405 lines
15 KiB
Python
405 lines
15 KiB
Python
"""A generic class to build line-oriented command interpreters.
|
|
|
|
Interpreters constructed with this class obey the following conventions:
|
|
|
|
1. End of file on input is processed as the command 'EOF'.
|
|
2. A command is parsed out of each line by collecting the prefix composed
|
|
of characters in the identchars member.
|
|
3. A command `foo' is dispatched to a method 'do_foo()'; the do_ method
|
|
is passed a single argument consisting of the remainder of the line.
|
|
4. Typing an empty line repeats the last command. (Actually, it calls the
|
|
method `emptyline', which may be overridden in a subclass.)
|
|
5. There is a predefined `help' method. Given an argument `topic', it
|
|
calls the command `help_topic'. With no arguments, it lists all topics
|
|
with defined help_ functions, broken into up to three topics; documented
|
|
commands, miscellaneous help topics, and undocumented commands.
|
|
6. The command '?' is a synonym for `help'. The command '!' is a synonym
|
|
for `shell', if a do_shell method exists.
|
|
7. If completion is enabled, completing commands will be done automatically,
|
|
and completing of commands args is done by calling complete_foo() with
|
|
arguments text, line, begidx, endidx. text is string we are matching
|
|
against, all returned matches must begin with it. line is the current
|
|
input line (lstripped), begidx and endidx are the beginning and end
|
|
indexes of the text being matched, which could be used to provide
|
|
different completion depending upon which position the argument is in.
|
|
|
|
The `default' method may be overridden to intercept commands for which there
|
|
is no do_ method.
|
|
|
|
The `completedefault' method may be overridden to intercept completions for
|
|
commands that have no complete_ method.
|
|
|
|
The data member `self.ruler' sets the character used to draw separator lines
|
|
in the help messages. If empty, no ruler line is drawn. It defaults to "=".
|
|
|
|
If the value of `self.intro' is nonempty when the cmdloop method is called,
|
|
it is printed out on interpreter startup. This value may be overridden
|
|
via an optional argument to the cmdloop() method.
|
|
|
|
The data members `self.doc_header', `self.misc_header', and
|
|
`self.undoc_header' set the headers used for the help function's
|
|
listings of documented functions, miscellaneous topics, and undocumented
|
|
functions respectively.
|
|
|
|
These interpreters use raw_input; thus, if the readline module is loaded,
|
|
they automatically support Emacs-like command history and editing features.
|
|
"""
|
|
|
|
import string
|
|
|
|
__all__ = ["Cmd"]
|
|
|
|
PROMPT = '(Cmd) '
|
|
IDENTCHARS = string.ascii_letters + string.digits + '_'
|
|
|
|
class Cmd:
|
|
"""A simple framework for writing line-oriented command interpreters.
|
|
|
|
These are often useful for test harnesses, administrative tools, and
|
|
prototypes that will later be wrapped in a more sophisticated interface.
|
|
|
|
A Cmd instance or subclass instance is a line-oriented interpreter
|
|
framework. There is no good reason to instantiate Cmd itself; rather,
|
|
it's useful as a superclass of an interpreter class you define yourself
|
|
in order to inherit Cmd's methods and encapsulate action methods.
|
|
|
|
"""
|
|
prompt = PROMPT
|
|
identchars = IDENTCHARS
|
|
ruler = '='
|
|
lastcmd = ''
|
|
intro = None
|
|
doc_leader = ""
|
|
doc_header = "Documented commands (type help <topic>):"
|
|
misc_header = "Miscellaneous help topics:"
|
|
undoc_header = "Undocumented commands:"
|
|
nohelp = "*** No help on %s"
|
|
use_rawinput = 1
|
|
|
|
def __init__(self, completekey='tab', stdin=None, stdout=None):
|
|
"""Instantiate a line-oriented interpreter framework.
|
|
|
|
The optional argument 'completekey' is the readline name of a
|
|
completion key; it defaults to the Tab key. If completekey is
|
|
not None and the readline module is available, command completion
|
|
is done automatically. The optional arguments stdin and stdout
|
|
specify alternate input and output file objects; if not specified,
|
|
sys.stdin and sys.stdout are used.
|
|
|
|
"""
|
|
import sys
|
|
if stdin is not None:
|
|
self.stdin = stdin
|
|
else:
|
|
self.stdin = sys.stdin
|
|
if stdout is not None:
|
|
self.stdout = stdout
|
|
else:
|
|
self.stdout = sys.stdout
|
|
self.cmdqueue = []
|
|
self.completekey = completekey
|
|
|
|
def cmdloop(self, intro=None):
|
|
"""Repeatedly issue a prompt, accept input, parse an initial prefix
|
|
off the received input, and dispatch to action methods, passing them
|
|
the remainder of the line as argument.
