Class: Kefka::Tracer

Inherits:
Object
  • Object
show all
Defined in:
lib/kefka.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(log_level = Logger::INFO) ⇒ Tracer

Returns a new instance of Tracer.



201
202
203
204
205
206
207
208
209
 
# File 'lib/kefka.rb', line 201

def initialize(log_level = Logger::INFO)
  @method_graph = MethodGraph.new
  @line_graph = LineGraph.new
  @callstack = []
  @local_values = {}
  @event_disable = []
  @logger = Logger.new($stderr)
  @logger.level = log_level
end

Instance Attribute Details

#callstack ⇒ Object (readonly)

Returns the value of attribute callstack.



197
198
199
 
# File 'lib/kefka.rb', line 197

def callstack
  @callstack
end

#code ⇒ Object (readonly)

Returns the value of attribute code.



197
198
199
 
# File 'lib/kefka.rb', line 197

def code
  @code
end

#line_graph ⇒ Object (readonly)

Returns the value of attribute line_graph.



197
198
199
 
# File 'lib/kefka.rb', line 197

def line_graph
  @line_graph
end

#local_values ⇒ Object (readonly)

Returns the value of attribute local_values.



197
198
199
 
# File 'lib/kefka.rb', line 197

def local_values
  @local_values
end

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



197
198
199
 
# File 'lib/kefka.rb', line 197

def logger
  @logger
end

#method_graph ⇒ Object (readonly)

Returns the value of attribute method_graph.



197
198
199
 
# File 'lib/kefka.rb', line 197

def method_graph
  @method_graph
end

Instance Method Details

#create_toplevel_method(file_path) ⇒ Object 



311
312
313
314
315
316
317
318
319
320
 
# File 'lib/kefka.rb', line 311

def create_toplevel_method(file_path)
  method = Method.new(
    :classname => "Toplevel",
    :id => nil,
    :file => file_path,
    :line => 1
  )
  method.source = File.readlines(file_path).join
  return method
end

#deep_copy(val) ⇒ Object 



304
305
306
307
308
 
# File 'lib/kefka.rb', line 304

def deep_copy(val)
  Marshal.load(Marshal.dump(val))
rescue TypeError
  "_unknown_"
end

#disable_event_handlers? ⇒ Boolean

Returns:

  • (Boolean) 


225
226
227
 
# File 'lib/kefka.rb', line 225

def disable_event_handlers?
  !@event_disable.empty?
end

#get_values_of_locals_from_binding(target, line_source) ⇒ Object 



294
295
296
297
298
299
300
301
302
 
# File 'lib/kefka.rb', line 294

def get_values_of_locals_from_binding(target, line_source)
  locals = LocalsHelper.get_locals(target,line_source)
  locals.inject({}) do |result,l|
    val = target.eval(l.to_s)
    val = deep_copy(val)
    result.merge!({ l => val.to_s })
    result
  end
end

#trace(file_path) ⇒ Object 



211
212
213
214
215
216
217
218
219
220
221
222
223
 
# File 'lib/kefka.rb', line 211

def trace(file_path)
  file = File.open(file_path)

  thread = Thread.new {
    @code = file.read
    toplevel_method = create_toplevel_method(file_path)
    @callstack << Call.new(:method => toplevel_method, :line => 1)
    eval(@code, TOPLEVEL_BINDING, file.path, 1)
  }

  thread.set_trace_func method(:trace_handler).to_proc
  thread.join
end

#trace_handler(event, file, line, id, binding, classname) ⇒ Object 



229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
 
# File 'lib/kefka.rb', line 229

def trace_handler(event, file, line, id, binding, classname)
  return if file == __FILE__

  @logger.debug "#{event} - #{file}:#{line} #{classname} #{id}"

  # skip event handling when iseq is happening inside class loading
  if disable_event_handlers?
    @event_disable.pop if event == "end"
    return
  end

  case event
  when "class"
    @event_disable << true
  when "call"
    called_from = @callstack.last
    caller_method = called_from.method

    method = Method.new(
      :classname => classname,
      :id => id,
      :file => file,
      :line => line
    )

    @line_graph.add_edge(called_from.dup,method)
    @method_graph.add_edge(caller_method,method)

    @callstack << Call.new(:method => method, :line => line)
  when "line"
    # skip variables that should not be tracked
    # 1. anything in current lib (i.e __FILE__)
    # 2. all local variables that are in TOP LEVEL BINDING before tracing
    #     - but these variables may be overwritten by the traced program,
    #       excluding them would mean not displaying certain relevant
    #       vars in that program
    #current_method = @callstack.last

    # update callstack last method's line
    if call = @callstack.last
      call.line = line
    end
    # given current file & line, determine what method I am in

    method = @method_graph.vertices
                          .select { |method| method.contains?(file,line) }
                          .first

    # skip if not in any previously called method
    if method
      line_source = method.source_at_line(line)

      iseq_key = [id,file,line].join(":")
      @local_values[iseq_key] = get_values_of_locals_from_binding(binding, line_source)
    end
  when "return"
    @callstack.pop
  else
    # do nothing
  end
rescue Exception => e
  puts "\n#{e.class}: #{e.message} \n    from #{e.backtrace.join("\n")}"
  Process.kill("KILL", $$)
end