bdb.py

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"""Debugger basics"""

import sys
import os
import types

__all__ = ["BdbQuit","Bdb","Breakpoint"]

BdbQuit = 'bdb.BdbQuit' # Exception to give up completely


class Bdb:

    """Generic Python debugger base class.

    This class takes care of details of the trace facility;
    a derived class should implement user interaction.
    The standard debugger class (pdb.Pdb) is an example.
    """

    def __init__(self):
        self.breaks = {}
        self.fncache = {}

    def canonic(self, filename):
        if filename == "<" + filename[1:-1] + ">":
            return filename
        canonic = self.fncache.get(filename)
        if not canonic:
            canonic = os.path.abspath(filename)
            canonic = os.path.normcase(canonic)
            self.fncache[filename] = canonic
        return canonic

    def reset(self):
        import linecache
        linecache.checkcache()
        self.botframe = None
        self.stopframe = None
        self.returnframe = None
        self.quitting = 0

    def trace_dispatch(self, frame, event, arg):
        if self.quitting:
            return # None
        if event == 'line':
            return self.dispatch_line(frame)
        if event == 'call':
            return self.dispatch_call(frame, arg)
        if event == 'return':
            return self.dispatch_return(frame, arg)
        if event == 'exception':
            return self.dispatch_exception(frame, arg)
        print 'bdb.Bdb.dispatch: unknown debugging event:', `event`
        return self.trace_dispatch

    def dispatch_line(self, frame):
        if self.stop_here(frame) or self.break_here(frame):
            self.user_line(frame)
            if self.quitting: raise BdbQuit
        return self.trace_dispatch

    def dispatch_call(self, frame, arg):
        # XXX 'arg' is no longer used
        if self.botframe is None:
            # First call of dispatch since reset()
            self.botframe = frame.f_back # (CT) Note that this may also be None!
            return self.trace_dispatch
        if not (self.stop_here(frame) or self.break_anywhere(frame)):
            # No need to trace this function
            return # None
        self.user_call(frame, arg)
        if self.quitting: raise BdbQuit
        return self.trace_dispatch

    def dispatch_return(self, frame, arg):
        if self.stop_here(frame) or frame == self.returnframe:
            self.user_return(frame, arg)
            if self.quitting: raise BdbQuit
        return self.trace_dispatch

    def dispatch_exception(self, frame, arg):
        if self.stop_here(frame):
            self.user_exception(frame, arg)
            if self.quitting: raise BdbQuit
        return self.trace_dispatch

    # Normally derived classes don't override the following
    # methods, but they may if they want to redefine the
    # definition of stopping and breakpoints.

    def stop_here(self, frame):
        # (CT) stopframe may now also be None, see dispatch_call.
        # (CT) the former test for None is therefore removed from here.
        if frame is self.stopframe:
            return 1
        while frame is not None and frame is not self.stopframe:
            if frame is self.botframe:
                return 1
            frame = frame.f_back
        return 0

    def break_here(self, frame):
        filename = self.canonic(frame.f_code.co_filename)
        if not self.breaks.has_key(filename):
            return 0
        lineno = frame.f_lineno
        if not lineno in self.breaks[filename]:
            return 0
        # flag says ok to delete temp. bp
        (bp, flag) = effective(filename, lineno, frame)
        if bp:
            self.currentbp = bp.number
            if (flag and bp.temporary):
                self.do_clear(str(bp.number))
            return 1
        else:
            return 0

    def do_clear(self, arg):
        raise NotImplementedError, "subclass of bdb must implement do_clear()"

    def break_anywhere(self, frame):
        return self.breaks.has_key(
            self.canonic(frame.f_code.co_filename))

    # Derived classes should override the user_* methods
    # to gain control.

    def user_call(self, frame, argument_list):
        """This method is called when there is the remote possibility
        that we ever need to stop in this function."""
        pass

    def user_line(self, frame):
        """This method is called when we stop or break at this line."""
        pass

    def user_return(self, frame, return_value):
        """This method is called when a return trap is set here."""
        pass

    def user_exception(self, frame, (exc_type, exc_value, exc_traceback)):
        """This method is called if an exception occurs,
        but only if we are to stop at or just below this level."""
        pass

