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# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
import argparse
import shlex
import sys
from operator import itemgetter
from mach.command_util import suggest_command
from .base import NoCommandError, UnknownCommandError, UnrecognizedArgumentError
class CommandFormatter(argparse.HelpFormatter):
"""Custom formatter to format just a subcommand."""
def add_usage(self, *args):
pass
class CommandAction(argparse.Action):
"""An argparse action that handles mach commands.
This class is essentially a reimplementation of argparse's sub-parsers
feature. We first tried to use sub-parsers. However, they were missing
The way this works involves light magic and a partial understanding of how
argparse works.
Arguments registered with an argparse.ArgumentParser have an action
associated with them. An action is essentially a class that when called
does something with the encountered argument(s). This class is one of those
action classes.
An instance of this class is created doing something like:
parser.add_argument('command', action=CommandAction, registrar=r)
Note that a mach.registrar.Registrar instance is passed in. The Registrar
holds information on all the mach commands that have been registered.
When this argument is registered with the ArgumentParser, an instance of
this class is instantiated. One of the subtle but important things it does
is tell the argument parser that it's interested in *all* of the remaining
program arguments. So, when the ArgumentParser calls this action, we will
receive the command name plus all of its arguments.
For more, read the docs in __call__.
"""
def __init__(
self,
option_strings,
dest,
required=True,
default=None,
registrar=None,
context=None,
):
# A proper API would have **kwargs here. However, since we are a little
# hacky, we intentionally omit it as a way of detecting potentially
# breaking changes with argparse's implementation.
#
# In a similar vein, default is passed in but is not needed, so we drop
# it.
argparse.Action.__init__(
self,
option_strings,
dest,
required=required,
help=argparse.SUPPRESS,
nargs=argparse.REMAINDER,
)
self._mach_registrar = registrar
self._context = context
def __call__(self, parser, namespace, values, option_string=None):
"""This is called when the ArgumentParser has reached our arguments.
Since we always register ourselves with nargs=argparse.REMAINDER,
values should be a list of remaining arguments to parse. The first
argument should be the name of the command to invoke and all remaining
arguments are arguments for that command.
The gist of the flow is that we look at the command being invoked. If
it's *help*, we handle that specially (because argparse's default help
handler isn't satisfactory). Else, we create a new, independent
ArgumentParser instance for just the invoked command (based on the
information contained in the command registrar) and feed the arguments
into that parser. We then merge the results with the main
ArgumentParser.
"""
if namespace.help:
# -h or --help is in the global arguments.
self._handle_main_help(parser, namespace.verbose)
sys.exit(0)
elif values:
command = values[0].lower()
args = values[1:]
if command == "help":
if args and args[0] not in ["-h", "--help"]:
# Make sure args[0] is indeed a command.
self._handle_command_help(parser, args[0], args)
else:
self._handle_main_help(parser, namespace.verbose)
sys.exit(0)
elif "-h" in args or "--help" in args:
# -h or --help is in the command arguments.
if "--" in args:
# -- is in command arguments
if (
"-h" in args[: args.index("--")]
or "--help" in args[: args.index("--")]
):
# Honor -h or --help only if it appears before --
self._handle_command_help(parser, command, args)
sys.exit(0)
else:
self._handle_command_help(parser, command, args)
sys.exit(0)
else:
raise NoCommandError(namespace)
# First see if the this is a user-defined alias
if command in self._context.settings.alias:
alias = self._context.settings.alias[command]
defaults = shlex.split(alias)
command = defaults.pop(0)
args = defaults + args
if command not in self._mach_registrar.command_handlers:
# Try to find similar commands, may raise UnknownCommandError.
command = suggest_command(command)
handler = self._mach_registrar.command_handlers.get(command)
prog = command
usage = "%(prog)s [global arguments] " + command + " [command arguments]"
subcommand = None
# If there are sub-commands, parse the intent out immediately.
if handler.subcommand_handlers and args:
# mach <command> help <subcommand>
if set(args[: args.index("--")] if "--" in args else args).intersection(
("help", "--help")
):
self._handle_subcommand_help(parser, handler, args)
sys.exit(0)
# mach <command> <subcommand> ...
elif args[0] in handler.subcommand_handlers:
subcommand = args[0]
handler = handler.subcommand_handlers[subcommand]
prog = prog + " " + subcommand
usage = (
"%(prog)s [global arguments] "
+ command
+ " "
+ subcommand
+ " [command arguments]"
)
args.pop(0)
