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[nongnu] elpa/diff-ansi f2207a67e3 1/7: Initial diff-ansi.


From: ELPA Syncer
Subject: [nongnu] elpa/diff-ansi f2207a67e3 1/7: Initial diff-ansi.
Date: Thu, 7 Jul 2022 11:58:41 -0400 (EDT)

branch: elpa/diff-ansi
commit f2207a67e3cc79433b43deeb463d0768357c350f
Author: Campbell Barton <ideasman42@gmail.com>
Commit: Campbell Barton <ideasman42@gmail.com>

    Initial diff-ansi.
---
 .elisp-autofmt |   0
 LICENSE        | 674 ++++++++++++++++++++++++++++++++++++++++
 diff-ansi.el   | 961 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 readme.rst     | 111 +++++++
 4 files changed, 1746 insertions(+)

diff --git a/.elisp-autofmt b/.elisp-autofmt
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000000..f288702d2f
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
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+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    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 3 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 warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR 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, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/diff-ansi.el b/diff-ansi.el
new file mode 100644
index 0000000000..5bc148e7db
--- /dev/null
+++ b/diff-ansi.el
@@ -0,0 +1,961 @@
+;;; diff-ansi.el --- Display diff's using alternative diffing tools -*- 
lexical-binding: t -*-
+
+;; Copyright (C) 2021  Campbell Barton
+
+;; Author: Campbell Barton <ideasman42@gmail.com>
+
+;; URL: https://gitlab.com/ideasman42/emacs-diff-ansi
+;; Version: 0.1
+;; Package-Requires: ((emacs "27.1"))
+
+;; 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 3 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 warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR 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, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; Support showing diffs using external tools.
+
+;;; Usage
+
+;; See readme.rst.
+;;
+
+;;; Code:
+(require 'ansi-color)
+
+;; ---------------------------------------------------------------------------
+;; Custom Variables
+
+(defgroup diff-ansi nil
+  "Configure smooth scrolling when jumping to new locations."
+  :group 'scrolling)
+
+(defcustom diff-ansi-use-magit-revision-diff t
+  "Use diff-ansi for `magit-revision-mode'."
+  :type 'boolean)
+
+
+(defcustom diff-ansi-tool 'delta
+  "Command to use for generating the diff."
+  :type
+  '
+  (choice
+    (symbol :tag "Use `delta' command." delta)
+    (symbol :tag "Use `diff-so-fancy' command." diff-so-fancy)
+    (symbol :tag "Use `ydiff' command." ydiff)
+
+    (symbol :tag "Use `diff-ansi-tool-custom' command." custom)))
+
+;; Note that this has it's values extracted and isn't used directly.
+(defface diff-ansi-default-face
+  (list (list t :foreground "black" :background "black"))
+  "Face used to render black color.")
+
+(defcustom diff-ansi-tool-custom nil
+  "Command to use when `diff-ansi-tool' is set to `custom'.
+This must take the diff content as the `standard-input'."
+  :type '(repeat string))
+
+;; Extra arguments for command presets.
+
+(defcustom diff-ansi-extra-args-for-delta
+  (list "--side-by-side" "--no-gitconfig" "--syntax-theme=github" 
"--true-color=always")
+  "Additional arguments to pass to `delta'."
+  :type '(repeat string))
+
+(defcustom diff-ansi-extra-args-for-diff-so-fancy (list)
+  "Additional arguments to pass to `diff-so-fancy'."
+  :type '(repeat string))
+
+(defcustom diff-ansi-extra-args-for-ydiff (list "--side-by-side")
+  "Additional arguments to pass to `ydiff'."
+  :type '(repeat string))
+
+;; ---------------------------------------------------------------------------
+;; Custom Variables (Advanced)
+
+(defcustom diff-ansi-method 'multiprocess
+  "Convert ANSI escape sequences."
+  :type
+  '
+  (choice
+    (symbol :tag "Convert immediately." immediate)
+    (symbol :tag "Convert progressively (using a timer)." progressive)
+    (symbol :tag "Convert using multiple sub-processes." multiprocess)))
+
+(defcustom diff-ansi-chunks-size 16384
+  "Number of characters to process at once.
+Used for `progressive' and `multiprocess' methods."
+  :type 'integer)
+
+(defcustom diff-ansi-multiprocess-jobs nil
+  "Number of simultaneous jobs to launch when using `multiprocess' method.
+
+A nil value detects the number of processes on the system (when supported)."
+  :type 'integer)
+
+;; ---------------------------------------------------------------------------
+;; Internal Variables
+
+(defvar-local diff-ansi--ansi-color-timer nil)
+
+(defvar diff-ansi--ansi-color-bg nil)
+
+(defconst diff-ansi--code-block-for-multiprocess-defs
+  ;; NOTE:
+  ;; - `diff-ansi--face-has-bg' is a bit heavy but necessary
+  ;;   to ensure all faces have a black-background.
