Method createRegularFile

src/libfetchers/git-utils.cc:1217–1314

    }

    void createRegularFile(const CanonPath & path, fun<void(CreateRegularFileSink &)> func) override
    {
        checkInterrupt();

        /* Multithreaded blob writing. We read the incoming file data into memory and asynchronously write it to a Git
           blob object. However, to avoid unbounded memory usage, if the amount of data in flight exceeds a threshold,
           we switch to writing directly to a Git write stream. */

        using WriteStream = std::unique_ptr<::git_writestream, decltype([](::git_writestream * stream) {
                                                if (stream)
                                                    stream->free(stream);
                                            })>;

        struct CRF : CreateRegularFileSink
        {
            CanonPath path;
            GitFileSystemObjectSinkImpl & parent;
            WriteStream stream;
            std::optional<decltype(parent.repoPool)::Handle> repo;

            std::string contents;
            bool executable = false;

            CRF(CanonPath path, GitFileSystemObjectSinkImpl & parent)
                : path(std::move(path))
                , parent(parent)
            {
            }

            ~CRF()
            {
                parent.totalBufSize -= contents.size();
            }

            void operator()(std::string_view data) override
            {
                if (!stream) {
                    contents.append(data);
                    parent.totalBufSize += data.size();

                    if (parent.totalBufSize > parent.maxBufSize) {
                        repo.emplace(parent.repoPool.get());

                        if (git_blob_create_from_stream(Setter(stream), **repo, nullptr))
                            throw GitError("creating a blob stream object");

                        if (stream->write(stream.get(), contents.data(), contents.size()))
                            throw GitError("writing a blob for tarball member '%s'", path);

                        parent.totalBufSize -= contents.size();
                        contents.clear();
                    }
                } else {
                    if (stream->write(stream.get(), data.data(), data.size()))
                        throw GitError("writing a blob for tarball member '%s'", path);
                }
            }