# We create a new parser, populate it with the command's arguments,
# then feed all remaining arguments to it, merging the results
# with ourselves. This is essentially what argparse subparsers
# do.
parser_args = {
"add_help": False,
"usage": usage,
}
remainder = None
if handler.parser:
subparser = handler.parser
subparser.context = self._context
subparser.prog = subparser.prog + " " + prog
for arg in subparser._actions[:]:
if arg.nargs == argparse.REMAINDER:
subparser._actions.remove(arg)
remainder = (
(arg.dest,),
{"default": arg.default, "nargs": arg.nargs, "help": arg.help},
)
else:
subparser = argparse.ArgumentParser(**parser_args)
for arg in handler.arguments:
# Remove our group keyword; it's not needed here.
group_name = arg[1].get("group")
if group_name:
del arg[1]["group"]
if arg[1].get("nargs") == argparse.REMAINDER:
# parse_known_args expects all argparse.REMAINDER ('...')
# arguments to be all stuck together. Instead, we want them to
# pick any extra argument, wherever they are.
# Assume a limited CommandArgument for those arguments.
assert len(arg[0]) == 1
assert all(k in ("default", "nargs", "help", "metavar") for k in arg[1])
remainder = arg
else:
subparser.add_argument(*arg[0], **arg[1])
# We define the command information on the main parser result so as to
# not interfere with arguments passed to the command.
setattr(namespace, "mach_handler", handler)
setattr(namespace, "command", command)
setattr(namespace, "subcommand", subcommand)
command_namespace, extra = subparser.parse_known_args(args)
setattr(namespace, "command_args", command_namespace)
if remainder:
(name,), options = remainder
# parse_known_args usefully puts all arguments after '--' in
# extra, but also puts '--' there. We don't want to pass it down
# to the command handler. Note that if multiple '--' are on the
# command line, only the first one is removed, so that subsequent
# ones are passed down.
if "--" in extra:
extra.remove("--")
# Commands with argparse.REMAINDER arguments used to force the
# other arguments to be '+' prefixed. If a user now passes such
# an argument, if will silently end up in extra. So, check if any
# of the allowed arguments appear in a '+' prefixed form, and error
# out if that's the case.
for args, _ in handler.arguments:
for arg in args:
arg = arg.replace("-", "+", 1)
if arg in extra:
raise UnrecognizedArgumentError(command, [arg])
if extra:
setattr(command_namespace, name, extra)
else:
setattr(command_namespace, name, options.get("default", []))
elif extra:
raise UnrecognizedArgumentError(command, extra)
def _handle_main_help(self, parser, verbose):
# Since we don't need full sub-parser support for the main help output,
# we create groups in the ArgumentParser and populate each group with
# arguments corresponding to command names. This has the side-effect
# that argparse renders it nicely.
r = self._mach_registrar
disabled_commands = []
cats = [(k, v[2]) for k, v in r.categories.items()]
sorted_cats = sorted(cats, key=itemgetter(1), reverse=True)
for category, priority in sorted_cats:
group = None
for command in sorted(r.commands_by_category[category]):
handler = r.command_handlers[command]
# Instantiate a handler class to see if it should be filtered
# out for the current context or not. Condition functions can be
# applied to the command's decorator.
if handler.conditions:
instance = handler.create_instance(
self._context, handler.virtualenv_name
)
is_filtered = False
for c in handler.conditions:
if not c(instance):
is_filtered = True
break
if is_filtered:
description = handler.description
disabled_command = {
"command": command,
"description": description,
}
disabled_commands.append(disabled_command)
continue
if group is None:
title, description, _priority = r.categories[category]
group = parser.add_argument_group(title, description)
description = handler.description
group.add_argument(command, help=description, action="store_true")
if disabled_commands and "disabled" in r.categories:
title, description, _priority = r.categories["disabled"]
group = parser.add_argument_group(title, description)
if verbose:
for c in disabled_commands:
group.add_argument(
c["command"], help=c["description"], action="store_true"
)
parser.print_help()
def _populate_command_group(self, parser, handler, group):
extra_groups = {}
for group_name in handler.argument_group_names:
group_full_name = "Command Arguments for " + group_name
extra_groups[group_name] = parser.add_argument_group(group_full_name)
for arg in handler.arguments:
# Apply our group keyword.
group_name = arg[1].get("group")
if group_name:
del arg[1]["group"]
group = extra_groups[group_name]
group.add_argument(*arg[0], **arg[1])
def _get_command_arguments_help(self, handler):