+  ;; - A single `let' or `progn' is needed for the code to be properly quoted.
+  (quote
+    (progn
+      (defun diff-ansi--face-has-bg (face)
+        (when (and face (listp face))
+          (or
+            (plist-get face :background)
+            (diff-ansi--face-has-bg (car face))
+            (diff-ansi--face-has-bg (cdr-safe face)))))
+
+      (defun diff-ansi--ansi-color-apply-text-property-face--local (beg end 
face)
+        (when face
+          (unless (diff-ansi--face-has-bg face)
+            (setq face
+              (cond
+                ((listp face)
+                  (list face diff-ansi--ansi-color-bg))
+                (t
+                  (cons face diff-ansi--ansi-color-bg)))))
+          (put-text-property beg end 'face face)))
+
+      (defun diff-ansi--ansi-color-apply-on-region-with-bg-impl (beg end)
+        (let
+          (
+            (ansi-color-apply-face-function
+              #'diff-ansi--ansi-color-apply-text-property-face--local))
+          (put-text-property beg end 'face diff-ansi--ansi-color-bg)
+          (ansi-color-apply-on-region beg end))))))
+
+;; Evaluate locally too.
+(eval diff-ansi--code-block-for-multiprocess-defs)
+
+;; Needed since the the `eval' causes the function to be hidden.
+(declare-function diff-ansi--ansi-color-apply-on-region-with-bg-impl 
"diff-ansi")
+
+
+;; ---------------------------------------------------------------------------
+;; Generic functions.
+
+(defmacro diff-ansi--with-advice (fn-orig where fn-advice &rest body)
+  "Execute BODY with advice added WHERE.
+Argument FN-ADVICE temporarily added to FN-ORIG."
+  `
+  (let ((fn-advice-var ,fn-advice))
+    (unwind-protect
+      (progn
+        (advice-add ,fn-orig ,where fn-advice-var)
+        ,@body)
+      (advice-remove ,fn-orig fn-advice-var))))
+
+(defmacro diff-ansi--with-temp-echo-area (&rest body)
+  "Run BODY with the message temporarily overwritten."
+  `
+  (let ((omessage (current-message)))
+    (unwind-protect
+      (progn
+        ,@body)
+      (let ((message-log-max nil))
+        (message omessage)))))
+
+(defmacro diff-ansi--with-temp-directory (name &rest body)
+  "Bind NAME to the name of a new temporary file and evaluate BODY.
+Delete the temporary file after BODY exits normally or non-locally.
+NAME will be bound to the file name of the temporary file.
+
+The following keyword arguments are supported:
+
+:prefix STRING
+  If non-nil, pass STRING to `make-temp-file' as the PREFIX argument.
+
+:suffix STRING
+  If non-nil, pass STRING to `make-temp-file' as the SUFFIX argument."
+  (declare (indent 1) (debug (symbolp body)))
+  (unless (symbolp name)
+    (error "Expected name to be as symbol, found %S" (type-of name)))
+  (let
+    (
+      (keyw nil)
+      (prefix nil)
+      (suffix nil)
+      (extra-keywords nil))
+    (while (keywordp (setq keyw (car body)))
+      (setq body (cdr body))
+      (pcase keyw
+        (:prefix (setq prefix (pop body)))
+        (:suffix (setq suffix (pop body)))
+        (_ (push keyw extra-keywords) (pop body))))
+    (when extra-keywords
+      (error "Invalid keywords: %s" (mapconcat #'symbol-name extra-keywords " 
")))
+    (let
+      (
+        (temp-file (make-symbol "temp-file"))
+        (prefix (or prefix ""))
+        (suffix (or suffix "")))
+      `
+      (let*
+        (
+          (,temp-file (file-name-as-directory (make-temp-file ,prefix t 
,suffix nil)))
+          (,name (file-name-as-directory ,temp-file)))
+        (unwind-protect
+          (progn
+            ,@body)
+          (ignore-errors (delete-directory ,temp-file :recursive)))))))
+
+;; See: https://emacs.stackexchange.com/a/70105/2418
+(defun diff-ansi--call-process-pipe-chain (&rest args)
+  "Call a chain of commands in ARGS, each argument must be a list of strings.
+
+Additional keyword arguments may also be passed in.
+
+:input - is used to pipe input into the first commands `standard-input'.
+- nil: no input is passed in.
+- string: text to be passed to the standard input.
+- buffer: buffer to be passed to the standard input
+
+:output - is used as the target for the final commands output.
+- nil: output is ignored.
+- t: output is returned as a string.
+- string: output is written to file-name.
+- buffer: output is written to the buffer."
+  (let
+    ( ;; To check if this is the first time executing.
