#!/usr/bin/ruby -w
#
# tdg - Thread Dump Grapher (any better name?)
#
#   Given a Java Thread Dump file as argument, it prints out
#   a  Grapviz (.dot) to generate a graph that shows which threads
#   are waiting on others for a lock.
#   (tested with a Sun JDK 1.4 thread dump)
#

class ThreadInfo

  attr_accessor  :stack, :name, :locks, :to_lock, :tid, :runnable

  def stack()
	  @stack
  end

  def stack=(stack)
	  @stack = stack
  end

  def initialize(id, name)
    
    @tid = id
    @name = name
    @runnable = false
    @locks= []
    @to_lock= nil
  end

end


### Main
filename = ARGV.shift

if filename == nil  || ! File.readable?(filename) :
   fail( "Usage: $0 <thread_dump_file>")
end

# Parse thread dump file
lock_to_thread = {}
threads = []
#thread_to_lock = {}

File.open(filename) do |file|
  processing = false
  currentThread = nil
  file.each_line do |line|

    # skip heading lines that are not part of the Thread dump
    processing ||= ( line =~ /Full thread dump/ )
    next if not processing

    
    case line
    when  /^"(.*)".*tid=(\w+) +nid=\w+ (runnable)?/ 
       currentThread = ThreadInfo.new($2, $1)
       currentThread.runnable = ($3 != nil)
       threads << currentThread

    when  /locked <(\w+)>/ 

       if currentThread != nil then
         currentThread.locks << $1

#         thread_to_lock[currentThread.tid] ||= []
#         thread_to_lock[currentThread.tid] << $1
         lock_to_thread[$1] = currentThread.tid
       end
     
     when /waiting to lock <(\w+)>/ 
       currentThread.to_lock = $1  if currentThread != nil
     
    end
  end
end




## Generate output
print <<EOS
digraph G {
        edge [fontname="Helvetica",fontsize=10,labelfontname="Helvetica",labelfontsize=10];
        node [fontname="Helvetica",fontsize=10,shape=record, style=filled];
        rankdir=LR;
        ranksep=1;
        bgcolor=white;
EOS

threads.each do |t|

  # we ignore threads that are not involved in lockings
  next if t.locks.empty? and t.to_lock == nil

  color = if t.runnable :
              "green"
          else  t.to_lock == nil ? "pink" : "red" end

  print <<-EOS
    Thread#{t.tid} [label="#{t.name}|Owns: #{t.locks.join(",") }"  fillcolor=#{color} ];
  EOS


  # print the Lock dependencies between threads (edges of the graph)
  if t.to_lock != nil then
    lockOwner = lock_to_thread[t.to_lock] || "Unknown"
    print <<-EOS
       Thread#{t.tid} -> Thread#{lockOwner} [taillabel="#{t.to_lock}" arrowhead=normal,arrowtail=none];
    EOS
  end
end


print "}"