use libarchive by preference

Signed-off-by: Thom May <thom@chef.io>

.travis.yml

@@ -2,11 +2,15 @@ sudo: false
 language: ruby
 cache: bundler
 
+addons:
+  apt:
+    packages:
+      - libarchive-dev
+
 matrix:
   include:
-    - rvm: 2.3.6
-    - rvm: 2.4.3
-    - rvm: 2.5.0
+    - rvm: 2.4.4
+    - rvm: 2.5.1
     - rvm: ruby-head
   allow_failures:
     - rvm: ruby-head

Gemfile

@@ -3,6 +3,4 @@ source "https://rubygems.org"
 # Specify your gem's dependencies in mixlib-archive.gemspec
 gemspec
 
-group(:changelog) do
-  gem "github_changelog_generator", git: "https://github.com/chef/github-changelog-generator"
-end
+gem "ffi-libarchive"

lib/mixlib/archive.rb

@@ -11,8 +11,14 @@ def initialize(archive, empty: false)
       @empty = empty
 
       archive = File.expand_path(archive)
-      # for now we only support Tar format archives.
-      @archiver = Mixlib::Archive::Tar.new(archive)
+      begin
+        # we prefer to use libarchive, which supports a great big pile o' stuff
+        require "mixlib/archive/lib_archive"
+        @archiver = Mixlib::Archive::LibArchive.new(archive)
+      rescue LoadError
+        # but if we can't use that, we'll fall back to ruby's native tar implementation
+        @archiver = Mixlib::Archive::Tar.new(archive)
+      end
     end
 
     class Log

lib/mixlib/archive/lib_archive.rb

@@ -0,0 +1,63 @@
+require "ffi-libarchive"
+
+module Mixlib
+  class Archive
+    class LibArchive
+      attr_reader :options
+      attr_reader :archive
+
+      def initialize(archive, options = {})
+        @archive = archive
+        @options = options
+      end
+
+      # Extracts the archive to the given +destination+
+      #
+      # === Parameters
+      # perms<Boolean>:: should the extracter use permissions from the archive.
+      # ignore[Array]:: an array of matches of file paths to ignore
+      def extract(destination, perms: true, ignore: [])
+        ignore_re = Regexp.union(ignore)
+        flags = perms ? ::Archive::EXTRACT_PERM : nil
+        Dir.chdir(destination) do
+          reader = ::Archive::Reader.open_filename(@archive)
+
+          reader.each_entry do |entry|
+            if entry.pathname =~ ignore_re
+              Mixlib::Archive::Log.warn "ignoring entry #{entry.pathname}"
+              next
+            end
+
+            reader.extract(entry, flags.to_i)
+          end
+          reader.close
+        end
+      end
+
+      # Creates an archive with the given set of +files+
+      #
+      # === Parameters
+      # gzip<Boolean>:: should the archive be gzipped?
+      def create(files, gzip: false)
+        compression = gzip ? ::Archive::COMPRESSION_GZIP : ::Archive::COMPRESSION_NONE
+        # "PAX restricted" will use PAX extensions when it has to, but will otherwise
+        # use ustar for maximum compatibility
+        format = ::Archive::FORMAT_TAR_PAX_RESTRICTED
+
+        ::Archive.write_open_filename(archive, compression, format) do |tar|
+          files.each do |fn|
+            tar.new_entry do |entry|
+              entry.pathname = fn
+              entry.copy_stat(fn)
+              tar.write_header(entry)
+              if File.file?(fn)
+                content = File.read(fn)
+                tar.write_data(content)
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/mixlib/archive/tar.rb

@@ -119,11 +119,11 @@ def reader(&block)
       ensure
         if file
           file.close unless file.closed?
-          file = nil
+          file = nil # rubocop:disable Lint/UselessAssignment
         end
         if raw
           raw.close unless raw.closed?
-          raw = nil
+          raw = nil # rubocop:disable Lint/UselessAssignment
         end
       end
 

spec/mixlib/archive_spec.rb

@@ -2,15 +2,17 @@
 
 describe Mixlib::Archive do
   let(:target) { "../fixtures/foo.tar" }
-  let (:destination) { Dir.mktmpdir }
-  let (:files) { %w{ file dir/file new_file.rb } }
+  let(:destination) { ::Dir.mktmpdir }
+  let(:files) { %w{ file dir/file new_file.rb } }
 
-  let (:archive) { described_class.new(target) }
-  let (:archiver) { double(Mixlib::Archive::Tar, extract: true) }
+  let(:archive) { described_class.new(target) }
+  let(:tar_archiver) { double(Mixlib::Archive::Tar, extract: true) }
+  let(:archiver) { double(Mixlib::Archive::LibArchive, extract: true) }
 
   before do
     allow(File).to receive(:expand_path).and_call_original
     allow(Mixlib::Archive::Tar).to receive(:new).with(any_args).and_return(archiver)
+    allow(Mixlib::Archive::LibArchive).to receive(:new).with(any_args).and_return(archiver)
   end
 
   after do
@@ -31,11 +33,12 @@
       before do
       end
 
-      it "with the correct archiver" do
+      it "with the default archiver" do
         expect(File).to receive(:expand_path).with(target).and_return(expanded_target)
-        expect(Mixlib::Archive::Tar).to receive(:new).with(expanded_target)
+        expect(Mixlib::Archive::LibArchive).to receive(:new).with(expanded_target)
         described_class.new(target)
       end
+
     end
   end
 

spec/spec_helper.rb

@@ -1,2 +1,5 @@
 $LOAD_PATH.unshift File.expand_path("../../lib", __FILE__)
+require "tmpdir"
 require "mixlib/archive"
+require "mixlib/archive/tar"
+require "mixlib/archive/lib_archive"