class Gem::CompactIndexClient::CacheFile

write cache files in a way that is robust to concurrent modifications if digests are given, the checksums will be verified

Constants

DEFAULT_FILE_MODE

Attributes

original_path [R]

path [R]

Public Class Methods

copy (path) { |file| ... }

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 24
def self.copy(path, &block)
  new(path) do |file|
    file.initialize_digests

    path.open("rb") do |s|
      file.open {|f| IO.copy_stream(s, f) }
    end

    yield file
  end
end

Initialize with a copy of the original file, then yield the instance.

new (original_path) { |self| ... }

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 47
def initialize(original_path, &block)
  @original_path = original_path
  @perm = original_path.file? ? original_path.stat.mode : DEFAULT_FILE_MODE
  @path = original_path.sub(/$/, ".#{$$}.tmp")
  return unless block_given?
  begin
    yield self
  ensure
    close
  end
end

write (path, data, digests = nil)

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 37
def self.write(path, data, digests = nil)
  return unless data
  new(path) do |file|
    file.digests = digests
    file.write(data)
  end
end

Write data to a temp file, then replace the original file with it verifying the digests if given.

Public Instance Methods

append (data)

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 100
def append(data)
  return false unless digests?
  open("a") {|f| f.write data }
  verify && commit
end

Returns false without appending when no digests since appending is too error prone to do without digests.

close ()

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 135
def close
  return if @closed
  FileUtils.remove_file(path) if @path&.file?
  @closed = true
end

Remove the temp file without replacing the original file. The file is permanently closed.

commit ()

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 127
def commit
  raise ClosedError, "Cannot commit closed file" if @closed
  FileUtils.mv(path, original_path)
  @closed = true
end

Replace the original file with the temp file without verifying digests. The file is permanently closed.

commit! ()

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 112
def commit!
  verify || raise(DigestMismatchError.new(@base64digests, @expected_digests))
  commit
end

digests= (expected_digests)

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 75
def digests=(expected_digests)
  @expected_digests = expected_digests

  if @expected_digests.nil?
    @digests = nil
  elsif @digests
    @digests = @digests.slice(*@expected_digests.keys)
  else
    initialize_digests(@expected_digests.keys)
  end
end

set the digests that will be verified at the end

digests? ()

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 87
def digests?
  @digests&.any?
end

initialize_digests (keys = nil)

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 64
def initialize_digests(keys = nil)
  @digests = keys ? SUPPORTED_DIGESTS.slice(*keys) : SUPPORTED_DIGESTS.dup
  @digests.transform_values! {|algo_class| Digest(algo_class).new }
end

initialize the digests using CompactIndexClient::SUPPORTED_DIGESTS, or a subset based on keys.

open (write_mode = "wb", perm = @perm) { |digests? ? digest_io: f| ... }

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 92
def open(write_mode = "wb", perm = @perm, &block)
  raise ClosedError, "Cannot reopen closed file" if @closed
  path.open(write_mode, perm) do |f|
    yield digests? ? Gem::Package::DigestIO.new(f, @digests) : f
  end
end

Open the temp file for writing, reusing original permissions, yielding the IO object.

reset_digests ()

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 70
def reset_digests
  @digests&.each_value(&:reset)
end

reset the digests so they don’t contain any previously read data

size ()

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 59
def size
  path.size
end

verify ()

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 118
def verify
  return true unless @expected_digests && digests?
  @base64digests = @digests.transform_values!(&:base64digest)
  @digests = nil
  @base64digests.all? {|algo, digest| @expected_digests[algo] == digest }
end

Verify the digests, returning true on match, false on mismatch.

write (data)

Source

# File lib/rubygems/compact_index_client/cache_file.rb, line 106
def write(data)
  reset_digests
  open {|f| f.write data }
  commit!
end