source file: /System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/traceback.py
file stats: 165 lines, 4 executed: 2.4% covered
   1. """Extract, format and print information about Python stack traces."""
   2. 
   3. import linecache
   4. import sys
   5. import types
   6. 
   7. __all__ = ['extract_stack', 'extract_tb', 'format_exception',
   8.            'format_exception_only', 'format_list', 'format_stack',
   9.            'format_tb', 'print_exc', 'print_exception', 'print_last',
  10.            'print_stack', 'print_tb', 'tb_lineno']
  11. 
  12. def _print(file, str='', terminator='\n'):
  13.     file.write(str+terminator)
  14. 
  15. 
  16. def print_list(extracted_list, file=None):
  17.     """Print the list of tuples as returned by extract_tb() or
  18.     extract_stack() as a formatted stack trace to the given file."""
  19.     if file is None:
  20.         file = sys.stderr
  21.     for filename, lineno, name, line in extracted_list:
  22.         _print(file,
  23.                '  File "%s", line %d, in %s' % (filename,lineno,name))
  24.         if line:
  25.             _print(file, '    %s' % line.strip())
  26. 
  27. def format_list(extracted_list):
  28.     """Format a list of traceback entry tuples for printing.
  29. 
  30.     Given a list of tuples as returned by extract_tb() or
  31.     extract_stack(), return a list of strings ready for printing.
  32.     Each string in the resulting list corresponds to the item with the
  33.     same index in the argument list.  Each string ends in a newline;
  34.     the strings may contain internal newlines as well, for those items
  35.     whose source text line is not None.
  36.     """
  37.     list = []
  38.     for filename, lineno, name, line in extracted_list:
  39.         item = '  File "%s", line %d, in %s\n' % (filename,lineno,name)
  40.         if line:
  41.             item = item + '    %s\n' % line.strip()
  42.         list.append(item)
  43.     return list
  44. 
  45. 
  46. def print_tb(tb, limit=None, file=None):
  47.     """Print up to 'limit' stack trace entries from the traceback 'tb'.
  48. 
  49.     If 'limit' is omitted or None, all entries are printed.  If 'file'
  50.     is omitted or None, the output goes to sys.stderr; otherwise
  51.     'file' should be an open file or file-like object with a write()
  52.     method.
  53.     """
  54.     if file is None:
  55.         file = sys.stderr
  56.     if limit is None:
  57.         if hasattr(sys, 'tracebacklimit'):
  58.             limit = sys.tracebacklimit
  59.     n = 0
  60.     while tb is not None and (limit is None or n < limit):
  61.         f = tb.tb_frame
  62.         lineno = tb.tb_lineno
  63.         co = f.f_code
  64.         filename = co.co_filename
  65.         name = co.co_name
  66.         _print(file,
  67.                '  File "%s", line %d, in %s' % (filename,lineno,name))
  68.         line = linecache.getline(filename, lineno)
  69.         if line: _print(file, '    ' + line.strip())
  70.         tb = tb.tb_next
  71.         n = n+1
  72. 
  73. def format_tb(tb, limit = None):
  74.     """A shorthand for 'format_list(extract_stack(f, limit))."""
  75.     return format_list(extract_tb(tb, limit))
  76. 
  77. def extract_tb(tb, limit = None):
  78.     """Return list of up to limit pre-processed entries from traceback.
  79. 
  80.     This is useful for alternate formatting of stack traces.  If
  81.     'limit' is omitted or None, all entries are extracted.  A
  82.     pre-processed stack trace entry is a quadruple (filename, line
  83.     number, function name, text) representing the information that is
  84.     usually printed for a stack trace.  The text is a string with
  85.     leading and trailing whitespace stripped; if the source is not
  86.     available it is None.
  87.     """
  88.     if limit is None:
  89.         if hasattr(sys, 'tracebacklimit'):
  90.             limit = sys.tracebacklimit
  91.     list = []
  92.     n = 0
  93.     while tb is not None and (limit is None or n < limit):
  94.         f = tb.tb_frame
  95.         lineno = tb.tb_lineno
  96.         co = f.f_code
  97.         filename = co.co_filename
  98.         name = co.co_name
  99.         line = linecache.getline(filename, lineno)
 100.         if line: line = line.strip()
 101.         else: line = None
 102.         list.append((filename, lineno, name, line))
 103.         tb = tb.tb_next
 104.         n = n+1
 105.     return list
 106. 
 107. 
 108. def print_exception(etype, value, tb, limit=None, file=None):
 109.     """Print exception up to 'limit' stack trace entries from 'tb' to 'file'.
 110. 
 111.     This differs from print_tb() in the following ways: (1) if
 112.     traceback is not None, it prints a header "Traceback (most recent
 113.     call last):"; (2) it prints the exception type and value after the
 114.     stack trace; (3) if type is SyntaxError and value has the
 115.     appropriate format, it prints the line where the syntax error
 116.     occurred with a caret on the next line indicating the approximate
 117.     position of the error.
 118.     """
 119.     if file is None:
 120.         file = sys.stderr
 121.     if tb:
 122.         _print(file, 'Traceback (most recent call last):')
 123.         print_tb(tb, limit, file)
 124.     lines = format_exception_only(etype, value)
 125.     for line in lines[:-1]:
 126.         _print(file, line, ' ')
 127.     _print(file, lines[-1], '')
 128. 
 129. def format_exception(etype, value, tb, limit = None):
 130.     """Format a stack trace and the exception information.
 131. 
 132.     The arguments have the same meaning as the corresponding arguments
 133.     to print_exception().  The return value is a list of strings, each
 134.     ending in a newline and some containing internal newlines.  When
 135.     these lines are concatenated and printed, exactly the same text is
 136.     printed as does print_exception().
