file_consumer.h

#pragma once

#include "file_contents.h"
#include "utils.h"

#include <clang-c/Index.h>

#include <functional>
#include <mutex>
#include <unordered_map>
#include <unordered_set>

struct IndexFile;

// Needed for unordered_map usage below.
MAKE_HASHABLE(CXFileUniqueID, t.data[0], t.data[1], t.data[2]);
bool operator==(const CXFileUniqueID& a, const CXFileUniqueID& b);

struct FileConsumerSharedState {
  mutable std::unordered_set<std::string> used_files;
  mutable std::mutex mutex;

  // Mark the file as used. Returns true if the file was not previously used.
  bool Mark(const std::string& file);
  // Reset the used state (ie, mark the file as unused).
  void Reset(const std::string& file);
};

// FileConsumer is used by the indexer. When it encouters a file, it tries to
// take ownership over it. If the indexer has ownership over a file, it will
// produce an index, otherwise, it will emit nothing for that declarations
// and references coming from that file.
//
// The indexer does this because header files do not have their own translation
// units but we still want to index them.
struct FileConsumer {
  FileConsumer(FileConsumerSharedState* shared_state,
               const std::string& parse_file);

  // Returns true if this instance owns given |file|. This will also attempt to
  // take ownership over |file|.
  //
  // Returns IndexFile for the file or nullptr. |is_first_ownership| is set
  // to true iff the function just took ownership over the file. Otherwise it
  // is set to false.
  //
  // note: file_contents is passed as a parameter instead of as a member
  // variable since it is large and we do not want to copy it.
  IndexFile* TryConsumeFile(CXFile file,
                            bool* is_first_ownership,
                            FileContentsMap* file_contents);

  // Returns and passes ownership of all local state.
  std::vector<std::unique_ptr<IndexFile>> TakeLocalState();

 private:
  void EmitError(CXFile file) const;

  std::unordered_map<CXFileUniqueID, std::unique_ptr<IndexFile>> local_;
  FileConsumerSharedState* shared_;
  std::string parse_file_;
};