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;;; git-blame.el --- Minor mode for incremental blame for Git -*- coding: utf-8 -*-
;; Copyright (C) 2007 David Kågedal
;; Authors: David Kågedal <>
;; Created: 31 Jan 2007
;; Message-ID: <87iren2vqx.fsf@morpheus.local>
;; License: GPL
;; Keywords: git, version control, release management
;; Compatibility: Emacs21, Emacs22 and EmacsCVS
;; Git 1.5 and up
;; This file is *NOT* part of GNU Emacs.
;; This file is distributed under the same terms as GNU Emacs.
;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation; either version 2 of
;; the License, or (at your option) any later version.
;; This program is distributed in the hope that it will be
;; useful, but WITHOUT ANY WARRANTY; without even the implied
;; PURPOSE. See the GNU General Public License for more details.
;; You should have received a copy of the GNU General Public
;; License along with this program; if not, write to the Free
;; Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
;; MA 02111-1307 USA
;;; Commentary:
;; Here is an Emacs implementation of incremental git-blame. When you
;; turn it on while viewing a file, the editor buffer will be updated by
;; setting the background of individual lines to a color that reflects
;; which commit it comes from. And when you move around the buffer, a
;; one-line summary will be shown in the echo area.
;;; Installation:
;; To use this package, put it somewhere in `load-path' (or add
;; directory with git-blame.el to `load-path'), and add the following
;; line to your .emacs:
;; (require 'git-blame)
;; If you do not want to load this package before it is necessary, you
;; can make use of the `autoload' feature, e.g. by adding to your .emacs
;; the following lines
;; (autoload 'git-blame-mode "git-blame"
;; "Minor mode for incremental blame for Git." t)
;; Then first use of `M-x git-blame-mode' would load the package.
;;; Compatibility:
;; It requires GNU Emacs 21 or later and Git 1.5.0 and up
;; If you'are using Emacs 20, try changing this:
;; (overlay-put ovl 'face (list :background
;; (cdr (assq 'color (cddddr info)))))
;; to
;; (overlay-put ovl 'face (cons 'background-color
;; (cdr (assq 'color (cddddr info)))))
;;; Code:
(eval-when-compile (require 'cl)) ; to use `push', `pop'
(defun git-blame-color-scale (&rest elements)
"Given a list, returns a list of triples formed with each
elements of the list.
a b => bbb bba bab baa abb aba aaa aab"
(let (result)
(dolist (a elements)
(dolist (b elements)
(dolist (c elements)
(setq result (cons (format "#%s%s%s" a b c) result)))))
;; (git-blame-color-scale "0c" "04" "24" "1c" "2c" "34" "14" "3c") =>
;; ("#3c3c3c" "#3c3c14" "#3c3c34" "#3c3c2c" "#3c3c1c" "#3c3c24"
;; "#3c3c04" "#3c3c0c" "#3c143c" "#3c1414" "#3c1434" "#3c142c" ...)
(defmacro git-blame-random-pop (l)
"Select a random element from L and returns it. Also remove
selected element from l."
;; only works on lists with unique elements
`(let ((e (elt ,l (random (length ,l)))))
(setq ,l (remove e ,l))
(defvar git-blame-log-oneline-format
"format:[%cr] %cn: %s"
"*Formatting option used for describing current line in the minibuffer.
This option is used to pass to git log --pretty= command-line option,
and describe which commit the current line was made.")
(defvar git-blame-dark-colors
(git-blame-color-scale "0c" "04" "24" "1c" "2c" "34" "14" "3c")
"*List of colors (format #RGB) to use in a dark environment.
To check out the list, evaluate (list-colors-display git-blame-dark-colors).")
(defvar git-blame-light-colors
(git-blame-color-scale "c4" "d4" "cc" "dc" "f4" "e4" "fc" "ec")
"*List of colors (format #RGB) to use in a light environment.
To check out the list, evaluate (list-colors-display git-blame-light-colors).")
(defvar git-blame-colors '()
"Colors used by git-blame. The list is built once when activating git-blame
minor mode.")
(defvar git-blame-ancient-color "dark green"
"*Color to be used for ancient commit.")
(defvar git-blame-autoupdate t
"*Automatically update the blame display while editing")
(defvar git-blame-proc nil
"The running git-blame process")
(make-variable-buffer-local 'git-blame-proc)
(defvar git-blame-overlays nil
"The git-blame overlays used in the current buffer.")
