catalog.h

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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef FLUTTER_TOOLS_LICENSES_CPP_SRC_CATALOG_H_
#define FLUTTER_TOOLS_LICENSES_CPP_SRC_CATALOG_H_
 
#include "flutter/third_party/re2/re2/re2.h"
#include "flutter/third_party/re2/re2/set.h"
#include "third_party/abseil-cpp/absl/container/flat_hash_map.h"
#include "third_party/abseil-cpp/absl/status/statusor.h"
 
#include <iosfwd>
#include <optional>
 
/// A storage of licenses that can be matched against.
/// The in memory representation of the `data/headers` and `data/licenses`
/// directories.  This represents a 2 tiered search, first the sector is used
/// to determine what matcher should be used, then a match is performend on
/// that. This approach was chosen to minimize the size of the RE2::Set.
class Catalog {
 public:
  /// VisibleForTesting
  struct Entry {
    std::string name;
    std::string unique;
    std::string matcher;
  };
 
  class Match {
   public:
    static Match MakeWithString(std::string_view matcher,
                                std::string matched_text) {
      return Match(matcher, std::move(matched_text));
    }
 
    static Match MakeWithView(std::string_view matcher,
                              std::string_view matched_text) {
      return Match(matcher, matched_text);
    }
 
    std::string_view GetMatcher() const { return matcher_; }
    std::string_view GetMatchedText() const {
      if (matched_text_.empty()) {
        return owned_matched_text_;
      } else {
        return matched_text_;
      }
    }
 
   private:
    Match(std::string_view matcher, std::string_view matched_text)
        : matcher_(matcher), matched_text_(matched_text) {}
    Match(std::string_view matcher, std::string matched_text)
        : matcher_(matcher), owned_matched_text_(std::move(matched_text)) {}
 
    std::string_view matcher_;
    std::string_view matched_text_;
    std::string owned_matched_text_;
  };
 
  static absl::StatusOr<Catalog> Open(std::string_view data_dir);
 
  /// Make a Catalog for testing.
  static absl::StatusOr<Catalog> Make(const std::vector<Entry>& entries);
 
  /// @brief Tries to identify a match for the `query` across the `Catalog`.
  /// @param query The text that will be matched against.
  /// @return absl::StatusCode::kNotFound when a match can't be found.
  /// absl::StatusCode::kInvalidArgument if more than one match comes up from
  /// the selector.
  absl::StatusOr<std::vector<Match>> FindMatch(std::string_view query) const;
 
  /// VisibleForTesting
  static absl::StatusOr<Entry> ParseEntry(std::istream& is);
 
 private:
  explicit Catalog(RE2::Set selector,
                   std::vector<std::unique_ptr<RE2>> matchers,
                   std::vector<std::string> names);
  RE2::Set selector_;
  std::vector<std::unique_ptr<RE2>> matchers_;
  std::vector<std::string> names_;
};
 
#endif  // FLUTTER_TOOLS_LICENSES_CPP_SRC_CATALOG_H_