+      (is-first t)
+
+      ;; Keywords.
+      (output nil)
+      (input nil)
+
+      ;; Iteration vars.
+      (buf-src nil)
+      (buf-dst nil))
+
+    ;; Parse keywords.
+    (let ((args-no-keywords nil))
+      (while args
+        (let ((arg-current (pop args)))
+          (cond
+            ((keywordp arg-current)
+              (unless args
+                (error "Keyword argument %S has no value!" arg-current))
+              (let ((v (pop args)))
+                (pcase arg-current
+                  (:input
+                    (cond
+                      ((null v)) ;; No input.
+                      ((eq v t)) ;; String input (standard input data).
+                      ((stringp v))
+                      ((bufferp v)
+                        (unless (buffer-live-p v)
+                          (error "Input buffer is invalid %S" v)))
+                      (t
+                        (error "Input expected a buffer, string or nil")))
+                    (setq input v))
+                  (:output
+                    (cond
+                      ((null output)) ;; No output.
+                      ((eq output t)) ;; String output (file path).
+                      ((stringp output)
+                        (when (string-equal output "")
+                          (error "Empty string used as file-path")))
+                      ((bufferp output)
+                        (unless (buffer-live-p output)
+                          (error "Input buffer is invalid %S" output)))
+
+                      (t
+                        (error "Output expected a buffer, string or nil")))
+                    (setq output v))
+
+                  (_ (error "Unknown argument %S" arg-current)))))
+            ((listp arg-current)
+              (push arg-current args-no-keywords))
+            (t
+              (error
+                "Arguments must be keyword, value pairs or lists of strings, 
found %S = %S"
+                (type-of arg-current)
+                arg-current)))))
+
+      (setq args (reverse args-no-keywords)))
+
+    ;; Setup two temporary buffers for source and destination,
+    ;; looping over arguments, executing and piping contents.
+    (with-temp-buffer
+      (setq buf-src (current-buffer))
+      (with-temp-buffer
+        (setq buf-dst (current-buffer))
+
+        ;; Loop over commands.
+        (while args
+          (let ((arg-current (pop args)))
+            (with-current-buffer buf-dst (erase-buffer))
+            (let*
+              (
+                (sentinel-called nil)
+                (proc
+                  (make-process
+                    :name "call-process-pipe-chain"
+                    :buffer
+                    (cond
+                      ;; Last command, use output.
+                      ((and (null args) (bufferp output))
+                        output)
+                      (t
+                        buf-dst))
+                    ;; Write to the intermediate buffer or the final output.
+                    :connection-type 'pipe
+                    :command arg-current
+                    :sentinel (lambda (_proc _msg) (setq sentinel-called t)))))
+
+              (cond
+                ;; Initially, we can only use the input argument.
+                (is-first
+                  (cond
+                    ((null input))
+                    ((bufferp input)
+                      (with-current-buffer input
+                        (process-send-region proc (point-min) (point-max))))
+                    ((stringp input)
+                      (process-send-string proc input))))
+                (t
+                  (with-current-buffer buf-src
+                    (process-send-region proc (point-min) (point-max))
+                    (erase-buffer))))
+
+              (process-send-eof proc)
+              (while (not sentinel-called)
+                (accept-process-output))
+
+              ;; Check exit-code.
+              (let ((exit-code (process-exit-status proc)))
+                (unless (zerop exit-code)
+                  (error "Command exited code=%d: %S" exit-code arg-current))))
+
+            ;; Swap source/destination buffers.
+            (setq buf-src
+              (prog1 buf-dst
+                (setq buf-dst buf-src)))
+
+            (setq is-first nil)))
+
+        ;; Return the result.
+        (cond
+          ;; Ignore output.
+          ((null output))
+          ;; Already written into.
+          ((bufferp output))
+          ;; Write to the output as a file-path.
+          ((stringp output)
+            (with-current-buffer buf-src (write-region nil nil output nil 0)))
+          ;; Return the output as a string.
+          ((eq output t)
+            ;; Since the argument was swapped, extract from the 'source'.
+            (with-current-buffer buf-src
+              (buffer-substring-no-properties (point-min) (point-max)))))))))
+
+(defun diff-ansi--call-process-parallel (args &rest keywords)
+  "Return the result of commands in ARGS.
+
+ARGS must be a list of commands (themselves a list of strings).
+
+Optional keywords in KEYWORDS.
+
+:idle FLOAT
+  The time (in seconds) to idle between checking for each processes result.
+
+:jobs INTEGER
+  The maximum number of processes to run at once.
+
+:output BOOLEAN / FUNCTION
+  The destination for the output.
+
+  - nil: ignores output.
+  - t: returns the result as an array of strings.
+  - function: runs the function with argument index & string result arguments.
+
+:progress-message STRING
+  When set, show progress percentage."
+  (let
+    ( ;; Keyword arguments.
