#--
# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
# All rights reserved.
# See LICENSE.txt for permissions.
#++
require 'rubygems'
##
# The format class knows the guts of the RubyGem .gem file format and provides
# the capability to read gem files
class Gem::OldFormat
attr_accessor :spec, :file_entries, :gem_path
##
# Constructs an instance of a Format object, representing the gem's data
# structure.
#
# gem:: [String] The file name of the gem
def initialize(gem_path)
require 'fileutils'
require 'zlib'
Gem.load_yaml
@gem_path = gem_path
end
##
# Reads the named gem file and returns a Format object, representing the
# data from the gem file
#
# file_path:: [String] Path to the gem file
def self.from_file_by_path(file_path)
unless File.exist?(file_path)
raise Gem::Exception, "Cannot load gem file [#{file_path}]"
end
File.open(file_path, 'rb') do |file|
from_io(file, file_path)
end
end
##
# Reads a gem from an io stream and returns a Format object, representing
# the data from the gem file
#
# io:: [IO] Stream from which to read the gem
def self.from_io(io, gem_path="(io)")
format = self.new(gem_path)
skip_ruby(io)
format.spec = read_spec(io)
format.file_entries = []
read_files_from_gem(io) do |entry, file_data|
format.file_entries << [entry, file_data]
end
format
end
private
##
# Skips the Ruby self-install header. After calling this method, the
# IO index will be set after the Ruby code.
#
# file:: [IO] The IO to process (skip the Ruby code)
def self.skip_ruby(file)
end_seen = false
loop {
line = file.gets
if(line == nil || line.chomp == "__END__") then
end_seen = true
break
end
}
if end_seen == false then
raise Gem::Exception.new("Failed to find end of ruby script while reading gem")
end
end
##
# Reads the specification YAML from the supplied IO and constructs
# a Gem::Specification from it. After calling this method, the
# IO index will be set after the specification header.
#
# file:: [IO] The IO to process
def self.read_spec(file)
yaml = ''
read_until_dashes file do |line|
yaml << line
end
Gem::Specification.from_yaml yaml
rescue YAML::Error => e
raise Gem::Exception, "Failed to parse gem specification out of gem file"
rescue ArgumentError => e
raise Gem::Exception, "Failed to parse gem specification out of gem file"
end
##
# Reads lines from the supplied IO until a end-of-yaml (---) is
# reached
#
# file:: [IO] The IO to process
# block:: [String] The read line
def self.read_until_dashes(file)
while((line = file.gets) && line.chomp.strip != "---") do
yield line
end
end
##
# Reads the embedded file data from a gem file, yielding an entry
# containing metadata about the file and the file contents themselves
# for each file that's archived in the gem.
# NOTE: Many of these methods should be extracted into some kind of
# Gem file read/writer
#
# gem_file:: [IO] The IO to process
def self.read_files_from_gem(gem_file)
errstr = "Error reading files from gem"
header_yaml = ''
begin
self.read_until_dashes(gem_file) do |line|
header_yaml << line
end
header = YAML.load(header_yaml)
raise Gem::Exception, errstr unless header
header.each do |entry|
file_data = ''
self.read_until_dashes(gem_file) do |line|
file_data << line
end
yield [entry, Zlib::Inflate.inflate(file_data.strip.unpack("m")[0])]
end
rescue Zlib::DataError
raise Gem::Exception, errstr
end
end
end
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