Make internalized string parser in JSON.parse GC-safe

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 515 matching lines @@
       : SequentialStringKey<uint8_t>(str, seed) { }
 
   virtual bool IsMatch(Object* string) V8_OVERRIDE {
     return String::cast(string)->IsOneByteEqualTo(string_);
   }
 
   virtual Handle<Object> AsHandle(Isolate* isolate) V8_OVERRIDE;
 };
 
 
-template<class Char>
-class SubStringKey : public HashTableKey {
+class SeqOneByteSubStringKey : public HashTableKey {
  public:
-  SubStringKey(Handle<String> string, int from, int length)
+  SeqOneByteSubStringKey(Handle<SeqOneByteString> string, int from, int length)
       : string_(string), from_(from), length_(length) {
-    if (string_->IsSlicedString()) {
-      string_ = Handle<String>(Unslice(*string_, &from_));
-    }
-    DCHECK(string_->IsSeqString() || string->IsExternalString());
+    DCHECK(string_->IsSeqOneByteString());
   }
 
   virtual uint32_t Hash() V8_OVERRIDE {
     DCHECK(length_ >= 0);
     DCHECK(from_ + length_ <= string_->length());
-    const Char* chars = GetChars() + from_;
+    const uint8_t* chars = string_->GetChars() + from_;
     hash_field_ = StringHasher::HashSequentialString(
         chars, length_, string_->GetHeap()->HashSeed());
     uint32_t result = hash_field_ >> String::kHashShift;
     DCHECK(result != 0);  // Ensure that the hash value of 0 is never computed.
     return result;
   }
 
   virtual uint32_t HashForObject(Object* other) V8_OVERRIDE {
     return String::cast(other)->Hash();
   }
 
   virtual bool IsMatch(Object* string) V8_OVERRIDE;
   virtual Handle<Object> AsHandle(Isolate* isolate) V8_OVERRIDE;
 
  private:
-  const Char* GetChars();
-  String* Unslice(String* string, int* offset) {
-    while (string->IsSlicedString()) {
-      SlicedString* sliced = SlicedString::cast(string);
-      *offset += sliced->offset();
-      string = sliced->parent();
-    }
-    return string;
-  }
-
-  Handle<String> string_;
+  Handle<SeqOneByteString> string_;
   int from_;
   int length_;
   uint32_t hash_field_;
 };
 
 
 class TwoByteStringKey : public SequentialStringKey<uc16> {
  public:
   explicit TwoByteStringKey(Vector<const uc16> str, uint32_t seed)
       : SequentialStringKey<uc16>(str, seed) { }
@@ skipping 6696 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_