| 1 | #!/usr/bin/env python2
|
| 2 | """
|
| 3 | scoped_resource.py
|
| 4 | """
|
| 5 | from __future__ import print_function
|
| 6 |
|
| 7 | import os
|
| 8 | import sys
|
| 9 |
|
| 10 | from mycpp import mylib
|
| 11 | from mycpp.mylib import log
|
| 12 | from typing import List, Optional, Any
|
| 13 |
|
| 14 |
|
| 15 | class MyError(Exception):
|
| 16 |
|
| 17 | def __init__(self):
|
| 18 | # type: () -> None
|
| 19 | pass
|
| 20 |
|
| 21 |
|
| 22 | def Error(error):
|
| 23 | # type: (bool) -> None
|
| 24 | if error:
|
| 25 | raise MyError()
|
| 26 |
|
| 27 |
|
| 28 | #class BadName(object):
|
| 29 | class ctx_BadName(object):
|
| 30 |
|
| 31 | def __init__(self):
|
| 32 | # type: () -> None
|
| 33 | self.i = 42
|
| 34 |
|
| 35 | def __exit__(self, type, value, traceback):
|
| 36 | # type: (Any, Any, Any) -> None
|
| 37 | self.i = 43
|
| 38 |
|
| 39 |
|
| 40 | class ctx_NoArgs(object):
|
| 41 | """Regression for most vexing parse."""
|
| 42 |
|
| 43 | def __init__(self):
|
| 44 | # type: () -> None
|
| 45 | print('> NoArgs')
|
| 46 |
|
| 47 | def __enter__(self):
|
| 48 | # type: () -> None
|
| 49 | """no-op, but it has to exist to be used as context manager."""
|
| 50 | pass
|
| 51 |
|
| 52 | def __exit__(self, type, value, traceback):
|
| 53 | # type: (Any, Any, Any) -> None
|
| 54 | print('< NoArgs')
|
| 55 |
|
| 56 |
|
| 57 | class ctx_DirStack(object):
|
| 58 |
|
| 59 | def __init__(self, state, entry):
|
| 60 | # type: (DirStack, str) -> None
|
| 61 | self.state = state
|
| 62 | state.Push(entry)
|
| 63 |
|
| 64 | # Bug #1986: add heap-allocated member of context manager
|
| 65 | self.restored = [] # type: List[str]
|
| 66 | self.restored.append('foo')
|
| 67 | self.non_pointer_member = 42 # make sure we don't root this
|
| 68 |
|
| 69 | def __enter__(self):
|
| 70 | # type: () -> None
|
| 71 | """no-op, but it has to exist to be used as context manager."""
|
| 72 | pass
|
| 73 |
|
| 74 | def __exit__(self, type, value, traceback):
|
| 75 | # type: (Any, Any, Any) -> None
|
| 76 | self.restored.pop()
|
| 77 | self.state.Pop()
|
| 78 |
|
| 79 |
|
| 80 | class DirStack(object):
|
| 81 | """For pushd/popd/dirs."""
|
| 82 |
|
| 83 | def __init__(self):
|
| 84 | # type: () -> None
|
| 85 | self.stack = [] # type: List[str]
|
| 86 | self.Reset() # Invariant: it always has at least ONE entry.
|
| 87 |
|
| 88 | def Reset(self):
|
| 89 | # type: () -> None
|
| 90 | del self.stack[:]
|
| 91 | self.stack.append('CWD')
|
| 92 |
|
| 93 | def Push(self, entry):
|
| 94 | # type: (str) -> None
|
| 95 | self.stack.append(entry)
|
| 96 |
|
| 97 | def Pop(self):
|
| 98 | # type: () -> Optional[str]
|
| 99 | if len(self.stack) <= 1:
|
| 100 | return None
|
| 101 | self.stack.pop() # remove last
|
| 102 | return self.stack[-1] # return second to last
|
| 103 |
|
| 104 | def Iter(self):
|
| 105 | # type: () -> List[str]
|
| 106 | """Iterate in reverse order."""
