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634 lines
21 KiB
Python
634 lines
21 KiB
Python
"""Debugger basics"""
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import fnmatch
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import sys
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import os
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__all__ = ["BdbQuit", "Bdb", "Breakpoint"]
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class BdbQuit(Exception):
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"""Exception to give up completely."""
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class Bdb:
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"""Generic Python debugger base class.
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This class takes care of details of the trace facility;
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a derived class should implement user interaction.
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The standard debugger class (pdb.Pdb) is an example.
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"""
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def __init__(self, skip=None):
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self.skip = set(skip) if skip else None
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self.breaks = {}
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self.fncache = {}
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def canonic(self, filename):
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if filename == "<" + filename[1:-1] + ">":
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return filename
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canonic = self.fncache.get(filename)
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if not canonic:
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canonic = os.path.abspath(filename)
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canonic = os.path.normcase(canonic)
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self.fncache[filename] = canonic
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return canonic
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def reset(self):
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import linecache
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linecache.checkcache()
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self.botframe = None
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self._set_stopinfo(None, None)
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def trace_dispatch(self, frame, event, arg):
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if self.quitting:
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return # None
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if event == 'line':
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return self.dispatch_line(frame)
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if event == 'call':
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return self.dispatch_call(frame, arg)
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if event == 'return':
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return self.dispatch_return(frame, arg)
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if event == 'exception':
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return self.dispatch_exception(frame, arg)
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if event == 'c_call':
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return self.trace_dispatch
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if event == 'c_exception':
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return self.trace_dispatch
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if event == 'c_return':
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return self.trace_dispatch
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print('bdb.Bdb.dispatch: unknown debugging event:', repr(event))
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return self.trace_dispatch
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def dispatch_line(self, frame):
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if self.stop_here(frame) or self.break_here(frame):
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self.user_line(frame)
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if self.quitting: raise BdbQuit
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return self.trace_dispatch
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def dispatch_call(self, frame, arg):
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# XXX 'arg' is no longer used
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if self.botframe is None:
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# First call of dispatch since reset()
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self.botframe = frame.f_back # (CT) Note that this may also be None!
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return self.trace_dispatch
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if not (self.stop_here(frame) or self.break_anywhere(frame)):
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# No need to trace this function
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return # None
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self.user_call(frame, arg)
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if self.quitting: raise BdbQuit
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return self.trace_dispatch
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def dispatch_return(self, frame, arg):
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if self.stop_here(frame) or frame == self.returnframe:
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self.user_return(frame, arg)
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if self.quitting: raise BdbQuit
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return self.trace_dispatch
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def dispatch_exception(self, frame, arg):
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if self.stop_here(frame):
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self.user_exception(frame, arg)
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if self.quitting: raise BdbQuit
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return self.trace_dispatch
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# Normally derived classes don't override the following
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# methods, but they may if they want to redefine the
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# definition of stopping and breakpoints.
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def is_skipped_module(self, module_name):
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for pattern in self.skip:
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if fnmatch.fnmatch(module_name, pattern):
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return True
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return False
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def stop_here(self, frame):
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# (CT) stopframe may now also be None, see dispatch_call.
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# (CT) the former test for None is therefore removed from here.
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if self.skip and \
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self.is_skipped_module(frame.f_globals.get('__name__')):
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return False
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if frame is self.stopframe:
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if self.stoplineno == -1:
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return False
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return frame.f_lineno >= self.stoplineno
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while frame is not None and frame is not self.stopframe:
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if frame is self.botframe:
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return True
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frame = frame.f_back
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return False
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def break_here(self, frame):
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filename = self.canonic(frame.f_code.co_filename)
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if filename not in self.breaks:
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return False
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lineno = frame.f_lineno
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if lineno not in self.breaks[filename]:
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# The line itself has no breakpoint, but maybe the line is the
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# first line of a function with breakpoint set by function name.
