From c6741b3502b559563f7a458fbad2f4963f166eff Mon Sep 17 00:00:00 2001
From: meep-eep <meep-eep@8092fc87-c524-0410-9efc-e669fe64eaf9>
Date: Sun, 29 May 2005 02:08:02 +0000
Subject: [PATCH] Add "." and ".." processing to expandPath, some better
 documentation.

git-svn-id: svn://svn.code.sf.net/p/sc2/code/trunk@1819 8092fc87-c524-0410-9efc-e669fe64eaf9
---
 sc2/src/sc2code/libs/file.h      |   5 +-
 sc2/src/sc2code/libs/file/dirs.c | 100 ++++++++++++++++++++++++++++++-
 2 files changed, 100 insertions(+), 5 deletions(-)

diff --git a/sc2/src/sc2code/libs/file.h b/sc2/src/sc2code/libs/file.h
index 38ee5798b..a7e3d309e 100644
--- a/sc2/src/sc2code/libs/file.h
+++ b/sc2/src/sc2code/libs/file.h
@@ -46,9 +46,10 @@ int expandPath (char *dest, size_t len, const char *src, int what);
 #define EP_ENVVARS   4
 		// Expand environment variables.
 #define EP_DOTS      8
-		// Process '..' and '.' (not implemented)
+		// Process ".." and "."
 #define EP_SLASHES   16
-		// Change (Windows style) backslashes to (Unix style) slashes.
+		// Consider backslashes as path component separators.
+		// They will be replaced by slashes.
 #define EP_ALL (EP_HOME | EP_ENVVARS | EP_ABSOLUTE | EP_DOTS | EP_SLASHES)
 		// Everything
 // Everything except Windows style backslashes on Unix Systems:
diff --git a/sc2/src/sc2code/libs/file/dirs.c b/sc2/src/sc2code/libs/file/dirs.c
index 4533dea04..cba5b5cbf 100644
--- a/sc2/src/sc2code/libs/file/dirs.c
+++ b/sc2/src/sc2code/libs/file/dirs.c
@@ -43,6 +43,7 @@
 
 static char *expandPathAbsolute (char *dest, size_t destLen,
 		const char *src, int what);
+static char *strrchr2(const char *start, int c, const char *end);
 
 
 int
@@ -183,8 +184,19 @@ getHomeDir (void)
 #endif
 }
 
-// Expand ~/ in a path, and replaces \ by / on Windows.
-// Environment variable parsing could be added here if we need it.
+// Performs various types of string expansions on a path.
+// 'what' is an OR'd compination of the folowing flags, which
+// specify what type of exmansions will be performed.
+// EP_HOME - Expand '~' for home dirs.
+// EP_ABSOLUTE - Make relative paths absolute
+// EP_ENVVARS - Expand environment variables
+// EP_DOTS - Process ".." and "."
+// EP_SLASHES - Consider backslashes as path component separators.
+//              They will be replaced by slashes.
+// Additionally, there's EP_ALL, which indicates all of the above,
+// and EP_SYSTEM_ALL, which does the same as EP_ALL, with the exception
+// of EP_SLASHES, which will only be included if the operating system
+// accepts backslashes as path terminators.
 // Returns 0 on success.
 // Returns -1 on failure, setting errno.
 int
@@ -360,7 +372,6 @@ expandPath (char *dest, size_t len, const char *src, int what)
 	else
 		srcend = src + strlen (src);
 
-	
 	if (what & EP_HOME)
 	{
 		if (src[0] == '~')
@@ -429,6 +440,77 @@ expandPath (char *dest, size_t len, const char *src, int what)
 			destptr++;
 		}
 	}
+	
+	if (what & EP_DOTS) {
+		// At this point backslashes are already replaced by slashes if they
+		// are specified to be path seperators.
+		// Note that the path can only get smaller, so no size checks
+		// need to be done.
+		char *pathStart;
+				// Start of the first path component, after any
+				// leading slashes or drive letters.
+		char *startPart;
+		char *endPart;
+
+		pathStart = dest;
+#ifdef WIN32
+		if (isDriveLetter(src[0]) && (src[1] == ':'))
+			pathStart += 2;
+#endif
+		if (pathStart[0] == '/')
+			pathStart++;
+
+		startPart = pathStart;
+		destptr = pathStart;
+		for (;;)
+		{
+			endPart = strchr(startPart, '/');
+			if (endPart == NULL)
+				endPart = startPart + strlen(startPart);
+
+			if (endPart - startPart == 1 && startPart[0] == '.')
+			{
+				// Found "." as path component. Ignore this component.
+			}
+			else if (endPart - startPart == 2 &&
+					startPart[0] == '.' && startPart[1] == '.')
+			{
+				// Found ".." as path component. Remove the previous
+				// component, and ignore this one.
+				char *lastSlash;
+				lastSlash = strrchr2(pathStart, '/', destptr - 1);
+				if (lastSlash == NULL)
+				{
+					if (destptr == pathStart)
+					{
+						// We ran out of path components to back out of.
+						errno = EINVAL;
+						return -1;
+					}
+					destptr = pathStart;
+				}
+				else
+					destptr = lastSlash;
+			}
+			else
+			{
+				// A normal path component; copy it.
+				// Using memmove as source and destination may overlap.
+				memmove(destptr, startPart, endPart - startPart);
+				destptr += (endPart - startPart);
+				if (*endPart == '/')
+				{
+					*destptr = '/';
+					destptr++;
+				}
+			}
+			if (*endPart == '\0')
+				break;
+			startPart = endPart + 1;
+		}
+		*destptr = '\0';	
+	}
+	
 	return 0;
 }
 
@@ -476,4 +558,16 @@ expandPathAbsolute (char *dest, size_t destLen, const char *src, int what)
 	return dest;
 }
 
+// As strrchr, but starts searching from the indicated end of the string.
+static char *
+strrchr2(const char *start, int c, const char *end) {
+	for (;;) {
+		end--;
+		if (end < start)
+			return (char *) NULL;
+		if (*end == c)
+			return (char *) end;
+	}
+}
+