Refactor GN source expansions.

tools/gn/substitution_list.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "tools/gn/substitution_list.h"
+
+#include <string.h>
+
+#include "tools/gn/value.h"
+
+SubstitutionList::SubstitutionList() {
+}
+
+SubstitutionList::~SubstitutionList() {
+}
+
+bool SubstitutionList::Parse(const Value& value, Err* err) {
+  if (!value.VerifyTypeIs(Value::LIST, err))
+    return false;
+
+  const std::vector<Value>& input_list = value.list_value();
+  list_.resize(input_list.size());
+  for (size_t i = 0; i < input_list.size(); i++) {
+    if (!list_[i].Parse(input_list[i], err))
+      return false;
+  }
+
+  FillRequiredTypes();
+  return true;
+}
+
+bool SubstitutionList::Parse(const std::vector<std::string>& values,
+                             const ParseNode* origin,
+                             Err* err) {
+  list_.resize(values.size());
+  for (size_t i = 0; i < values.size(); i++) {
+    if (!list_[i].Parse(values[i], origin, err))
+      return false;
+  }
+
+  FillRequiredTypes();
+  return true;
+}
+
+SubstitutionList SubstitutionList::MakeForTest(
+    const char* a,
+    const char* b,
+    const char* c) {
+  std::vector<std::string> input_strings;
+  input_strings.push_back(a);
+  if (b)
+    input_strings.push_back(b);
+  if (c)
+    input_strings.push_back(c);
+
+  Err err;
+  SubstitutionList result;
+  result.Parse(input_strings, NULL, &err);
+  return result;
+}
+
+void SubstitutionList::FillRequiredTypes() {
+  bool required_type_bits[SUBSTITUTION_NUM_TYPES];
+  memset(&required_type_bits, 0, SUBSTITUTION_NUM_TYPES);
+  for (size_t i = 0; i < list_.size(); i++)
+    list_[i].FillRequiredTypes(required_type_bits);
+
+  for (size_t i = SUBSTITUTION_FIRST_PATTERN; i < SUBSTITUTION_NUM_TYPES; i++) {
+    if (required_type_bits[i])
+      required_types_.push_back(static_cast<SubstitutionType>(i));
+  }
+}