282 lines
10 KiB
Python
282 lines
10 KiB
Python
"""Extract, format and print information about Python stack traces."""
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import linecache
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import sys
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import types
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__all__ = ['extract_stack', 'extract_tb', 'format_exception',
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'format_exception_only', 'format_list', 'format_stack',
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'format_tb', 'print_exc', 'print_exception', 'print_last',
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'print_stack', 'print_tb', 'tb_lineno']
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def _print(file, str='', terminator='\n'):
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file.write(str+terminator)
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def print_list(extracted_list, file=None):
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"""Print the list of tuples as returned by extract_tb() or
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extract_stack() as a formatted stack trace to the given file."""
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if not file:
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file = sys.stderr
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for filename, lineno, name, line in extracted_list:
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_print(file,
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' File "%s", line %d, in %s' % (filename,lineno,name))
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if line:
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_print(file, ' %s' % line.strip())
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def format_list(extracted_list):
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"""Given a list of tuples as returned by extract_tb() or
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extract_stack(), return a list of strings ready for printing.
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Each string in the resulting list corresponds to the item with
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the same index in the argument list. Each string ends in a
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newline; the strings may contain internal newlines as well, for
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those items whose source text line is not None."""
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list = []
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for filename, lineno, name, line in extracted_list:
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item = ' File "%s", line %d, in %s\n' % (filename,lineno,name)
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if line:
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item = item + ' %s\n' % line.strip()
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list.append(item)
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return list
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def print_tb(tb, limit=None, file=None):
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"""Print up to 'limit' stack trace entries from the traceback 'tb'.
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If 'limit' is omitted or None, all entries are printed. If 'file' is
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omitted or None, the output goes to sys.stderr; otherwise 'file'
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should be an open file or file-like object with a write() method."""
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if not file:
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file = sys.stderr
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if limit is None:
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if hasattr(sys, 'tracebacklimit'):
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limit = sys.tracebacklimit
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n = 0
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while tb is not None and (limit is None or n < limit):
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f = tb.tb_frame
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lineno = tb_lineno(tb)
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co = f.f_code
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filename = co.co_filename
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name = co.co_name
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_print(file,
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' File "%s", line %d, in %s' % (filename,lineno,name))
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line = linecache.getline(filename, lineno)
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if line: _print(file, ' ' + line.strip())
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tb = tb.tb_next
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n = n+1
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def format_tb(tb, limit = None):
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"""A shorthand for 'format_list(extract_stack(f, limit))."""
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return format_list(extract_tb(tb, limit))
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def extract_tb(tb, limit = None):
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"""Return a list of up to 'limit' pre-processed stack trace entries
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extracted from the traceback object 'traceback'. This is useful for
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alternate formatting of stack traces. If 'limit' is omitted or None,
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all entries are extracted. A pre-processed stack trace entry is a
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quadruple (filename, line number, function name, text) representing
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the information that is usually printed for a stack trace. The text
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is a string with leading and trailing whitespace stripped; if the
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source is not available it is None."""
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if limit is None:
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if hasattr(sys, 'tracebacklimit'):
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limit = sys.tracebacklimit
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list = []
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n = 0
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while tb is not None and (limit is None or n < limit):
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f = tb.tb_frame
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lineno = tb_lineno(tb)
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co = f.f_code
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filename = co.co_filename
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name = co.co_name
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line = linecache.getline(filename, lineno)
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if line: line = line.strip()
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else: line = None
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list.append((filename, lineno, name, line))
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tb = tb.tb_next
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n = n+1
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return list
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def print_exception(etype, value, tb, limit=None, file=None):
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"""Print exception information and up to 'limit' stack trace entries
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from the traceback 'tb' to 'file'. This differs from print_tb() in
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the following ways: (1) if traceback is not None, it prints a header
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"Traceback (most recent call last):"; (2) it prints the exception type and
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value after the stack trace; (3) if type is SyntaxError and value has
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the appropriate format, it prints the line where the syntax error
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occurred with a caret on the next line indicating the approximate
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position of the error."""
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if not file:
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file = sys.stderr
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if tb:
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_print(file, 'Traceback (most recent call last):')
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print_tb(tb, limit, file)
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lines = format_exception_only(etype, value)
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for line in lines[:-1]:
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_print(file, line, ' ')
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_print(file, lines[-1], '')
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def format_exception(etype, value, tb, limit = None):
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"""Format a stack trace and the exception information. The arguments
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have the same meaning as the corresponding arguments to
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print_exception(). The return value is a list of strings, each
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ending in a newline and some containing internal newlines. When
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these lines are concatenated and printed, exactly the same text is
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printed as does print_exception()."""
