The diff-so-fancy project is also written in perl, and most
of its users pipe diffs through both diff-highlight and
diff-so-fancy. It would be nice if this could be done in a
single script. So let's pull most of diff-highlight's code
into its own module which can be used by diff-so-fancy.
In addition, we'll abstract a few basic items like reading
from stdio so that a script using the module can do more
processing before or after diff-highlight handles the lines.
See the README update for more details.
One small downside is that the diff-highlight script must
now be built using the Makefile. There are ways around this,
but it quickly gets into perl arcana. Let's go with the
simple solution. As a bonus, our Makefile now respects the
PERL_PATH variable if it is set.
Signed-off-by: Jeff King <peff@xxxxxxxx>
---
Scott and I discussed this off-list, and this was the least-gross
solution I came up with. The plan would be for diff-so-fancy to pull in
this copy of diff-highlight from git.git and have a wrapper script
similar to the diff-highlight.perl found here.
contrib/diff-highlight/.gitignore | 2 ++
.../{diff-highlight => DiffHighlight.pm} | 40 +++++++++++++---------
contrib/diff-highlight/Makefile | 21 ++++++++++--
contrib/diff-highlight/README | 30 ++++++++++++++++
contrib/diff-highlight/diff-highlight.perl | 8 +++++
5 files changed, 82 insertions(+), 19 deletions(-)
create mode 100644 contrib/diff-highlight/.gitignore
rename contrib/diff-highlight/{diff-highlight => DiffHighlight.pm} (91%)
mode change 100755 => 100644
create mode 100644 contrib/diff-highlight/diff-highlight.perl
diff --git a/contrib/diff-highlight/.gitignore b/contrib/diff-highlight/.gitignore
new file mode 100644
index 000000000..c07454824
--- /dev/null
+++ b/contrib/diff-highlight/.gitignore
@@ -0,0 +1,2 @@
+shebang.perl
+diff-highlight
diff --git a/contrib/diff-highlight/diff-highlight b/contrib/diff-highlight/DiffHighlight.pm
old mode 100755
new mode 100644
similarity index 91%
rename from contrib/diff-highlight/diff-highlight
rename to contrib/diff-highlight/DiffHighlight.pm
index 81bd8040e..663992e53
--- a/contrib/diff-highlight/diff-highlight
+++ b/contrib/diff-highlight/DiffHighlight.pm
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+package DiffHighlight;
use 5.008;
use warnings FATAL => 'all';
@@ -29,13 +29,14 @@ my @removed;
my @added;
my $in_hunk;
-# Some scripts may not realize that SIGPIPE is being ignored when launching the
-# pager--for instance scripts written in Python.
-$SIG{PIPE} = 'DEFAULT';
+our $line_cb = sub { print @_ };
+our $flush_cb = sub { local $| = 1 };
+
+sub handle_line {
+ local $_ = shift;
-while (<>) {
if (!$in_hunk) {
- print;
+ $line_cb->($_);
$in_hunk = /^$GRAPH*$COLOR*\@\@ /;
}
elsif (/^$GRAPH*$COLOR*-/) {
@@ -49,7 +50,7 @@ while (<>) {
@removed = ();
@added = ();
- print;
+ $line_cb->($_);
$in_hunk = /^$GRAPH*$COLOR*[\@ ]/;
}
@@ -62,15 +63,22 @@ while (<>) {
# place to flush. Flushing on a blank line is a heuristic that
# happens to match git-log output.
if (!length) {
- local $| = 1;
+ $flush_cb->();
}
}
-# Flush any queued hunk (this can happen when there is no trailing context in
-# the final diff of the input).
-show_hunk(\@removed, \@added);
+sub flush {
+ # Flush any queued hunk (this can happen when there is no trailing
+ # context in the final diff of the input).
