qemerge

#!/usr/bin/ruby -w

require 'thread'

# masked packages (partial name only)
masked = %w(
	     glibc
	     gcc
	     sun-jdk
	     vanilla-sources
	     firefox
	     mono
          )
	  
# Checks if the new package is not an entirely new version but just a new
# revision.
# I.e., it will succeed if the installed package is at version 3.3.0-r2
# and the new package is at 3.3.0-r3.
def differ_by_revision (inst, new)
    exp = /(.*)-r/
    inst =~ exp
    inst_version = $1 || inst

    new =~ exp
    new_version = $1 || new

    true if inst_version == new_version
end

options = ARGV[0].to_s

# list of packages to update
packages = `emerge -p #{options.delete('f')} #{ARGV[1..-1].join(" ")
}`.collect do |line| 
    line =~ /\[ebuild.*\].*/
    line
end

# filter revisions
todo = packages.collect do |line|
    line =~ /\[ebuild.*\] ([-\w]*\/[-+\w\.]*) (\[(.*)\])?/ 
    package = $1
    new_version = $3	
    package =~ /-(\d[-_\d\.r\w]+)\b/
    inst_version = $1
    
    package unless differ_by_revision(inst_version, new_version)
end.compact!

puts

#filter masked
todo.collect! do |p| 
    if masked.detect { |x| p.include?(x) }
    	puts(" [/] #{p}")
    else
        p
    end
end.compact!

printf("\n I'm going to install the following packages:\n\n")
todo.each { |p| puts(" . #{p}") }
puts

exit if options.include?('p')

# - There can be only one thread fecthing at once
# - There can be only one thread emerging at once
# - There can be one thread fetching while some other thread emerges
# - Before emerging, the thread must acquire one mutex and remains
#   blocked util that mutex becomes available
threads = []
mutex = Mutex.new() 
todo.each { |p| 
    next if masked.detect { |x| p.include?(x) }
    puts(" - fetching #{p}...")
    r = system("emerge -f =#{p} &> /dev/null")
    printf(" - %-60s [ %-5s ]\n", p, r) 

    next if not r or options.include?('f')

    threads << Thread.new(p) do |package| 
        mutex.synchronize do
            puts(" + emerging #{package}...")
	    s = system("emerge -1 =#{package} &> /dev/null")
	    printf(" + %-60s [ %-5s ]\n", package, s)
	end 
    end
}

threads.each { |t| t.join() }