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1# Copyright (c) 2009 Google Inc. All rights reserved.
2# Copyright (c) 2009 Apple Inc. All rights reserved.
3#
4# Redistribution and use in source and binary forms, with or without
5# modification, are permitted provided that the following conditions are
6# met:
7#
8#     * Redistributions of source code must retain the above copyright
9# notice, this list of conditions and the following disclaimer.
10#     * Redistributions in binary form must reproduce the above
11# copyright notice, this list of conditions and the following disclaimer
12# in the documentation and/or other materials provided with the
13# distribution.
14#     * Neither the name of Google Inc. nor the names of its
15# contributors may be used to endorse or promote products derived from
16# this software without specific prior written permission.
17#
18# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29#
30# MultiCommandTool provides a framework for writing svn-like/git-like tools
31# which are called with the following format:
32# tool-name [global options] command-name [command options]
33
34import logging
35import sys
36
37from optparse import OptionParser, IndentedHelpFormatter, SUPPRESS_USAGE, make_option
38
39from webkitpy.tool.grammar import pluralize
40
41_log = logging.getLogger(__name__)
42
43
44class TryAgain(Exception):
45    pass
46
47
48class Command(object):
49    name = None
50    show_in_main_help = False
51    def __init__(self, help_text, argument_names=None, options=None, long_help=None, requires_local_commits=False):
52        self.help_text = help_text
53        self.long_help = long_help
54        self.argument_names = argument_names
55        self.required_arguments = self._parse_required_arguments(argument_names)
56        self.options = options
57        self.requires_local_commits = requires_local_commits
58        self._tool = None
59        # option_parser can be overriden by the tool using set_option_parser
60        # This default parser will be used for standalone_help printing.
61        self.option_parser = HelpPrintingOptionParser(usage=SUPPRESS_USAGE, add_help_option=False, option_list=self.options)
62
63    def _exit(self, code):
64        sys.exit(code)
65
66    # This design is slightly awkward, but we need the
67    # the tool to be able to create and modify the option_parser
68    # before it knows what Command to run.
69    def set_option_parser(self, option_parser):
70        self.option_parser = option_parser
71        self._add_options_to_parser()
72
73    def _add_options_to_parser(self):
74        options = self.options or []
75        for option in options:
76            self.option_parser.add_option(option)
77
78    # The tool calls bind_to_tool on each Command after adding it to its list.
79    def bind_to_tool(self, tool):
80        # Command instances can only be bound to one tool at a time.
81        if self._tool and tool != self._tool:
82            raise Exception("Command already bound to tool!")
83        self._tool = tool
84
85    @staticmethod
86    def _parse_required_arguments(argument_names):
87        required_args = []
88        if not argument_names:
89            return required_args
90        split_args = argument_names.split(" ")
91        for argument in split_args:
92            if argument[0] == '[':
93                # For now our parser is rather dumb.  Do some minimal validation that
94                # we haven't confused it.
95                if argument[-1] != ']':
96                    raise Exception("Failure to parse argument string %s.  Argument %s is missing ending ]" % (argument_names, argument))
97            else:
98                required_args.append(argument)
99        return required_args
100
101    def name_with_arguments(self):
102        usage_string = self.name
103        if self.options:
104            usage_string += " [options]"
105        if self.argument_names:
106            usage_string += " " + self.argument_names
107        return usage_string
108
109    def parse_args(self, args):
110        return self.option_parser.parse_args(args)
111
112    def check_arguments_and_execute(self, options, args, tool=None):
113        if len(args) < len(self.required_arguments):
114            _log.error("%s required, %s provided.  Provided: %s  Required: %s\nSee '%s help %s' for usage." % (
115                       pluralize("argument", len(self.required_arguments)),
116                       pluralize("argument", len(args)),
117                       "'%s'" % " ".join(args),
118                       " ".join(self.required_arguments),
119                       tool.name(),
120                       self.name))
121            return 1
122        return self.execute(options, args, tool) or 0
123
124    def standalone_help(self):
125        help_text = self.name_with_arguments().ljust(len(self.name_with_arguments()) + 3) + self.help_text + "\n\n"
126        if self.long_help:
127            help_text += "%s\n\n" % self.long_help
128        help_text += self.option_parser.format_option_help(IndentedHelpFormatter())
129        return help_text
130
131    def execute(self, options, args, tool):
132        raise NotImplementedError, "subclasses must implement"
133
134    # main() exists so that Commands can be turned into stand-alone scripts.
135    # Other parts of the code will likely require modification to work stand-alone.
136    def main(self, args=sys.argv):
137        (options, args) = self.parse_args(args)
138        # Some commands might require a dummy tool
139        return self.check_arguments_and_execute(options, args)
140
141
142# FIXME: This should just be rolled into Command.  help_text and argument_names do not need to be instance variables.
143class AbstractDeclarativeCommand(Command):
144    help_text = None
145    argument_names = None
146    long_help = None
147    def __init__(self, options=None, **kwargs):
148        Command.__init__(self, self.help_text, self.argument_names, options=options, long_help=self.long_help, **kwargs)
149
150
151class HelpPrintingOptionParser(OptionParser):
152    def __init__(self, epilog_method=None, *args, **kwargs):
153        self.epilog_method = epilog_method
154        OptionParser.__init__(self, *args, **kwargs)
155
156    def error(self, msg):
157        self.print_usage(sys.stderr)
158        error_message = "%s: error: %s\n" % (self.get_prog_name(), msg)
159        # This method is overriden to add this one line to the output:
160        error_message += "\nType \"%s --help\" to see usage.\n" % self.get_prog_name()
161        self.exit(1, error_message)
162
163    # We override format_epilog to avoid the default formatting which would paragraph-wrap the epilog
164    # and also to allow us to compute the epilog lazily instead of in the constructor (allowing it to be context sensitive).