|
|
|
|
"""
|
|
|
|
self.preloop()
|
|
if self.use_rawinput and self.completekey:
|
|
try:
|
|
import readline
|
|
self.old_completer = readline.get_completer()
|
|
readline.set_completer(self.complete)
|
|
readline.parse_and_bind(self.completekey+": complete")
|
|
except ImportError:
|
|
pass
|
|
try:
|
|
if intro is not None:
|
|
self.intro = intro
|
|
if self.intro:
|
|
self.stdout.write(str(self.intro)+"\n")
|
|
stop = None
|
|
while not stop:
|
|
if self.cmdqueue:
|
|
line = self.cmdqueue.pop(0)
|
|
else:
|
|
if self.use_rawinput:
|
|
try:
|
|
line = raw_input(self.prompt)
|
|
except EOFError:
|
|
line = 'EOF'
|
|
else:
|
|
self.stdout.write(self.prompt)
|
|
self.stdout.flush()
|
|
line = self.stdin.readline()
|
|
if not len(line):
|
|
line = 'EOF'
|
|
else:
|
|
line = line[:-1] # chop \n
|
|
line = self.precmd(line)
|
|
stop = self.onecmd(line)
|
|
stop = self.postcmd(stop, line)
|
|
self.postloop()
|
|
finally:
|
|
if self.use_rawinput and self.completekey:
|
|
try:
|
|
import readline
|
|
readline.set_completer(self.old_completer)
|
|
except ImportError:
|
|
pass
|
|
|
|
|
|
def precmd(self, line):
|
|
"""Hook method executed just before the command line is
|
|
interpreted, but after the input prompt is generated and issued.
|
|
|
|
"""
|
|
return line
|
|
|
|
def postcmd(self, stop, line):
|
|
"""Hook method executed just after a command dispatch is finished."""
|
|
return stop
|
|
|
|
def preloop(self):
|
|
"""Hook method executed once when the cmdloop() method is called."""
|
|
pass
|
|
|
|
def postloop(self):
|
|
"""Hook method executed once when the cmdloop() method is about to
|
|
return.
|
|
|
|
"""
|
|
pass
|
|
|
|
def parseline(self, line):
|
|
"""Parse the line into a command name and a string containing
|
|
the arguments. Returns a tuple containing (command, args, line).
|
|
'command' and 'args' may be None if the line couldn't be parsed.
|
|
"""
|
|
line = line.strip()
|
|
if not line:
|
|
return None, None, line
|
|
elif line[0] == '?':
|
|
line = 'help ' + line[1:]
|
|
elif line[0] == '!':
|
|
if hasattr(self, 'do_shell'):
|
|
line = 'shell ' + line[1:]
|
|
else:
|
|
return None, None, line
|
|
i, n = 0, len(line)
|
|
while i < n and line[i] in self.identchars: i = i+1
|
|
cmd, arg = line[:i], line[i:].strip()
|
|
return cmd, arg, line
|
|
|
|
def onecmd(self, line):
|
|
"""Interpret the argument as though it had been typed in response
|
|
to the prompt.
|
|
|
|
This may be overridden, but should not normally need to be;
|
|
see the precmd() and postcmd() methods for useful execution hooks.
|
|
The return value is a flag indicating whether interpretation of
|
|
commands by the interpreter should stop.
|
|
|
|
"""
|
|
cmd, arg, line = self.parseline(line)
|
|
if not line:
|
|
return self.emptyline()
|
|
if cmd is None:
|
|
return self.default(line)
|
|
self.lastcmd = line
|
|
if cmd == '':
|
|
return self.default(line)
|
|
else:
|
|
try:
|
|
func = getattr(self, 'do_' + cmd)
|
|
except AttributeError:
|
|
return self.default(line)
|
|
return func(arg)
|
|
|
|
def emptyline(self):
|
|
"""Called when an empty line is entered in response to the prompt.
|
|
|
|
If this method is not overridden, it repeats the last nonempty
|
|
command entered.
|
|
|
|
"""
|
|
if self.lastcmd:
|
|
return self.onecmd(self.lastcmd)
|
|
|
|
def default(self, line):
|
|
"""Called on an input line when the command prefix is not recognized.
|
|
|
|
If this method is not overridden, it prints an error message and
|
|
returns.
|
|
|
|
"""
|
|
self.stdout.write('*** Unknown syntax: %s\n'%line)
|
|
|
|
def completedefault(self, *ignored):
|
|
"""Method called to complete an input line when no command-specific
|
|
complete_*() method is available.
|
|
|
|
By default, it returns an empty list.
|
|
|
|
"""
|
|
return []
|
|
|
|
def completenames(self, text, *ignored):
|
|
dotext = 'do_'+text
|
|
return [a[3:] for a in self.get_names() if a.startswith(dotext)]
|
|
|
|
def complete(self, text, state):
|
|
"""Return the next possible completion for 'text'.
|
|
|
|
If a command has not been entered, then complete against command list.
|
|
Otherwise try to call complete_<command> to get list of completions.