|
| 107 | # mycpp REWRITE:
|
| 108 | #return reversed(self.stack)
|
| 109 | ret = [] # type: List[str]
|
| 110 | ret.extend(self.stack)
|
| 111 | ret.reverse()
|
| 112 | return ret
|
| 113 |
|
| 114 | def __repr__(self):
|
| 115 | # type: () -> str
|
| 116 | return repr(self.stack)
|
| 117 |
|
| 118 |
|
| 119 | # C++ translation
|
| 120 | #
|
| 121 | # class _ErrExit__Context; // forward declaration
|
| 122 | # class _ErrExit {
|
| 123 | # };
|
| 124 | #
|
| 125 | # class _ErrExit__Context {
|
| 126 | # _ErrExit__Context(_ErrExit* state) : state_(state) {
|
| 127 | # state->Push();
|
| 128 | # }
|
| 129 | # ~_ErrExit__Context() {
|
| 130 | # state->Pop();
|
| 131 | # }
|
| 132 | # };
|
| 133 |
|
| 134 |
|
| 135 | def DoWork(d, do_raise):
|
| 136 | # type: (DirStack, bool) -> None
|
| 137 |
|
| 138 | # problem
|
| 139 | # with self.mem.ctx_Call(...)
|
| 140 | # PushCall/PopCall
|
| 141 | # with self.mem.ctx_Temp(...)
|
| 142 | # PushTemp/PopCall
|
| 143 | # with self.mem.ctx_Source(...)
|
| 144 | # PushSource/PopSource
|
| 145 | #
|
| 146 | # Scope_Call
|
| 147 | # Scope_Temp
|
| 148 |
|
| 149 | # PROBLEM: WE LOST TYPE CHECKING!
|
| 150 | #with e.Context('zz') as _:
|
| 151 | with ctx_DirStack(d, 'foo') as _:
|
| 152 | log(' in context stack %d', len(d.stack))
|
| 153 | if do_raise:
|
| 154 | Error(do_raise)
|
| 155 |
|
| 156 |
|
| 157 | def run_tests():
|
| 158 | # type: () -> None
|
| 159 |
|
| 160 | # Use cases:
|
| 161 | #
|
| 162 | # Many in cmd_exec.py
|
| 163 | #
|
| 164 | # fd_state.Push(...) and Pop
|
| 165 | # BeginAlias, EndAlias
|
| 166 | # PushSource, PopSource (opens files)
|
| 167 | # source
|
| 168 | # eval -- no file opened, but need to change the current file
|
| 169 | # PushTemp, PopTemp for env bindings
|
| 170 | # PushErrExit, PopErrExit
|
| 171 | # loop_level in cmd_exec
|
| 172 |
|
| 173 | d = DirStack()
|
| 174 |
|
| 175 | for do_raise in [False, True]:
|
| 176 | log('')
|
| 177 | log('-> dir stack %d', len(d.stack))
|
| 178 | try:
|
| 179 | DoWork(d, do_raise)
|
| 180 | except MyError:
|
| 181 | log('exited with exception')
|
| 182 | log('<- dir stack %d', len(d.stack))
|
| 183 |
|
| 184 | # C++ translation
|
| 185 | #
|
| 186 | # _Errexit e;
|
| 187 | # e.errexit = true;
|
| 188 | #
|
| 189 | # log("-> errexit %d", e.errexit)
|
| 190 | # {
|
| 191 | # _ErrExit__Context(e);
|
| 192 | # log(" errexit %d", e.errexit)
|
| 193 | # }
|
| 194 | # log("<- errexit %d", e.errexit)
|
| 195 |
|
| 196 | with ctx_NoArgs():
|
| 197 | print('hi')
|
| 198 |
|
| 199 |
|
| 200 | def run_benchmarks():
|
| 201 | # type: () -> None
|
| 202 | d = DirStack()
|
| 203 | for i in xrange(1000000):
|
| 204 | # Does NOT trigger the bug!
|
| 205 | #mylib.MaybeCollect()
|
| 206 | try:
|
| 207 | with ctx_DirStack(d, 'foo') as _:
|
| 208 | # Bug #1986: add collection in this loop
|
| 209 | mylib.MaybeCollect()
|
| 210 | if i % 10000 == 0:
|
| 211 | raise MyError()
|
| 212 | except MyError:
|
| 213 | log('exception')
|
| 214 |
|
| 215 |
|
| 216 | if __name__ == '__main__':
|
| 217 | if os.getenv('BENCHMARK'):
|
| 218 | log('Benchmarking...')
|
| 219 | run_benchmarks()
|
| 220 | else:
|
| 221 | run_tests()
|