 137.     """
 138.     if tb:
 139.         list = ['Traceback (most recent call last):\n']
 140.         list = list + format_tb(tb, limit)
 141.     else:
 142.         list = []
 143.     list = list + format_exception_only(etype, value)
 144.     return list
 145. 
 146. def format_exception_only(etype, value):
 147.     """Format the exception part of a traceback.
 148. 
 149.     The arguments are the exception type and value such as given by
 150.     sys.last_type and sys.last_value. The return value is a list of
 151.     strings, each ending in a newline.  Normally, the list contains a
 152.     single string; however, for SyntaxError exceptions, it contains
 153.     several lines that (when printed) display detailed information
 154.     about where the syntax error occurred.  The message indicating
 155.     which exception occurred is the always last string in the list.
 156.     """
 157.     list = []
 158.     if type(etype) == types.ClassType:
 159.         stype = etype.__name__
 160.     else:
 161.         stype = etype
 162.     if value is None:
 163.         list.append(str(stype) + '\n')
 164.     else:
 165.         if etype is SyntaxError:
 166.             try:
 167.                 msg, (filename, lineno, offset, line) = value
 168.             except:
 169.                 pass
 170.             else:
 171.                 if not filename: filename = "<string>"
 172.                 list.append('  File "%s", line %d\n' %
 173.                             (filename, lineno))
 174.                 if line is not None:
 175.                     i = 0
 176.                     while i < len(line) and line[i].isspace():
 177.                         i = i+1
 178.                     list.append('    %s\n' % line.strip())
 179.                     if offset is not None:
 180.                         s = '    '
 181.                         for c in line[i:offset-1]:
 182.                             if c.isspace():
 183.                                 s = s + c
 184.                             else:
 185.                                 s = s + ' '
 186.                         list.append('%s^\n' % s)
 187.                     value = msg
 188.         s = _some_str(value)
 189.         if s:
 190.             list.append('%s: %s\n' % (str(stype), s))
 191.         else:
 192.             list.append('%s\n' % str(stype))
 193.     return list
 194. 
 195. def _some_str(value):
 196.     try:
 197.         return str(value)
 198.     except:
 199.         return '<unprintable %s object>' % type(value).__name__
 200. 
 201. 
 202. def print_exc(limit=None, file=None):
 203.     """Shorthand for 'print_exception(sys.exc_type, sys.exc_value, sys.exc_traceback, limit, file)'.
 204.     (In fact, it uses sys.exc_info() to retrieve the same information
 205.     in a thread-safe way.)"""
 206.     if file is None:
 207.         file = sys.stderr
 208.     try:
 209.         etype, value, tb = sys.exc_info()
 210.         print_exception(etype, value, tb, limit, file)
 211.     finally:
 212.         etype = value = tb = None
 213. 
 214. def print_last(limit=None, file=None):
 215.     """This is a shorthand for 'print_exception(sys.last_type,
 216.     sys.last_value, sys.last_traceback, limit, file)'."""
 217.     if file is None:
 218.         file = sys.stderr
 219.     print_exception(sys.last_type, sys.last_value, sys.last_traceback,
 220.                     limit, file)
 221. 
 222. 
 223. def print_stack(f=None, limit=None, file=None):
 224.     """Print a stack trace from its invocation point.
 225. 
 226.     The optional 'f' argument can be used to specify an alternate
 227.     stack frame at which to start. The optional 'limit' and 'file'
 228.     arguments have the same meaning as for print_exception().
 229.     """
 230.     if f is None:
 231.         try:
 232.             raise ZeroDivisionError
 233.         except ZeroDivisionError:
 234.             f = sys.exc_info()[2].tb_frame.f_back
 235.     print_list(extract_stack(f, limit), file)
 236. 
 237. def format_stack(f=None, limit=None):
 238.     """Shorthand for 'format_list(extract_stack(f, limit))'."""
 239.     if f is None:
 240.         try:
 241.             raise ZeroDivisionError
 242.         except ZeroDivisionError:
 243.             f = sys.exc_info()[2].tb_frame.f_back
 244.     return format_list(extract_stack(f, limit))
 245. 
 246. def extract_stack(f=None, limit = None):
 247.     """Extract the raw traceback from the current stack frame.
 248. 
 249.     The return value has the same format as for extract_tb().  The
 250.     optional 'f' and 'limit' arguments have the same meaning as for
 251.     print_stack().  Each item in the list is a quadruple (filename,
 252.     line number, function name, text), and the entries are in order
 253.     from oldest to newest stack frame.
 254.     """
 255.     if f is None:
 256.         try:
 257.             raise ZeroDivisionError
 258.         except ZeroDivisionError:
 259.             f = sys.exc_info()[2].tb_frame.f_back
 260.     if limit is None:
 261.         if hasattr(sys, 'tracebacklimit'):
 262.             limit = sys.tracebacklimit
 263.     list = []
 264.     n = 0
 265.     while f is not None and (limit is None or n < limit):
 266.         lineno = f.f_lineno
 267.         co = f.f_code
 268.         filename = co.co_filename
 269.         name = co.co_name
 270.         line = linecache.getline(filename, lineno)
 271.         if line: line = line.strip()
 272.         else: line = None
 273.         list.append((filename, lineno, name, line))
 274.         f = f.f_back
 275.         n = n+1
 276.     list.reverse()
 277.     return list
 278. 
 279. def tb_lineno(tb):
 280.     """Calculate correct line number of traceback given in tb.
 281. 
 282.     Obsolete in 2.3.
 283.     """
 284.     return tb.tb_lineno