Viewing file:  codehack.py (2.55 KB) -rw-r--r--
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# A subroutine for extracting a function name from a code object
# (with cache)
import sys
from stat import *
import string
import os
import linecache
# XXX The functions getcodename() and getfuncname() are now obsolete
# XXX as code and function objects now have a name attribute --
# XXX co.co_name and f.func_name.
# XXX getlineno() is now also obsolete because of the new attribute
# XXX of code objects, co.co_firstlineno.
# Extract the function or class name from a code object.
# This is a bit of a hack, since a code object doesn't contain
# the name directly. So what do we do:
# - get the filename (which *is* in the code object)
# - look in the code string to find the first SET_LINENO instruction
# (this must be the first instruction)
# - get the line from the file
# - if the line starts with 'class' or 'def' (after possible whitespace),
# extract the following identifier
#
# This breaks apart when the function was read from <stdin>
# or constructed by exec(), when the file is not accessible,
# and also when the file has been modified or when a line is
# continued with a backslash before the function or class name.
#
# Because this is a pretty expensive hack, a cache is kept.
SET_LINENO = 127 # The opcode (see "opcode.h" in the Python source)
identchars = string.ascii_letters + string.digits + '_' # Identifier characters
_namecache = {} # The cache
def getcodename(co):
try:
return co.co_name
except AttributeError:
pass
key = `co` # arbitrary but uniquely identifying string
if _namecache.has_key(key): return _namecache[key]
filename = co.co_filename
code = co.co_code
name = ''
if ord(code[0]) == SET_LINENO:
lineno = ord(code[1]) | ord(code[2]) << 8
line = linecache.getline(filename, lineno)
words = line.split()
if len(words) >= 2 and words[0] in ('def', 'class'):
name = words[1]
for i in range(len(name)):
if name[i] not in identchars:
name = name[:i]
break
_namecache[key] = name
return name
# Use the above routine to find a function's name.
def getfuncname(func):
try:
return func.func_name
except AttributeError:
pass
return getcodename(func.func_code)
# A part of the above code to extract just the line number from a code object.
def getlineno(co):
try:
return co.co_firstlineno
except AttributeError:
pass
code = co.co_code
if ord(code[0]) == SET_LINENO:
return ord(code[1]) | ord(code[2]) << 8
else:
return -1
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