165    def format_epilog(self, epilog):
166        if self.epilog_method:
167            return "\n%s\n" % self.epilog_method()
168        return ""
169
170
171class HelpCommand(AbstractDeclarativeCommand):
172    name = "help"
173    help_text = "Display information about this program or its subcommands"
174    argument_names = "[COMMAND]"
175
176    def __init__(self):
177        options = [
178            make_option("-a", "--all-commands", action="store_true", dest="show_all_commands", help="Print all available commands"),
179        ]
180        AbstractDeclarativeCommand.__init__(self, options)
181        self.show_all_commands = False # A hack used to pass --all-commands to _help_epilog even though it's called by the OptionParser.
182
183    def _help_epilog(self):
184        # Only show commands which are relevant to this checkout's SCM system.  Might this be confusing to some users?
185        if self.show_all_commands:
186            epilog = "All %prog commands:\n"
187            relevant_commands = self._tool.commands[:]
188        else:
189            epilog = "Common %prog commands:\n"
190            relevant_commands = filter(self._tool.should_show_in_main_help, self._tool.commands)
191        longest_name_length = max(map(lambda command: len(command.name), relevant_commands))
192        relevant_commands.sort(lambda a, b: cmp(a.name, b.name))
193        command_help_texts = map(lambda command: "   %s   %s\n" % (command.name.ljust(longest_name_length), command.help_text), relevant_commands)
194        epilog += "%s\n" % "".join(command_help_texts)
195        epilog += "See '%prog help --all-commands' to list all commands.\n"
196        epilog += "See '%prog help COMMAND' for more information on a specific command.\n"
197        return epilog.replace("%prog", self._tool.name()) # Use of %prog here mimics OptionParser.expand_prog_name().
198
199    # FIXME: This is a hack so that we don't show --all-commands as a global option:
200    def _remove_help_options(self):
201        for option in self.options:
202            self.option_parser.remove_option(option.get_opt_string())
203
204    def execute(self, options, args, tool):
205        if args:
206            command = self._tool.command_by_name(args[0])
207            if command:
208                print command.standalone_help()
209                return 0
210
211        self.show_all_commands = options.show_all_commands
212        self._remove_help_options()
213        self.option_parser.print_help()
214        return 0
215
216
217class MultiCommandTool(object):
218    global_options = None
219
220    def __init__(self, name=None, commands=None):
221        self._name = name or OptionParser(prog=name).get_prog_name() # OptionParser has nice logic for fetching the name.
222        # Allow the unit tests to disable command auto-discovery.
223        self.commands = commands or [cls() for cls in self._find_all_commands() if cls.name]
224        self.help_command = self.command_by_name(HelpCommand.name)
225        # Require a help command, even if the manual test list doesn't include one.
226        if not self.help_command:
227            self.help_command = HelpCommand()
228            self.commands.append(self.help_command)
229        for command in self.commands:
230            command.bind_to_tool(self)
231
232    @classmethod
233    def _add_all_subclasses(cls, class_to_crawl, seen_classes):
234        for subclass in class_to_crawl.__subclasses__():
235            if subclass not in seen_classes:
236                seen_classes.add(subclass)
237                cls._add_all_subclasses(subclass, seen_classes)
238
239    @classmethod
240    def _find_all_commands(cls):
241        commands = set()
242        cls._add_all_subclasses(Command, commands)
243        return sorted(commands)
244
245    def name(self):
246        return self._name
247
248    def _create_option_parser(self):
249        usage = "Usage: %prog [options] COMMAND [ARGS]"
250        return HelpPrintingOptionParser(epilog_method=self.help_command._help_epilog, prog=self.name(), usage=usage)
251
252    @staticmethod
253    def _split_command_name_from_args(args):
254        # Assume the first argument which doesn't start with "-" is the command name.
255        command_index = 0
256        for arg in args:
257            if arg[0] != "-":
258                break
259            command_index += 1
260        else:
261            return (None, args[:])
262
263        command = args[command_index]
264        return (command, args[:command_index] + args[command_index + 1:])
265
266    def command_by_name(self, command_name):
267        for command in self.commands:
268            if command_name == command.name:
269                return command
270        return None
271
272    def path(self):
273        raise NotImplementedError, "subclasses must implement"
274
275    def command_completed(self):
276        pass
277
278    def should_show_in_main_help(self, command):
279        return command.show_in_main_help
280
281    def should_execute_command(self, command):
282        return True
283
284    def _add_global_options(self, option_parser):
285        global_options = self.global_options or []
286        for option in global_options:
287            option_parser.add_option(option)
288
289    def handle_global_options(self, options):
290        pass
291
292    def main(self, argv=sys.argv):
293        (command_name, args) = self._split_command_name_from_args(argv[1:])
294
295        option_parser = self._create_option_parser()
296        self._add_global_options(option_parser)
297
298        command = self.command_by_name(command_name) or self.help_command
299        if not command:
300            option_parser.error("%s is not a recognized command" % command_name)
301
302        command.set_option_parser(option_parser)
303        (options, args) = command.parse_args(args)
304        self.handle_global_options(options)
305
306        (should_execute, failure_reason) = self.should_execute_command(command)
307        if not should_execute:
308            _log.error(failure_reason)
309            return 0 # FIXME: Should this really be 0?
310
311        while True:
312            try:
313                result = command.check_arguments_and_execute(options, args, self)
314                break
315            except TryAgain, e:
316                pass
317
318        self.command_completed()
319        return result
320