Refactor script position calculation

src/runtime/runtime-debug.cc

Index: src/runtime/runtime-debug.cc
diff --git a/src/runtime/runtime-debug.cc b/src/runtime/runtime-debug.cc
index e3f3beb6976da53443707168c427ff0247e525ed..b65324fb8fc076a968fc926dbca95705bfb1af10 100644
--- a/src/runtime/runtime-debug.cc
+++ b/src/runtime/runtime-debug.cc
@@ -1501,6 +1501,105 @@ RUNTIME_FUNCTION(Runtime_GetScript) {
   return *Script::GetWrapper(found);
 }
 
+RUNTIME_FUNCTION(Runtime_ScriptLineCount) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSValue, script, 0);
+
+  RUNTIME_ASSERT(script->value()->IsScript());
+  Handle<Script> script_handle = Handle<Script>(Script::cast(script->value()));
+
+  Script::InitLineEnds(script_handle);
+
+  FixedArray* line_ends_array = FixedArray::cast(script_handle->line_ends());
+  return Smi::FromInt(line_ends_array->length());
+}
+
+RUNTIME_FUNCTION(Runtime_ScriptLineStartPosition) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 2);
+  CONVERT_ARG_CHECKED(JSValue, script, 0);
+  CONVERT_NUMBER_CHECKED(int32_t, line, Int32, args[1]);
+
+  RUNTIME_ASSERT(script->value()->IsScript());
+  Handle<Script> script_handle = Handle<Script>(Script::cast(script->value()));
+
+  Script::InitLineEnds(script_handle);
+
+  FixedArray* line_ends_array = FixedArray::cast(script_handle->line_ends());
+  const int line_count = line_ends_array->length();
+
+  // If line == line_count, we return the first position beyond the last line.
+  if (line < 0 || line > line_count) {
+    return Smi::FromInt(-1);
+  } else if (line == 0) {
+    return Smi::FromInt(0);
+  } else {
+    DCHECK(0 < line && line <= line_count);
+    const int pos = Smi::cast(line_ends_array->get(line - 1))->value() + 1;
+    return Smi::FromInt(pos);
+  }
+}
+
+RUNTIME_FUNCTION(Runtime_ScriptLineEndPosition) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 2);
+  CONVERT_ARG_CHECKED(JSValue, script, 0);
+  CONVERT_NUMBER_CHECKED(int32_t, line, Int32, args[1]);
+
+  RUNTIME_ASSERT(script->value()->IsScript());
+  Handle<Script> script_handle = Handle<Script>(Script::cast(script->value()));
+
+  Script::InitLineEnds(script_handle);
+
+  FixedArray* line_ends_array = FixedArray::cast(script_handle->line_ends());
+  const int line_count = line_ends_array->length();
+
+  if (line < 0 || line >= line_count) {
+    return Smi::FromInt(-1);
+  } else {
+    return Smi::cast(line_ends_array->get(line));
+  }
+}
+
+RUNTIME_FUNCTION(Runtime_ScriptPositionInfo) {
+  HandleScope scope(isolate);
+  DCHECK(args.length() == 3);
+  CONVERT_ARG_CHECKED(JSValue, script, 0);
+  CONVERT_NUMBER_CHECKED(int32_t, position, Int32, args[1]);
+  CONVERT_BOOLEAN_ARG_CHECKED(with_offset, 2);
+
+  RUNTIME_ASSERT(script->value()->IsScript());
+  Handle<Script> script_handle = Handle<Script>(Script::cast(script->value()));
+
+  Script::PositionInfo info;
+  const Script::OffsetFlag offset_flag =
+      with_offset ? Script::WITH_OFFSET : Script::NO_OFFSET;
+  if (!script_handle->GetPositionInfo(position, &info, offset_flag)) {
+    return isolate->heap()->null_value();
+  }
+
+  Handle<String> source =
+      handle(String::cast(script_handle->source()), isolate);
+  Handle<String> sourceText =
+      isolate->factory()->NewSubString(source, info.line_start, info.line_end);
+
+  Handle<JSObject> jsinfo =
+      isolate->factory()->NewJSObject(isolate->object_function());
+
+  JSObject::AddProperty(jsinfo, isolate->factory()->script_string(),
+                        script_handle, NONE);
+  JSObject::AddProperty(jsinfo, isolate->factory()->position_string(),
+                        handle(Smi::FromInt(position), isolate), NONE);
+  JSObject::AddProperty(jsinfo, isolate->factory()->line_string(),
+                        handle(Smi::FromInt(info.line), isolate), NONE);
+  JSObject::AddProperty(jsinfo, isolate->factory()->column_string(),
+                        handle(Smi::FromInt(info.column), isolate), NONE);
+  JSObject::AddProperty(jsinfo, isolate->factory()->sourceText_string(),
+                        sourceText, NONE);
+
+  return *jsinfo;
+}
 
 // Set one shot breakpoints for the callback function that is passed to a
 // built-in function such as Array.forEach to enable stepping into the callback,