Rewrite `org-indent-region'

* lisp/org.el (org-indent-region): Update function according to recent
  `org-indent-line' change.  Optimize it.

* testing/lisp/test-org.el (test-org/indent-region): New test.

lisp/org.el

@@ -22424,15 +22424,101 @@ Also align node properties according to `org-property-format'."
   (message "Block at point indented"))
 
 (defun org-indent-region (start end)
-  "Indent region."
+  "Indent each non-blank line in the region.
+Called from a program, START and END specify the region to
+indent.  The function will not indent contents of example blocks,
+verse blocks and export blocks as leading white spaces are
+assumed to be significant there."
   (interactive "r")
   (save-excursion
-    (let ((line-end (org-current-line end)))
-      (goto-char start)
-      (while (< (org-current-line) line-end)
-	(cond ((org-in-src-block-p t) (org-src-native-tab-command-maybe))
-	      (t (call-interactively 'org-indent-line)))
-	(move-beginning-of-line 2)))))
+    (goto-char start)
+    (beginning-of-line)
+    (let ((indent-to
+	   (lambda (ind pos)
+	     ;; Set IND as indentation for all lines between point and
+	     ;; POS or END, whichever comes first.  Blank lines are
+	     ;; ignored.  Leave point after POS once done.
+	     (let ((limit (copy-marker  (min end pos))))
+	       (while (< (point) limit)
+		 (unless (org-looking-at-p "[ \t]*$") (org-indent-line-to ind))
+		 (forward-line))
+	       (set-marker limit nil))))
+	  (end (copy-marker end)))
+      (while (< (point) end)
+	(if (or (org-looking-at-p " \r\t\n") (org-at-heading-p)) (forward-line)
+	  (let* ((element (org-element-at-point))
+		 (type (org-element-type element))
+		 (element-end (copy-marker (org-element-property :end element)))
+		 (ind (org--get-expected-indentation element nil)))
+	    (if (or (memq type '(paragraph table table-row))
+		    (not (or (org-element-property :contents-begin element)
+			     (memq type
+				   '(example-block export-block src-block)))))
+		;; Elements here are indented as a single block.  Also
+		;; align node properties.
+		(progn
+		  (when (eq type 'node-property)
+		    (org--align-node-property)
+		    (beginning-of-line))
+		  (funcall indent-to ind element-end))
+	      ;; Elements in this category consist of three parts:
+	      ;; before the contents, the contents, and after the
+	      ;; contents.  The contents are treated specially,
+	      ;; according to the element type, or not indented at
+	      ;; all.  Other parts are indented as a single block.
+	      (let* ((post (copy-marker
+			    (or (org-element-property :post-affiliated element)
+				(org-element-property :begin element))))
+		     (cbeg
+		      (copy-marker
+		       (cond
+			((not (org-element-property :contents-begin element))
+			 ;; Fake contents for source blocks.
+			 (org-with-wide-buffer
+			  (goto-char post)
+			  (forward-line)
+			  (point)))
+			((memq type '(footnote-definition item plain-list))
+			 ;; Contents in these elements could start on
+			 ;; the same line as the beginning of the
+			 ;; element.  Make sure we start indenting
+			 ;; from the second line.
+			 (org-with-wide-buffer
+			  (goto-char post)
+			  (forward-line)
+			  (point)))
+			(t (org-element-property :contents-begin element)))))
+		     (cend (copy-marker
+			    (or (org-element-property :contents-end element)
+				;; Fake contents for source blocks.
+				(org-with-wide-buffer
+				 (goto-char element-end)
+				 (skip-chars-backward " \r\t\n")
+				 (line-beginning-position))))))
+		(funcall indent-to ind cbeg)
+		(when (< (point) end)
+		  (case type
+		    ((example-block export-block verse-block))
+		    (src-block
+		     ;; In a source block, indent source code according
+		     ;; to language major mode, but only if
+		     ;; `org-src-tab-acts-natively' is non-nil.
+		     (when (and (< (point) end) org-src-tab-acts-natively)
+		       (ignore-errors
+			 (let (org-src-strip-leading-and-trailing-blank-lines
+			       ;; Region boundaries in edit buffer.
+			       (start (1+ (- (point) cbeg)))
+			       (end (- (min cend end) cbeg)))
+			   (org-babel-do-in-edit-buffer
+			    (indent-region start end))))))
+		    (t (org-indent-region (point) (min cend end))))
+		  (goto-char (min cend end))
+		  (when (< (point) end) (funcall indent-to ind element-end)))
+		(set-marker post nil)
+		(set-marker cbeg nil)
+		(set-marker cend nil)))
+	    (set-marker element-end nil))))
+      (set-marker end nil))))
 
