// Copyright 2018 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/metadata.h"

#include "tools/gn/filesystem_utils.h"

bool Metadata::WalkStep(const BuildSettings* settings,
                        const std::vector<std::string>& keys_to_extract,
                        const std::vector<std::string>& keys_to_walk,
                        const SourceDir& rebase_dir,
                        std::vector<Value>* next_walk_keys,
                        std::vector<Value>* result,
                        Err* err) const {
  // If there's no metadata, there's nothing to find, so quick exit.
  if (contents_.empty()) {
    next_walk_keys->emplace_back(nullptr, "");
    return true;
  }

  // Pull the data from each specified key.
  for (const auto& key : keys_to_extract) {
    auto iter = contents_.find(key);
    if (iter == contents_.end())
      continue;
    assert(iter->second.type() == Value::LIST);

    if (!rebase_dir.is_null()) {
      for (const auto& val : iter->second.list_value()) {
        if (!val.VerifyTypeIs(Value::STRING, err))
          return false;
        std::string filename = source_dir_.ResolveRelativeAs(
            /*as_file = */ true, val, err, settings->root_path_utf8());
        if (err->has_error())
          return false;

        result->emplace_back(
            val.origin(),
            RebasePath(filename, rebase_dir, settings->root_path_utf8()));
      }
    } else {
      result->insert(result->end(), iter->second.list_value().begin(),
                     iter->second.list_value().end());
    }
  }

  // Get the targets to look at next. If no keys_to_walk are present, we push
  // the empty string to the list so that the target knows to include its deps
  // and data_deps. The values used here must be lists of strings.
  bool found_walk_key = false;
  for (const auto& key : keys_to_walk) {
    auto iter = contents_.find(key);
    if (iter != contents_.end()) {
      found_walk_key = true;
      assert(iter->second.type() == Value::LIST);
      for (const auto& val : iter->second.list_value()) {
        if (!val.VerifyTypeIs(Value::STRING, err))
          return false;
        next_walk_keys->emplace_back(val);
      }
    }
  }

  if (!found_walk_key)
    next_walk_keys->emplace_back(nullptr, "");

  return true;
}