[builtins] Move StringIndexOf to a C++ builtin.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 7157645334519512abe42fd134935264a3a0a5f9..2c2ee0f40d8922eba55c69444b395fbd35c723e5 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -11595,41 +11595,64 @@ ComparisonResult String::Compare(Handle<String> x, Handle<String> y) {
   return result;
 }
 
-int String::IndexOf(Isolate* isolate, Handle<String> sub, Handle<String> pat,
-                    int start_index) {

[Benedikt Meurer, 2016/09/23 03:51:33]

I'd like to keep this version of String::IndexOf as-is, and add a wrapper around
it that does the error checking and stuff.

-  DCHECK(0 <= start_index);
-  DCHECK(start_index <= sub->length());
+Object* String::IndexOf(Isolate* isolate, Handle<Object> receiver,
+                        Handle<Object> search, Handle<Object> position) {
+  if (receiver->IsNull(isolate) || receiver->IsUndefined(isolate)) {
+    THROW_NEW_ERROR_RETURN_FAILURE(
+        isolate, NewTypeError(MessageTemplate::kCalledOnNullOrUndefined,
+                              isolate->factory()->NewStringFromAsciiChecked(
+                                  "String.prototype.indexOf")));
+  }
+  Handle<String> receiver_string;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, receiver_string,
+                                     Object::ToString(isolate, receiver));
 
-  int pattern_length = pat->length();
-  if (pattern_length == 0) return start_index;
+  Handle<String> search_string;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, search_string,
+                                     Object::ToString(isolate, search));
 
-  int subject_length = sub->length();
-  if (start_index + pattern_length > subject_length) return -1;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, position,
+                                     Object::ToInteger(isolate, position));
 
-  sub = String::Flatten(sub);
-  pat = String::Flatten(pat);
+  double position_number = std::max(position->Number(), 0.0);
+  position_number =
+      std::min(position_number, static_cast<double>(receiver_string->length()));
+  uint32_t start_index = static_cast<uint32_t>(position_number);
 
+  uint32_t search_length = search_string->length();
+  if (search_length == 0) return Smi::FromInt(start_index);
+
+  uint32_t receiver_length = receiver_string->length();
+  if (start_index + search_length > receiver_length) return Smi::FromInt(-1);
+
+  receiver_string = String::Flatten(receiver_string);
+  search_string = String::Flatten(search_string);
+
+  int first_index = -1;
   DisallowHeapAllocation no_gc;  // ensure vectors stay valid
   // Extract flattened substrings of cons strings before getting encoding.
-  String::FlatContent seq_sub = sub->GetFlatContent();
-  String::FlatContent seq_pat = pat->GetFlatContent();
+  String::FlatContent receiver_content = receiver_string->GetFlatContent();
+  String::FlatContent search_content = search_string->GetFlatContent();
 
   // dispatch on type of strings
-  if (seq_pat.IsOneByte()) {
-    Vector<const uint8_t> pat_vector = seq_pat.ToOneByteVector();
-    if (seq_sub.IsOneByte()) {
-      return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
-                          start_index);
+  if (search_content.IsOneByte()) {
+    Vector<const uint8_t> pat_vector = search_content.ToOneByteVector();
+    if (receiver_content.IsOneByte()) {
+      return Smi::FromInt(SearchString(isolate,
+                                       receiver_content.ToOneByteVector(),
+                                       pat_vector, start_index));
     }
-    return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector,
-                        start_index);
+    return Smi::FromInt(
+        first_index = SearchString(isolate, receiver_content.ToUC16Vector(),
+                                   pat_vector, start_index));
   }
-  Vector<const uc16> pat_vector = seq_pat.ToUC16Vector();
-  if (seq_sub.IsOneByte()) {
-    return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
-                        start_index);
+  Vector<const uc16> pat_vector = search_content.ToUC16Vector();
+  if (receiver_content.IsOneByte()) {
+    return Smi::FromInt(SearchString(
+        isolate, receiver_content.ToOneByteVector(), pat_vector, start_index));
   }
-  return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector, start_index);
+  return Smi::FromInt(SearchString(isolate, receiver_content.ToUC16Vector(),
+                                   pat_vector, start_index));
 }
 
 namespace {  // for String.Prototype.lastIndexOf