+      (idle nil)
+      (jobs nil)
+      (output nil)
+      (output-is-fn nil)
+      (progress-message nil))
+
+    ;; Parse keywords.
+    (while keywords
+      (let ((arg-current (pop keywords)))
+        (cond
+          ((keywordp arg-current)
+            (unless keywords
+              (error "Keyword argument %S has no value!" arg-current))
+            (let ((v (pop keywords)))
+              (pcase arg-current
+                (:idle
+                  (cond
+                    ((null v)) ;; Ignore.
+                    ((floatp v))
+                    (t
+                      (error "Argument :idle expected a float, not a %S" 
(type-of v))))
+                  (setq idle v))
+
+                (:jobs
+                  (cond
+                    ((null v)) ;; Ignore.
+                    ((eq v t)) ;; String output (result vector)
+                    ((symbolp v))
+                    (t
+                      (error "Output expected nil, t or a symbol")))
+                  (setq jobs v))
+
+                (:output
+                  (cond
+                    ((null v)) ;; Ignore.
+                    ((eq v t)) ;; String output (result vector)
+                    ((functionp v)
+                      (setq output-is-fn t))
+                    (t
+                      (error "Output expected nil, t or a symbol, not a %S" 
(type-of v))))
+                  (setq output v))
+
+                (:progress-message
+                  (cond
+                    ((null v)) ;; Ignore.
+                    ((stringp v)
+                      (setq output-is-fn t))
+                    (t
+                      (error "Progress-message expected nil or string, not a 
%S" (type-of v))))
+                  (setq progress-message v))
+
+                (_ (error "Unknown argument %S" arg-current)))))
+          (t
+            (error
+              "Optional arguments must be keyword, value pairs, found %S = %S"
+              (type-of arg-current)
+              arg-current)))))
+
+    ;; Set defaults when unset.
+    (unless idle
+      (setq idle 0.01))
+
+    ;; TODO: detect.
+    (unless jobs
+      (setq jobs
+        (cond
+          ((fboundp 'num-processors) ;; Emacs 29+
+            (* 2 (num-processors)))
+          (t
+            (or diff-ansi-multiprocess-jobs 64)))))
+
+    (let*
+      (
+        (args-len (length args))
+        (results (make-vector args-len nil))
+        (procs (make-vector args-len nil))
+        (jobs-pending nil)
+        (count-complete 0)
+        (count-running 0)
+        (no-error t)
+
+        (output-funcall-next 0)
+
+        (filter-job-fn
+          (lambda (proc str)
+            (let ((id (process-get proc :my-job-id)))
+              (aset results id (cons str (aref results id))))))
+
+        (sentinel-job-fn
+          (lambda (proc _msg)
+            (let ((id (process-get proc :my-job-id)))
+              ;; Clear the process in the array so it's never touched again.
+              (aset procs id nil)
+              (let ((exit-code (process-exit-status proc)))
+                (unless (zerop exit-code)
+                  (setq no-error nil)
+                  (error "Command exited code=%d: %S" exit-code (aref args 
id))))
+
+              (delete-process proc)
+
+              (setq count-complete (1+ count-complete))
+              (setq count-running (1- count-running))
+              (when output
+                (let ((str (mapconcat #'identity (reverse (aref results id)) 
"")))
+                  (aset results id str)))
+
+              (when progress-message
+                (let ((message-log-max nil))
+                  (message
+                    "%s%.2f%%"
+                    progress-message
+                    (* 100.0 (/ (float count-complete) args-len))))))))
+
+        (start-job-fn
+          (lambda (i)
+            (setq count-running (1+ count-running))
+            (let
+              (
+                (proc
+                  (make-process
+                    :name (concat "call-process-parallel" (number-to-string i))
+                    ;; Write to the intermediate buffer or the final output.
+                    :connection-type 'pipe
+                    :command (aref args i)
+                    :filter filter-job-fn
+                    :sentinel sentinel-job-fn)))
+
+              (process-put proc :my-job-id i)))))
+
+      ;; Convert `args' to a vector for fast indexing.
+      (setq args (vconcat args))
+
+      ;; Setup indices to represent jobs that aren't complete.
+      (let ((i args-len))
+        (while (not (zerop i))
+          (push (setq i (1- i)) jobs-pending)))
+
+      ;; Main loop to complete
+      (diff-ansi--with-temp-echo-area
+        (while
+          (progn
+            ;; Run every time, important to run before exiting.
+            (when output-is-fn
+              (let
+                (
+                  (str nil)
+                  (is-modified nil))
+                (while
+                  (and
+                    (< output-funcall-next args-len)
+                    (stringp (setq str (aref results output-funcall-next))))
+                  ;; Overwrite with `t' (never to use again).
