[gobject-introspection] Add a pre-commit hook and enforce it

[Johan Dahlin <johan src gnome org>]

commit 98ca5de2eeb098e5f256abd9938e5a40861b4f1e
Author: Johan Dahlin <johan gnome org>
Date:   Tue Aug 17 15:52:03 2010 -0300

    Add a pre-commit hook and enforce it

 Makefile.am     |    4 +++
 misc/pre-commit |   70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 98016cd..1c09fbb 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -41,6 +41,10 @@ upload-release: $(distdir).tar.gz
 	ssh gnome.org install-module $(distdir).tar.gz
 
 check-local:
+	@test -f .git/hooks/pre-commit || (echo -e "ERROR: missing \
+	pre-commit hook.\n\ncopy misc/pre-commit to .git/hooks"; false)
+	@test -x .git/hooks/pre-commit || (echo -e "ERROR: pre-commit \
+	is not executable\n\nrun chmod +x .git/hooks/pre-commit"; false)
 	@echo "  PEP-8 INQUISITION"
 	@find $(top_srcdir)/giscanner -name \*.py | sort | uniq | xargs $(PYTHON) $(top_srcdir)/misc/pep8.py --repeat --exclude=config.py
 	@echo "  CHECK Pyflakes"
diff --git a/misc/pre-commit b/misc/pre-commit
new file mode 100755
index 0000000..b25dce6
--- /dev/null
+++ b/misc/pre-commit
@@ -0,0 +1,70 @@
+#!/bin/sh
+#
+# An example hook script to verify what is about to be committed.
+# Called by git-commit with no arguments.  The hook should
+# exit with non-zero status after issuing an appropriate message if
+# it wants to stop the commit.
+#
+# To enable this hook, make this file executable.
+
+# This is slightly modified from Andrew Morton's Perfect Patch.
+# Lines you introduce should not have trailing whitespace.
+# Also check for an indentation that has SP before a TAB.
+
+if git-rev-parse --verify HEAD 2>/dev/null
+then
+	git-diff-index -p -M --cached HEAD --
+else
+	# NEEDSWORK: we should produce a diff with an empty tree here
+	# if we want to do the same verification for the initial import.
+	:
+fi |
+perl -e '
+    my $found_bad = 0;
+    my $filename;
+    my $reported_filename = "";
+    my $lineno;
+    sub bad_line {
+	my ($why, $line) = @_;
+	if (!$found_bad) {
+	    print STDERR "*\n";
+	    print STDERR "* You have some suspicious patch lines:\n";
+	    print STDERR "*\n";
+	    $found_bad = 1;
+	}
+	if ($reported_filename ne $filename) {
+	    print STDERR "* In $filename\n";
+	    $reported_filename = $filename;
+	}
+	print STDERR "* $why (line $lineno)\n";
+	print STDERR "$filename:$lineno:$line\n";
+    }
+    while (<>) {
+	if (m|^diff --git a/(.*) b/\1$|) {
+	    $filename = $1;
+	    next;
+	}
+	if (/^@@ -\S+ \+(\d+)/) {
+	    $lineno = $1 - 1;
+	    next;
+	}
+	if (/^ /) {
+	    $lineno++;
+	    next;
+	}
+	if (s/^\+//) {
+	    $lineno++;
+	    chomp;
+	    if (/\s$/) {
+		bad_line("trailing whitespace", $_);
+	    }
+	    if (/^\s* \t/) {
+		bad_line("indent SP followed by a TAB", $_);
+	    }
+	    if (/^([<>])\1{6} |^={7}$/) {
+		bad_line("unresolved merge conflict", $_);
+	    }
+	}
+    }
+    exit($found_bad);
+'