From d0398c8a835c82d168b189274a2defaf99e096fe Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Thu, 24 Dec 2020 23:24:41 -0800
Subject: [PATCH] Common/FileSystem: Fix canonicalization of paths beginning
 with `./`

If we don't skip past the following separator when the destination
is empty, then `./file` gets canonicalized as `/file`.

Also, consider the case where we end up with an empty string (for
example, from `foo/..`). Canonicalize this as `.`.
---
 src/common/file_system.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/common/file_system.cpp b/src/common/file_system.cpp
index e3da145c8..53445e00b 100644
--- a/src/common/file_system.cpp
+++ b/src/common/file_system.cpp
@@ -75,6 +75,9 @@ void CanonicalizePath(char* Destination, u32 cbDestination, const char* Path, bo
           // remove the previous \, if we have one trailing the dot it'll append it anyway
           if (destinationLength > 0)
             Destination[--destinationLength] = '\0';
+          // if there was no previous \, skip past the next one
+          else if (nextCh != '\0')
+            i++;
 
           continue;
         }
@@ -126,6 +129,10 @@ void CanonicalizePath(char* Destination, u32 cbDestination, const char* Path, bo
     i++;
   }
 
+  // if we end up with the empty string, return '.'
+  if (destinationLength == 0)
+    Destination[destinationLength++] = '.';
+
   // ensure nullptr termination
   if (destinationLength < cbDestination)
     Destination[destinationLength] = '\0';