From 0c977dbc8180892af42d7ab9235fd3e51d6c4078 Mon Sep 17 00:00:00 2001 From: Jeff King Date: Thu, 15 Jun 2017 12:30:55 -0400 Subject: [PATCH] diff-highlight: split code into module 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 Signed-off-by: Junio C Hamano --- 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 0000000000..c07454824e --- /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 81bd8040e3..663992e530 --- 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 @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 @@ @removed = (); @added = (); - print; + $line_cb->($_); $in_hunk = /^$GRAPH*$COLOR*[\@ ]/; } @@ -62,15 +63,22 @@ # place to flush. Flushing on a blank line is a heuristic that # happens to match git-log output. if (!length) { - local $| = 1; + $flush_cb->(); } } -# Flush any queued hunk (this can happen when there is no trailing context in -# the final diff of the input). -show_hunk(\@removed, \@added); +sub flush { + # Flush any queued hunk (this can happen when there is no trailing + # context in the final diff of the input). + show_hunk(\@removed, \@added); +} -exit 0; +sub highlight_stdin { + while () { + handle_line($_); + } + 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 9018724524..fbf5c58249 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 836b97a730..d4c2343175 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 $line_cb. After providing all lines, call +DiffHighlight::flush() to flush any unprocessed lines. + +If you just want to process stdin, DiffHighlight::highlight_stdin() +is a convenience helper which will loop and flush for you. + + Bugs ---- diff --git a/contrib/diff-highlight/diff-highlight.perl b/contrib/diff-highlight/diff-highlight.perl new file mode 100644 index 0000000000..9b3e9c1f4d --- /dev/null +++ b/contrib/diff-highlight/diff-highlight.perl @@ -0,0 +1,8 @@ +package main; + +# Some scripts may not realize that SIGPIPE is being ignored when launching the +# pager--for instance scripts written in Python. +$SIG{PIPE} = 'DEFAULT'; + +DiffHighlight::highlight_stdin(); +exit 0;