+                  (funcall output output-funcall-next str)
+                  (aset results output-funcall-next t)
+                  (setq output-funcall-next (1+ output-funcall-next))
+                  (setq is-modified t))
+                (when is-modified
+
+                  (redisplay))))
+
+            ;; Check if exiting is needed.
+            (and no-error (not (eq count-complete args-len))))
+
+          ;; Fill the queue.
+          (while (and jobs-pending (< count-running jobs))
+            (funcall start-job-fn (pop jobs-pending)))
+
+          (sleep-for idle)))
+
+      (unless no-error
+        (dotimes (i args-len)
+          (let ((proc (aref procs i)))
+            (when proc
+              (delete-process proc)))))
+
+      (cond
+        ((eq output t)
+          results)
+        (t
+          nil)))))
+
+(defun diff-ansi--face-attr-to-hex-literal (face attr)
+  "Return the HEX color from FACE and ATTR."
+  (apply #'format
+    (cons
+      "#%02x%02x%02x"
+      (mapcar
+        ;; Shift by -8 to map the value returned by `color values':
+        ;; 0..65535 to 0..255 for `#RRGGBB` string formatting.
+        (lambda (n) (ash n -8)) (color-values (face-attribute face attr))))))
+
+
+;; ---------------------------------------------------------------------------
+;; Diff/ANSI Wrapper
+
+(defun diff-ansi--ansi-color-apply-on-region-with-bg (beg end)
+  "Wrapper function for `ansi-color-apply-on-region', applying color in (BEG 
END)."
+  (setq diff-ansi--ansi-color-bg
+    (list
+      :background (diff-ansi--face-attr-to-hex-literal 'diff-ansi-default-face 
:background)
+      :extend t))
+  (diff-ansi--ansi-color-apply-on-region-with-bg-impl beg end))
+
+(defun diff-ansi--ansi-color-apply-on-region-with-bg-str (black-color)
+  "Create string that can be passed to a sub-process using BLACK-COLOR."
+  (format
+    "(progn %s %s %s %s %s)"
+    "(require 'ansi-color)"
+    (format "(defconst diff-ansi--ansi-color-bg (list :background \"%s\" 
:extend t))" black-color)
+    diff-ansi--code-block-for-multiprocess-defs
+    "(diff-ansi--ansi-color-apply-on-region-with-bg-impl (point-min) 
(point-max))"
+    "(prin1 (buffer-substring (point-min) (point-max)) 
#'external-debugging-output)"))
+
+
+;; ---------------------------------------------------------------------------
+;; Diff Implementations
+
+(defun diff-ansi--command-preset-impl ()
+  "Return the command to run delta."
+  (pcase diff-ansi-tool
+    ('delta
+      (append
+        (list
+          "delta"
+          (format "--width=%d" (window-body-width (get-buffer-window 
(current-buffer)))))
+        diff-ansi-extra-args-for-delta))
+    ('diff-so-fancy (append (list "diff-so-fancy") 
diff-ansi-extra-args-for-diff-so-fancy))
+    ('ydiff
+      (append
+        (list
+          "ydiff"
+          "--color=always"
+          (format "--width=%d" (/ (window-body-width (get-buffer-window 
(current-buffer)) 2))))
+        diff-ansi-extra-args-for-ydiff))
+    ('custom diff-ansi-tool-custom)
+    (_ (error "Unknown tool %S" diff-ansi-tool))))
+
+
+;; ---------------------------------------------------------------------------
+;; ANSI Conversion (Immediate)
+
+(defun diff-ansi--immediate-impl (beg end &optional target-buf)
+  "Colorize the text between BEG and END immediately.
+Store the result in TARGET-BUF when non-nil."
+  (let
+    (
+      (diff-command (diff-ansi--command-preset-impl))
+      (diff-str (buffer-substring-no-properties beg end)))
+
+    (unless target-buf
+      (delete-region beg end)
+      (goto-char beg))
+
+    (with-current-buffer (or target-buf (current-buffer))
+      (let ((inhibit-read-only t))
+        (setq beg (point))
+        (diff-ansi--call-process-pipe-chain diff-command :input diff-str 
:output (current-buffer))
+        (setq end (point))
+
+        (diff-ansi--ansi-color-apply-on-region-with-bg beg (point))))))
+
+
+;; ---------------------------------------------------------------------------
+;; ANSI Conversion (Progressive)
+
+(defun diff-ansi-progressive-highlight-impl (buf range)
+  "Callback to update colors for BUF in RANGE."
+  (unless (input-pending-p)
+    (with-current-buffer buf
+      (let*
+        (
+          (do-redisplay nil)
+          (inhibit-read-only t)
+          (end (cdr range))
+          (end-trailing-chars (- (buffer-size) end))
+          (disp-beg (car range))
+          (disp-end
+            (min
+              end ;; Clamp twice because `line-end-position' could exceed the 
value.
