Add a public API for using an empty sring.

v8::String::Empty()


Review URL: http://codereview.chromium.org/42423

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1556 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

include/v8.h

@@ -735,6 +735,11 @@ class V8EXPORT String : public Primitive {
   int WriteAscii(char* buffer, int start = 0, int length = -1) const;  // ASCII
   int WriteUtf8(char* buffer, int length = -1) const; // UTF-8
 
+  /**
+   * A zero length string.
+   */
+  static v8::Local<v8::String> Empty();
+
   /**
    * Returns true if the string is external
    */

src/api.cc

@@ -2472,9 +2472,17 @@ Local<External> v8::External::New(void* data) {
 }
 
 
+Local<String> v8::String::Empty() {
+  EnsureInitialized("v8::String::Empty()");
+  LOG_API("String::Empty()");
+  return Utils::ToLocal(i::Factory::empty_symbol());
+}
+
+
 Local<String> v8::String::New(const char* data, int length) {
   EnsureInitialized("v8::String::New()");
   LOG_API("String::New(char)");
+  if (length == 0) return Empty();
   if (length == -1) length = strlen(data);
   i::Handle<i::String> result =
       i::Factory::NewStringFromUtf8(i::Vector<const char>(data, length));
@@ -2503,6 +2511,7 @@ static int TwoByteStringLength(const uint16_t* data) {
 Local<String> v8::String::New(const uint16_t* data, int length) {
   EnsureInitialized("v8::String::New()");
   LOG_API("String::New(uint16_)");
+  if (length == 0) return Empty();
   if (length == -1) length = TwoByteStringLength(data);
   i::Handle<i::String> result =
       i::Factory::NewStringFromTwoByte(i::Vector<const uint16_t>(data, length));