From f332726eaad74ac2aac0c3fb2dcb662acdbc3a31 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@osdl.org>
Date: Tue, 16 Aug 2005 20:44:32 -0700
Subject: [PATCH] [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>
---
 diffcore-pathspec.c |  2 +
 read-cache.c        |  2 +
 setup.c             | 93 +++++++++++++++++++++++++--------------------
 3 files changed, 55 insertions(+), 42 deletions(-)

diff --git a/diffcore-pathspec.c b/diffcore-pathspec.c
index a48acbc965..68fe009132 100644
--- a/diffcore-pathspec.c
+++ b/diffcore-pathspec.c
@@ -29,6 +29,8 @@ static int matches_pathspec(const char *name, struct path_spec *s, int cnt)
 		    name[len] == 0 ||
 		    name[len] == '/')
 			return 1;
+		if (!len)
+			return 1;
 	}
 	return 0;
 }
diff --git a/read-cache.c b/read-cache.c
index 5820f18d9a..ced597318e 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -191,6 +191,8 @@ int ce_path_match(const struct cache_entry *ce, const char **pathspec)
 			return 1;
 		if (name[matchlen] == '/' || !name[matchlen])
 			return 1;
+		if (!matchlen)
+			return 1;
 	}
 	return 0;
 }
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;
 }
-- 
2.47.1