|
|
"""
|
|
if state == 0:
|
|
import readline
|
|
origline = readline.get_line_buffer()
|
|
line = origline.lstrip()
|
|
stripped = len(origline) - len(line)
|
|
begidx = readline.get_begidx() - stripped
|
|
endidx = readline.get_endidx() - stripped
|
|
if begidx>0:
|
|
cmd, args, foo = self.parseline(line)
|
|
if cmd == '':
|
|
compfunc = self.completedefault
|
|
else:
|
|
try:
|
|
compfunc = getattr(self, 'complete_' + cmd)
|
|
except AttributeError:
|
|
compfunc = self.completedefault
|
|
else:
|
|
compfunc = self.completenames
|
|
self.completion_matches = compfunc(text, line, begidx, endidx)
|
|
try:
|
|
return self.completion_matches[state]
|
|
except IndexError:
|
|
return None
|
|
|
|
def get_names(self):
|
|
# Inheritance says we have to look in class and
|
|
# base classes; order is not important.
|
|
names = []
|
|
classes = [self.__class__]
|
|
while classes:
|
|
aclass = classes.pop(0)
|
|
if aclass.__bases__:
|
|
classes = classes + list(aclass.__bases__)
|
|
names = names + dir(aclass)
|
|
return names
|
|
|
|
def complete_help(self, *args):
|
|
return self.completenames(*args)
|
|
|
|
def do_help(self, arg):
|
|
if arg:
|
|
# XXX check arg syntax
|
|
try:
|
|
func = getattr(self, 'help_' + arg)
|
|
except AttributeError:
|
|
try:
|
|
doc=getattr(self, 'do_' + arg).__doc__
|
|
if doc:
|
|
self.stdout.write("%s\n"%str(doc))
|
|
return
|
|
except AttributeError:
|
|
pass
|
|
self.stdout.write("%s\n"%str(self.nohelp % (arg,)))
|
|
return
|
|
func()
|
|
else:
|
|
names = self.get_names()
|
|
cmds_doc = []
|
|
cmds_undoc = []
|
|
help = {}
|
|
for name in names:
|
|
if name[:5] == 'help_':
|
|
help[name[5:]]=1
|
|
names.sort()
|
|
# There can be duplicates if routines overridden
|
|
prevname = ''
|
|
for name in names:
|
|
if name[:3] == 'do_':
|
|
if name == prevname:
|
|
continue
|
|
prevname = name
|
|
cmd=name[3:]
|
|
if cmd in help:
|
|
cmds_doc.append(cmd)
|
|
del help[cmd]
|
|
elif getattr(self, name).__doc__:
|
|
cmds_doc.append(cmd)
|
|
else:
|
|
cmds_undoc.append(cmd)
|
|
self.stdout.write("%s\n"%str(self.doc_leader))
|
|
self.print_topics(self.doc_header, cmds_doc, 15,80)
|
|
self.print_topics(self.misc_header, help.keys(),15,80)
|
|
self.print_topics(self.undoc_header, cmds_undoc, 15,80)
|
|
|
|
def print_topics(self, header, cmds, cmdlen, maxcol):
|
|
if cmds:
|
|
self.stdout.write("%s\n"%str(header))
|
|
if self.ruler:
|
|
self.stdout.write("%s\n"%str(self.ruler * len(header)))
|
|
self.columnize(cmds, maxcol-1)
|
|
self.stdout.write("\n")
|
|
|
|
def columnize(self, list, displaywidth=80):
|
|
"""Display a list of strings as a compact set of columns.
|
|
|
|
Each column is only as wide as necessary.
|
|
Columns are separated by two spaces (one was not legible enough).
|
|
"""
|
|
if not list:
|
|
self.stdout.write("<empty>\n")
|
|
return
|
|
nonstrings = [i for i in range(len(list))
|
|
if not isinstance(list[i], str)]
|
|
if nonstrings:
|
|
raise TypeError, ("list[i] not a string for i in %s" %
|
|
", ".join(map(str, nonstrings)))
|
|
size = len(list)
|
|
if size == 1:
|
|
self.stdout.write('%s\n'%str(list[0]))
|
|
return
|
|
# Try every row count from 1 upwards
|
|
for nrows in range(1, len(list)):
|
|
ncols = (size+nrows-1) // nrows
|
|
colwidths = []
|
|
totwidth = -2
|
|
for col in range(ncols):
|
|
colwidth = 0
|
|
for row in range(nrows):
|
|
i = row + nrows*col
|
|
if i >= size:
|
|
break
|
|
x = list[i]
|
|
colwidth = max(colwidth, len(x))
|
|
colwidths.append(colwidth)
|
|
totwidth += colwidth + 2
|
|
if totwidth > displaywidth:
|
|
break
|
|
if totwidth <= displaywidth:
|
|
break
|
|
else:
|
|
nrows = len(list)
|
|
ncols = 1
|
|
colwidths = [0]
|
|
for row in range(nrows):
|
|
texts = []
|
|
for col in range(ncols):
|
|
i = row + nrows*col
|
|
if i >= size:
|
|
x = ""
|
|
else:
|
|
x = list[i]
|
|
texts.append(x)
|
|
while texts and not texts[-1]:
|
|
del texts[-1]
|
|
for col in range(len(texts)):
|
|
texts[col] = texts[col].ljust(colwidths[col])
|
|
self.stdout.write("%s\n"%str(" ".join(texts)))
|