brew/Library/Homebrew/download_strategy.rb

#  Copyright 2009 Max Howell and other contributors.
#
#  Redistribution and use in source and binary forms, with or without
#  modification, are permitted provided that the following conditions
#  are met:
#
#  1. Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#  2. Redistributions in binary form must reproduce the above copyright
#     notice, this list of conditions and the following disclaimer in the
#     documentation and/or other materials provided with the distribution.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
#  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
#  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
#  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
#  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
#  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
#  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
#  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
#  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
class AbstractDownloadStrategy
  def initialize url, name, version
    @url=url
    @unique_token="#{name}-#{version}" unless name.to_s.empty? or name == '__UNKNOWN__'
  end
end

class HttpDownloadStrategy <AbstractDownloadStrategy
  def fetch
    ohai "Downloading #{@url}"
    if @unique_token
      @dl=HOMEBREW_CACHE+(@unique_token+ext)
    else
      @dl=HOMEBREW_CACHE+File.basename(@url)
    end
    unless @dl.exist?
      begin
        curl @url, '-o', @dl
      rescue Exception
        @dl.unlink if @dl.exist?
        raise
      end
    else
      puts "File already downloaded and cached"
    end
    return @dl # thus performs checksum verification
  end
  def stage
    # magic numbers stolen from /usr/share/file/magic/
    File.open(@dl) do |f|
      # get the first four bytes
      case f.read(4)
      when /^PK\003\004/ # .zip archive
        safe_system '/usr/bin/unzip', '-qq', @dl
        chdir
      when /^\037\213/, /^BZh/ # gzip/bz2 compressed
        # TODO check if it's really a tar archive
        safe_system '/usr/bin/tar', 'xf', @dl
        chdir
      else
        # we are assuming it is not an archive, use original filename
        # this behaviour is due to ScriptFileFormula expectations
        # So I guess we should cp, but we mv, for this historic reason
        # HOWEVER if this breaks some expectation you had we *will* change the
        # behaviour, just open an issue at github
        FileUtils.mv @dl, File.basename(@url)
      end
    end
  end
private
  def chdir
    entries=Dir['*']
    case entries.length
      when 0 then raise "Empty archive"
      when 1 then Dir.chdir entries.first rescue nil
    end
  end
  def ext
    # GitHub uses odd URLs for zip files, so check for those
    rx=%r[http://(www\.)?github\.com/.*/(zip|tar)ball/]
    if rx.match @url
      if $2 == 'zip'
        '.zip'
      else
        '.tgz'
      end
    else
      Pathname.new(@url).extname
    end
  end
end

class SubversionDownloadStrategy <AbstractDownloadStrategy
  def fetch
    ohai "Checking out #{@url}"
    @co=HOMEBREW_CACHE+@unique_token
    unless @co.exist?
      safe_system '/usr/bin/svn', 'checkout', @url, @co
    else
      # TODO svn up?
      puts "Repository already checked out"
    end
  end
  def stage
    # Force the export, since the target directory will already exist
    safe_system '/usr/bin/svn', 'export', '--force', @co, Dir.pwd
  end
end

class GitDownloadStrategy <AbstractDownloadStrategy
  def fetch
    ohai "Cloning #{@url}"
    @clone=HOMEBREW_CACHE+@unique_token
    unless @clone.exist?
      safe_system 'git', 'clone', @url, @clone
    else
      # TODO git pull?
      puts "Repository already cloned"
    end
  end
  def stage
    dst=Dir.getwd
    Dir.chdir @clone do
      # http://stackoverflow.com/questions/160608/how-to-do-a-git-export-like-svn-export
      safe_system 'git', 'checkout-index', '-af', "--prefix=#{dst}/"
    end
  end
end