Fresh start

1 files changed, 123 insertions, 0 deletions

diff --git a/jni/ruby/lib/rubygems/package/tar_reader.rb b/jni/ruby/lib/rubygems/package/tar_reader.rb
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+++ b/jni/ruby/lib/rubygems/package/tar_reader.rb
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+# -*- coding: utf-8 -*-
+#--
+# Copyright (C) 2004 Mauricio Julio Fernández Pradier
+# See LICENSE.txt for additional licensing information.
+#++
+
+##
+# TarReader reads tar files and allows iteration over their items
+
+class Gem::Package::TarReader
+
+  include Enumerable
+
+  ##
+  # Raised if the tar IO is not seekable
+
+  class UnexpectedEOF < StandardError; end
+
+  ##
+  # Creates a new TarReader on +io+ and yields it to the block, if given.
+
+  def self.new(io)
+    reader = super
+
+    return reader unless block_given?
+
+    begin
+      yield reader
+    ensure
+      reader.close
+    end
+
+    nil
+  end
+
+  ##
+  # Creates a new tar file reader on +io+ which needs to respond to #pos,
+  # #eof?, #read, #getc and #pos=
+
+  def initialize(io)
+    @io = io
+    @init_pos = io.pos
+  end
+
+  ##
+  # Close the tar file
+
+  def close
+  end
+
+  ##
+  # Iterates over files in the tarball yielding each entry
+
+  def each
+    return enum_for __method__ unless block_given?
+
+    until @io.eof? do
+      header = Gem::Package::TarHeader.from @io
+      return if header.empty?
+
+      entry = Gem::Package::TarReader::Entry.new header, @io
+      size = entry.header.size
+
+      yield entry
+
+      skip = (512 - (size % 512)) % 512
+      pending = size - entry.bytes_read
+
+      begin
+        # avoid reading...
+        @io.seek pending, IO::SEEK_CUR
+        pending = 0
+      rescue Errno::EINVAL, NameError
+        while pending > 0 do
+          bytes_read = @io.read([pending, 4096].min).size
+          raise UnexpectedEOF if @io.eof?
+          pending -= bytes_read
+        end
+      end
+
+      @io.read skip # discard trailing zeros
+
+      # make sure nobody can use #read, #getc or #rewind anymore
+      entry.close
+    end
+  end
+
+  alias each_entry each
+
+  ##
+  # NOTE: Do not call #rewind during #each
+
+  def rewind
+    if @init_pos == 0 then
+      raise Gem::Package::NonSeekableIO unless @io.respond_to? :rewind
+      @io.rewind
+    else
+      raise Gem::Package::NonSeekableIO unless @io.respond_to? :pos=
+      @io.pos = @init_pos
+    end
+  end
+
+  ##
+  # Seeks through the tar file until it finds the +entry+ with +name+ and
+  # yields it.  Rewinds the tar file to the beginning when the block
+  # terminates.
+
+  def seek name # :yields: entry
+    found = find do |entry|
+      entry.full_name == name
+    end
+
+    return unless found
+
+    return yield found
+  ensure
+    rewind
+  end
+
+end
+
+require 'rubygems/package/tar_reader/entry'
+