| """Extract, format and print information about Python stack traces.""" | |
| import linecache | |
| import sys | |
| import types | |
| __all__ = ['extract_stack', 'extract_tb', 'format_exception', | |
| 'format_exception_only', 'format_list', 'format_stack', | |
| 'format_tb', 'print_exc', 'format_exc', 'print_exception', | |
| 'print_last', 'print_stack', 'print_tb', 'tb_lineno'] | |
| def _print(file, str='', terminator='\n'): | |
| file.write(str+terminator) | |
| def print_list(extracted_list, file=None): | |
| """Print the list of tuples as returned by extract_tb() or | |
| extract_stack() as a formatted stack trace to the given file.""" | |
| if file is None: | |
| file = sys.stderr | |
| for filename, lineno, name, line in extracted_list: | |
| _print(file, | |
| ' File "%s", line %d, in %s' % (filename,lineno,name)) | |
| if line: | |
| _print(file, ' %s' % line.strip()) | |
| def format_list(extracted_list): | |
| """Format a list of traceback entry tuples for printing. | |
| Given a list of tuples as returned by extract_tb() or | |
| extract_stack(), return a list of strings ready for printing. | |
| Each string in the resulting list corresponds to the item with the | |
| same index in the argument list. Each string ends in a newline; | |
| the strings may contain internal newlines as well, for those items | |
| whose source text line is not None. | |
| """ | |
| list = [] | |
| for filename, lineno, name, line in extracted_list: | |
| item = ' File "%s", line %d, in %s\n' % (filename,lineno,name) | |
| if line: | |
| item = item + ' %s\n' % line.strip() | |
| list.append(item) | |
| return list | |
| def print_tb(tb, limit=None, file=None): | |
| """Print up to 'limit' stack trace entries from the traceback 'tb'. | |
| If 'limit' is omitted or None, all entries are printed. If 'file' | |
| is omitted or None, the output goes to sys.stderr; otherwise | |
| 'file' should be an open file or file-like object with a write() | |
| method. | |
| """ | |
| if file is None: | |
| file = sys.stderr | |
| if limit is None: | |
| if hasattr(sys, 'tracebacklimit'): | |
| limit = sys.tracebacklimit | |
| n = 0 | |
| while tb is not None and (limit is None or n < limit): | |
| f = tb.tb_frame | |
| lineno = tb.tb_lineno | |
| co = f.f_code | |
| filename = co.co_filename | |
| name = co.co_name | |
| _print(file, | |
| ' File "%s", line %d, in %s' % (filename, lineno, name)) | |
| linecache.checkcache(filename) | |
| line = linecache.getline(filename, lineno, f.f_globals) | |
| if line: _print(file, ' ' + line.strip()) | |
| tb = tb.tb_next | |
| n = n+1 | |
| def format_tb(tb, limit = None): | |
| """A shorthand for 'format_list(extract_stack(f, limit)).""" | |
| return format_list(extract_tb(tb, limit)) | |
| def extract_tb(tb, limit = None): | |
| """Return list of up to limit pre-processed entries from traceback. | |
| This is useful for alternate formatting of stack traces. If | |
| 'limit' is omitted or None, all entries are extracted. A | |
| pre-processed stack trace entry is a quadruple (filename, line | |
| number, function name, text) representing the information that is | |
| usually printed for a stack trace. The text is a string with | |
| leading and trailing whitespace stripped; if the source is not | |
| available it is None. | |
| """ | |
| if limit is None: | |
| if hasattr(sys, 'tracebacklimit'): | |
| limit = sys.tracebacklimit | |
| list = [] | |
| n = 0 | |
| while tb is not None and (limit is None or n < limit): | |
| f = tb.tb_frame | |
| lineno = tb.tb_lineno | |
| co = f.f_code | |
| filename = co.co_filename | |
| name = co.co_name | |
| linecache.checkcache(filename) | |
| line = linecache.getline(filename, lineno, f.f_globals) | |
| if line: line = line.strip() | |
