cpython/Lib/tb.py

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Python
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1990-12-26 11:40:07 -04:00
# Print tracebacks, with a dump of local variables.
# Also an interactive stack trace browser.
import sys
try:
import mac
os = mac
except NameError:
import posix
os = posix
from stat import *
import string
def br(): browser(sys.last_traceback)
def tb(): printtb(sys.last_traceback)
def browser(tb):
if not tb:
print 'No traceback.'
return
tblist = []
while tb:
tblist.append(tb)
tb = tb.tb_next
ptr = len(tblist)-1
tb = tblist[ptr]
while 1:
if tb <> tblist[ptr]:
tb = tblist[ptr]
print `ptr` + ':',
printtbheader(tb)
try:
line = raw_input('TB: ')
except KeyboardInterrupt:
print '\n[Interrupted]'
break
except EOFError:
print '\n[EOF]'
break
cmd = string.strip(line)
if cmd:
if cmd = 'quit':
break
elif cmd = 'list':
browserlist(tb)
elif cmd = 'up':
if ptr-1 >= 0: ptr = ptr-1
else: print 'Bottom of stack.'
elif cmd = 'down':
if ptr+1 < len(tblist): ptr = ptr+1
else: print 'Top of stack.'
elif cmd = 'locals':
printsymbols(tb.tb_frame.f_locals)
elif cmd = 'globals':
printsymbols(tb.tb_frame.f_globals)
elif cmd in ('?', 'help'):
browserhelp()
else:
browserexec(tb, cmd)
def browserlist(tb):
filename = tb.tb_frame.f_code.co_filename
lineno = tb.tb_lineno
last = lineno
first = max(1, last-10)
for i in range(first, last+1):
if i = lineno: prefix = '***' + string.rjust(`i`, 4) + ':'
else: prefix = string.rjust(`i`, 7) + ':'
line = readfileline(filename, i)
if line[-1:] = '\n': line = line[:-1]
print prefix + line
def browserexec(tb, cmd):
locals = tb.tb_frame.f_locals
globals = tb.tb_frame.f_globals
try:
exec(cmd+'\n', globals, locals)
except:
print '*** Exception:',
print sys.exc_type,
if sys.exc_value <> None:
print ':', sys.exc_value,
print
print 'Type help to get help.'
def browserhelp():
print
print ' This is the traceback browser. Commands are:'
print ' up : move one level up in the call stack'
print ' down : move one level down in the call stack'
print ' locals : print all local variables at this level'
print ' globals : print all global variables at this level'
print ' list : list source code around the failure'
print ' help : print help (what you are reading now)'
print ' quit : back to command interpreter'
print ' Typing any other 1-line statement will execute it'
print ' using the current level\'s symbol tables'
print
def printtb(tb):
while tb:
print1tb(tb)
tb = tb.tb_next
def print1tb(tb):
printtbheader(tb)
if tb.tb_frame.f_locals is not tb.tb_frame.f_globals:
printsymbols(tb.tb_frame.f_locals)
def printtbheader(tb):
filename = tb.tb_frame.f_code.co_filename
lineno = tb.tb_lineno
info = '"' + filename + '"(' + `lineno` + ')'
line = readfileline(filename, lineno)
if line:
info = info + ': ' + string.strip(line)
print info
def printsymbols(d):
keys = d.keys()
keys.sort()
for name in keys:
print ' ' + string.ljust(name, 12) + ':',
printobject(d[name], 4)
print
def printobject(v, maxlevel):
if v = None:
print 'None',
elif type(v) in (type(0), type(0.0)):
print v,
elif type(v) = type(''):
if len(v) > 20:
print `v[:17] + '...'`,
else:
print `v`,
elif type(v) = type(()):
print '(',
printlist(v, maxlevel)
print ')',
elif type(v) = type([]):
print '[',
printlist(v, maxlevel)
print ']',
elif type(v) = type({}):
print '{',
printdict(v, maxlevel)
print '}',
else:
print v,
def printlist(v, maxlevel):
n = len(v)
if n = 0: return
if maxlevel <= 0:
print '...',
return
for i in range(min(6, n)):
printobject(v[i], maxlevel-1)
if i+1 < n: print ',',
if n > 6: print '...',
def printdict(v, maxlevel):
keys = v.keys()
n = len(keys)
if n = 0: return
if maxlevel <= 0:
print '...',
return
keys.sort()
for i in range(min(6, n)):
key = keys[i]
print `key` + ':',
printobject(v[key], maxlevel-1)
if i+1 < n: print ',',
if n > 6: print '...',
_filecache = {}
def readfileline(filename, lineno):
try:
stat = os.stat(filename)
except os.error, msg:
print 'Cannot stat', filename, '--', msg
return ''
cache_ok = 0
if _filecache.has_key(filename):
cached_stat, lines = _filecache[filename]
if stat[ST_SIZE] = cached_stat[ST_SIZE] and \
stat[ST_MTIME] = cached_stat[ST_MTIME]:
cache_ok = 1
else:
print 'Stale cache entry for', filename
del _filecache[filename]
if not cache_ok:
lines = readfilelines(filename)
if not lines:
return ''
_filecache[filename] = stat, lines
if 0 <= lineno-1 < len(lines):
return lines[lineno-1]
else:
print 'Line number out of range, last line is', len(lines)
return ''
def readfilelines(filename):
try:
fp = open(filename, 'r')
except:
print 'Cannot open', filename
return []
lines = []
while 1:
line = fp.readline()
if not line: break
lines.append(line)
if not lines:
print 'Empty file', filename
return lines