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comparison: DebugClients/Python3/coverage/pytracer.py
DebugClients/Python3/coverage/pytracer.py
- changeset 4489
- d0d6e4ad31bd
- child 5051
- 3586ebd9fac8
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| 1 # Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0 | |
| 2 # For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt | |
| 3 | |
| 4 """Raw data collector for coverage.py.""" | |
| 5 | |
| 6 import dis | |
| 7 import sys | |
| 8 | |
| 9 from coverage import env | |
| 10 | |
| 11 # We need the YIELD_VALUE opcode below, in a comparison-friendly form. | |
| 12 YIELD_VALUE = dis.opmap['YIELD_VALUE'] | |
| 13 if env.PY2: | |
| 14 YIELD_VALUE = chr(YIELD_VALUE) | |
| 15 | |
| 16 | |
| 17 class PyTracer(object): | |
| 18 """Python implementation of the raw data tracer.""" | |
| 19 | |
| 20 # Because of poor implementations of trace-function-manipulating tools, | |
| 21 # the Python trace function must be kept very simple. In particular, there | |
| 22 # must be only one function ever set as the trace function, both through | |
| 23 # sys.settrace, and as the return value from the trace function. Put | |
| 24 # another way, the trace function must always return itself. It cannot | |
| 25 # swap in other functions, or return None to avoid tracing a particular | |
| 26 # frame. | |
| 27 # | |
| 28 # The trace manipulator that introduced this restriction is DecoratorTools, | |
| 29 # which sets a trace function, and then later restores the pre-existing one | |
| 30 # by calling sys.settrace with a function it found in the current frame. | |
| 31 # | |
| 32 # Systems that use DecoratorTools (or similar trace manipulations) must use | |
| 33 # PyTracer to get accurate results. The command-line --timid argument is | |
| 34 # used to force the use of this tracer. | |
| 35 | |
| 36 def __init__(self): | |
| 37 # Attributes set from the collector: | |
| 38 self.data = None | |
| 39 self.trace_arcs = False | |
| 40 self.should_trace = None | |
| 41 self.should_trace_cache = None | |
| 42 self.warn = None | |
| 43 # The threading module to use, if any. | |
| 44 self.threading = None | |
| 45 | |
| 46 self.cur_file_dict = [] | |
| 47 self.last_line = [0] | |
| 48 | |
| 49 self.data_stack = [] | |
| 50 self.last_exc_back = None | |
| 51 self.last_exc_firstlineno = 0 | |
| 52 self.thread = None | |
| 53 self.stopped = False | |
| 54 | |
| 55 def __repr__(self): | |
| 56 return "<PyTracer at 0x{0:0x}: {1} lines in {2} files>".format( | |
| 57 id(self), | |
| 58 sum(len(v) for v in self.data.values()), | |
| 59 len(self.data), | |
| 60 ) | |
| 61 | |
| 62 def _trace(self, frame, event, arg_unused): | |
| 63 """The trace function passed to sys.settrace.""" | |
| 64 | |
| 65 if self.stopped: | |
| 66 return | |
| 67 | |
| 68 if self.last_exc_back: | |
| 69 if frame == self.last_exc_back: | |
| 70 # Someone forgot a return event. | |
| 71 if self.trace_arcs and self.cur_file_dict: | |
| 72 pair = (self.last_line, -self.last_exc_firstlineno) | |
| 73 self.cur_file_dict[pair] = None | |
| 74 self.cur_file_dict, self.last_line = self.data_stack.pop() | |
| 75 self.last_exc_back = None | |
| 76 | |
| 77 if event == 'call': | |
| 78 # Entering a new function context. Decide if we should trace | |
| 79 # in this file. | |
| 80 self.data_stack.append((self.cur_file_dict, self.last_line)) | |
| 81 filename = frame.f_code.co_filename | |
| 82 disp = self.should_trace_cache.get(filename) | |
| 83 if disp is None: | |
| 84 disp = self.should_trace(filename, frame) | |
| 85 self.should_trace_cache[filename] = disp | |
| 86 | |
| 87 self.cur_file_dict = None | |
| 88 if disp.trace: | |
| 89 tracename = disp.source_filename | |
| 90 if tracename not in self.data: | |
| 91 self.data[tracename] = {} | |
| 92 self.cur_file_dict = self.data[tracename] | |
| 93 # The call event is really a "start frame" event, and happens for | |
| 94 # function calls and re-entering generators. The f_lasti field is | |
| 95 # -1 for calls, and a real offset for generators. Use -1 as the | |
| 96 # line number for calls, and the real line number for generators. | |
| 97 self.last_line = -1 if (frame.f_lasti < 0) else frame.f_lineno | |
| 98 elif event == 'line': | |
| 99 # Record an executed line. | |
| 100 if self.cur_file_dict is not None: | |
| 101 lineno = frame.f_lineno | |
| 102 if self.trace_arcs: | |
| 103 self.cur_file_dict[(self.last_line, lineno)] = None | |
| 104 else: | |
| 105 self.cur_file_dict[lineno] = None | |
| 106 self.last_line = lineno | |
| 107 elif event == 'return': | |
| 108 if self.trace_arcs and self.cur_file_dict: | |
| 109 # Record an arc leaving the function, but beware that a | |
| 110 # "return" event might just mean yielding from a generator. | |
| 111 bytecode = frame.f_code.co_code[frame.f_lasti] | |
| 112 if bytecode != YIELD_VALUE: | |
| 113 first = frame.f_code.co_firstlineno | |
| 114 self.cur_file_dict[(self.last_line, -first)] = None | |
| 115 # Leaving this function, pop the filename stack. | |
| 116 self.cur_file_dict, self.last_line = self.data_stack.pop() | |
| 117 elif event == 'exception': | |
| 118 self.last_exc_back = frame.f_back | |
| 119 self.last_exc_firstlineno = frame.f_code.co_firstlineno | |
| 120 return self._trace | |
| 121 | |
| 122 def start(self): | |
| 123 """Start this Tracer. | |
| 124 | |
| 125 Return a Python function suitable for use with sys.settrace(). | |
| 126 | |
| 127 """ | |
| 128 if self.threading: | |
| 129 self.thread = self.threading.currentThread() | |
| 130 sys.settrace(self._trace) | |
| 131 self.stopped = False | |
| 132 return self._trace | |
| 133 | |
| 134 def stop(self): | |
| 135 """Stop this Tracer.""" | |
| 136 self.stopped = True | |
| 137 if self.threading and self.thread != self.threading.currentThread(): | |
| 138 # Called on a different thread than started us: we can't unhook | |
| 139 # ourselves, but we've set the flag that we should stop, so we | |
| 140 # won't do any more tracing. | |
| 141 return | |
| 142 | |
| 143 if self.warn: | |
| 144 if sys.gettrace() != self._trace: | |
| 145 msg = "Trace function changed, measurement is likely wrong: %r" | |
| 146 self.warn(msg % (sys.gettrace(),)) | |
| 147 | |
| 148 sys.settrace(None) | |
| 149 | |
| 150 def get_stats(self): | |
| 151 """Return a dictionary of statistics, or None.""" | |
| 152 return None |