| else: line = None | |
| list.append((filename, lineno, name, line)) | |
| tb = tb.tb_next | |
| n = n+1 | |
| return list | |
| def print_exception(etype, value, tb, limit=None, file=None): | |
| """Print exception up to 'limit' stack trace entries from 'tb' to 'file'. | |
| This differs from print_tb() in the following ways: (1) if | |
| traceback is not None, it prints a header "Traceback (most recent | |
| call last):"; (2) it prints the exception type and value after the | |
| stack trace; (3) if type is SyntaxError and value has the | |
| appropriate format, it prints the line where the syntax error | |
| occurred with a caret on the next line indicating the approximate | |
| position of the error. | |
| """ | |
| if file is None: | |
| file = sys.stderr | |
| if tb: | |
| _print(file, 'Traceback (most recent call last):') | |
| print_tb(tb, limit, file) | |
| lines = format_exception_only(etype, value) | |
| for line in lines: | |
| _print(file, line, '') | |
| def format_exception(etype, value, tb, limit = None): | |
| """Format a stack trace and the exception information. | |
| The arguments have the same meaning as the corresponding arguments | |
| to print_exception(). The return value is a list of strings, each | |
| ending in a newline and some containing internal newlines. When | |
| these lines are concatenated and printed, exactly the same text is | |
| printed as does print_exception(). | |
| """ | |
| if tb: | |
| list = ['Traceback (most recent call last):\n'] | |
| list = list + format_tb(tb, limit) | |
| else: | |
| list = [] | |
| list = list + format_exception_only(etype, value) | |
| return list | |
| def format_exception_only(etype, value): | |
| """Format the exception part of a traceback. | |
| The arguments are the exception type and value such as given by | |
| sys.last_type and sys.last_value. The return value is a list of | |
| strings, each ending in a newline. | |
| Normally, the list contains a single string; however, for | |
| SyntaxError exceptions, it contains several lines that (when | |
| printed) display detailed information about where the syntax | |
| error occurred. | |
| The message indicating which exception occurred is always the last | |
| string in the list. | |
| """ | |
| # An instance should not have a meaningful value parameter, but | |
| # sometimes does, particularly for string exceptions, such as | |
| # >>> raise string1, string2 # deprecated | |
| # | |
| # Clear these out first because issubtype(string1, SyntaxError) | |
| # would throw another exception and mask the original problem. | |
| if (isinstance(etype, BaseException) or | |
| isinstance(etype, types.InstanceType) or | |
| etype is None or type(etype) is str): | |
| return [_format_final_exc_line(etype, value)] | |
| stype = etype.__name__ | |
| if not issubclass(etype, SyntaxError): | |
| return [_format_final_exc_line(stype, value)] | |
| # It was a syntax error; show exactly where the problem was found. | |
| lines = [] | |
| try: | |
| msg, (filename, lineno, offset, badline) = value.args | |
| except Exception: | |
| pass | |
| else: | |
| filename = filename or "<string>" | |
| lines.append(' File "%s", line %d\n' % (filename, lineno)) | |
| if badline is not None: | |
| lines.append(' %s\n' % badline.strip()) | |
| if offset is not None: | |
| caretspace = badline.rstrip('\n')[:offset].lstrip() | |
| # non-space whitespace (likes tabs) must be kept for alignment | |
| caretspace = ((c.isspace() and c or ' ') for c in caretspace) | |
| # only three spaces to account for offset1 == pos 0 | |
| lines.append(' %s^\n' % ''.join(caretspace)) | |
| value = msg | |
| lines.append(_format_final_exc_line(stype, value)) | |
| return lines | |
| def _format_final_exc_line(etype, value): | |
