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Merge branch 'jk/git-tricks'

* jk/git-tricks:
  completion: match ctags symbol names in grep patterns
  contrib: add git-jump script
  contrib: add diff highlight script
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2 parents e8e1c29 + 29eec71 commit 324bc2a7ee1cffbf959652a54f4d3d59a1173104 @gitster gitster committed Oct 31, 2011
@@ -1430,6 +1430,10 @@ _git_gitk ()
_gitk
}
+__git_match_ctag() {
+ awk "/^${1////\\/}/ { print \$1 }" "$2"
+}
+
_git_grep ()
{
__git_has_doubledash && return
@@ -1452,6 +1456,15 @@ _git_grep ()
;;
esac
+ case "$cword,$prev" in
+ 2,*|*,-*)
+ if test -r tags; then
+ __gitcomp "$(__git_match_ctag "$cur" tags)"
+ return
+ fi
+ ;;
+ esac
+
__gitcomp "$(__git_refs)"
}
@@ -0,0 +1,57 @@
+diff-highlight
+==============
+
+Line oriented diffs are great for reviewing code, because for most
+hunks, you want to see the old and the new segments of code next to each
+other. Sometimes, though, when an old line and a new line are very
+similar, it's hard to immediately see the difference.
+
+You can use "--color-words" to highlight only the changed portions of
+lines. However, this can often be hard to read for code, as it loses
+the line structure, and you end up with oddly formatted bits.
+
+Instead, this script post-processes the line-oriented diff, finds pairs
+of lines, and highlights the differing segments. It's currently very
+simple and stupid about doing these tasks. In particular:
+
+ 1. It will only highlight a pair of lines if they are the only two
+ lines in a hunk. It could instead try to match up "before" and
+ "after" lines for a given hunk into pairs of similar lines.
+ However, this may end up visually distracting, as the paired
+ lines would have other highlighted lines in between them. And in
+ practice, the lines which most need attention called to their
+ small, hard-to-see changes are touching only a single line.
+
+ 2. It will find the common prefix and suffix of two lines, and
+ consider everything in the middle to be "different". It could
+ instead do a real diff of the characters between the two lines and
+ find common subsequences. However, the point of the highlight is to
+ call attention to a certain area. Even if some small subset of the
+ highlighted area actually didn't change, that's OK. In practice it
+ ends up being more readable to just have a single blob on the line
+ showing the interesting bit.
+
+The goal of the script is therefore not to be exact about highlighting
+changes, but to call attention to areas of interest without being
+visually distracting. Non-diff lines and existing diff coloration is
+preserved; the intent is that the output should look exactly the same as
+the input, except for the occasional highlight.
+
+Use
+---
+
+You can try out the diff-highlight program with:
+
+---------------------------------------------
+git log -p --color | /path/to/diff-highlight
+---------------------------------------------
+
+If you want to use it all the time, drop it in your $PATH and put the
+following in your git configuration:
+
+---------------------------------------------
+[pager]
+ log = diff-highlight | less
+ show = diff-highlight | less
+ diff = diff-highlight | less
+---------------------------------------------
@@ -0,0 +1,124 @@
+#!/usr/bin/perl
+
+# Highlight by reversing foreground and background. You could do
+# other things like bold or underline if you prefer.
+my $HIGHLIGHT = "\x1b[7m";
+my $UNHIGHLIGHT = "\x1b[27m";
+my $COLOR = qr/\x1b\[[0-9;]*m/;
+
+my @window;
+
+while (<>) {
+ # We highlight only single-line changes, so we need
+ # a 4-line window to make a decision on whether
+ # to highlight.
+ push @window, $_;
+ next if @window < 4;
+ if ($window[0] =~ /^$COLOR*(\@| )/ &&
+ $window[1] =~ /^$COLOR*-/ &&
+ $window[2] =~ /^$COLOR*\+/ &&
+ $window[3] !~ /^$COLOR*\+/) {
+ print shift @window;
+ show_pair(shift @window, shift @window);
+ }
+ else {
+ print shift @window;
+ }
+
+ # Most of the time there is enough output to keep things streaming,
+ # but for something like "git log -Sfoo", you can get one early
+ # commit and then many seconds of nothing. We want to show
+ # that one commit as soon as possible.