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lineno = frame.f_code.co_firstlineno
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if lineno not in self.breaks[filename]:
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return False
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# flag says ok to delete temp. bp
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(bp, flag) = effective(filename, lineno, frame)
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if bp:
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self.currentbp = bp.number
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if (flag and bp.temporary):
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self.do_clear(str(bp.number))
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return True
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else:
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return False
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def do_clear(self, arg):
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raise NotImplementedError("subclass of bdb must implement do_clear()")
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def break_anywhere(self, frame):
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return self.canonic(frame.f_code.co_filename) in self.breaks
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# Derived classes should override the user_* methods
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# to gain control.
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def user_call(self, frame, argument_list):
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"""This method is called when there is the remote possibility
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that we ever need to stop in this function."""
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pass
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def user_line(self, frame):
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"""This method is called when we stop or break at this line."""
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pass
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def user_return(self, frame, return_value):
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"""This method is called when a return trap is set here."""
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pass
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def user_exception(self, frame, exc_info):
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"""This method is called if an exception occurs,
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but only if we are to stop at or just below this level."""
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pass
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def _set_stopinfo(self, stopframe, returnframe, stoplineno=0):
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self.stopframe = stopframe
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self.returnframe = returnframe
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self.quitting = False
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# stoplineno >= 0 means: stop at line >= the stoplineno
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# stoplineno -1 means: don't stop at all
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self.stoplineno = stoplineno
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# Derived classes and clients can call the following methods
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# to affect the stepping state.
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def set_until(self, frame, lineno=None):
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"""Stop when the line with the line no greater than the current one is
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reached or when returning from current frame"""
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# the name "until" is borrowed from gdb
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if lineno is None:
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lineno = frame.f_lineno + 1
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self._set_stopinfo(frame, frame, lineno)
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def set_step(self):
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"""Stop after one line of code."""
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self._set_stopinfo(None, None)
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def set_next(self, frame):
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"""Stop on the next line in or below the given frame."""
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self._set_stopinfo(frame, None)
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def set_return(self, frame):
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"""Stop when returning from the given frame."""
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self._set_stopinfo(frame.f_back, frame)
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def set_trace(self, frame=None):
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"""Start debugging from `frame`.
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If frame is not specified, debugging starts from caller's frame.
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"""
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if frame is None:
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frame = sys._getframe().f_back
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self.reset()
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while frame:
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frame.f_trace = self.trace_dispatch
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self.botframe = frame
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frame = frame.f_back
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self.set_step()
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sys.settrace(self.trace_dispatch)
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def set_continue(self):
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# Don't stop except at breakpoints or when finished
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self._set_stopinfo(self.botframe, None, -1)
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if not self.breaks:
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# no breakpoints; run without debugger overhead
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sys.settrace(None)
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frame = sys._getframe().f_back
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while frame and frame is not self.botframe:
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del frame.f_trace
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frame = frame.f_back
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def set_quit(self):
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self.stopframe = self.botframe
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self.returnframe = None
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self.quitting = True
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sys.settrace(None)
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# Derived classes and clients can call the following methods
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# to manipulate breakpoints. These methods return an
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# error message is something went wrong, None if all is well.
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# Set_break prints out the breakpoint line and file:lineno.
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# Call self.get_*break*() to see the breakpoints or better
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# for bp in Breakpoint.bpbynumber: if bp: bp.bpprint().
