Fix issue 289: check external source strings validity in Runtime_DebugGetLoadedScripts

src/runtime.cc

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6491 matching lines @@
   bool has_pending_exception;
   Handle<Object> receiver = Top::global();
   Handle<Object> result =
     Execution::Call(compiled_function, receiver, 0, NULL,
                     &has_pending_exception);
   if (has_pending_exception) return Failure::Exception();
   return *result;
 }
 
 
+// If an object given is an external string, check that the underlying
+// resource is accessible. For other kinds of objects, always return true.
+static bool IsExternalStringValid(Object* str) {
+  if (!str->IsString() || !StringShape(String::cast(str)).IsExternal()) {
+    return true;
+  }
+  if (StringShape(String::cast(str)).IsAsciiRepresentation()) {
+    return ExternalAsciiString::cast(str)->resource() != 0;
+  } else if (StringShape(String::cast(str)).IsTwoByteRepresentation()) {
+    return ExternalTwoByteString::cast(str)->resource() != 0;
+  } else {
+    return true;
+  }
+}
+
+
 // Helper function used by Runtime_DebugGetLoadedScripts below.
 static int DebugGetLoadedScripts(FixedArray* instances, int instances_size) {
   NoHandleAllocation ha;
   AssertNoAllocation no_alloc;
 
   // Scan heap for Script objects.
   int count = 0;
   HeapIterator iterator;
   while (iterator.has_next()) {
     HeapObject* obj = iterator.next();
     ASSERT(obj != NULL);
-    if (obj->IsScript()) {
+    if (obj->IsScript() && IsExternalStringValid(Script::cast(obj)->source())) {
       if (instances != NULL && count < instances_size) {
         instances->set(count, obj);
       }
       count++;
     }
   }
 
   return count;
 }
 
@@ skipping 394 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage();
   }
 }
 
 
 } }  // namespace v8::internal