(make-variable-buffer-local 'git-blame-overlays)
(defvar git-blame-cache nil
"A cache of git-blame information for the current buffer")
(make-variable-buffer-local 'git-blame-cache)
(defvar git-blame-idle-timer nil
"An idle timer that updates the blame")
(make-variable-buffer-local 'git-blame-cache)
(defvar git-blame-update-queue nil
"A queue of update requests")
(make-variable-buffer-local 'git-blame-update-queue)
;; FIXME: docstrings
(defvar git-blame-file nil)
(defvar git-blame-current nil)
(defvar git-blame-mode nil)
(make-variable-buffer-local 'git-blame-mode)
(defvar git-blame-mode-line-string " blame"
"String to display on the mode line when git-blame is active.")
(or (assq 'git-blame-mode minor-mode-alist)
(setq minor-mode-alist
(cons '(git-blame-mode git-blame-mode-line-string) minor-mode-alist)))
(defun git-blame-mode (&optional arg)
"Toggle minor mode for displaying Git blame
With prefix ARG, turn the mode on if ARG is positive."
(interactive "P")
((null arg)
(if git-blame-mode (git-blame-mode-off) (git-blame-mode-on)))
((> (prefix-numeric-value arg) 0) (git-blame-mode-on))
(t (git-blame-mode-off))))
(defun git-blame-mode-on ()
"Turn on git-blame mode.
See also function `git-blame-mode'."
(make-local-variable 'git-blame-colors)
(if git-blame-autoupdate
(add-hook 'after-change-functions 'git-blame-after-change nil t)
(remove-hook 'after-change-functions 'git-blame-after-change t))
(let ((bgmode (cdr (assoc 'background-mode (frame-parameters)))))
(if (eq bgmode 'dark)
(setq git-blame-colors git-blame-dark-colors)
(setq git-blame-colors git-blame-light-colors)))
(setq git-blame-cache (make-hash-table :test 'equal))
(setq git-blame-mode t)
(defun git-blame-mode-off ()
"Turn off git-blame mode.
See also function `git-blame-mode'."
(if git-blame-idle-timer (cancel-timer git-blame-idle-timer))
(setq git-blame-mode nil))
(defun git-reblame ()
"Recalculate all blame information in the current buffer"
(unless git-blame-mode
(error "Git-blame is not active"))
(defun git-blame-run (&optional startline endline)
(if git-blame-proc
;; Should maybe queue up a new run here
(message "Already running git blame")
(let ((display-buf (current-buffer))
(blame-buf (get-buffer-create
(concat " git blame for " (buffer-name))))
(args '("--incremental" "--contents" "-")))
(if startline
(setq args (append args
(list "-L" (format "%d,%d" startline endline)))))
(setq args (append args
(list (file-name-nondirectory buffer-file-name))))
(setq git-blame-proc
(apply 'start-process
"git-blame" blame-buf
"git" "blame"
(with-current-buffer blame-buf
(make-local-variable 'git-blame-file)
(make-local-variable 'git-blame-current)
(setq git-blame-file display-buf)
(setq git-blame-current nil))
(set-process-filter git-blame-proc 'git-blame-filter)
(set-process-sentinel git-blame-proc 'git-blame-sentinel)
(process-send-region git-blame-proc (point-min) (point-max))
(process-send-eof git-blame-proc))))
(defun remove-git-blame-text-properties (start end)
(let ((modified (buffer-modified-p))
(inhibit-read-only t))
(remove-text-properties start end '(point-entered nil))
(set-buffer-modified-p modified)))
(defun git-blame-cleanup ()
"Remove all blame properties"
(mapcar 'delete-overlay git-blame-overlays)
(setq git-blame-overlays nil)
(remove-git-blame-text-properties (point-min) (point-max)))
(defun git-blame-update-region (start end)
"Rerun blame to get updates between START and END"
(let ((overlays (overlays-in start end)))
(while overlays
(let ((overlay (pop overlays)))
(if (< (overlay-start overlay) start)
(setq start (overlay-start overlay)))
(if (> (overlay-end overlay) end)
(setq end (overlay-end overlay)))
(setq git-blame-overlays (delete overlay git-blame-overlays))
(delete-overlay overlay))))
(remove-git-blame-text-properties start end)
;; We can be sure that start and end are at line breaks
(git-blame-run (1+ (count-lines (point-min) start))
(count-lines (point-min) end)))
(defun git-blame-sentinel (proc status)
(with-current-buffer (process-buffer proc)
(with-current-buffer git-blame-file
(setq git-blame-proc nil)
(if git-blame-update-queue
;;(kill-buffer (process-buffer proc))
;;(message "git blame finished")
(defvar in-blame-filter nil)
(defun git-blame-filter (proc str)
(set-buffer (process-buffer proc))
(goto-char (process-mark proc))