# This code is worth explaining. Because we are doing funky things with
# argument registration to allow the same option in both global and
# command arguments, we can't simply put all arguments on the same
# parser instance because argparse would complain. We can't register an
# argparse subparser here because it won't properly show help for
# global arguments. So, we employ a strategy similar to command
# execution where we construct a 2nd, independent ArgumentParser for
# just the command data then supplement the main help's output with
# this 2nd parser's. We use a custom formatter class to ignore some of
# the help output.
parser_args = {
"formatter_class": CommandFormatter,
"add_help": False,
}
if handler.parser:
c_parser = handler.parser
c_parser.context = self._context
c_parser.formatter_class = NoUsageFormatter
# Accessing _action_groups is a bit shady. We are highly dependent
# on the argparse implementation not changing. We fail fast to
# detect upstream changes so we can intelligently react to them.
group = c_parser._action_groups[1]
# By default argparse adds two groups called "positional arguments"
# and "optional arguments". We want to rename these to reflect standard
# mach terminology.
c_parser._action_groups[0].title = "Command Parameters"
c_parser._action_groups[1].title = "Command Arguments"
if not handler.description:
handler.description = c_parser.description
c_parser.description = None
else:
c_parser = argparse.ArgumentParser(**parser_args)
group = c_parser.add_argument_group("Command Arguments")
self._populate_command_group(c_parser, handler, group)
return c_parser
def _handle_command_help(self, parser, command, args):
handler = self._mach_registrar.command_handlers.get(command)
if not handler:
raise UnknownCommandError(command, "query")
if handler.subcommand_handlers:
self._handle_subcommand_help(parser, handler, args)
return
c_parser = self._get_command_arguments_help(handler)
# Set the long help of the command to the docstring (if present) or
# the command decorator description argument (if present).
if handler.docstring:
parser.description = format_docstring(handler.docstring)
elif handler.description:
parser.description = handler.description
parser.usage = "%(prog)s [global arguments] " + command + " [command arguments]"
# This is needed to preserve line endings in the description field,
# which may be populated from a docstring.
parser.formatter_class = argparse.RawDescriptionHelpFormatter
parser.print_help()
print("")
c_parser.print_help()
def _handle_subcommand_main_help(self, parser, handler):
parser.usage = (
"%(prog)s [global arguments] "
+ handler.name
+ " subcommand [subcommand arguments]"
)
group = parser.add_argument_group("Sub Commands")
def by_decl_order(item):
return item[1].decl_order
def by_name(item):
return item[1].subcommand
subhandlers = handler.subcommand_handlers.items()
for subcommand, subhandler in sorted(
subhandlers,
key=by_decl_order if handler.order == "declaration" else by_name,
):
group.add_argument(
subcommand, help=subhandler.description, action="store_true"
)
if handler.docstring:
parser.description = format_docstring(handler.docstring)
c_parser = self._get_command_arguments_help(handler)
parser.formatter_class = argparse.RawDescriptionHelpFormatter
parser.print_help()
print("")
c_parser.print_help()
def _handle_subcommand_help(self, parser, handler, args):
subcommand = set(args).intersection(list(handler.subcommand_handlers.keys()))
if not subcommand:
return self._handle_subcommand_main_help(parser, handler)
subcommand = subcommand.pop()
subhandler = handler.subcommand_handlers[subcommand]
# Initialize the parser if necessary
subhandler.parser
c_parser = subhandler.parser or argparse.ArgumentParser(add_help=False)
c_parser.formatter_class = CommandFormatter
group = c_parser.add_argument_group("Sub Command Arguments")
self._populate_command_group(c_parser, subhandler, group)
if subhandler.docstring:
parser.description = format_docstring(subhandler.docstring)
parser.formatter_class = argparse.RawDescriptionHelpFormatter
parser.usage = (
"%(prog)s [global arguments] "
+ handler.name
+ " "
+ subcommand
+ " [command arguments]"
)
parser.print_help()
print("")
c_parser.print_help()
class NoUsageFormatter(argparse.HelpFormatter):
def _format_usage(self, *args, **kwargs):
return ""
def format_docstring(docstring):
"""Format a raw docstring into something suitable for presentation.
This function is based on the example function in PEP-0257.
"""
if not docstring:
return ""
lines = docstring.expandtabs().splitlines()
indent = sys.maxsize
for line in lines[1:]:
stripped = line.lstrip()
if stripped:
indent = min(indent, len(line) - len(stripped))
trimmed = [lines[0].strip()]
if indent < sys.maxsize:
for line in lines[1:]:
trimmed.append(line[indent:].rstrip())
while trimmed and not trimmed[-1]:
trimmed.pop()
while trimmed and not trimmed[0]:
trimmed.pop(0)
return "\n".join(trimmed)