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def set_break(self, filename, lineno, temporary=False, cond=None,
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funcname=None):
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filename = self.canonic(filename)
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import linecache # Import as late as possible
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line = linecache.getline(filename, lineno)
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if not line:
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return 'Line %s:%d does not exist' % (filename, lineno)
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list = self.breaks.setdefault(filename, [])
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if lineno not in list:
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list.append(lineno)
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bp = Breakpoint(filename, lineno, temporary, cond, funcname)
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def _prune_breaks(self, filename, lineno):
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if (filename, lineno) not in Breakpoint.bplist:
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self.breaks[filename].remove(lineno)
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if not self.breaks[filename]:
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del self.breaks[filename]
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def clear_break(self, filename, lineno):
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filename = self.canonic(filename)
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if filename not in self.breaks:
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return 'There are no breakpoints in %s' % filename
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if lineno not in self.breaks[filename]:
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return 'There is no breakpoint at %s:%d' % (filename, lineno)
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# If there's only one bp in the list for that file,line
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# pair, then remove the breaks entry
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for bp in Breakpoint.bplist[filename, lineno][:]:
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bp.deleteMe()
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self._prune_breaks(filename, lineno)
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def clear_bpbynumber(self, arg):
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try:
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bp = self.get_bpbynumber(arg)
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except ValueError as err:
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return str(err)
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bp.deleteMe()
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self._prune_breaks(bp.file, bp.line)
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def clear_all_file_breaks(self, filename):
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filename = self.canonic(filename)
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if filename not in self.breaks:
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return 'There are no breakpoints in %s' % filename
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for line in self.breaks[filename]:
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blist = Breakpoint.bplist[filename, line]
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for bp in blist:
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bp.deleteMe()
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del self.breaks[filename]
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def clear_all_breaks(self):
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if not self.breaks:
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return 'There are no breakpoints'
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for bp in Breakpoint.bpbynumber:
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if bp:
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bp.deleteMe()
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self.breaks = {}
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def get_bpbynumber(self, arg):
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if not arg:
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raise ValueError('Breakpoint number expected')
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try:
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number = int(arg)
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except ValueError:
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raise ValueError('Non-numeric breakpoint number %s' % arg)
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try:
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bp = Breakpoint.bpbynumber[number]
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except IndexError:
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raise ValueError('Breakpoint number %d out of range' % number)
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if bp is None:
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raise ValueError('Breakpoint %d already deleted' % number)
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return bp
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def get_break(self, filename, lineno):
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filename = self.canonic(filename)
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return filename in self.breaks and \
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lineno in self.breaks[filename]
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def get_breaks(self, filename, lineno):
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filename = self.canonic(filename)
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return filename in self.breaks and \
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lineno in self.breaks[filename] and \
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Breakpoint.bplist[filename, lineno] or []
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def get_file_breaks(self, filename):
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filename = self.canonic(filename)
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if filename in self.breaks:
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return self.breaks[filename]
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else:
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return []
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def get_all_breaks(self):
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return self.breaks
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# Derived classes and clients can call the following method
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# to get a data structure representing a stack trace.
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def get_stack(self, f, t):
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stack = []
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if t and t.tb_frame is f:
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t = t.tb_next
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while f is not None:
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stack.append((f, f.f_lineno))
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if f is self.botframe:
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break
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f = f.f_back
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stack.reverse()
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i = max(0, len(stack) - 1)
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while t is not None:
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stack.append((t.tb_frame, t.tb_lineno))
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t = t.tb_next
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if f is None:
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i = max(0, len(stack) - 1)
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return stack, i
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def format_stack_entry(self, frame_lineno, lprefix=': '):
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import linecache, reprlib
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frame, lineno = frame_lineno
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filename = self.canonic(frame.f_code.co_filename)
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s = '%s(%r)' % (filename, lineno)
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if frame.f_code.co_name:
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s += frame.f_code.co_name
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else:
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s += "<lambda>"
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if '__args__' in frame.f_locals:
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args = frame.f_locals['__args__']
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else:
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args = None
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if args:
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s += reprlib.repr(args)
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else:
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s += '()'
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if '__return__' in frame.f_locals:
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rv = frame.f_locals['__return__']
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s += '->'
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s += reprlib.repr(rv)
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line = linecache.getline(filename, lineno, frame.f_globals)
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if line:
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s += lprefix + line.strip()
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return s
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# The following methods can be called by clients to use
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# a debugger to debug a statement or an expression.
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# Both can be given as a string, or a code object.