+ show_hunk(\@removed, \@added);
+}
-exit 0;
+sub highlight_stdin {
+ while (<STDIN>) {
+ handle_line($_);
+ }
+ flush();
+}
# Ideally we would feed the default as a human-readable color to
# git-config as the fallback value. But diff-highlight does
@@ -88,7 +96,7 @@ sub show_hunk {
# If one side is empty, then there is nothing to compare or highlight.
if (!@$a || !@$b) {
- print @$a, @$b;
+ $line_cb->(@$a, @$b);
return;
}
@@ -97,17 +105,17 @@ sub show_hunk {
# stupid, and only handle multi-line hunks that remove and add the same
# number of lines.
if (@$a != @$b) {
- print @$a, @$b;
+ $line_cb->(@$a, @$b);
return;
}
my @queue;
for (my $i = 0; $i < @$a; $i++) {
my ($rm, $add) = highlight_pair($a->[$i], $b->[$i]);
- print $rm;
+ $line_cb->($rm);
push @queue, $add;
}
- print @queue;
+ $line_cb->(@queue);
}
sub highlight_pair {
diff --git a/contrib/diff-highlight/Makefile b/contrib/diff-highlight/Makefile
index 901872452..fbf5c5824 100644
--- a/contrib/diff-highlight/Makefile
+++ b/contrib/diff-highlight/Makefile
@@ -1,5 +1,20 @@
-# nothing to build
-all:
+all: diff-highlight
-test:
+PERL_PATH = /usr/bin/perl
+-include ../../config.mak
+
+PERL_PATH_SQ = $(subst ','\'',$(PERL_PATH))
+
+diff-highlight: shebang.perl DiffHighlight.pm diff-highlight.perl
+ cat $^ >$@+
+ chmod +x $@+
+ mv $@+ $@
+
+shebang.perl: FORCE
+ @echo '#!$(PERL_PATH_SQ)' >$@+
+ @cmp $@+ $@ >/dev/null 2>/dev/null || mv $@+ $@
+
+test: all
$(MAKE) -C t
+
+.PHONY: FORCE
diff --git a/contrib/diff-highlight/README b/contrib/diff-highlight/README
index 836b97a73..d4c234317 100644
--- a/contrib/diff-highlight/README
+++ b/contrib/diff-highlight/README
@@ -99,6 +99,36 @@ newHighlight = "black #aaffaa"
---------------------------------------------
+Using diff-highlight as a module
+--------------------------------
+
+If you want to pre- or post- process the highlighted lines as part of
+another perl script, you can use the DiffHighlight module. You can
+either "require" it or just cat the module together with your script (to
+avoid run-time dependencies).
+
+Your script may set up one or more of the following variables:
+
+ - $DiffHighlight::line_cb - this should point to a function which is
+ called whenever DiffHighlight has lines (which may contain
+ highlights) to output. The default function prints each line to
+ stdout. Note that the function may be called with multiple lines.
+
+ - $DiffHighlight::flush_cb - this should point to a function which
+ flushes the output (because DiffHighlight believes it has completed
+ processing a logical chunk of input). The default function flushes
+ stdout.
+
+The script may then feed lines, one at a time, to DiffHighlight::handle_line().
+When lines are done processing, they will be fed to $line_cb. Note that
+DiffHighlight may queue up many input lines (to analyze a whole hunk)
+before calling $line_cb. After providing all lines, call
+DiffHighlight::flush() to flush any unprocessed lines.
+
+If you just want to process stdin, DiffHighlight::highlight_stdin()
+is a convenience helper which will loop and flush for you.
+
+
Bugs
----
diff --git a/contrib/diff-highlight/diff-highlight.perl b/contrib/diff-highlight/diff-highlight.perl
new file mode 100644
index 000000000..9b3e9c1f4
--- /dev/null
+++ b/contrib/diff-highlight/diff-highlight.perl
@@ -0,0 +1,8 @@
+package main;
+
+# Some scripts may not realize that SIGPIPE is being ignored when launching the
+# pager--for instance scripts written in Python.
+$SIG{PIPE} = 'DEFAULT';
+
+DiffHighlight::highlight_stdin();
+exit 0;
--
2.13.1.766.g6bea926c5