    # Derived classes and clients can call the following methods
    # to affect the stepping state.

    def set_step(self):
        """Stop after one line of code."""
        self.stopframe = None
        self.returnframe = None
        self.quitting = 0

    def set_next(self, frame):
        """Stop on the next line in or below the given frame."""
        self.stopframe = frame
        self.returnframe = None
        self.quitting = 0

    def set_return(self, frame):
        """Stop when returning from the given frame."""
        self.stopframe = frame.f_back
        self.returnframe = frame
        self.quitting = 0

    def set_trace(self):
        """Start debugging from here."""
        frame = sys._getframe().f_back
        self.reset()
        while frame:
            frame.f_trace = self.trace_dispatch
            self.botframe = frame
            frame = frame.f_back
        self.set_step()
        sys.settrace(self.trace_dispatch)

    def set_continue(self):
        # Don't stop except at breakpoints or when finished
        self.stopframe = self.botframe
        self.returnframe = None
        self.quitting = 0
        if not self.breaks:
            # no breakpoints; run without debugger overhead
            sys.settrace(None)
            frame = sys._getframe().f_back
            while frame and frame is not self.botframe:
                del frame.f_trace
                frame = frame.f_back

    def set_quit(self):
        self.stopframe = self.botframe
        self.returnframe = None
        self.quitting = 1
        sys.settrace(None)

    # Derived classes and clients can call the following methods
    # to manipulate breakpoints.  These methods return an
    # error message is something went wrong, None if all is well.
    # Set_break prints out the breakpoint line and file:lineno.
    # Call self.get_*break*() to see the breakpoints or better
    # for bp in Breakpoint.bpbynumber: if bp: bp.bpprint().

    def set_break(self, filename, lineno, temporary=0, cond = None):
        filename = self.canonic(filename)
        import linecache # Import as late as possible
        line = linecache.getline(filename, lineno)
        if not line:
            return 'Line %s:%d does not exist' % (filename,
                                   lineno)
        if not self.breaks.has_key(filename):
            self.breaks[filename] = []
        list = self.breaks[filename]
        if not lineno in list:
            list.append(lineno)
        bp = Breakpoint(filename, lineno, temporary, cond)

    def clear_break(self, filename, lineno):
        filename = self.canonic(filename)
        if not self.breaks.has_key(filename):
            return 'There are no breakpoints in %s' % filename
        if lineno not in self.breaks[filename]:
            return 'There is no breakpoint at %s:%d' % (filename,
                                    lineno)
        # If there's only one bp in the list for that file,line
        # pair, then remove the breaks entry
        for bp in Breakpoint.bplist[filename, lineno][:]:
            bp.deleteMe()
        if not Breakpoint.bplist.has_key((filename, lineno)):
            self.breaks[filename].remove(lineno)
        if not self.breaks[filename]:
            del self.breaks[filename]

    def clear_bpbynumber(self, arg):
        try:
            number = int(arg)
        except:
            return 'Non-numeric breakpoint number (%s)' % arg
        try:
            bp = Breakpoint.bpbynumber[number]
        except IndexError:
            return 'Breakpoint number (%d) out of range' % number
        if not bp:
            return 'Breakpoint (%d) already deleted' % number
        self.clear_break(bp.file, bp.line)

    def clear_all_file_breaks(self, filename):
        filename = self.canonic(filename)
        if not self.breaks.has_key(filename):
            return 'There are no breakpoints in %s' % filename
        for line in self.breaks[filename]:
            blist = Breakpoint.bplist[filename, line]
            for bp in blist:
                bp.deleteMe()
        del self.breaks[filename]

    def clear_all_breaks(self):
        if not self.breaks:
            return 'There are no breakpoints'
        for bp in Breakpoint.bpbynumber:
            if bp:
                bp.deleteMe()
        self.breaks = {}

    def get_break(self, filename, lineno):
        filename = self.canonic(filename)
        return self.breaks.has_key(filename) and \
            lineno in self.breaks[filename]

    def get_breaks(self, filename, lineno):
        filename = self.canonic(filename)
        return self.breaks.has_key(filename) and \
            lineno in self.breaks[filename] and \
            Breakpoint.bplist[filename, lineno] or []

    def get_file_breaks(self, filename):
        filename = self.canonic(filename)
        if self.breaks.has_key(filename):
            return self.breaks[filename]
        else: