[nongnu] elpa/prop-menu 97a0ab1 7/9: Make Emacs 24.3 happy

[ELPA Syncer]

branch: elpa/prop-menu
commit 97a0ab12afc63f608106099f02439a8fa742182e
Author: David Raymond Christiansen <david@davidchristiansen.dk>
Commit: David Raymond Christiansen <david@davidchristiansen.dk>

    Make Emacs 24.3 happy
    
    This installs a compatiblity shim for Emacs 24.3, where elisp
    programmers needed to implement their own sorting of overlays by
    priority.
---
 prop-menu.el | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/prop-menu.el b/prop-menu.el
index bb92a2e..32220fc 100644
--- a/prop-menu.el
+++ b/prop-menu.el
@@ -63,14 +63,37 @@ Major modes that provide context menus are expected to 
populate
 this variable with appropriate functions.")
 (make-variable-buffer-local 'prop-menu-item-functions)
 
-(let ((counter 0))
-  (defun prop-menu--unique-val ()
-    (cl-incf counter)))
+(defvar prop-menu--unique-val-counter 0
+  "A global counter for unique values for prop-menu.")
+(defun prop-menu--unique-val ()
+  "Get a unique value for internal tagging."
+  (cl-incf prop-menu--unique-val-counter))
+
+(defun prop-menu--overlays-at (where)
+  "Return the overlays at location WHERE, sorted in order of priority."
+  (cond ((< emacs-major-version 24)
+         (error "Can't get overlays for prop-menu in Emacs versions < 24"))
+        ((and (= emacs-major-version 24)
+              (< emacs-minor-version 4))
+         ;; The SORTED argument to `overlays-at' was added in Emacs 24.4. 
Here, we fake it.
+         (let ((overlays (overlays-at where)))
+           (sort overlays
+                 #'(lambda (o1 o2)
+                     (let ((p1 (or (overlay-get o1 'priority) 0))
+                           (p2 (or (overlay-get o2 'priority) 0)))
+                       (when (not (numberp p1)) (setq p1 0))
+                       (when (not (numberp p2)) (setq p2 0))
+                       (or (> p1 p2)
+                           (and (= p1 p2)
+                                (> (overlay-start o1) (overlay-start 
o2)))))))))
+        ;; In Emacs 24.4 and up, we can just have Emacs do the sorting.
+        ;; Warnings are disabled here to not break CI for Emacs 24.3.
+        (t (with-no-warnings (overlays-at where t)))))
 
 (defun prop-menu--items-for-location (where)
   "Return the menu items based on the text properties and overlays at WHERE."
   (let* ((text-props (text-properties-at where))
-         (overlays (overlays-at where t))
+         (overlays (prop-menu--overlays-at where))
          (overlay-props-list (mapcar #'overlay-properties overlays))
          (props (prop-menu--merge-plists (cons text-props 
overlay-props-list))))
     (apply #'append