Limit length of strings copied into a heap snapshot

src/objects.cc

 // Copyright 2011 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 5808 matching lines @@
 
   // Negative length means the to the end of the string.
   if (length < 0) length = kMaxInt - offset;
 
   // Compute the size of the UTF-8 string. Start at the specified offset.
   Access<StringInputBuffer> buffer(
       heap->isolate()->objects_string_input_buffer());
   buffer->Reset(offset, this);
   int character_position = offset;
   int utf8_bytes = 0;
-  while (buffer->has_more()) {
+  while (buffer->has_more() && character_position++ < offset + length) {
     uint16_t character = buffer->GetNext();
-    if (character_position < offset + length) {
-      utf8_bytes += unibrow::Utf8::Length(character);
-    }
-    character_position++;
+    utf8_bytes += unibrow::Utf8::Length(character);
   }
 
   if (length_return) {
     *length_return = utf8_bytes;
   }
 
   char* result = NewArray<char>(utf8_bytes + 1);
 
   // Convert the UTF-16 string to a UTF-8 buffer. Start at the specified offset.
   buffer->Rewind();
   buffer->Seek(offset);
   character_position = offset;
   int utf8_byte_position = 0;
-  while (buffer->has_more()) {
+  while (buffer->has_more() && character_position++ < offset + length) {
     uint16_t character = buffer->GetNext();
-    if (character_position < offset + length) {
-      if (allow_nulls == DISALLOW_NULLS && character == 0) {
-        character = ' ';
-      }
-      utf8_byte_position +=
-          unibrow::Utf8::Encode(result + utf8_byte_position, character);
+    if (allow_nulls == DISALLOW_NULLS && character == 0) {
+      character = ' ';
     }
-    character_position++;
+    utf8_byte_position +=
+        unibrow::Utf8::Encode(result + utf8_byte_position, character);
   }
   result[utf8_byte_position] = 0;
   return SmartArrayPointer<char>(result);
 }
 
 
 SmartArrayPointer<char> String::ToCString(AllowNullsFlag allow_nulls,
                                           RobustnessFlag robust_flag,
                                           int* length_return) {
   return ToCString(allow_nulls, robust_flag, 0, -1, length_return);
@@ skipping 6653 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single break point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 
 } }  // namespace v8::internal