+;; isearch minibuffer history
+(add-hook 'minibuffer-setup-hook 'minibuffer-history-isearch-setup)
+
+(defvar minibuffer-history-isearch-message-overlay)
+(make-variable-buffer-local 'minibuffer-history-isearch-message-overlay)
+
+(defun minibuffer-history-isearch-setup ()
+ "Set up a minibuffer for using isearch to search the minibuffer history.
+Intended to be added to `minibuffer-setup-hook'."
+ (set (make-local-variable 'isearch-search-fun-function)
+ 'minibuffer-history-isearch-search)
+ (set (make-local-variable 'isearch-message-function)
+ 'minibuffer-history-isearch-message)
+ (set (make-local-variable 'isearch-wrap-function)
+ 'minibuffer-history-isearch-wrap)
+ (set (make-local-variable 'isearch-push-state-function)
+ 'minibuffer-history-isearch-push-state)
+ (add-hook 'isearch-mode-end-hook 'minibuffer-history-isearch-end nil t))
+
+(defun minibuffer-history-isearch-end ()
+ "Clean up the minibuffer after terminating isearch in the minibuffer."
+ (if minibuffer-history-isearch-message-overlay
+ (delete-overlay minibuffer-history-isearch-message-overlay)))
+
+(defun minibuffer-history-isearch-search ()
+ "Return the proper search function, for isearch in minibuffer history."
+ (cond
+ (isearch-word
+ (if isearch-forward 'word-search-forward 'word-search-backward))
+ (t
+ (lambda (string bound noerror)
+ (let ((search-fun
+ ;; Use standard functions to search within minibuffer text
+ (cond
+ (isearch-regexp
+ (if isearch-forward 're-search-forward 're-search-backward))
+ (t
+ (if isearch-forward 'search-forward 'search-backward))))
+ found)
+ ;; Avoid lazy-highlighting matches in the minibuffer prompt when
+ ;; searching forward. Lazy-highlight calls this lambda with the
+ ;; bound arg, so skip the minibuffer prompt.
+ (if (and bound isearch-forward (< (point) (minibuffer-prompt-end)))
+ (goto-char (minibuffer-prompt-end)))
+ (or
+ ;; 1. First try searching in the initial minibuffer text
+ (funcall search-fun string
+ (if isearch-forward bound (minibuffer-prompt-end))
+ noerror)
+ ;; 2. If the above search fails, start putting next/prev history
+ ;; elements in the minibuffer successively, and search the string
+ ;; in them. Do this only when bound is nil (i.e. not while
+ ;; lazy-highlighting search strings in the current minibuffer text).
+ (unless bound
+ (condition-case nil
+ (progn
+ (while (not found)
+ (cond (isearch-forward
+ (next-history-element 1)
+ (goto-char (minibuffer-prompt-end)))
+ (t
+ (previous-history-element 1)
+ (goto-char (point-max))))
+ (setq isearch-barrier (point) isearch-opoint (point))
+ ;; After putting the next/prev history element, search
+ ;; the string in them again, until next-history-element
+ ;; or previous-history-element raises an error at the
+ ;; beginning/end of history.
+ (setq found (funcall search-fun string
+ (unless isearch-forward
+ ;; For backward search, don't search
+ ;; in the minibuffer prompt
+ (minibuffer-prompt-end))
+ noerror)))
+ ;; Return point of the new search result
+ (point))
+ ;; Return nil when next(prev)-history-element fails
+ (error nil)))))))))
+
+(defun minibuffer-history-isearch-message (&optional c-q-hack ellipsis)
+ "Display the minibuffer history search prompt.
+If there are no search errors, this function displays an overlay with
+the isearch prompt which replaces the original minibuffer prompt.
+Otherwise, it displays the standard isearch message returned from
+`isearch-message'."
+ (if (not (and (minibufferp) isearch-success (not isearch-error)))
+ ;; Use standard function `isearch-message' when not in the minibuffer,
+ ;; or search fails, or has an error (like incomplete regexp).
+ ;; This function overwrites minibuffer text with isearch message,
+ ;; so it's possible to see what is wrong in the search string.
+ (isearch-message c-q-hack ellipsis)
+ ;; Otherwise, put the overlay with the standard isearch prompt over
+ ;; the initial minibuffer prompt.
+ (if (overlayp minibuffer-history-isearch-message-overlay)
+ (move-overlay minibuffer-history-isearch-message-overlay
+ (point-min) (minibuffer-prompt-end))
+ (setq minibuffer-history-isearch-message-overlay
+ (make-overlay (point-min) (minibuffer-prompt-end)))
+ (overlay-put minibuffer-history-isearch-message-overlay 'evaporate t))
+ (overlay-put minibuffer-history-isearch-message-overlay
+ 'display (isearch-message-prefix c-q-hack ellipsis))
+ ;; And clear any previous isearch message.
+ (message "")))
+
+(defun minibuffer-history-isearch-wrap ()
+ "Wrap the minibuffer history search when search is failed.
+Move point to the first history element for a forward search,
+or to the last history element for a backward search."
+ (unless isearch-word
+ ;; When `minibuffer-history-isearch-search' fails on reaching the
+ ;; beginning/end of the history, wrap the search to the first/last
+ ;; minibuffer history element.
+ (if isearch-forward
+ (goto-history-element (length (symbol-value minibuffer-history-variable)))
+ (goto-history-element 0))
+ (setq isearch-success t))
+ (goto-char (if isearch-forward (minibuffer-prompt-end) (point-max))))
+
+(defun minibuffer-history-isearch-push-state ()
+ "Save a function restoring the state of minibuffer history search.
+Save `minibuffer-history-position' to the additional state parameter
+in the search status stack."
+ `(lambda (cmd)
+ (minibuffer-history-isearch-pop-state cmd ,minibuffer-history-position)))
+
+(defun minibuffer-history-isearch-pop-state (cmd hist-pos)
+ "Restore the minibuffer history search state.
+Go to the history element by the absolute history position `hist-pos'."
+ (goto-history-element hist-pos))
+
+\f