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def run(self, cmd, globals=None, locals=None):
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if globals is None:
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import __main__
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globals = __main__.__dict__
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if locals is None:
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locals = globals
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self.reset()
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if isinstance(cmd, str):
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cmd = compile(cmd, "<string>", "exec")
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sys.settrace(self.trace_dispatch)
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try:
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exec(cmd, globals, locals)
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except BdbQuit:
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pass
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finally:
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self.quitting = True
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sys.settrace(None)
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def runeval(self, expr, globals=None, locals=None):
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if globals is None:
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import __main__
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globals = __main__.__dict__
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if locals is None:
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locals = globals
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self.reset()
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sys.settrace(self.trace_dispatch)
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try:
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return eval(expr, globals, locals)
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except BdbQuit:
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pass
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finally:
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self.quitting = True
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sys.settrace(None)
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def runctx(self, cmd, globals, locals):
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# B/W compatibility
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self.run(cmd, globals, locals)
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# This method is more useful to debug a single function call.
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def runcall(self, func, *args, **kwds):
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self.reset()
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sys.settrace(self.trace_dispatch)
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res = None
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try:
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res = func(*args, **kwds)
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except BdbQuit:
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pass
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finally:
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self.quitting = True
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sys.settrace(None)
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return res
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def set_trace():
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Bdb().set_trace()
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class Breakpoint:
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"""Breakpoint class.
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Implements temporary breakpoints, ignore counts, disabling and
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(re)-enabling, and conditionals.
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Breakpoints are indexed by number through bpbynumber and by
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the file,line tuple using bplist. The former points to a
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single instance of class Breakpoint. The latter points to a
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list of such instances since there may be more than one
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breakpoint per line.
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"""
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# XXX Keeping state in the class is a mistake -- this means
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# you cannot have more than one active Bdb instance.
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next = 1 # Next bp to be assigned
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bplist = {} # indexed by (file, lineno) tuple
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bpbynumber = [None] # Each entry is None or an instance of Bpt
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# index 0 is unused, except for marking an
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# effective break .... see effective()
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def __init__(self, file, line, temporary=False, cond=None, funcname=None):
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self.funcname = funcname
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# Needed if funcname is not None.
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self.func_first_executable_line = None
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self.file = file # This better be in canonical form!
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self.line = line
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self.temporary = temporary
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self.cond = cond
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self.enabled = True
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self.ignore = 0
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self.hits = 0
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self.number = Breakpoint.next
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Breakpoint.next += 1
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# Build the two lists
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self.bpbynumber.append(self)
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if (file, line) in self.bplist:
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self.bplist[file, line].append(self)
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else:
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self.bplist[file, line] = [self]
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def deleteMe(self):
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index = (self.file, self.line)
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self.bpbynumber[self.number] = None # No longer in list
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self.bplist[index].remove(self)
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if not self.bplist[index]:
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# No more bp for this f:l combo
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del self.bplist[index]
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def enable(self):
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self.enabled = True
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def disable(self):
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self.enabled = False
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def bpprint(self, out=None):
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if out is None:
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out = sys.stdout
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print(self.bpformat(), file=out)
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def bpformat(self):
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if self.temporary:
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disp = 'del '
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else:
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disp = 'keep '
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if self.enabled:
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disp = disp + 'yes '
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else:
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disp = disp + 'no '
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ret = '%-4dbreakpoint %s at %s:%d' % (self.number, disp,
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self.file, self.line)
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if self.cond:
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ret += '\n\tstop only if %s' % (self.cond,)
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if self.ignore:
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ret += '\n\tignore next %d hits' % (self.ignore,)
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if self.hits:
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if self.hits > 1:
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ss = 's'
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else:
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ss = ''
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ret += '\n\tbreakpoint already hit %d time%s' % (self.hits, ss)
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return ret
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def __str__(self):
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return 'breakpoint %s at %s:%s' % (self.number, self.file, self.line)
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# -----------end of Breakpoint class----------
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def checkfuncname(b, frame):
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"""Check whether we should break here because of `b.funcname`."""