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if tb:
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list = ['Traceback (most recent call last):\n']
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list = list + format_tb(tb, limit)
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else:
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list = []
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list = list + format_exception_only(etype, value)
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return list
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def format_exception_only(etype, value):
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"""Format the exception part of a traceback. The arguments are the
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exception type and value such as given by sys.last_type and
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sys.last_value. The return value is a list of strings, each ending
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in a newline. Normally, the list contains a single string;
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however, for SyntaxError exceptions, it contains several lines that
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(when printed) display detailed information about where the syntax
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error occurred. The message indicating which exception occurred is
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the always last string in the list."""
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list = []
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if type(etype) == types.ClassType:
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stype = etype.__name__
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else:
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stype = etype
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if value is None:
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list.append(str(stype) + '\n')
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else:
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if etype is SyntaxError:
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try:
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msg, (filename, lineno, offset, line) = value
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except:
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pass
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else:
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if not filename: filename = "<string>"
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list.append(' File "%s", line %d\n' %
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(filename, lineno))
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i = 0
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while i < len(line) and line[i].isspace():
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i = i+1
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list.append(' %s\n' % line.strip())
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s = ' '
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for c in line[i:offset-1]:
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if c.isspace():
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s = s + c
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else:
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s = s + ' '
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list.append('%s^\n' % s)
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value = msg
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s = _some_str(value)
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if s:
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list.append('%s: %s\n' % (str(stype), s))
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else:
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list.append('%s\n' % str(stype))
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return list
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def _some_str(value):
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try:
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return str(value)
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except:
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return '<unprintable %s object>' % type(value).__name__
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def print_exc(limit=None, file=None):
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"""This is a shorthand for 'print_exception(sys.exc_type,
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sys.exc_value, sys.exc_traceback, limit, file)'.
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(In fact, it uses sys.exc_info() to retrieve the same information
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in a thread-safe way.)"""
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if not file:
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file = sys.stderr
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try:
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etype, value, tb = sys.exc_info()
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print_exception(etype, value, tb, limit, file)
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finally:
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etype = value = tb = None
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def print_last(limit=None, file=None):
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"""This is a shorthand for 'print_exception(sys.last_type,
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sys.last_value, sys.last_traceback, limit, file)'."""
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if not file:
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file = sys.stderr
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print_exception(sys.last_type, sys.last_value, sys.last_traceback,
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limit, file)
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def print_stack(f=None, limit=None, file=None):
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"""This function prints a stack trace from its invocation point.
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The optional 'f' argument can be used to specify an alternate stack
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frame at which to start. The optional 'limit' and 'file' arguments
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have the same meaning as for print_exception()."""
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if f is None:
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try:
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raise ZeroDivisionError
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except ZeroDivisionError:
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f = sys.exc_info()[2].tb_frame.f_back
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print_list(extract_stack(f, limit), file)
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def format_stack(f=None, limit=None):
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"""A shorthand for 'format_list(extract_stack(f, limit))'."""
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if f is None:
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try:
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raise ZeroDivisionError
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except ZeroDivisionError:
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f = sys.exc_info()[2].tb_frame.f_back
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return format_list(extract_stack(f, limit))
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def extract_stack(f=None, limit = None):
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"""Extract the raw traceback from the current stack frame. The
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return value has the same format as for extract_tb(). The optional
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'f' and 'limit' arguments have the same meaning as for print_stack().
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Each item in the list is a quadruple (filename, line number,
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function name, text), and the entries are in order from oldest
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to newest stack frame."""
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if f is None:
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try:
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raise ZeroDivisionError
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except ZeroDivisionError:
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f = sys.exc_info()[2].tb_frame.f_back
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if limit is None:
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if hasattr(sys, 'tracebacklimit'):
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limit = sys.tracebacklimit
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list = []
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n = 0
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while f is not None and (limit is None or n < limit):
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lineno = f.f_lineno # XXX Too bad if -O is used
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co = f.f_code
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filename = co.co_filename
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name = co.co_name
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line = linecache.getline(filename, lineno)
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if line: line = line.strip()
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else: line = None
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list.append((filename, lineno, name, line))
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f = f.f_back
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n = n+1
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list.reverse()
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return list
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def tb_lineno(tb):
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"""Calculate the correct line number of the traceback given in tb
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(even with -O on)."""
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# Coded by Marc-Andre Lemburg from the example of PyCode_Addr2Line()
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# in compile.c.
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# Revised version by Jim Hugunin to work with JPython too.
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c = tb.tb_frame.f_code
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if not hasattr(c, 'co_lnotab'):
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return tb.tb_lineno
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tab = c.co_lnotab
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line = c.co_firstlineno
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stopat = tb.tb_lasti
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addr = 0
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for i in range(0, len(tab), 2):
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addr = addr + ord(tab[i])
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if addr > stopat:
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break
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line = line + ord(tab[i+1])
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return line
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