SystemTools: Improve RelativePath() to handle ./ ../ and //

This fixes bug #12065, #14462 and #14765.

Change-Id: I80c6506767d8b1c7ab2607800458ae3064909b3f

SystemTools.cxx

@@ -3425,9 +3425,12 @@ kwsys_stl::string SystemTools::RelativePath(const kwsys_stl::string& local, cons
     return "";
     }
 
+  kwsys_stl::string l = SystemTools::CollapseFullPath(local);
+  kwsys_stl::string r = SystemTools::CollapseFullPath(remote);
+
   // split up both paths into arrays of strings using / as a separator
-  kwsys_stl::vector<kwsys::String> localSplit = SystemTools::SplitString(local, '/', true);
-  kwsys_stl::vector<kwsys::String> remoteSplit = SystemTools::SplitString(remote, '/', true);
+  kwsys_stl::vector<kwsys::String> localSplit = SystemTools::SplitString(l, '/', true);
+  kwsys_stl::vector<kwsys::String> remoteSplit = SystemTools::SplitString(r, '/', true);
   kwsys_stl::vector<kwsys::String> commonPath; // store shared parts of path in this array
   kwsys_stl::vector<kwsys::String> finalPath;  // store the final relative path here
   // count up how many matching directory names there are from the start

testSystemTools.cxx

@@ -562,6 +562,33 @@ static bool CheckEnvironmentOperations()
   return res;
 }
 
+
+static bool CheckRelativePath(
+  const kwsys_stl::string& local,
+  const kwsys_stl::string& remote,
+  const kwsys_stl::string& expected)
+{
+  kwsys_stl::string result = kwsys::SystemTools::RelativePath(local, remote);
+  if(expected != result)
+    {
+    kwsys_ios::cerr << "RelativePath(" << local << ", " << remote
+      << ")  yielded " << result << " instead of " << expected << kwsys_ios::endl;
+    return false;
+    }
+  return true;
+}
+
+static bool CheckRelativePaths()
+{
+  bool res = true;
+  res &= CheckRelativePath("/usr/share", "/bin/bash", "../../bin/bash");
+  res &= CheckRelativePath("/usr/./share/", "/bin/bash", "../../bin/bash");
+  res &= CheckRelativePath("/usr//share/", "/bin/bash", "../../bin/bash");
+  res &= CheckRelativePath("/usr/share/../bin/", "/bin/bash", "../../bin/bash");
+  res &= CheckRelativePath("/usr/share", "/usr/share//bin", "bin");
+  return res;
+}
+
 //----------------------------------------------------------------------------
 int testSystemTools(int, char*[])
 {
@@ -593,5 +620,7 @@ int testSystemTools(int, char*[])
 
   res &= CheckEnvironmentOperations();
 
+  res &= CheckRelativePaths();
+
   return res ? 0 : 1;
 }