090,22 @@ alive."
     (setq markdown-live-preview-idle-timer nil))
   (remove-hook 'kill-buffer-hook #'markdown-live-preview-teardown-source t))
 
+(defun markdown-live-preview-teardown-sync ()
+  (when (buffer-live-p markdown-live-preview-view-buffer)
+    (kill-buffer markdown-live-preview-view-buffer))
+  (setq markdown-live-preview-view-buffer nil)
+  (remove-hook 'after-save-hook #'markdown-live-preview-do-sync-preview t)
+  ;; if set to 'delete-on-export, the output has already been deleted
+  (when (eq markdown-live-preview-delete-export 'delete-on-destroy)
+    (let ((outfile-name (markdown-live-preview-get-filename)))
+      (when (file-exists-p outfile-name)
+        (delete-file outfile-name)))))
+
+(defun markdown-live-preview-teardown-source ()
+  (if markdown-live-preview-current-buffer-sync-async
+      (markdown-live-preview-teardown-sync)
+    (markdown-live-preview-teardown-async)))
+
 (defun markdown-display-buffer-other-window (buf)
   (let ((cur-buf (current-buffer)))
     (switch-to-buffer-other-window buf)
@@ -6046,21 +6116,26 @@ alive."
   "Turn on `markdown-live-preview-mode' if not already on, and switch to its
 output buffer in another window."
   (if markdown-live-preview-mode
-      (if markdown-live-preview-view-buffer
-          (markdown-display-buffer-other-window
-           markdown-live-preview-view-buffer)
-        ;; TODO: better error message
-        (message "%s" "Error: no view buffer was created!")))
+      (markdown-display-buffer-other-window markdown-live-preview-view-buffer))
     (markdown-live-preview-mode))
 
 (defun markdown-live-preview-re-export ()
   (interactive)
   "If the current buffer is a buffer displaying the exported version of a
-`markdown-live-preview-mode' buffer, call `markdown-live-preview-export' and
-update this buffer's contents."
+`markdown-live-preview-mode' buffer, call `markdown-live-preview-sync-export'
+and update this buffer's contents."
   (when markdown-live-preview-source-buffer
     (with-current-buffer markdown-live-preview-source-buffer
-      (markdown-live-preview-async-export))))
+      (if markdown-live-preview-current-buffer-sync-async
+          (markdown-live-preview-sync-export)
+        (markdown-live-preview-async-export)))))
+
+(defun markdown-live-preview-do-sync-preview ()
+  (unless markdown-live-preview-currently-exporting
+    (if (buffer-live-p markdown-live-preview-view-buffer)
+        (markdown-live-preview-sync-export)
+      (markdown-display-buffer-other-window
+       (markdown-live-preview-sync-export)))))
 
 
 ;;; Links =====================================================================

tests/markdown-test.el

@@ -3748,7 +3748,7 @@ Detail: https://github.com/jrblevin/markdown-mode/issues/79"
                               'around 'markdown-create-fake-eww)
            (ad-activate #'markdown-live-preview-window-eww)))))
 
-(ert-deftest test-markdown-ext/live-preview-exports ()
+(defun markdown-test/live-preview-exports ()
   (markdown-test-temp-file "inline.text"
     (unless (require 'eww nil t)
       (should-error (markdown-live-preview-mode)))
@@ -3768,7 +3768,14 @@ Detail: https://github.com/jrblevin/markdown-mode/issues/79"
        (accept-process-output)
        (should (buffer-live-p markdown-live-preview-view-buffer))))))
 
-(ert-deftest test-markdown-ext/live-preview-delete-exports ()
+(ert-deftest test-markdown-ext/live-preview-exports-sync ()
+  (let ((markdown-live-preview-do-sync t))
+    (markdown-test/live-preview-exports)))
+
+(ert-deftest test-markdown-ext/live-preview-exports-async ()
+  (markdown-test/live-preview-exports))
+
+(defun markdown-test/live-preview-delete-exports ()
   (let ((markdown-live-preview-idle-delay .01)
         file-output)
     (markdown-temp-eww
@@ -3796,6 +3803,13 @@ Detail: https://github.com/jrblevin/markdown-mode/issues/79"
            (should (file-exists-p file-output)))
        (delete-file file-output)))))
 
+(ert-deftest test-markdown-ext/live-preview-delete-exports-sync ()
+  (let ((markdown-live-preview-do-sync t))
+    (markdown-test/live-preview-delete-exports)))
+
+(ert-deftest test-markdown-ext/live-preview-delete-exports-async ()
+  (markdown-test/live-preview-delete-exports))
+
 (provide 'markdown-test)
 
 ;;; markdown-test.el ends here