[PATCH] Improve handling of "." and ".." in git-diff-*

This fixes up usage of ".." (without an ending slash) and "." (with or
without the ending slash) in the git diff family.

It also fixes pathspec matching for the case of an empty pathspec, since a
"." in the top-level directory (or enough ".." under subdirectories) will
result in an empty pathspec. We used to not match it against anything, but
it should in fact match everything.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 51 insertions, 42 deletions

diff --git a/setup.c b/setup.c
index 896fca5032..1710b16854 100644
--- a/setup.c
+++ b/setup.c
@@ -1,23 +1,60 @@
 #include "cache.h"
 
+static char *prefix_path(const char *prefix, int len, char *path)
+{
+	char *orig = path;
+	for (;;) {
+		char c;
+		if (*path != '.')
+			break;
+		c = path[1];
+		/* "." */
+		if (!c) {
+			path++;
+			break;
+		}
+		/* "./" */
+		if (c == '/') {
+			path += 2;
+			continue;
+		}
+		if (c != '.')
+			break;
+		c = path[2];
+		if (!c)
+			path += 2;
+		else if (c == '/')
+			path += 3;
+		else
+			break;
+		/* ".." and "../" */
+		/* Remove last component of the prefix */
+		do {
+			if (!len)
+				die("'%s' is outside repository", orig);
+			len--;
+		} while (len && prefix[len-1] != '/');
+		continue;
+	}
+	if (len) {
+		int speclen = strlen(path);
+		char *n = xmalloc(speclen + len + 1);
+	
+		memcpy(n, prefix, len);
+		memcpy(n + len, path, speclen+1);
+		path = n;
+	}
+	return path;
+}
+
 const char **get_pathspec(const char *prefix, char **pathspec)
 {
 	char *entry = *pathspec;
 	char **p;
 	int prefixlen;
 
-	if (!prefix) {
-		char **p;
-		if (!entry)
-			return NULL;
-		p = pathspec;
-		do {
-			if (*entry != '.')
-				continue;
-			/* fixup ? */
-		} while ((entry = *++p) != NULL);
-		return (const char **) pathspec;
-	}
+	if (!prefix && !entry)
+		return NULL;
 
 	if (!entry) {
 		static const char *spec[2];
@@ -27,38 +64,10 @@ const char **get_pathspec(const char *prefix, char **pathspec)
 	}
 
 	/* Otherwise we have to re-write the entries.. */
-	prefixlen = strlen(prefix);
 	p = pathspec;
+	prefixlen = prefix ? strlen(prefix) : 0;
 	do {
-		int speclen, len = prefixlen;
-		char *n;
-
-		for (;;) {
-			if (!strcmp(entry, ".")) {
-				entry++;
-				break;
-			}
-			if (!strncmp(entry, "./", 2)) {
-				entry += 2;
-				continue;
-			}
-			if (!strncmp(entry, "../", 3)) {
-				do {
-					if (!len)
-						die("'%s' is outside repository", *p);
-					len--;
-				} while (len && prefix[len-1] != '/');
-				entry += 3;
-				continue;
-			}
-			break;
-		}
-		speclen = strlen(entry);
-		n = xmalloc(speclen + len + 1);
-		
-		memcpy(n, prefix, len);
-		memcpy(n + len, entry, speclen+1);
-		*p = n;
+		*p = prefix_path(prefix, prefixlen, entry);
 	} while ((entry = *++p) != NULL);
 	return (const char **) pathspec;
 }