+ #
+ # Since we can receive arbitrary input, there's no optimal
+ # place to flush. Flushing on a blank line is a heuristic that
+ # happens to match git-log output.
+ if (!length) {
+ local $| = 1;
+ }
+}
+
+# Special case a single-line hunk at the end of file.
+if (@window == 3 &&
+ $window[0] =~ /^$COLOR*(\@| )/ &&
+ $window[1] =~ /^$COLOR*-/ &&
+ $window[2] =~ /^$COLOR*\+/) {
+ print shift @window;
+ show_pair(shift @window, shift @window);
+}
+
+# And then flush any remaining lines.
+while (@window) {
+ print shift @window;
+}
+
+exit 0;
+
+sub show_pair {
+ my @a = split_line(shift);
+ my @b = split_line(shift);
+
+ # Find common prefix, taking care to skip any ansi
+ # color codes.
+ my $seen_plusminus;
+ my ($pa, $pb) = (0, 0);
+ while ($pa < @a && $pb < @b) {
+ if ($a[$pa] =~ /$COLOR/) {
+ $pa++;
+ }
+ elsif ($b[$pb] =~ /$COLOR/) {
+ $pb++;
+ }
+ elsif ($a[$pa] eq $b[$pb]) {
+ $pa++;
+ $pb++;
+ }
+ elsif (!$seen_plusminus && $a[$pa] eq '-' && $b[$pb] eq '+') {
+ $seen_plusminus = 1;
+ $pa++;
+ $pb++;
+ }
+ else {
+ last;
+ }
+ }
+
+ # Find common suffix, ignoring colors.
+ my ($sa, $sb) = ($#a, $#b);
+ while ($sa >= $pa && $sb >= $pb) {
+ if ($a[$sa] =~ /$COLOR/) {
+ $sa--;
+ }
+ elsif ($b[$sb] =~ /$COLOR/) {
+ $sb--;
+ }
+ elsif ($a[$sa] eq $b[$sb]) {
+ $sa--;
+ $sb--;
+ }
+ else {
+ last;
+ }
+ }
+
+ print highlight(\@a, $pa, $sa);
+ print highlight(\@b, $pb, $sb);
+}
+
+sub split_line {
+ local $_ = shift;
+ return map { /$COLOR/ ? $_ : (split //) }
+ split /($COLOR*)/;
+}
+
+sub highlight {
+ my ($line, $prefix, $suffix) = @_;
+
+ return join('',
+ @{$line}[0..($prefix-1)],
+ $HIGHLIGHT,
+ @{$line}[$prefix..$suffix],
+ $UNHIGHLIGHT,
+ @{$line}[($suffix+1)..$#$line]
+ );
+}
View
@@ -0,0 +1,92 @@
+git-jump
+========
+
+Git-jump is a script for helping you jump to "interesting" parts of your
+project in your editor. It works by outputting a set of interesting
+spots in the "quickfix" format, which editors like vim can use as a
+queue of places to visit (this feature is usually used to jump to errors
+produced by a compiler). For example, given a diff like this:
+
+------------------------------------
+diff --git a/foo.c b/foo.c
+index a655540..5a59044 100644
+--- a/foo.c
++++ b/foo.c
+@@ -1,3 +1,3 @@
+ int main(void) {
+- printf("hello word!\n");
++ printf("hello world!\n");
+ }
+-----------------------------------
+
+git-jump will feed this to the editor:
+
+-----------------------------------
+foo.c:2: printf("hello word!\n");
+-----------------------------------
+
+Obviously this trivial case isn't that interesting; you could just open
+`foo.c` yourself. But when you have many changes scattered across a
+project, you can use the editor's support to "jump" from point to point.
