pdb.py

mallet是自然语言处理、机器学习领域的一个开源项目。

#! /usr/bin/env python

"""A Python debugger."""

# (See pdb.doc for documentation.)

import sys
import linecache
import cmd
import bdb
from repr import Repr
import os
import re

# Create a custom safe Repr instance and increase its maxstring.
# The default of 30 truncates error messages too easily.
_repr = Repr()
_repr.maxstring = 200
_saferepr = _repr.repr

__all__ = ["run", "pm", "Pdb", "runeval", "runctx", "runcall", "set_trace",
           "post_mortem", "help"]

def find_function(funcname, filename):
    cre = re.compile(r'def\s+%s\s*[(]' % funcname)
    try:
        fp = open(filename)
    except IOError:
        return None
    # consumer of this info expects the first line to be 1
    lineno = 1
    answer = None
    while 1:
        line = fp.readline()
        if line == '':
            break
        if cre.match(line):
            answer = funcname, filename, lineno
            break
        lineno = lineno + 1
    fp.close()
    return answer


# Interaction prompt line will separate file and call info from code
# text using value of line_prefix string.  A newline and arrow may
# be to your liking.  You can set it once pdb is imported using the
# command "pdb.line_prefix = '\n% '".
# line_prefix = ': '    # Use this to get the old situation back
line_prefix = '\n-> '   # Probably a better default

class Pdb(bdb.Bdb, cmd.Cmd):

    def __init__(self):
        bdb.Bdb.__init__(self)
        cmd.Cmd.__init__(self)
        self.prompt = '(Pdb) '
        self.aliases = {}
        # Try to load readline if it exists
        try:
            import readline
        except ImportError:
            pass

        # Read $HOME/.pdbrc and ./.pdbrc
        self.rcLines = []
        if os.environ.has_key('HOME'):
            envHome = os.environ['HOME']
            try:
                rcFile = open(os.path.join(envHome, ".pdbrc"))
            except IOError:
                pass
            else:
                for line in rcFile.readlines():
                    self.rcLines.append(line)
                rcFile.close()
        try:
            rcFile = open(".pdbrc")
        except IOError:
            pass
        else:
            for line in rcFile.readlines():
                self.rcLines.append(line)
            rcFile.close()

    def reset(self):
        bdb.Bdb.reset(self)
        self.forget()

    def forget(self):
        self.lineno = None
        self.stack = []
        self.curindex = 0
        self.curframe = None

    def setup(self, f, t):
        self.forget()
        self.stack, self.curindex = self.get_stack(f, t)
        self.curframe = self.stack[self.curindex][0]
        self.execRcLines()

    # Can be executed earlier than 'setup' if desired
    def execRcLines(self):
        if self.rcLines:
            # Make local copy because of recursion
            rcLines = self.rcLines
            # executed only once
            self.rcLines = []
            for line in rcLines:
                line = line[:-1]
                if len (line) > 0 and line[0] != '#':
                    self.onecmd (line)

    # Override Bdb methods (except user_call, for now)

    def user_line(self, frame):
        """This function is called when we stop or break at this line."""
        self.interaction(frame, None)

    def user_return(self, frame, return_value):
        """This function is called when a return trap is set here."""
        frame.f_locals['__return__'] = return_value
        print '--Return--'
        self.interaction(frame, None)

    def user_exception(self, frame, (exc_type, exc_value, exc_traceback)):
        """This function is called if an exception occurs,
        but only if we are to stop at or just below this level."""
        frame.f_locals['__exception__'] = exc_type, exc_value
        if type(exc_type) == type(''):
            exc_type_name = exc_type
        else: exc_type_name = exc_type.__name__
        print exc_type_name + ':', _saferepr(exc_value)
        self.interaction(frame, exc_traceback)

    # General interaction function

    def interaction(self, frame, traceback):
        self.setup(frame, traceback)
        self.print_stack_entry(self.stack[self.curindex])
        self.cmdloop()
        self.forget()

    def default(self, line):
        if line[:1] == '!': line = line[1:]
        locals = self.curframe.f_locals
        globals = self.curframe.f_globals
        try:
            code = compile(line + '\n', '<stdin>', 'single')
            exec code in globals, locals
        except:
            t, v = sys.exc_info()[:2]
            if type(t) == type(''):
                exc_type_name = t
            else: exc_type_name = t.__name__
            print '***', exc_type_name + ':', v

    def precmd(self, line):
        """Handle alias expansion and ';;' separator."""
        if not line.strip():
            return line
        args = line.split()
        while self.aliases.has_key(args[0]):
            line = self.aliases[args[0]]
            ii = 1
            for tmpArg in args[1:]:
                line = line.replace("%" + str(ii),
                                      tmpArg)
                ii = ii + 1
            line = line.replace("%*", ' '.join(args[1:]))
            args = line.split()
        # split into ';;' separated commands
        # unless it's an alias command
        if args[0] != 'alias':
            marker = line.find(';;')
            if marker >= 0:
                # queue up everything after marker
                next = line[marker+2:].lstrip()
                self.cmdqueue.append(next)
                line = line[:marker].rstrip()
        return line

