class Bundler::CompactIndexClient::Updater

# File lib/bundler/compact_index_client/updater.rb, line 23
def initialize(fetcher)
  @fetcher = fetcher
  require "tmpdir"
end

# File lib/bundler/compact_index_client/updater.rb, line 105
def checksum_for_file(path)
  return nil unless path.file?
  # This must use IO.read instead of Digest.file().hexdigest
  # because we need to preserve \n line endings on windows when calculating
  # the checksum
  SharedHelpers.filesystem_access(path, :read) do
    SharedHelpers.digest(:MD5).hexdigest(IO.read(path))
  end
end

# File lib/bundler/compact_index_client/updater.rb, line 92
def etag_for(path)
  sum = checksum_for_file(path)
  sum ? %("#{sum}") : nil
end

# File lib/bundler/compact_index_client/updater.rb, line 97
def slice_body(body, range)
  if body.respond_to?(:byteslice)
    body.byteslice(range)
  else # pre-1.9.3
    body.unpack("@#{range.first}a#{range.end + 1}").first
  end
end

# File lib/bundler/compact_index_client/updater.rb, line 28
def update(local_path, remote_path, retrying = nil)
  headers = {}

  Dir.mktmpdir("bundler-compact-index-") do |local_temp_dir|
    local_temp_path = Pathname.new(local_temp_dir).join(local_path.basename)

    # first try to fetch any new bytes on the existing file
    if retrying.nil? && local_path.file?
      SharedHelpers.filesystem_access(local_temp_path) do
        FileUtils.cp local_path, local_temp_path
      end
      headers["If-None-Match"] = etag_for(local_temp_path)
      headers["Range"] =
        if local_temp_path.size.nonzero?
          # Subtract a byte to ensure the range won't be empty.
          # Avoids 416 (Range Not Satisfiable) responses.
          "bytes=#{local_temp_path.size - 1}-"
        else
          "bytes=#{local_temp_path.size}-"
        end
    else
      # Fastly ignores Range when Accept-Encoding: gzip is set
      headers["Accept-Encoding"] = "gzip"
    end

    response = @fetcher.call(remote_path, headers)
    return nil if response.is_a?(Net::HTTPNotModified)

    content = response.body
    if response["Content-Encoding"] == "gzip"
      content = Zlib::GzipReader.new(StringIO.new(content)).read
    end

    SharedHelpers.filesystem_access(local_temp_path) do
      if response.is_a?(Net::HTTPPartialContent) && local_temp_path.size.nonzero?
        local_temp_path.open("a") {|f| f << slice_body(content, 1..-1) }
      else
        local_temp_path.open("w") {|f| f << content }
      end
    end

    response_etag = (response["ETag"] || "").gsub(%r{\AW/}, "")
    if etag_for(local_temp_path) == response_etag
      SharedHelpers.filesystem_access(local_path) do
        FileUtils.mv(local_temp_path, local_path)
      end
      return nil
    end

    if retrying
      raise MisMatchedChecksumError.new(remote_path, response_etag, etag_for(local_temp_path))
    end

    update(local_path, remote_path, :retrying)
  end
rescue Errno::EACCES
  raise Bundler::PermissionError,
    "Bundler does not have write access to create a temp directory " \
    "within #{Dir.tmpdir}. Bundler must have write access to your " \
    "systems temp directory to function properly. "
rescue Zlib::GzipFile::Error
  raise Bundler::HTTPError
end