+              (save-excursion
+                (goto-char (min (+ disp-beg diff-ansi-chunks-size) end))
+                (line-end-position)))))
+        (save-excursion
+          (cond
+            ((eq disp-beg disp-end)
+              (cancel-timer diff-ansi--ansi-color-timer)
+              (setq diff-ansi--ansi-color-timer nil))
+            (t
+              (let ((disp-end-mark (set-marker (make-marker) disp-end)))
+                (diff-ansi--ansi-color-apply-on-region-with-bg disp-beg 
disp-end)
+
+                (setq do-redisplay t)
+                ;; Update the display start and actual end.
+                (setcar range (marker-position disp-end-mark))
+                (setcdr range (- (buffer-size) end-trailing-chars))))))
+
+        ;; Re-display outside the block that moves the cursor.
+        (when do-redisplay
+          (redisplay))))))
+
+(defun diff-ansi--progressive-impl (beg end &optional target-buf)
+  "Colorize the text between BEG and END using a timer.
+Store the result in TARGET-BUF when non-nil."
+  (when diff-ansi--ansi-color-timer
+    (cancel-timer diff-ansi--ansi-color-timer)
+    (setq diff-ansi--ansi-color-timer nil))
+  (let
+    (
+      (diff-command (diff-ansi--command-preset-impl))
+      (diff-str (buffer-substring-no-properties beg end)))
+
+    (unless target-buf
+      (delete-region beg end)
+      (goto-char beg))
+
+    (with-current-buffer (or target-buf (current-buffer))
+      (let ((inhibit-read-only t))
+        (setq beg (point))
+        (diff-ansi--call-process-pipe-chain diff-command :input diff-str 
:output (current-buffer))
+        (setq end (point))
+
+        (setq diff-ansi--ansi-color-timer
+          (run-at-time
+            0.0
+            0.001
+            #'diff-ansi-progressive-highlight-impl
+            (current-buffer)
+            (cons beg end)))))))
+
+
+;; ---------------------------------------------------------------------------
+;; ANSI Conversion (Multi-Processing)
+
+(defun diff-ansi--multiprocess-impl (beg end &optional target-buf)
+  "Colorize the text between BEG and END using multiple processes.
+Store the result in TARGET-BUF when non-nil."
+  (let
+    (
+      (diff-command (diff-ansi--command-preset-impl))
+      (diff-str (buffer-substring-no-properties beg end))
+      (per-chunk-args nil))
+
+    (unless target-buf
+      (delete-region beg end)
+      (goto-char beg))
+
+    (with-current-buffer (or target-buf (current-buffer))
+      (let ((inhibit-read-only t))
+        (diff-ansi--with-temp-directory temp-dir
+          :prefix "diff-ansi"
+          (with-temp-buffer
+            ;; Use the temp buffer.
+            (diff-ansi--call-process-pipe-chain
+              diff-command
+              :input diff-str
+              :output (current-buffer))
+
+            (goto-char (point-min))
+            (let*
+              (
+                (black-color
+                  (diff-ansi--face-attr-to-hex-literal 'diff-ansi-default-face 
:background))
+                (emacs-bin (expand-file-name invocation-name 
invocation-directory))
+                (emacs-eval-arg 
(diff-ansi--ansi-color-apply-on-region-with-bg-str black-color))
+
+                (point-prev (point))
+                ;; Index (for unique names.
+                (i 0))
+              (while (not (eobp))
+                (setq point-prev (point))
+                (goto-char (min (+ (point) diff-ansi-chunks-size) (point-max)))
+                (end-of-line)
+
+                (let ((output (concat temp-dir (number-to-string i))))
+                  (write-region point-prev (point) output nil 0)
+                  (push (list emacs-bin "--batch" output "--eval" 
emacs-eval-arg) per-chunk-args))
+                (setq i (1+ i)))
+
+              (setq per-chunk-args (reverse per-chunk-args))))
+
+          ;; Out of the temp buffer.
+          (setq beg (point))
+          (diff-ansi--call-process-parallel per-chunk-args
+            :output (lambda (_i str) (insert (read str)))
+            :progress-message "Diff progress: ")
+          (setq end (point)))))))
+
+
+;; ---------------------------------------------------------------------------
+;; Internal Logic
+
+;; Helper function (not public).
+(defun diff-ansi--magit-insert-revision-diff-advice-fn (old-fn &rest args)
+  "Internal function use to advise using `diff-ansi-advice-add'.
+
+This calls OLD-FN with ARGS."
+  (let ((point-begin (point)))
+    (diff-ansi--with-advice 'magit-wash-sequence
+      :override (lambda (&rest _) nil)
+
+      (apply old-fn args)
+
+      (with-demoted-errors "diff-ansi: %S"
+        ;; Don't do anything to the diff, it may cause problems.