 
 ;;; Filling

testing/lisp/test-org.el

@@ -597,6 +597,76 @@
 	      (org-indent-line)
 	      (buffer-string))))))
 
+(ert-deftest test-org/indent-region ()
+  "Test `org-indent-region' specifications."
+  ;; Indent paragraph.
+  (should
+   (equal "A\nB\nC"
+	  (org-test-with-temp-text " A\nB\n  C"
+	    (org-indent-region (point-min) (point-max))
+	    (buffer-string))))
+  ;; Indent greater elements along with their contents.
+  (should
+   (equal "#+BEGIN_CENTER\nA\nB\n#+END_CENTER"
+	  (org-test-with-temp-text "#+BEGIN_CENTER\n A\n  B\n#+END_CENTER"
+	    (org-indent-region (point-min) (point-max))
+	    (buffer-string))))
+  ;; Ignore contents of verse blocks and example blocks.
+  (should
+   (equal "#+BEGIN_VERSE\n A\n  B\n#+END_VERSE"
+	  (org-test-with-temp-text "#+BEGIN_VERSE\n A\n  B\n#+END_VERSE"
+	    (org-indent-region (point-min) (point-max))
+	    (buffer-string))))
+  (should
+   (equal "#+BEGIN_EXAMPLE\n A\n  B\n#+END_EXAMPLE"
+	  (org-test-with-temp-text "#+BEGIN_EXAMPLE\n A\n  B\n#+END_EXAMPLE"
+	    (org-indent-region (point-min) (point-max))
+	    (buffer-string))))
+  ;; Indent according to mode if `org-src-tab-acts-natively' is
+  ;; non-nil.  Otherwise, do not indent code at all.
+  (should
+   (equal "#+BEGIN_SRC emacs-lisp\n(and A\n     B)\n#+END_SRC"
+	  (org-test-with-temp-text
+	      "#+BEGIN_SRC emacs-lisp\n (and A\nB)\n#+END_SRC"
+	    (let ((org-src-tab-acts-natively t)
+		  (org-edit-src-content-indentation 0))
+	      (org-indent-region (point-min) (point-max)))
+	    (buffer-string))))
+  (should
+   (equal "#+BEGIN_SRC emacs-lisp\n (and A\nB)\n#+END_SRC"
+	  (org-test-with-temp-text
+	      "#+BEGIN_SRC emacs-lisp\n (and A\nB)\n#+END_SRC"
+	    (let ((org-src-tab-acts-natively nil)
+		  (org-edit-src-content-indentation 0))
+	      (org-indent-region (point-min) (point-max)))
+	    (buffer-string))))
+  ;; Align node properties according to `org-property-format'.  Handle
+  ;; nicely empty values.
+  (should
+   (equal ":PROPERTIES:\n:key:      value\n:END:"
+	  (org-test-with-temp-text ":PROPERTIES:\n:key: value\n:END:"
+	    (let ((org-property-format "%-10s %s"))
+	      (org-indent-region (point-min) (point-max)))
+	    (buffer-string))))
+  (should
+   (equal ":PROPERTIES:\n:key:\n:END:"
+	  (org-test-with-temp-text ":PROPERTIES:\n:key:\n:END:"
+	    (let ((org-property-format "%-10s %s"))
+	      (org-indent-region (point-min) (point-max)))
+	    (buffer-string))))
+  ;; Special case: plain lists and footnote definitions.
+  (should
+   (equal "- A\n  B\n  - C\n\n    D"
+	  (org-test-with-temp-text "- A\n   B\n  - C\n\n     D"
+	    (org-indent-region (point-min) (point-max))
+	    (buffer-string))))
+  (should
+   (equal "[fn:1] Definition\n\nDefinition"
+	  (org-test-with-temp-text "[fn:1] Definition\n\n  Definition"
+	    (org-indent-region (point-min) (point-max))
+	    (buffer-string)))))
+
+
 
 ;;; Editing