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# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
"""Raw data collector for coverage.py."""
import atexit
import dis
import sys
from coverage import env
# We need the YIELD_VALUE opcode below, in a comparison-friendly form.
YIELD_VALUE = dis.opmap['YIELD_VALUE']
if env.PY2:
YIELD_VALUE = chr(YIELD_VALUE)
class PyTracer(object):
"""Python implementation of the raw data tracer."""
# Because of poor implementations of trace-function-manipulating tools,
# the Python trace function must be kept very simple. In particular, there
# must be only one function ever set as the trace function, both through
# sys.settrace, and as the return value from the trace function. Put
# another way, the trace function must always return itself. It cannot
# swap in other functions, or return None to avoid tracing a particular
# frame.
#
# The trace manipulator that introduced this restriction is DecoratorTools,
# which sets a trace function, and then later restores the pre-existing one
# by calling sys.settrace with a function it found in the current frame.
#
# Systems that use DecoratorTools (or similar trace manipulations) must use
# PyTracer to get accurate results. The command-line --timid argument is
# used to force the use of this tracer.
def __init__(self):
# Attributes set from the collector:
self.data = None
self.trace_arcs = False
self.should_trace = None
self.should_trace_cache = None
self.warn = None
# The threading module to use, if any.
self.threading = None
self.cur_file_dict = None
self.last_line = 0 # int, but uninitialized.
self.cur_file_name = None
self.data_stack = []
self.last_exc_back = None
self.last_exc_firstlineno = 0
self.thread = None
self.stopped = False
self._activity = False
self.in_atexit = False
# On exit, self.in_atexit = True
atexit.register(setattr, self, 'in_atexit', True)
def __repr__(self):
return "<PyTracer at {0}: {1} lines in {2} files>".format(
id(self),
sum(len(v) for v in self.data.values()),
len(self.data),
)
def log(self, marker, *args):
"""For hard-core logging of what this tracer is doing."""
with open("/tmp/debug_trace.txt", "a") as f:
f.write("{} {:x}.{:x}[{}] {:x} {}\n".format(
marker,
id(self),
self.thread.ident,
len(self.data_stack),
self.threading.currentThread().ident,
" ".join(map(str, args))
))
def _trace(self, frame, event, arg_unused):
"""The trace function passed to sys.settrace."""
#self.log(":", frame.f_code.co_filename, frame.f_lineno, event)
if (self.stopped and sys.gettrace() == self._trace):
# The PyTrace.stop() method has been called, possibly by another
# thread, let's deactivate ourselves now.
#self.log("X", frame.f_code.co_filename, frame.f_lineno)
sys.settrace(None)
return None
if self.last_exc_back:
if frame == self.last_exc_back:
# Someone forgot a return event.
if self.trace_arcs and self.cur_file_dict:
pair = (self.last_line, -self.last_exc_firstlineno)
self.cur_file_dict[pair] = None
self.cur_file_dict, self.cur_file_name, self.last_line = self.data_stack.pop()
self.last_exc_back = None
if event == 'call':
# Entering a new function context. Decide if we should trace
# in this file.
self._activity = True
self.data_stack.append((self.cur_file_dict, self.cur_file_name, self.last_line))
filename = frame.f_code.co_filename
self.cur_file_name = filename
disp = self.should_trace_cache.get(filename)
if disp is None:
disp = self.should_trace(filename, frame)
self.should_trace_cache[filename] = disp
self.cur_file_dict = None
if disp.trace:
tracename = disp.source_filename
if tracename not in self.data:
self.data[tracename] = {}
self.cur_file_dict = self.data[tracename]
# The call event is really a "start frame" event, and happens for
# function calls and re-entering generators. The f_lasti field is
# -1 for calls, and a real offset for generators. Use <0 as the
# line number for calls, and the real line number for generators.
if getattr(frame, 'f_lasti', -1) < 0:
self.last_line = -frame.f_code.co_firstlineno
else:
self.last_line = frame.f_lineno
elif event == 'line':
# Record an executed line.
if self.cur_file_dict is not None:
lineno = frame.f_lineno
#if frame.f_code.co_filename != self.cur_file_name:
# self.log("*", frame.f_code.co_filename, self.cur_file_name, lineno)
if self.trace_arcs:
self.cur_file_dict[(self.last_line, lineno)] = None
else:
self.cur_file_dict[lineno] = None
self.last_line = lineno
elif event == 'return':
if self.trace_arcs and self.cur_file_dict:
# Record an arc leaving the function, but beware that a
# "return" event might just mean yielding from a generator.
# Jython seems to have an empty co_code, so just assume return.
code = frame.f_code.co_code
if (not code) or code[frame.f_lasti] != YIELD_VALUE:
first = frame.f_code.co_firstlineno
self.cur_file_dict[(self.last_line, -first)] = None
# Leaving this function, pop the filename stack.
self.cur_file_dict, self.cur_file_name, self.last_line = self.data_stack.pop()
elif event == 'exception':
self.last_exc_back = frame.f_back
self.last_exc_firstlineno = frame.f_code.co_firstlineno
return self._trace
def start(self):
"""Start this Tracer.
Return a Python function suitable for use with sys.settrace().
"""
self.stopped = False
if self.threading:
if self.thread is None:
self.thread = self.threading.currentThread()
else:
if self.thread.ident != self.threading.currentThread().ident:
# Re-starting from a different thread!? Don't set the trace
# function, but we are marked as running again, so maybe it
# will be ok?
#self.log("~", "starting on different threads")
return self._trace
sys.settrace(self._trace)
return self._trace
def stop(self):
"""Stop this Tracer."""
# Get the activate tracer callback before setting the stop flag to be
# able to detect if the tracer was changed prior to stopping it.
tf = sys.gettrace()
# Set the stop flag. The actual call to sys.settrace(None) will happen
# in the self._trace callback itself to make sure to call it from the
# right thread.
self.stopped = True
if self.threading and self.thread.ident != self.threading.currentThread().ident:
# Called on a different thread than started us: we can't unhook
# ourselves, but we've set the flag that we should stop, so we
# won't do any more tracing.
#self.log("~", "stopping on different threads")
return
if self.warn:
# PyPy clears the trace function before running atexit functions,
# so don't warn if we are in atexit on PyPy and the trace function
# has changed to None.
dont_warn = (env.PYPY and env.PYPYVERSION >= (5, 4) and self.in_atexit and tf is None)
if (not dont_warn) and tf != self._trace:
self.warn(
"Trace function changed, measurement is likely wrong: %r" % (tf,),
slug="trace-changed",
)
def activity(self):
"""Has there been any activity?"""
return self._activity
def reset_activity(self):
"""Reset the activity() flag."""
self._activity = False
def get_stats(self):
"""Return a dictionary of statistics, or None."""
return None
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