|
|
if not b.funcname:
|
|
# Breakpoint was set via line number.
|
|
if b.line != frame.f_lineno:
|
|
# Breakpoint was set at a line with a def statement and the function
|
|
# defined is called: don't break.
|
|
return False
|
|
return True
|
|
|
|
# Breakpoint set via function name.
|
|
|
|
if frame.f_code.co_name != b.funcname:
|
|
# It's not a function call, but rather execution of def statement.
|
|
return False
|
|
|
|
# We are in the right frame.
|
|
if not b.func_first_executable_line:
|
|
# The function is entered for the 1st time.
|
|
b.func_first_executable_line = frame.f_lineno
|
|
|
|
if b.func_first_executable_line != frame.f_lineno:
|
|
# But we are not at the first line number: don't break.
|
|
return False
|
|
return True
|
|
|
|
# Determines if there is an effective (active) breakpoint at this
|
|
# line of code. Returns breakpoint number or 0 if none
|
|
def effective(file, line, frame):
|
|
"""Determine which breakpoint for this file:line is to be acted upon.
|
|
|
|
Called only if we know there is a bpt at this
|
|
location. Returns breakpoint that was triggered and a flag
|
|
that indicates if it is ok to delete a temporary bp.
|
|
|
|
"""
|
|
possibles = Breakpoint.bplist[file, line]
|
|
for b in possibles:
|
|
if not b.enabled:
|
|
continue
|
|
if not checkfuncname(b, frame):
|
|
continue
|
|
# Count every hit when bp is enabled
|
|
b.hits += 1
|
|
if not b.cond:
|
|
# If unconditional, and ignoring go on to next, else break
|
|
if b.ignore > 0:
|
|
b.ignore -= 1
|
|
continue
|
|
else:
|
|
# breakpoint and marker that it's ok to delete if temporary
|
|
return (b, True)
|
|
else:
|
|
# Conditional bp.
|
|
# Ignore count applies only to those bpt hits where the
|
|
# condition evaluates to true.
|
|
try:
|
|
val = eval(b.cond, frame.f_globals, frame.f_locals)
|
|
if val:
|
|
if b.ignore > 0:
|
|
b.ignore -= 1
|
|
# continue
|
|
else:
|
|
return (b, True)
|
|
# else:
|
|
# continue
|
|
except:
|
|
# if eval fails, most conservative thing is to stop on
|
|
# breakpoint regardless of ignore count. Don't delete
|
|
# temporary, as another hint to user.
|
|
return (b, False)
|
|
return (None, None)
|
|
|
|
|
|
# -------------------- testing --------------------
|
|
|
|
class Tdb(Bdb):
|
|
def user_call(self, frame, args):
|
|
name = frame.f_code.co_name
|
|
if not name: name = '???'
|
|
print('+++ call', name, args)
|
|
def user_line(self, frame):
|
|
import linecache
|
|
name = frame.f_code.co_name
|
|
if not name: name = '???'
|
|
fn = self.canonic(frame.f_code.co_filename)
|
|
line = linecache.getline(fn, frame.f_lineno, frame.f_globals)
|
|
print('+++', fn, frame.f_lineno, name, ':', line.strip())
|
|
def user_return(self, frame, retval):
|
|
print('+++ return', retval)
|
|
def user_exception(self, frame, exc_stuff):
|
|
print('+++ exception', exc_stuff)
|
|
self.set_continue()
|
|
|
|
def foo(n):
|
|
print('foo(', n, ')')
|
|
x = bar(n*10)
|
|
print('bar returned', x)
|
|
|
|
def bar(a):
|
|
print('bar(', a, ')')
|
|
return a/2
|
|
|
|
def test():
|
|
t = Tdb()
|
|
t.run('import bdb; bdb.foo(10)')
|