Fix a crash in Logger::LogCompiledFunctions due to a presence of scripts with disposed source.

src/debug.cc

 // Copyright 2006-2008 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 1659 matching lines @@
   Handle<Object> fun(Top::global()->GetProperty(*function_name));
   ASSERT(fun->IsJSFunction());
   bool caught_exception;
   Handle<Object> js_object = Execution::TryCall(
       Handle<JSFunction>::cast(fun),
       Handle<JSObject>(Debug::debug_context()->global()),
       0, NULL, &caught_exception);
 }
 
 
-// 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 (String::cast(str)->IsAsciiRepresentation()) {
-    return ExternalAsciiString::cast(str)->resource() != NULL;
-  } else if (String::cast(str)->IsTwoByteRepresentation()) {
-    return ExternalTwoByteString::cast(str)->resource() != NULL;
-  } else {
-    return true;
-  }
-}
-
-
 void Debug::CreateScriptCache() {
   HandleScope scope;
 
   // Perform two GCs to get rid of all unreferenced scripts. The first GC gets
   // rid of all the cached script wrappers and the second gets rid of the
   // scripts which is no longer referenced.
   Heap::CollectAllGarbage(false);
   Heap::CollectAllGarbage(false);
 
   ASSERT(script_cache_ == NULL);
   script_cache_ = new ScriptCache();
 
   // Scan heap for Script objects.
   int count = 0;
   HeapIterator iterator;
   while (iterator.has_next()) {
     HeapObject* obj = iterator.next();
     ASSERT(obj != NULL);
-    if (obj->IsScript() && IsExternalStringValid(Script::cast(obj)->source())) {
+    if (obj->IsScript() && Script::cast(obj)->HasValidSource()) {
       script_cache_->Add(Handle<Script>(Script::cast(obj)));
       count++;
     }
   }
 }
 
 
 void Debug::DestroyScriptCache() {
   // Get rid of the script cache if it was created.
   if (script_cache_ != NULL) {
@@ skipping 994 matching lines @@
 
 
 void LockingCommandMessageQueue::Clear() {
   ScopedLock sl(lock_);
   queue_.Clear();
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal