1 files changed, 175 insertions, 0 deletions
diff --git a/userdiff.c b/userdiff.c
new file mode 100644
index 0000000000..d95257ab3b
--- /dev/null
+++ b/userdiff.c
@@ -0,0 +1,175 @@
+#include "userdiff.h"
+#include "cache.h"
+#include "attr.h"
+
+static struct userdiff_driver *drivers;
+static int ndrivers;
+static int drivers_alloc;
+
+#define FUNCNAME(name, pattern) \
+	{ name, NULL, -1, { pattern, REG_EXTENDED } }
+static struct userdiff_driver builtin_drivers[] = {
+FUNCNAME("html", "^[ \t]*(<[Hh][1-6][ \t].*>.*)$"),
+FUNCNAME("java",
+	 "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
+	 "^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\\([^;]*)$"),
+FUNCNAME("objc",
+	 /* Negate C statements that can look like functions */
+	 "!^[ \t]*(do|for|if|else|return|switch|while)\n"
+	 /* Objective-C methods */
+	 "^[ \t]*([-+][ \t]*\\([ \t]*[A-Za-z_][A-Za-z_0-9* \t]*\\)[ \t]*[A-Za-z_].*)$\n"
+	 /* C functions */
+	 "^[ \t]*(([ \t]*[A-Za-z_][A-Za-z_0-9]*){2,}[ \t]*\\([^;]*)$\n"
+	 /* Objective-C class/protocol definitions */
+	 "^(@(implementation|interface|protocol)[ \t].*)$"),
+FUNCNAME("pascal",
+	 "^((procedure|function|constructor|destructor|interface|"
+		"implementation|initialization|finalization)[ \t]*.*)$"
+	 "\n"
+	 "^(.*=[ \t]*(class|record).*)$"),
+FUNCNAME("php", "^[\t ]*((function|class).*)"),
+FUNCNAME("python", "^[ \t]*((class|def)[ \t].*)$"),
+FUNCNAME("ruby", "^[ \t]*((class|module|def)[ \t].*)$"),
+FUNCNAME("bibtex", "(@[a-zA-Z]{1,}[ \t]*\\{{0,1}[ \t]*[^ \t\"@',\\#}{~%]*).*$"),
+FUNCNAME("tex", "^(\\\\((sub)*section|chapter|part)\\*{0,1}\\{.*)$"),
+{ "default", NULL, -1, { NULL, 0 } },
+};
+#undef FUNCNAME
+
+static struct userdiff_driver driver_true = {
+	"diff=true",
+	NULL,
+	0,
+	{ NULL, 0 }
+};
+
+static struct userdiff_driver driver_false = {
+	"!diff",
+	NULL,
+	1,
+	{ NULL, 0 }
+};
+
+static struct userdiff_driver *userdiff_find_by_namelen(const char *k, int len)
+{
+	int i;
+	for (i = 0; i < ndrivers; i++) {
+		struct userdiff_driver *drv = drivers + i;
+		if (!strncmp(drv->name, k, len) && !drv->name[len])
+			return drv;
+	}
+	for (i = 0; i < ARRAY_SIZE(builtin_drivers); i++) {
+		struct userdiff_driver *drv = builtin_drivers + i;
+		if (!strncmp(drv->name, k, len) && !drv->name[len])
+			return drv;
+	}
+	return NULL;
+}
+
+static struct userdiff_driver *parse_driver(const char *var,
+		const char *value, const char *type)
+{
+	struct userdiff_driver *drv;
+	const char *dot;
+	const char *name;
+	int namelen;
+
+	if (prefixcmp(var, "diff."))
+		return NULL;
+	dot = strrchr(var, '.');
+	if (dot == var + 4)
+		return NULL;
+	if (strcmp(type, dot+1))
+		return NULL;
+
+	name = var + 5;
+	namelen = dot - name;
+	drv = userdiff_find_by_namelen(name, namelen);
+	if (!drv) {
+		ALLOC_GROW(drivers, ndrivers+1, drivers_alloc);
+		drv = &drivers[ndrivers++];
+		memset(drv, 0, sizeof(*drv));
+		drv->name = xmemdupz(name, namelen);
+		drv->binary = -1;
+	}
+	return drv;
+}
+
+static int parse_funcname(struct userdiff_funcname *f, const char *k,
+		const char *v, int cflags)
+{
+	if (git_config_string(&f->pattern, k, v) < 0)
+		return -1;
+	f->cflags = cflags;
+	return 1;
+}
+
+static int parse_string(const char **d, const char *k, const char *v)
+{
+	if (git_config_string(d, k, v) < 0)
+		return -1;
+	return 1;
+}
+
+static int parse_tristate(int *b, const char *k, const char *v)
+{
+	if (v && !strcasecmp(v, "auto"))
+		*b = -1;
+	else
+		*b = git_config_bool(k, v);
+	return 1;
+}
+
+int userdiff_config_basic(const char *k, const char *v)
+{
+	struct userdiff_driver *drv;
+
+	if ((drv = parse_driver(k, v, "funcname")))
+		return parse_funcname(&drv->funcname, k, v, 0);
+	if ((drv = parse_driver(k, v, "xfuncname")))
+		return parse_funcname(&drv->funcname, k, v, REG_EXTENDED);
+	if ((drv = parse_driver(k, v, "binary")))
+		return parse_tristate(&drv->binary, k, v);
+
+	return 0;
+}
+
+int userdiff_config_porcelain(const char *k, const char *v)
+{
+	struct userdiff_driver *drv;
+
+	if ((drv = parse_driver(k, v, "command")))
+		return parse_string(&drv->external, k, v);
+	if ((drv = parse_driver(k, v, "textconv")))
+		return parse_string(&drv->textconv, k, v);
+
+	return 0;
+}
+
+struct userdiff_driver *userdiff_find_by_name(const char *name) {
+	int len = strlen(name);
+	return userdiff_find_by_namelen(name, len);
+}
+
+struct userdiff_driver *userdiff_find_by_path(const char *path)
+{
+	static struct git_attr *attr;
+	struct git_attr_check check;
+
+	if (!attr)
+		attr = git_attr("diff", 4);
+	check.attr = attr;
+
+	if (!path)
+		return NULL;
+	if (git_checkattr(path, 1, &check))
+		return NULL;
+
+	if (ATTR_TRUE(check.value))
+		return &driver_true;
+	if (ATTR_FALSE(check.value))
+		return &driver_false;
+	if (ATTR_UNSET(check.value))
+		return NULL;
+	return userdiff_find_by_name(check.value);
+}