| """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 raise 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 |