+        (diff-ansi-region point-begin (point-max))))))
+
+(defun diff-ansi--enable ()
+  "Enable the buffer local minor mode."
+  (when diff-ansi-use-magit-revision-diff
+    (require 'magit-diff)
+    (advice-add 'magit-insert-revision-diff
+      :around #'diff-ansi--magit-insert-revision-diff-advice-fn)))
+
+(defun diff-ansi--disable ()
+  "Disable the buffer local minor mode."
+  (when diff-ansi-use-magit-revision-diff
+    (require 'magit-diff)
+    (advice-remove 'magit-insert-revision-diff 
#'diff-ansi--magit-insert-revision-diff-advice-fn)))
+
+;; ---------------------------------------------------------------------------
+;; Public Functions
+
+;;;###autoload
+(defun diff-ansi-region (beg end &rest args)
+  "Convert the diff between points BEG and END into an ANSI-diff.
+
+Optional keywords in ARGS.
+
+:create-buffer
+  When t, create a new buffer for the diff contents and return it.
+  Note that the buffer is not made active.
+
+:preserve-point
+  When t, place the cursor at the relative line offset based on the location
+  in the original buffer (this uses a simple method that doesn't ensure
+  an exact match for the current line).
+
+Return the buffer used to write data into on success."
+
+
+  (let
+    ( ;; Keyword arguments.
+      (create-buffer nil)
+      (preserve-point nil)
+
+      ;; To update end after the buffer has been resized.
+      (end-trailing-chars (- (buffer-size) end))
+
+      ;; For `preserve-point'.
+      (lines-to-beg nil)
+      (lines-to-end nil)
+      ;; For `into-buffer'.
+      (target-buf nil))
+
+    ;; Handle keyword arguments.
+    (while args
+      (let ((arg-current (pop args)))
+        (cond
+          ((keywordp arg-current)
+            (unless args
+              (error "Keyword argument %S has no value!" arg-current))
+            (let ((v (pop args)))
+              (pcase arg-current
+                (:create-buffer
+                  (cond
+                    ((null v)) ;; No input.
+                    ((eq v t)) ;; OK.
+                    (t
+                      (error "Expected `:create-buffer', to be nil or t")))
+                  (setq create-buffer v))
+
+                (:preserve-point
+                  (cond
+                    ((null v)) ;; No input.
+                    ((eq v t)) ;; OK.
+                    (t
+                      (error "Expected `:preserve-point', to be nil or t")))
+                  (setq preserve-point v))
+                (_ (error "Unknown argument %S" arg-current)))))
+          (t
+            (error
+              "All arguments must be keyword, value pairs, found %S = %S"
+              (type-of arg-current)
+              arg-current)))))
+
+    (when preserve-point
+      (setq lines-to-beg (count-lines (point) beg))
+      (setq lines-to-end (count-lines (point) end)))
+
+    (when create-buffer
+      (setq target-buf (generate-new-buffer (concat (buffer-name) " 
(ansi-diff)")))
+      (with-current-buffer target-buf
+        (setq buffer-read-only t)
+        (setq buffer-undo-list t)
+        ;; We don't have our own mode (is it even needed?).
+        ;; Just set text mode for basic navigation functionality.
+        (text-mode)
+        ;; Don't display fill column.
+        (setq-local fill-column nil)))
+
+    (let ((method diff-ansi-method))
+
+      ;; Fallback to immediate when the task wont be split.
+      (when (<= (- end beg) diff-ansi-chunks-size)
+        (setq method 'immediate))
+
+      (cond
+        ((eq method 'immediate)
+          (diff-ansi--immediate-impl beg end target-buf))
+        ((eq method 'progressive)
+          (diff-ansi--progressive-impl beg end target-buf))
+        ((eq method 'multiprocess)
+          (diff-ansi--multiprocess-impl beg end target-buf))
+        (t
+          (error "Unknown method: %S" method))))
+
+    ;; Update end.
+    (unless target-buf
+      (setq end (- (point-max) end-trailing-chars)))
+
+    ;; This is only an approximation, as the diff views may not be exactly 
compatible.
+    (when preserve-point
+      (with-current-buffer (or target-buf (current-buffer))
+        (when target-buf
+          (setq beg (point-min))
+          (setq end (point-max)))
+        (cond
+          ((zerop lines-to-beg)
+            (goto-char beg))
+          ((zerop lines-to-end)
+            (goto-char end))
+          (t
+            ;; Match the relative vertical offset.
+            (let*
+              (
+                (lines-total-after (count-lines beg end))
+                (factor (/ (float lines-total-after) (float (+ lines-to-beg 
lines-to-end)))))
+              (goto-char beg)
+              (forward-line (truncate (* lines-to-beg factor))))))))
+
+    (cond
+      (create-buffer
+        (set-buffer-modified-p nil)
+        target-buf)
+      (t
+        (current-buffer)))))
+
+;;;###autoload
+(defun diff-ansi-buffer ()
+  "Create an ANSI-diff buffer from the existing plain-diff buffer."
