Minor refactorings.

[SVN r21200]

src/build/targets.jam

@@ -545,13 +545,12 @@ class file-reference : abstract-target
                [ virtual-target.from-file $(self.name) : $(self.project) ] ;        
     }    
 
-    rule location ( )
+    # Returns true if the referred file really exists;
+    rule exists ( )
     {
-        # FIXME: use of glob seems like a horribly inefficient way
-        # to lookup a file.
         local location = [ path.root $(self.name)
-          [ project.attribute $(self.project) source-location ] ] ;
-        return [ path.glob $(location:D) : $(location:D=) ] ;
+          [ project.attribute $(self.project) source-location ] ] ;        
+        return [ path.exists $(location) ] ;
     }    
 }
 
@@ -615,7 +614,7 @@ rule find ( id : current-location )
     if ! $(target) && ! $(have-project-reference) && $(base-project)
     {
         target = [ new file-reference $(target-part) : $(base-project) ] ;        
-        if ! [ $(target).location ]
+        if ! [ $(target).exists ]
         {
             # File actually does not exist.
             # Reset 'target' so that an error is issued.

src/util/path.jam

@@ -195,6 +195,16 @@ rule glob ( dir : patterns + )
     return [ sequence.transform make : [ GLOB [ native $(dir) ] : $(patterns) ] ] ;
 }
 
+#
+#    Returns true is the specified file exists.
+#
+rule exists ( file )
+{
+    return [ path.glob $(file:D) : $(file:D=) ] ;
+}
+
+
+
 #
 #   Find out the absolute name of path and returns the list of all the parents,
 #   starting with the immediate one. Parents are returned as relative names.