Define 'crlf' attribute.

This defines the semantics of 'crlf' attribute as an example.
When a path has this attribute unset (i.e. '!crlf'), autocrlf
line-end conversion is not applied.

Eventually we would want to let users to build a pipeline of
processing to munge blob data to filesystem format (and in the
other direction) based on combination of attributes, and at that
point the mechanism in convert_to_{git,working_tree}() that
looks at 'crlf' attribute needs to be enhanced.  Perhaps the
existing 'crlf' would become the first step in the input chain,
and the last step in the output chain.

Signed-off-by: Junio C Hamano <junkio@cox.net>

attr.c

@@ -378,3 +378,21 @@ int git_checkattr(const char *path, int num, struct git_attr_check *check)
 		rem = fill(path, pathlen, stk, check, num, rem);
 	return 0;
 }
+
+static void setup_binary_check(struct git_attr_check *check)
+{
+	static struct git_attr *attr_binary;
+
+	if (!attr_binary)
+		attr_binary = git_attr("binary", 6);
+	check->attr = attr_binary;
+}
+
+int git_path_is_binary(const char *path)
+{
+	struct git_attr_check attr_binary_check;
+
+	setup_binary_check(&attr_binary_check);
+	return (!git_checkattr(path, 1, &attr_binary_check) &&
+		(0 < attr_binary_check.isset));
+}

convert.c

@@ -1,4 +1,6 @@
 #include "cache.h"
+#include "attr.h"
+
 /*
  * convert.c - convert a file when checking it out and checking it in.
  *
@@ -72,17 +74,12 @@ static int is_binary(unsigned long size, struct text_stat *stats)
 	return 0;
 }
 
-int convert_to_git(const char *path, char **bufp, unsigned long *sizep)
+static int autocrlf_to_git(const char *path, char **bufp, unsigned long *sizep)
 {
 	char *buffer, *nbuf;
 	unsigned long size, nsize;
 	struct text_stat stats;
 
-	/*
-	 * FIXME! Other pluggable conversions should go here,
-	 * based on filename patterns. Right now we just do the
-	 * stupid auto-CRLF one.
-	 */
 	if (!auto_crlf)
 		return 0;
 
@@ -128,7 +125,7 @@ int convert_to_git(const char *path, char **bufp, unsigned long *sizep)
 	return 1;
 }
 
-int convert_to_working_tree(const char *path, char **bufp, unsigned long *sizep)
+static int autocrlf_to_working_tree(const char *path, char **bufp, unsigned long *sizep)
 {
 	char *buffer, *nbuf;
 	unsigned long size, nsize;
@@ -184,3 +181,41 @@ int convert_to_working_tree(const char *path, char **bufp, unsigned long *sizep)
 
 	return 1;
 }
+
+static void setup_crlf_check(struct git_attr_check *check)
+{
+	static struct git_attr *attr_crlf;
+
+	if (!attr_crlf)
+		attr_crlf = git_attr("crlf", 4);
+	check->attr = attr_crlf;
+}
+
+static int git_path_is_binary(const char *path)
+{
+	struct git_attr_check attr_crlf_check;
+
+	setup_crlf_check(&attr_crlf_check);
+
+	/*
+	 * If crlf is not mentioned, default to autocrlf;
+	 * disable autocrlf only when crlf attribute is explicitly
+	 * unset.
+	 */
+	return (!git_checkattr(path, 1, &attr_crlf_check) &&
+		(0 == attr_crlf_check.isset));
+}
+
+int convert_to_git(const char *path, char **bufp, unsigned long *sizep)
+{
+	if (git_path_is_binary(path))
+		return 0;
+	return autocrlf_to_git(path, bufp, sizep);
+}
+
+int convert_to_working_tree(const char *path, char **bufp, unsigned long *sizep)
+{
+	if (git_path_is_binary(path))
+		return 0;
+	return autocrlf_to_working_tree(path, bufp, sizep);
+}

t/t0020-crlf.sh

@@ -214,4 +214,28 @@ test_expect_success 'apply patch --index (autocrlf=true)' '
 	}
 '
 
+test_expect_success '.gitattributes says two is binary' '
+
+	echo "two !crlf" >.gitattributes &&
+	rm -f tmp one dir/two &&
+	git repo-config core.autocrlf true &&
+	git read-tree --reset -u HEAD &&
+
+	if remove_cr dir/two >/dev/null
+	then
+		echo "Huh?"
+		false
+	else
+		: happy
+	fi &&
+
+	if remove_cr one >/dev/null
+	then
+		: happy
+	else
+		echo "Huh?"
+		false
+	fi
+'
+
 test_done