+
+Git-jump can generate three types of interesting lists:
+
+ 1. The beginning of any diff hunks.
+
+ 2. The beginning of any merge conflict markers.
+
+ 3. Any grep matches.
+
+
+Using git-jump
+--------------
+
+To use it, just drop git-jump in your PATH, and then invoke it like
+this:
+
+--------------------------------------------------
+# jump to changes not yet staged for commit
+git jump diff
+
+# jump to changes that are staged for commit; you can give
+# arbitrary diff options
+git jump diff --cached
+
+# jump to merge conflicts
+git jump merge
+
+# jump to all instances of foo_bar
+git jump grep foo_bar
+
+# same as above, but case-insensitive; you can give
+# arbitrary grep options
+git jump grep -i foo_bar
+--------------------------------------------------
+
+
+Related Programs
+----------------
+
+You can accomplish some of the same things with individual tools. For
+example, you can use `git mergetool` to start vimdiff on each unmerged
+file. `git jump merge` is for the vim-wielding luddite who just wants to
+jump straight to the conflict text with no fanfare.
+
+As of git v1.7.2, `git grep` knows the `--open-files-in-pager` option,
+which does something similar to `git jump grep`. However, it is limited
+to positioning the cursor to the correct line in only the first file,
+leaving you to locate subsequent hits in that file or other files using
+the editor or pager. By contrast, git-jump provides the editor with a
+complete list of files and line numbers for each match.
+
+
+Limitations
+-----------
+
+This scripts was written and tested with vim. Given that the quickfix
+format is the same as what gcc produces, I expect emacs users have a
+similar feature for iterating through the list, but I know nothing about
+how to activate it.
+
+The shell snippets to generate the quickfix lines will almost certainly
+choke on filenames with exotic characters (like newlines).
View
@@ -0,0 +1,69 @@
+#!/bin/sh
+
+usage() {
+ cat <<\EOF
+usage: git jump <mode> [<args>]
+
+Jump to interesting elements in an editor.
+The <mode> parameter is one of:
+
+diff: elements are diff hunks. Arguments are given to diff.
+
+merge: elements are merge conflicts. Arguments are ignored.
+
+grep: elements are grep hits. Arguments are given to grep.
+EOF
+}
+
+open_editor() {
+ editor=`git var GIT_EDITOR`
+ eval "$editor -q \$1"
+}
+
+mode_diff() {
+ git diff --relative "$@" |
+ perl -ne '
+ if (m{^\+\+\+ b/(.*)}) { $file = $1; next }
+ defined($file) or next;
+ if (m/^@@ .*\+(\d+)/) { $line = $1; next }
+ defined($line) or next;
+ if (/^ /) { $line++; next }
+ if (/^[-+]\s*(.*)/) {
+ print "$file:$line: $1\n";
+ $line = undef;
+ }
+ '
+}
+
+mode_merge() {
+ git ls-files -u |
+ perl -pe 's/^.*?\t//' |
+ sort -u |
+ while IFS= read fn; do
+ grep -Hn '^<<<<<<<' "$fn"
+ done
+}
+
+# Grep -n generates nice quickfix-looking lines by itself,
+# but let's clean up extra whitespace, so they look better if the
+# editor shows them to us in the status bar.
+mode_grep() {
+ git grep -n "$@" |
+ perl -pe '
+ s/[ \t]+/ /g;
+ s/^ *//;
+ '
+}
+
+if test $# -lt 1; then
+ usage >&2
+ exit 1
+fi
+mode=$1; shift
+
+trap 'rm -f "$tmp"' 0 1 2 3 15
+tmp=`mktemp -t git-jump.XXXXXX` || exit 1
+type "mode_$mode" >/dev/null 2>&1 || { usage >&2; exit 1; }
+"mode_$mode" "$@" >"$tmp"
+test -s "$tmp" || exit 0
+open_editor "$tmp"

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