| """Return a list of a single line -- normal case for format_exception_only""" | |
| valuestr = _some_str(value) | |
| if value is None or not valuestr: | |
| line = "%s\n" % etype | |
| else: | |
| line = "%s: %s\n" % (etype, valuestr) | |
| return line | |
| def _some_str(value): | |
| try: | |
| return str(value) | |
| except Exception: | |
| pass | |
| try: | |
| value = unicode(value) | |
| return value.encode("ascii", "backslashreplace") | |
| except Exception: | |
| pass | |
| return '<unprintable %s object>' % type(value).__name__ | |
| def print_exc(limit=None, file=None): | |
| """Shorthand for 'print_exception(sys.exc_type, sys.exc_value, sys.exc_traceback, limit, file)'. | |
| (In fact, it uses sys.exc_info() to retrieve the same information | |
| in a thread-safe way.)""" | |
| if file is None: | |
| file = sys.stderr | |
| try: | |
| etype, value, tb = sys.exc_info() | |
| print_exception(etype, value, tb, limit, file) | |
| finally: | |
| etype = value = tb = None | |
| def format_exc(limit=None): | |
| """Like print_exc() but return a string.""" | |
| try: | |
| etype, value, tb = sys.exc_info() | |
| return ''.join(format_exception(etype, value, tb, limit)) | |
| finally: | |
| etype = value = tb = None | |
| def print_last(limit=None, file=None): | |
| """This is a shorthand for 'print_exception(sys.last_type, | |
| sys.last_value, sys.last_traceback, limit, file)'.""" | |
| if not hasattr(sys, "last_type"): | |
| raise ValueError("no last exception") | |
| if file is None: | |
| file = sys.stderr | |
| print_exception(sys.last_type, sys.last_value, sys.last_traceback, | |
| limit, file) | |
| def print_stack(f=None, limit=None, file=None): | |
| """Print a stack trace from its invocation point. | |
| The optional 'f' argument can be used to specify an alternate | |
| stack frame at which to start. The optional 'limit' and 'file' | |
| arguments have the same meaning as for print_exception(). | |
| """ | |
| if f is None: | |
| try: | |
| raise ZeroDivisionError | |
| except ZeroDivisionError: | |
| f = sys.exc_info()[2].tb_frame.f_back | |
| print_list(extract_stack(f, limit), file) | |
| def format_stack(f=None, limit=None): | |
| """Shorthand for 'format_list(extract_stack(f, limit))'.""" | |
| if f is None: | |
| try: | |
| raise ZeroDivisionError | |
| except ZeroDivisionError: | |
| f = sys.exc_info()[2].tb_frame.f_back | |
| return format_list(extract_stack(f, limit)) | |
| def extract_stack(f=None, limit = None): | |
| """Extract the raw traceback from the current stack frame. | |
| The return value has the same format as for extract_tb(). The | |
| optional 'f' and 'limit' arguments have the same meaning as for | |
| print_stack(). Each item in the list is a quadruple (filename, | |
| line number, function name, text), and the entries are in order | |
| from oldest to newest stack frame. | |
| """ | |
| if f is None: | |
| try: | |
| raise ZeroDivisionError | |
| except ZeroDivisionError: | |
| f = sys.exc_info()[2].tb_frame.f_back | |
| if limit is None: | |
| if hasattr(sys, 'tracebacklimit'): | |
| limit = sys.tracebacklimit | |
| list = [] | |
| n = 0 | |
| while f is not None and (limit is None or n < limit): | |
| lineno = f.f_lineno | |
| co = f.f_code | |
| filename = co.co_filename | |
| name = co.co_name | |
| linecache.checkcache(filename) | |
| line = linecache.getline(filename, lineno, f.f_globals) | |
| if line: line = line.strip() | |
| else: line = None | |
| list.append((filename, lineno, name, line)) | |
| f = f.f_back | |
| n = n+1 | |
| list.reverse() | |
| return list | |
| def tb_lineno(tb): | |
| """Calculate correct line number of traceback given in tb. | |
| Obsolete in 2.3. | |
| """ | |
| return tb.tb_lineno |