third_party/waf/waflib/extras/why.py

   1 #! /usr/bin/env python
   2 # encoding: utf-8
   3 # Thomas Nagy, 2010 (ita)
   4
   5 """
   6 This tool modifies the task signature scheme to store and obtain
   7 information about the task execution (why it must run, etc)::
   8
   9         def configure(conf):
  10                 conf.load('why')
  11
  12 After adding the tool, a full rebuild is necessary:
  13 waf clean build --zones=task
  14 """
  15
  16 from waflib import Task, Utils, Logs, Errors
  17
  18 def signature(self):
  19         # compute the result one time, and suppose the scan_signature will give the good result
  20         try:
  21                 return self.cache_sig
  22         except AttributeError:
  23                 pass
  24
  25         self.m = Utils.md5()
  26         self.m.update(self.hcode)
  27         id_sig = self.m.digest()
  28
  29         # explicit deps
  30         self.m = Utils.md5()
  31         self.sig_explicit_deps()
  32         exp_sig = self.m.digest()
  33
  34         # env vars
  35         self.m = Utils.md5()
  36         self.sig_vars()
  37         var_sig = self.m.digest()
  38
  39         # implicit deps / scanner results
  40         self.m = Utils.md5()
  41         if self.scan:
  42                 try:
  43                         self.sig_implicit_deps()
  44                 except Errors.TaskRescan:
  45                         return self.signature()
  46         impl_sig = self.m.digest()
  47
  48         ret = self.cache_sig = impl_sig + id_sig + exp_sig + var_sig
  49         return ret
  50
  51
  52 Task.Task.signature = signature
  53
  54 old = Task.Task.runnable_status
  55 def runnable_status(self):
  56         ret = old(self)
  57         if ret == Task.RUN_ME:
  58                 try:
  59                         old_sigs = self.generator.bld.task_sigs[self.uid()]
  60                 except (KeyError, AttributeError):
  61                         Logs.debug("task: task must run as no previous signature exists")
  62                 else:
  63                         new_sigs = self.cache_sig
  64                         def v(x):
  65                                 return Utils.to_hex(x)
  66
  67                         Logs.debug('Task %r', self)
  68                         msgs = ['* Implicit or scanner dependency', '* Task code', '* Source file, explicit or manual dependency', '* Configuration data variable']
  69                         tmp = 'task: -> %s: %s %s'
  70                         for x in range(len(msgs)):
  71                                 l = len(Utils.SIG_NIL)
  72                                 a = new_sigs[x*l : (x+1)*l]
  73                                 b = old_sigs[x*l : (x+1)*l]
  74                                 if (a != b):
  75                                         Logs.debug(tmp, msgs[x].ljust(35), v(a), v(b))
  76         return ret
  77 Task.Task.runnable_status = runnable_status
  78