+  (interactive)
+  (let ((buf (diff-ansi-region (point-min) (point-max) :create-buffer t 
:preserve-point t)))
+    (switch-to-buffer buf)))
+
+;;;###autoload
+(define-minor-mode diff-ansi-mode
+  "Enable `diff-ansi' integration."
+  :global nil
+  (cond
+    (diff-ansi-mode
+      (diff-ansi--enable))
+    (t
+      (diff-ansi--disable))))
+
+(provide 'diff-ansi)
+;;; diff-ansi.el ends here
diff --git a/readme.rst b/readme.rst
new file mode 100644
index 0000000000..75273b7584
--- /dev/null
+++ b/readme.rst
@@ -0,0 +1,111 @@
+#########
+Diff ANSI
+#########
+
+Integrate external diff commands into Emacs for improved visualization.
+
+Available via `melpa <https://melpa.org/#/diff-ansi>`__.
+
+
+Motivation
+==========
+
+*This package aims to expose the best possible diff rendering, to save time 
and improve reading diff's in Emacs!*
+
+When reading diff's, features such as side-by-side display, word-level changes 
and syntax highlighting
+can help understanding the changes that have been made.
+
+3rd party tools are available that support these features - this package aims 
to make those accessible within Emacs.
+
+.. figure:: 
https://gitlab.com/ideasman42/emacs-diff-ansi/uploads/0dc4a85d55627707c801b002a8fc6ab0/diff-ansi-screenshot.png
+   :scale: 50 %
+   :align: center
+
+   Screenshot of the ``diff-ansi`` used in Magit's log view.
+
+
+Usage
+=====
+
+Currently there are two main uses for this package.
+
+- You may run ``diff-ansi-buffer`` to display the current diff buffer.
+- Enable ``diff-ansi-mode`` minor mode which installs hooks to use enhanced 
diff display for Magit's revision display.
+
+
+Commands
+--------
+
+``diff-ansi-buffer``
+   Create a new read-only buffer displaying diff contents from the current 
buffer.
+
+``diff-ansi-mode``
+   Enable a minor mode to use ``diff-ansi`` functionality where possible.
+
+
+Customization
+-------------
+
+``diff-ansi-tool``: ``'delta``
+   The external tool to use for displaying diffs.
+
+   - `'delta <https://github.com/dandavison/delta>`__ supports side-by-side 
view, word level differences and syntax highlighting.
+   - `'diff-so-fancy <https://github.com/so-fancy/diff-so-fancy>`__ supports 
word level differences.
+   - `'ydiff <https://github.com/yinwang0/ydiff>`__ supports side-by-side view 
& word level differences.
+   - ``'custom`` call a custom command using (``diff-ansi-tool-custom``).
+
+``diff-ansi-extra-args-for-delta``
+   Additional arguments to pass to delta.
+
+``diff-ansi-extra-args-for-ydiff``
+   Additional arguments to pass to delta.
+
+``diff-ansi-tool-custom``
+   The command to use when ``diff-ansi-tool`` is set to ``'custom``.
+
+``diff-ansi-use-magit-revision-diff``
+   Use ``diff-ansi`` when viewing commits in magit.
+
+``diff-ansi-default-face``
+   The background color of this face is used when no color is specified.
+
+Advanced Customization
+^^^^^^^^^^^^^^^^^^^^^^
+
+Note that in general these settings can be left as-is,
+but may be extended to adjust default behavior.
+
+``diff-ansi-method``: ``'multiprocess``
+   Method used for decoding ANSI sequences.
+
+   - ``'immediate`` to convert immediate (blocking may be slow).
+   - ``'progressive`` uses a timer (avoids blocking input).
+   - ``'multiprocess`` to span multiple external processes for improved 
performance on large diffs.
+
+``diff-ansi-chunks-size``: 8192
+   The number of characters to process at a time for
+   when ``diff-ansi-method`` is set to ``progressive`` or ``multiprocess``.
+
+``diff-ansi-multiprocess-jobs``
+   The number of processes to run simultaneously
+   when ``diff-ansi-method`` is set to ``multiprocess``.
+
+
+Details
+=======
+
+- Converting ANSI escape sequences can be slow for large diffs,
+  this is why ``multiprocess`` support is default to avoid long wait times 
viewing diffs.
+
+
+Installation
+============
+
+The package is available in melpa as ``diff-ansi``, here is an example with 
``use-package``:
+
+The package can be installed using ``straight``.
+
+.. code-block:: elisp
+
+   (use-package diff-ansi
+     :commands (diff-ansi-mode diff-ansi-buffer)))



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