Project

General

Profile

1 11 aaronmk
# Exception handling
2
3 1371 aaronmk
import copy
4 433 aaronmk
import atexit
5 343 aaronmk
import sys
6 1368 aaronmk
import traceback
7 13 aaronmk
8 989 aaronmk
import format
9 343 aaronmk
import strings
10 826 aaronmk
import term
11 343 aaronmk
import util
12
13 445 aaronmk
def raise_(e): raise e
14
15 1371 aaronmk
def sys_traceback():
16
    '''Note that Python tracebacks seems to have a bug that truncates them to
17
    only a few stack frames. See <http://bugs.python.org/issue7378>.'''
18
    return sys.exc_info()[2]
19
        # can't just return pointer to traceback because it will change :-(
20 1368 aaronmk
21 1576 aaronmk
def has_tracebacks(e): return hasattr(e, 'tracebacks')
22 1368 aaronmk
23 1371 aaronmk
def add_traceback(e):
24
    '''Adds current traceback to an exception if it doesn't already have one'''
25
    traceback_ = sys_traceback() # get first in case later code throws exception
26 1576 aaronmk
    if not has_tracebacks(e): e.tracebacks = []
27
    if util.list_get(e.tracebacks, 0) == traceback_: return
28
    e.tracebacks.insert(0, traceback_) # tracebacks have most recent call last
29 1371 aaronmk
30 1576 aaronmk
def get_traceback_str(traceback_):
31 1371 aaronmk
    return ''.join(traceback.format_exception(None, None, traceback_)[:-1])
32
        # remove final "None" line ("exception name")
33
34 1576 aaronmk
def get_e_tracebacks_str(e):
35
    try: tracebacks = e.tracebacks
36
    except AttributeError: return ''
37
    return ''.join(get_traceback_str(t) for t in tracebacks)
38
39 2246 aaronmk
def add_msg(e, msg): e.args = (strings.ensure_newl(strings.ustr(e))+msg,)
40 343 aaronmk
41 2246 aaronmk
def repl_msg(e, **repls): e.args = (strings.ustr(e) % repls,)
42 279 aaronmk
43 974 aaronmk
def e_ct_exit_status(e_ct): return min(e_ct, 255)
44
45 13 aaronmk
class ExceptionWithCause(Exception):
46 2144 aaronmk
    def __init__(self, msg, cause=None, cause_newline=False):
47 1610 aaronmk
        add_traceback(self)
48 2144 aaronmk
        if cause != None:
49
            if cause_newline: msg += '\ncause'
50
            msg += ': '+str_(cause)
51 13 aaronmk
        Exception.__init__(self, msg)
52 343 aaronmk
53 1636 aaronmk
def str_(e):
54 2246 aaronmk
    return u''.join(traceback.format_exception_only(type(e), e)).rstrip()
55 433 aaronmk
56 2045 aaronmk
def print_ex(e, emph=True, detail=True, plain=False):
57
    if plain:
58
        emph = False
59
        detail = False
60 1938 aaronmk
61
    msg = str_(e)+'\n'
62 2045 aaronmk
    if detail: msg += get_e_tracebacks_str(e)
63 826 aaronmk
    if emph:
64
        first_line, nl, rest = msg.partition('\n')
65
        msg = term.error(first_line)+nl+rest
66
    sys.stderr.write(msg)
67 788 aaronmk
68 433 aaronmk
class ExTracker:
69
    def __init__(self):
70
        self.e_ct = 0
71
72 974 aaronmk
    def msg(self): return 'Encountered '+str(self.e_ct)+' error(s)'
73
74 433 aaronmk
    def track(self, e, **format):
75
        self.e_ct += 1
76
        print_ex(e, **format)
77 985 aaronmk
78
    def exit(self):
79
        if self.e_ct > 0: raise SystemExit(e_ct_exit_status(self.e_ct))
80 975 aaronmk
81
class ExPercentTracker(ExTracker):
82 983 aaronmk
    def __init__(self, iter_text='iteration'):
83 977 aaronmk
        ExTracker.__init__(self)
84 983 aaronmk
        self.iter_text = iter_text
85 977 aaronmk
        self.iter_ct = None
86 1616 aaronmk
        self.err_iter_ct = None
87
        self.last_iter_num = None
88 975 aaronmk
89 977 aaronmk
    def add_iters(self, iter_ct):
90
        if self.iter_ct == None: self.iter_ct = 0
91
        self.iter_ct += iter_ct
92
93 1616 aaronmk
    def track(self, e, iter_num=None, **format):
94
        if iter_num != None:
95
            if iter_num != self.last_iter_num: # a new iter produced an error
96
                if self.err_iter_ct == None: self.err_iter_ct = 0
97
                self.err_iter_ct += 1
98
                self.last_iter_num = iter_num
99
        ExTracker.track(self, e, **format)
100
101 977 aaronmk
    def msg(self):
102
        msg = ExTracker.msg(self)
103 1616 aaronmk
        iter_text_plural = self.iter_text+'(s)'
104
        numerator = self.e_ct
105
        if self.err_iter_ct != None:
106 1618 aaronmk
            msg += ' in '+format.int2str(self.err_iter_ct)
107 1616 aaronmk
            numerator = self.err_iter_ct
108 1648 aaronmk
        if self.iter_ct != None and self.iter_ct > 0:
109 1616 aaronmk
            msg += ('/'+format.int2str(self.iter_ct)+' '+iter_text_plural+' = '
110
            +format.to_percent(float(numerator)/self.iter_ct))
111 977 aaronmk
        return msg