1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/python/mozbuild/mozpack/errors.py Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,137 @@
1.4 +# This Source Code Form is subject to the terms of the Mozilla Public
1.5 +# License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 +# file, You can obtain one at http://mozilla.org/MPL/2.0/.
1.7 +
1.8 +import sys
1.9 +from contextlib import contextmanager
1.10 +
1.11 +
1.12 +class ErrorMessage(Exception):
1.13 + '''Exception type raised from errors.error() and errors.fatal()'''
1.14 +
1.15 +
1.16 +class AccumulatedErrors(Exception):
1.17 + '''Exception type raised from errors.accumulate()'''
1.18 +
1.19 +
1.20 +class ErrorCollector(object):
1.21 + '''
1.22 + Error handling/logging class. A global instance, errors, is provided for
1.23 + convenience.
1.24 +
1.25 + Warnings, errors and fatal errors may be logged by calls to the following
1.26 + functions:
1.27 + errors.warn(message)
1.28 + errors.error(message)
1.29 + errors.fatal(message)
1.30 +
1.31 + Warnings only send the message on the logging output, while errors and
1.32 + fatal errors send the message and throw an ErrorMessage exception. The
1.33 + exception, however, may be deferred. See further below.
1.34 +
1.35 + Errors may be ignored by calling:
1.36 + errors.ignore_errors()
1.37 +
1.38 + After calling that function, only fatal errors throw an exception.
1.39 +
1.40 + The warnings, errors or fatal errors messages may be augmented with context
1.41 + information when a context is provided. Context is defined by a pair
1.42 + (filename, linenumber), and may be set with errors.context() used as a
1.43 + context manager:
1.44 + with errors.context(filename, linenumber):
1.45 + errors.warn(message)
1.46 +
1.47 + Arbitrary nesting is supported, both for errors.context calls:
1.48 + with errors.context(filename1, linenumber1):
1.49 + errors.warn(message)
1.50 + with errors.context(filename2, linenumber2):
1.51 + errors.warn(message)
1.52 +
1.53 + as well as for function calls:
1.54 + def func():
1.55 + errors.warn(message)
1.56 + with errors.context(filename, linenumber):
1.57 + func()
1.58 +
1.59 + Errors and fatal errors can have their exception thrown at a later time,
1.60 + allowing for several different errors to be reported at once before
1.61 + throwing. This is achieved with errors.accumulate() as a context manager:
1.62 + with errors.accumulate():
1.63 + if test1:
1.64 + errors.error(message1)
1.65 + if test2:
1.66 + errors.error(message2)
1.67 +
1.68 + In such cases, a single AccumulatedErrors exception is thrown, but doesn't
1.69 + contain information about the exceptions. The logged messages do.
1.70 + '''
1.71 + out = sys.stderr
1.72 + WARN = 1
1.73 + ERROR = 2
1.74 + FATAL = 3
1.75 + _level = ERROR
1.76 + _context = []
1.77 + _count = None
1.78 +
1.79 + def ignore_errors(self, ignore=True):
1.80 + if ignore:
1.81 + self._level = self.FATAL
1.82 + else:
1.83 + self._level = self.ERROR
1.84 +
1.85 + def _full_message(self, level, msg):
1.86 + if level >= self._level:
1.87 + level = 'Error'
1.88 + else:
1.89 + level = 'Warning'
1.90 + if self._context:
1.91 + file, line = self._context[-1]
1.92 + return "%s: %s:%d: %s" % (level, file, line, msg)
1.93 + return "%s: %s" % (level, msg)
1.94 +
1.95 + def _handle(self, level, msg):
1.96 + msg = self._full_message(level, msg)
1.97 + if level >= self._level:
1.98 + if self._count is None:
1.99 + raise ErrorMessage(msg)
1.100 + self._count += 1
1.101 + print >>self.out, msg
1.102 +
1.103 + def fatal(self, msg):
1.104 + self._handle(self.FATAL, msg)
1.105 +
1.106 + def error(self, msg):
1.107 + self._handle(self.ERROR, msg)
1.108 +
1.109 + def warn(self, msg):
1.110 + self._handle(self.WARN, msg)
1.111 +
1.112 + def get_context(self):
1.113 + if self._context:
1.114 + return self._context[-1]
1.115 +
1.116 + @contextmanager
1.117 + def context(self, file, line):
1.118 + if file and line:
1.119 + self._context.append((file, line))
1.120 + yield
1.121 + if file and line:
1.122 + self._context.pop()
1.123 +
1.124 + @contextmanager
1.125 + def accumulate(self):
1.126 + assert self._count is None
1.127 + self._count = 0
1.128 + yield
1.129 + count = self._count
1.130 + self._count = None
1.131 + if count:
1.132 + raise AccumulatedErrors()
1.133 +
1.134 + @property
1.135 + def count(self):
1.136 + # _count can be None.
1.137 + return self._count if self._count else 0
1.138 +
1.139 +
1.140 +errors = ErrorCollector()
