# Exception handling

import atexit

import sys

import traceback

import format

import strings

import term

import util

def raise_(e): raise e

def add_exc_info(e):

    '''Note that this will create a circular reference in the traceback

    (See <http://docs.python.org/library/sys.html#sys.exc_info>)'''

    e.exc_info = sys.exc_info()

def get_exc_info(e):

    try: exc_info = e.exc_info

    except AttributeError: exc_info = sys.exc_info()

    assert exc_info[1] is e

    return exc_info

def add_msg(e, msg): e.args = (strings.ensure_newl(str(e))+msg,)

def repl_msg(e, **repls): e.args = (str(e) % repls,)

def e_ct_exit_status(e_ct): return min(e_ct, 255)

class ExceptionWithCause(Exception):

    def __init__(self, msg, cause=None):

        Exception.__init__(self, msg)

        if cause != None: add_msg(self, 'cause: '+str_(cause))

def str_(e, with_traceback=True):

    lines = traceback.format_exception_only(type(e), e)

    if with_traceback: lines += traceback.format_tb(get_exc_info(e)[2])

    return ''.join(lines)

def print_ex(e, emph=True, **format):

    msg = str_(e, **format)

    if emph:

        first_line, nl, rest = msg.partition('\n')

        msg = term.error(first_line)+nl+rest

    sys.stderr.write(msg)

class ExTracker:

    def __init__(self):

        self.e_ct = 0

    def msg(self): return 'Encountered '+str(self.e_ct)+' error(s)'

    def track(self, e, **format):

        self.e_ct += 1

        print_ex(e, **format)

    def exit(self):

        if self.e_ct > 0: raise SystemExit(e_ct_exit_status(self.e_ct))

class ExPercentTracker(ExTracker):

    def __init__(self, iter_text='iteration'):

        ExTracker.__init__(self)

        self.iter_text = iter_text

        self.iter_ct = None

    def add_iters(self, iter_ct):

        if self.iter_ct == None: self.iter_ct = 0

        self.iter_ct += iter_ct

    def msg(self):

        msg = ExTracker.msg(self)

        if self.iter_ct != None: msg += ('/'+format.int2str(self.iter_ct)+' '

            +self.iter_text+'(s) = '

            +format.to_percent(float(self.e_ct)/self.iter_ct))

        return msg