Prevent duplicate entries in the bundled libraries

compiler/java/com/google/dart/compiler/SystemLibraryManager.java

Index: compiler/java/com/google/dart/compiler/SystemLibraryManager.java
===================================================================
--- compiler/java/com/google/dart/compiler/SystemLibraryManager.java	(revision 5968)
+++ compiler/java/com/google/dart/compiler/SystemLibraryManager.java	(working copy)
@@ -198,6 +198,7 @@
   protected SystemLibrary[] getDefaultLibraries() {
     libraries = new ArrayList<SystemLibrary>();
     longToShortUriMap = new HashMap<URI, URI>();
+    HashMap<URI, SystemLibrary> shortUriToLibraryMap = new HashMap<URI, SystemLibrary>();

[zundel, 2012/03/29 15:17:36]

This map looks like

dart:html --> systemlibrary1 
dart:core --> systemlibrary2

hostMap looks like

html --> systemlibrary1
core --> systemlibrary2

They are so alike, I think we could substitute one for the other.

[danrubel, 2012/03/29 17:00:57]

Done.

 
     // Cycle through the import.config, extracting explicit mappings and searching directories
     URI base = this.sdkLibPathUri;
@@ -239,7 +240,7 @@
             // for libraries and don't want the error to be fatal.
             continue;
           }
-          addLib(shortName, host, host, child, dartFile.getName());
+          addLib(shortUriToLibraryMap, shortName, host, host, child, dartFile.getName());
         }
       } else {
         // Otherwise treat the entry as an explicit shortName to dart file mapping
@@ -250,7 +251,7 @@
         explicitShortNames.add(shortName);
         String scheme = shortName.substring(0, index + 1);
         String host = shortName.substring(index + 1);
-        addLib(scheme, host, host, file.getParentFile(), file.getName());
+        addLib(shortUriToLibraryMap, scheme, host, host, file.getParentFile(), file.getName());
       }
     }
     return libraries.toArray(new SystemLibrary[libraries.size()]);
@@ -274,15 +275,13 @@
     return importConfig;
   }
 
-  private boolean addLib(String scheme, String host, String name, File dir, String libFileName)
+  private boolean addLib(HashMap<URI, SystemLibrary> shortUriToLibraryMap, String scheme, String host, String name, File dir, String libFileName)
       throws AssertionError {
     File libFile = new File(dir, libFileName);
     if (!libFile.isFile()) {
       throw new InternalCompilerException("Error mapping dart:" + host + ", path " 
           + libFile.getAbsolutePath() + " is not a file.");
     }
-    SystemLibrary lib = new SystemLibrary(name, host, libFileName, dir);
-    libraries.add(lib);
     String libSpec = scheme + name;
     URI libUri;
     URI expandedUri;
@@ -292,6 +291,13 @@
     } catch (URISyntaxException e) {
       throw new AssertionError(e);
     }
+    SystemLibrary lib = shortUriToLibraryMap.get(libUri);
+    if (lib != null) {
+      libraries.remove(lib);
+    }
+    lib = new SystemLibrary(name, host, libFileName, dir);
+    libraries.add(lib);
+    shortUriToLibraryMap.put(libUri, lib);
     URI resolvedUri = lib.translateUri(expandedUri);
     longToShortUriMap.put(resolvedUri, libUri);
     longToShortUriMap.put(expandedUri, libUri);