    # Command definitions, called by cmdloop()
    # The argument is the remaining string on the command line
    # Return true to exit from the command loop

    do_h = cmd.Cmd.do_help

    def do_break(self, arg, temporary = 0):
        # break [ ([filename:]lineno | function) [, "condition"] ]
        if not arg:
            if self.breaks:  # There's at least one
                print "Num Type         Disp Enb   Where"
                for bp in bdb.Breakpoint.bpbynumber:
                    if bp:
                        bp.bpprint()
            return
        # parse arguments; comma has lowest precedence
        # and cannot occur in filename
        filename = None
        lineno = None
        cond = None
        comma = arg.find(',')
        if comma > 0:
            # parse stuff after comma: "condition"
            cond = arg[comma+1:].lstrip()
            arg = arg[:comma].rstrip()
        # parse stuff before comma: [filename:]lineno | function
        colon = arg.rfind(':')
        if colon >= 0:
            filename = arg[:colon].rstrip()
            f = self.lookupmodule(filename)
            if not f:
                print '*** ', `filename`,
                print 'not found from sys.path'
                return
            else:
                filename = f
            arg = arg[colon+1:].lstrip()
            try:
                lineno = int(arg)
            except ValueError, msg:
                print '*** Bad lineno:', arg
                return
        else:
            # no colon; can be lineno or function
            try:
                lineno = int(arg)
            except ValueError:
                try:
                    func = eval(arg,
                                self.curframe.f_globals,
                                self.curframe.f_locals)
                except:
                    func = arg
                try:
                    if hasattr(func, 'im_func'):
                        func = func.im_func
                    code = func.func_code
                    lineno = code.co_firstlineno
                    filename = code.co_filename
                except:
                    # last thing to try
                    (ok, filename, ln) = self.lineinfo(arg)
                    if not ok:
                        print '*** The specified object',
                        print `arg`,
                        print 'is not a function'
                        print ('or was not found '
                               'along sys.path.')
                        return
                    lineno = int(ln)
        if not filename:
            filename = self.defaultFile()
        # Check for reasonable breakpoint
        line = self.checkline(filename, lineno)
        if line:
            # now set the break point
            err = self.set_break(filename, line, temporary, cond)
            if err: print '***', err
            else:
                bp = self.get_breaks(filename, line)[-1]
                print "Breakpoint %d at %s:%d" % (bp.number,
                                                  bp.file,
                                                  bp.line)

    # To be overridden in derived debuggers
    def defaultFile(self):
        """Produce a reasonable default."""
        filename = self.curframe.f_code.co_filename
        if filename == '<string>' and mainpyfile:
            filename = mainpyfile
        return filename

    do_b = do_break

    def do_tbreak(self, arg):
        self.do_break(arg, 1)

    def lineinfo(self, identifier):
        failed = (None, None, None)
        # Input is identifier, may be in single quotes
        idstring = identifier.split("'")
        if len(idstring) == 1:
            # not in single quotes
            id = idstring[0].strip()
        elif len(idstring) == 3:
            # quoted
            id = idstring[1].strip()
        else:
            return failed
        if id == '': return failed
        parts = id.split('.')
        # Protection for derived debuggers
        if parts[0] == 'self':
            del parts[0]
            if len(parts) == 0:
                return failed
        # Best first guess at file to look at
        fname = self.defaultFile()
        if len(parts) == 1:
            item = parts[0]
        else:
            # More than one part.
            # First is module, second is method/class
            f = self.lookupmodule(parts[0])
            if f:
                fname = f
            item = parts[1]
        answer = find_function(item, fname)
        return answer or failed

    def checkline(self, filename, lineno):
        """Return line number of first line at or after input
        argument such that if the input points to a 'def', the
        returned line number is the first
        non-blank/non-comment line to follow.  If the input
        points to a blank or comment line, return 0.  At end
        of file, also return 0."""

        line = linecache.getline(filename, lineno)
        if not line:
            print 'End of file'
            return 0
        line = line.strip()
        # Don't allow setting breakpoint at a blank line
        if ( not line or (line[0] == '#') or