- The dart:io library uses Uri from dart:uri.

bin/gen_snapshot.cc

Index: bin/gen_snapshot.cc
===================================================================
--- bin/gen_snapshot.cc	(revision 5205)
+++ bin/gen_snapshot.cc	(working copy)
@@ -182,8 +182,17 @@
     if (tag == kCanonicalizeUrl) {
       return url;
     }
-    // TODO(iposva): Make sure only the known libraries are being added.
-    return Dart_True();
+    ASSERT(tag == kImportTag);
+    // Handle imports of other built-in libraries present in the SDK.
+    if (DartUtils::IsDartIOLibURL(url_string)) {
+      return Builtin::LoadLibrary(Builtin::kIOLibrary);
+    } else if (DartUtils::IsDartJsonLibURL(url_string)) {
+      return Builtin::LoadLibrary(Builtin::kJsonLibrary);
+    } else if (DartUtils::IsDartUriLibURL(url_string)) {
+      return Builtin::LoadLibrary(Builtin::kUriLibrary);
+    } else if (DartUtils::IsDartUtfLibURL(url_string)) {
+      return Builtin::LoadLibrary(Builtin::kUtfLibrary);
+    }

[siva, 2012/03/09 18:02:39]

The fall through case here is going to produce an incorrect error message. e.g
"import 'dart:xyz'" will result in an "unexpected tag encountered" message.

There should probably be an else here which returns an error message indicating
library not found.

   }
   return Dart_Error("unexpected tag encountered %d", tag);
 }