Module: Utils::Gzip Private

Extended by:
Output::Mixin
Defined in:
utils/gzip.rb

Overview

This module is part of a private API. This module may only be used in the Homebrew/brew repository. Third parties should avoid using this module if possible, as it may be removed or changed without warning.

Helper functions for creating gzip files.

Constant Summary collapse

GZIP_BUFFER_SIZE =

This constant is part of a private API. This constant may only be used in the Homebrew/brew repository. Third parties should avoid using this constant if possible, as it may be removed or changed without warning.

Apple's gzip also uses zlib so use the same buffer size here. https://github.com/apple-oss-distributions/file_cmds/blob/file_cmds-400/gzip/gzip.c#L147

T.let(64 * 1024, Integer)

Class Method Summary collapse

Methods included from Output::Mixin

issue_reporting_message, odebug, odeprecated, odie, odisabled, ofail, oh1, oh1_title, ohai, ohai_title, onoe, opoo, opoo_outside_github_actions, opoo_without_github_actions_annotation, pretty_deprecated, pretty_disabled, pretty_duration, pretty_install_status, pretty_installed, pretty_uninstalled, pretty_upgradable

Class Method Details

.compress(*paths, reproducible: true, mtime: ENV["SOURCE_DATE_EPOCH"].to_i) ⇒ Array<Pathname>

Compress one or more files with gzip, reproducibly by default.

Unlike the system gzip, this avoids recording the build-time modification time so that the output is deterministic (see https://docs.brew.sh/Reproducible-Builds). Each file is compressed in place, placing the result next to the original with a .gz suffix, and the resulting paths are returned.

Parameters:

  • paths (String, Pathname)
  • reproducible (Boolean) (defaults to: true)
  • mtime (Integer, Time) (defaults to: ENV["SOURCE_DATE_EPOCH"].to_i)

Returns:



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# File 'utils/gzip.rb', line 71

def self.compress(*paths, reproducible: true, mtime: ENV["SOURCE_DATE_EPOCH"].to_i)
  if reproducible
    paths.map do |path|
      compress_with_options(path, mtime:)
    end
  else
    paths.map do |path|
      safe_system "gzip", path
      Pathname.new("#{path}.gz")
    end
  end
end

.compress_with_options(path, mtime: ENV["SOURCE_DATE_EPOCH"].to_i, orig_name: File.basename(path), output: "#{path}.gz") ⇒ Pathname

This method is part of a private API. This method may only be used in the Homebrew/brew repository. Third parties should avoid using this method if possible, as it may be removed or changed without warning.

Parameters:

Returns:



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# File 'utils/gzip.rb', line 23

def self.compress_with_options(path, mtime: ENV["SOURCE_DATE_EPOCH"].to_i, orig_name: File.basename(path),
                               output: "#{path}.gz")
  # There are two problems if `mtime` is less than or equal to 0:
  #
  # 1. Ideally, we would just set mtime = 0 if SOURCE_DATE_EPOCH is absent, but Ruby's
  #    Zlib::GzipWriter does not properly handle the case of setting mtime = 0:
  #    https://bugs.ruby-lang.org/issues/16285
  #
  #    This was fixed in https://github.com/ruby/zlib/pull/10. This workaround
  #    won't be needed once we are using zlib gem version 1.1.0 or newer.
  #
  # 2. If mtime is less than 0, gzip may fail to cast a negative number to an unsigned int
  #    https://github.com/Homebrew/homebrew-core/pull/246155#issuecomment-3345772366
  if mtime.to_i <= 0
    odebug "Setting `mtime = 1` to avoid zlib gem bug and unsigned integer cast when `mtime <= 0`."
    mtime = 1
  end

  File.open(path, "rb") do |fp|
    odebug "Creating gzip file at #{output}"
    gz = Zlib::GzipWriter.open(output)
    gz.mtime = mtime
    gz.orig_name = orig_name
    gz.write(fp.read(GZIP_BUFFER_SIZE)) until fp.eof?
  ensure
    # GzipWriter should be closed in case of error as well
    gz.close
  end

  FileUtils.rm_f path
  Pathname.new(output)
end