Lib/tb.py

   1 # Print tracebacks, with a dump of local variables.
   2 # Also an interactive stack trace browser.
   3
   4 import sys
   5 import os
   6 from stat import *
   7 import string
   8 import linecache
   9
  10 def br(): browser(sys.last_traceback)
  11
  12 def tb(): printtb(sys.last_traceback)
  13
  14 def browser(tb):
  15         if not tb:
  16                 print 'No traceback.'
  17                 return
  18         tblist = []
  19         while tb:
  20                 tblist.append(tb)
  21                 tb = tb.tb_next
  22         ptr = len(tblist)-1
  23         tb = tblist[ptr]
  24         while 1:
  25                 if tb <> tblist[ptr]:
  26                         tb = tblist[ptr]
  27                         print `ptr` + ':',
  28                         printtbheader(tb)
  29                 try:
  30                         line = raw_input('TB: ')
  31                 except KeyboardInterrupt:
  32                         print '\n[Interrupted]'
  33                         break
  34                 except EOFError:
  35                         print '\n[EOF]'
  36                         break
  37                 cmd = string.strip(line)
  38                 if cmd:
  39                         if cmd == 'quit':
  40                                 break
  41                         elif cmd == 'list':
  42                                 browserlist(tb)
  43                         elif cmd == 'up':
  44                                 if ptr-1 >= 0: ptr = ptr-1
  45                                 else: print 'Bottom of stack.'
  46                         elif cmd == 'down':
  47                                 if ptr+1 < len(tblist): ptr = ptr+1
  48                                 else: print 'Top of stack.'
  49                         elif cmd == 'locals':
  50                                 printsymbols(tb.tb_frame.f_locals)
  51                         elif cmd == 'globals':
  52                                 printsymbols(tb.tb_frame.f_globals)
  53                         elif cmd in ('?', 'help'):
  54                                 browserhelp()
  55                         else:
  56                                 browserexec(tb, cmd)
  57
  58 def browserlist(tb):
  59         filename = tb.tb_frame.f_code.co_filename
  60         lineno = tb.tb_lineno
  61         last = lineno
  62         first = max(1, last-10)
  63         for i in range(first, last+1):
  64                 if i == lineno: prefix = '***' + string.rjust(`i`, 4) + ':'
  65                 else: prefix = string.rjust(`i`, 7) + ':'
  66                 line = linecache.getline(filename, i)
  67                 if line[-1:] == '\n': line = line[:-1]
  68                 print prefix + line
  69
  70 def browserexec(tb, cmd):
  71         locals = tb.tb_frame.f_locals
  72         globals = tb.tb_frame.f_globals
  73         try:
  74                 exec(cmd+'\n', globals, locals)
  75         except:
  76                 print '*** Exception:',
  77                 print sys.exc_type,
  78                 if sys.exc_value <> None:
  79                         print ':', sys.exc_value,
  80                 print
  81                 print 'Type help to get help.'
  82
  83 def browserhelp():
  84         print
  85         print '    This is the traceback browser.  Commands are:'
  86         print '        up      : move one level up in the call stack'
  87         print '        down    : move one level down in the call stack'
  88         print '        locals  : print all local variables at this level'
  89         print '        globals : print all global variables at this level'
  90         print '        list    : list source code around the failure'
  91         print '        help    : print help (what you are reading now)'
  92         print '        quit    : back to command interpreter'
  93         print '    Typing any other 1-line statement will execute it'
  94         print '    using the current level\'s symbol tables'
  95         print
  96
  97 def printtb(tb):
  98         while tb:
  99                 print1tb(tb)
 100                 tb = tb.tb_next
 101
 102 def print1tb(tb):
 103         printtbheader(tb)
 104         if tb.tb_frame.f_locals is not tb.tb_frame.f_globals:
 105                 printsymbols(tb.tb_frame.f_locals)
 106
 107 def printtbheader(tb):
 108         filename = tb.tb_frame.f_code.co_filename
 109         lineno = tb.tb_lineno
 110         info = '"' + filename + '"(' + `lineno` + ')'
 111         line = linecache.getline(filename, lineno)
 112         if line:
 113                 info = info + ': ' + string.strip(line)
 114         print info
 115
 116 def printsymbols(d):
 117         keys = d.keys()
 118         keys.sort()
 119         for name in keys:
 120                 print '  ' + string.ljust(name, 12) + ':',
 121                 printobject(d[name], 4)
 122                 print
 123
 124 def printobject(v, maxlevel):
 125         if v == None:
 126                 print 'None',
 127         elif type(v) in (type(0), type(0.0)):
 128                 print v,
 129         elif type(v) == type(''):
 130                 if len(v) > 20:
 131                         print `v[:17] + '...'`,
 132                 else:
 133                         print `v`,
 134         elif type(v) == type(()):
 135                 print '(',
 136                 printlist(v, maxlevel)
 137                 print ')',
 138         elif type(v) == type([]):
 139                 print '[',
 140                 printlist(v, maxlevel)
 141                 print ']',
 142         elif type(v) == type({}):
 143                 print '{',
 144                 printdict(v, maxlevel)
 145                 print '}',
 146         else:
 147                 print v,
 148
 149 def printlist(v, maxlevel):
 150         n = len(v)
 151         if n == 0: return
 152         if maxlevel <= 0:
 153                 print '...',
 154                 return
 155         for i in range(min(6, n)):
 156                 printobject(v[i], maxlevel-1)
 157                 if i+1 < n: print ',',
 158         if n > 6: print '...',
 159
 160 def printdict(v, maxlevel):
 161         keys = v.keys()
 162         n = len(keys)
 163         if n == 0: return
 164         if maxlevel <= 0:
 165                 print '...',
 166                 return
 167         keys.sort()
 168         for i in range(min(6, n)):
 169                 key = keys[i]
 170                 print `key` + ':',
 171                 printobject(v[key], maxlevel-1)
 172                 if i+1 < n: print ',',
 173         if n > 6: print '...',