Introduce new API to expose external string resource regardless of encoding.

test/cctest/test-api.cc

 // Copyright 2012 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 386 matching lines @@
     LocalContext env;
     TestResource* resource = new TestResource(two_byte_source, &dispose_count);
     Local<String> source = String::NewExternal(resource);
     Local<Script> script = Script::Compile(source);
     Local<Value> value = script->Run();
     CHECK(value->IsNumber());
     CHECK_EQ(7, value->Int32Value());
     CHECK(source->IsExternal());
     CHECK_EQ(resource,
              static_cast<TestResource*>(source->GetExternalStringResource()));
+    String::Encoding encoding = String::UNKNOWN_ENCODING;
+    CHECK_EQ(static_cast<const String::ExternalStringResourceBase*>(resource),
+             source->GetExternalStringResourceBase(&encoding));
+    CHECK_EQ(String::TWO_BYTE_ENCODING, encoding);
     HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
     CHECK_EQ(0, dispose_count);
   }
   v8::internal::Isolate::Current()->compilation_cache()->Clear();
   HEAP->CollectAllAvailableGarbage();
   CHECK_EQ(1, dispose_count);
 }
 
 
 THREADED_TEST(ScriptUsingAsciiStringResource) {
   int dispose_count = 0;
   const char* c_source = "1 + 2 * 3";
   {
     v8::HandleScope scope;
     LocalContext env;
-    Local<String> source =
-        String::NewExternal(new TestAsciiResource(i::StrDup(c_source),
-                                                  &dispose_count));
+    TestAsciiResource* resource = new TestAsciiResource(i::StrDup(c_source),
+                                                        &dispose_count);
+    Local<String> source = String::NewExternal(resource);
+    CHECK(source->IsExternalAscii());
+    CHECK_EQ(static_cast<const String::ExternalStringResourceBase*>(resource),
+             source->GetExternalAsciiStringResource());
+    String::Encoding encoding = String::UNKNOWN_ENCODING;
+    CHECK_EQ(static_cast<const String::ExternalStringResourceBase*>(resource),
+             source->GetExternalStringResourceBase(&encoding));
+    CHECK_EQ(String::ASCII_ENCODING, encoding);
     Local<Script> script = Script::Compile(source);
     Local<Value> value = script->Run();
     CHECK(value->IsNumber());
     CHECK_EQ(7, value->Int32Value());
     HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
     CHECK_EQ(0, dispose_count);
   }
   i::Isolate::Current()->compilation_cache()->Clear();
   HEAP->CollectAllAvailableGarbage();
   CHECK_EQ(1, dispose_count);
 }
 
 
 THREADED_TEST(ScriptMakingExternalString) {
   int dispose_count = 0;
   uint16_t* two_byte_source = AsciiToTwoByteString("1 + 2 * 3");
   {
     v8::HandleScope scope;
     LocalContext env;
     Local<String> source = String::New(two_byte_source);
     // Trigger GCs so that the newly allocated string moves to old gen.
     HEAP->CollectGarbage(i::NEW_SPACE);  // in survivor space now
     HEAP->CollectGarbage(i::NEW_SPACE);  // in old gen now
+    CHECK_EQ(source->IsExternal(), false);
+    CHECK_EQ(source->IsExternalAscii(), false);
+    String::Encoding encoding = String::UNKNOWN_ENCODING;
+    CHECK_EQ(NULL, source->GetExternalStringResourceBase(&encoding));
+    CHECK_EQ(String::ASCII_ENCODING, encoding);
     bool success = source->MakeExternal(new TestResource(two_byte_source,
                                                          &dispose_count));
     CHECK(success);
     Local<Script> script = Script::Compile(source);
     Local<Value> value = script->Run();
     CHECK(value->IsNumber());
     CHECK_EQ(7, value->Int32Value());
     HEAP->CollectAllGarbage(i::Heap::kNoGCFlags);
     CHECK_EQ(0, dispose_count);
   }
@@ skipping 16998 matching lines @@
 
   i::Semaphore* sem_;
   volatile int sem_value_;
 };
 
 
 THREADED_TEST(SemaphoreInterruption) {
   ThreadInterruptTest().RunTest();
 }
 #endif  // WIN32