(insert-before-markers str)
(goto-char 0)
(unless in-blame-filter
(let ((more t)
(in-blame-filter t))
(while more
(setq more (git-blame-parse)))))))
(defun git-blame-parse ()
(cond ((looking-at "\\([0-9a-f]\\{40\\}\\) \\([0-9]+\\) \\([0-9]+\\) \\([0-9]+\\)\n")
(let ((hash (match-string 1))
(src-line (string-to-number (match-string 2)))
(res-line (string-to-number (match-string 3)))
(num-lines (string-to-number (match-string 4))))
(setq git-blame-current
(if (string= hash "0000000000000000000000000000000000000000")
hash src-line res-line num-lines))))
(delete-region (point) (match-end 0))
((looking-at "filename \\(.+\\)\n")
(let ((filename (match-string 1)))
(git-blame-add-info "filename" filename))
(delete-region (point) (match-end 0))
((looking-at "\\([a-z-]+\\) \\(.+\\)\n")
(let ((key (match-string 1))
(value (match-string 2)))
(git-blame-add-info key value))
(delete-region (point) (match-end 0))
((looking-at "boundary\n")
(setq git-blame-current nil)
(delete-region (point) (match-end 0))
(defun git-blame-new-commit (hash src-line res-line num-lines)
(set-buffer git-blame-file)
(let ((info (gethash hash git-blame-cache))
(inhibit-point-motion-hooks t)
(inhibit-modification-hooks t))
(when (not info)
;; Assign a random color to each new commit info
;; Take care not to select the same color multiple times
(let ((color (if git-blame-colors
(git-blame-random-pop git-blame-colors)
(setq info (list hash src-line res-line num-lines
(git-describe-commit hash)
(cons 'color color))))
(puthash hash info git-blame-cache))
(goto-line res-line)
(while (> num-lines 0)
(if (get-text-property (point) 'git-blame)
(let* ((start (point))
(end (progn (forward-line 1) (point)))
(ovl (make-overlay start end)))
(push ovl git-blame-overlays)
(overlay-put ovl 'git-blame info)
(overlay-put ovl 'help-echo hash)
(overlay-put ovl 'face (list :background
(cdr (assq 'color (nthcdr 5 info)))))
;; the point-entered property doesn't seem to work in overlays
;;(overlay-put ovl 'point-entered
;; `(lambda (x y) (git-blame-identify ,hash)))
(let ((modified (buffer-modified-p)))
(put-text-property (if (= start 1) start (1- start)) (1- end)
`(lambda (x y) (git-blame-identify ,hash)))
(set-buffer-modified-p modified))))
(setq num-lines (1- num-lines))))))
(defun git-blame-add-info (key value)
(if git-blame-current
(nconc git-blame-current (list (cons (intern key) value)))))
(defun git-blame-current-commit ()
(let ((info (get-char-property (point) 'git-blame)))
(if info
(car info)
(error "No commit info"))))
(defun git-describe-commit (hash)
(call-process "git" nil t nil
"log" "-1"
(concat "--pretty=" git-blame-log-oneline-format)
(buffer-substring (point-min) (point-max))))
(defvar git-blame-last-identification nil)
(make-variable-buffer-local 'git-blame-last-identification)
(defun git-blame-identify (&optional hash)
(let ((info (gethash (or hash (git-blame-current-commit)) git-blame-cache)))
(when (and info (not (eq info git-blame-last-identification)))
(message "%s" (nth 4 info))
(setq git-blame-last-identification info))))
;; (defun git-blame-after-save ()
;; (when git-blame-mode
;; (git-blame-cleanup)
;; (git-blame-run)))
;; (add-hook 'after-save-hook 'git-blame-after-save)
(defun git-blame-after-change (start end length)
(when git-blame-mode
(git-blame-enq-update start end)))
(defvar git-blame-last-update nil)
(make-variable-buffer-local 'git-blame-last-update)
(defun git-blame-enq-update (start end)
"Mark the region between START and END as needing blame update"
;; Try to be smart and avoid multiple callouts for sequential
;; editing
(cond ((and git-blame-last-update
(= start (cdr git-blame-last-update)))
(setcdr git-blame-last-update end))
((and git-blame-last-update
(= end (car git-blame-last-update)))
(setcar git-blame-last-update start))
(setq git-blame-last-update (cons start end))
(setq git-blame-update-queue (nconc git-blame-update-queue
(list git-blame-last-update)))))
(unless (or git-blame-proc git-blame-idle-timer)
(setq git-blame-idle-timer
(run-with-idle-timer 0.5 nil 'git-blame-delayed-update))))
(defun git-blame-delayed-update ()
(setq git-blame-idle-timer nil)
(if git-blame-update-queue
(let ((first (pop git-blame-update-queue))
(inhibit-point-motion-hooks t))
(git-blame-update-region (car first) (cdr first)))))
(provide 'git-blame)
;;; git-blame.el ends here