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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 sys
35
36from optparse import OptionParser, IndentedHelpFormatter, SUPPRESS_USAGE, make_option
37
38from webkitpy.tool.grammar import pluralize
39from webkitpy.common.system.deprecated_logging import log
40
41
42class TryAgain(Exception):
43    pass
44
45
46class Command(object):
47    name = None
48    show_in_main_help = False
49    def __init__(self, help_text, argument_names=None, options=None, long_help=None, requires_local_commits=False):
50        self.help_text = help_text
51        self.long_help = long_help
52        self.argument_names = argument_names
53        self.required_arguments = self._parse_required_arguments(argument_names)
54        self.options = options
55        self.requires_local_commits = requires_local_commits
56        self._tool = None
57        # option_parser can be overriden by the tool using set_option_parser
58        # This default parser will be used for standalone_help printing.
59        self.option_parser = HelpPrintingOptionParser(usage=SUPPRESS_USAGE, add_help_option=False, option_list=self.options)
60
61    # This design is slightly awkward, but we need the
62    # the tool to be able to create and modify the option_parser
63    # before it knows what Command to run.
64    def set_option_parser(self, option_parser):
65        self.option_parser = option_parser
66        self._add_options_to_parser()
67
68    def _add_options_to_parser(self):
69        options = self.options or []
70        for option in options:
71            self.option_parser.add_option(option)
72
73    # The tool calls bind_to_tool on each Command after adding it to its list.
74    def bind_to_tool(self, tool):
75        # Command instances can only be bound to one tool at a time.
76        if self._tool and tool != self._tool:
77            raise Exception("Command already bound to tool!")
78        self._tool = tool
79
80    @staticmethod
81    def _parse_required_arguments(argument_names):
82        required_args = []
83        if not argument_names:
84            return required_args
85        split_args = argument_names.split(" ")
86        for argument in split_args:
87            if argument[0] == '[':
88                # For now our parser is rather dumb.  Do some minimal validation that
89                # we haven't confused it.
90                if argument[-1] != ']':
91                    raise Exception("Failure to parse argument string %s.  Argument %s is missing ending ]" % (argument_names, argument))
92            else:
93                required_args.append(argument)
94        return required_args
95
96    def name_with_arguments(self):
97        usage_string = self.name
98        if self.options:
99            usage_string += " [options]"
100        if self.argument_names:
101            usage_string += " " + self.argument_names
102        return usage_string
103
104    def parse_args(self, args):
105        return self.option_parser.parse_args(args)
106
107    def check_arguments_and_execute(self, options, args, tool=None):
108        if len(args) < len(self.required_arguments):
109            log("%s required, %s provided.  Provided: %s  Required: %s\nSee '%s help %s' for usage." % (
110                pluralize("argument", len(self.required_arguments)),
111                pluralize("argument", len(args)),
112                "'%s'" % " ".join(args),
113                " ".join(self.required_arguments),
114                tool.name(),
115                self.name))
116            return 1
117        return self.execute(options, args, tool) or 0
118
119    def standalone_help(self):
120        help_text = self.name_with_arguments().ljust(len(self.name_with_arguments()) + 3) + self.help_text + "\n\n"
121        if self.long_help:
122            help_text += "%s\n\n" % self.long_help
123        help_text += self.option_parser.format_option_help(IndentedHelpFormatter())
124        return help_text
125
126    def execute(self, options, args, tool):
127        raise NotImplementedError, "subclasses must implement"
128
129    # main() exists so that Commands can be turned into stand-alone scripts.
130    # Other parts of the code will likely require modification to work stand-alone.
131    def main(self, args=sys.argv):
132        (options, args) = self.parse_args(args)
133        # Some commands might require a dummy tool
134        return self.check_arguments_and_execute(options, args)
135
136
137# FIXME: This should just be rolled into Command.  help_text and argument_names do not need to be instance variables.
138class AbstractDeclarativeCommand(Command):
139    help_text = None
140    argument_names = None
141    long_help = None
142    def __init__(self, options=None, **kwargs):
143        Command.__init__(self, self.help_text, self.argument_names, options=options, long_help=self.long_help, **kwargs)
144
145
146class HelpPrintingOptionParser(OptionParser):
147    def __init__(self, epilog_method=None, *args, **kwargs):
148        self.epilog_method = epilog_method
149        OptionParser.__init__(self, *args, **kwargs)
150
151    def error(self, msg):
152        self.print_usage(sys.stderr)
153        error_message = "%s: error: %s\n" % (self.get_prog_name(), msg)
154        # This method is overriden to add this one line to the output:
155        error_message += "\nType \"%s --help\" to see usage.\n" % self.get_prog_name()
156        self.exit(1, error_message)
157
158    # We override format_epilog to avoid the default formatting which would paragraph-wrap the epilog
159    # and also to allow us to compute the epilog lazily instead of in the constructor (allowing it to be context sensitive).
160    def format_epilog(self, epilog):
161        if self.epilog_method:
162            return "\n%s\n" % self.epilog_method()
163        return ""
164
165
166class HelpCommand(AbstractDeclarativeCommand):
167    name = "help"
168    help_text = "Display information about this program or its subcommands"
169    argument_names = "[COMMAND]"
170
171    def __init__(self):
172        options = [
173            make_option("-a", "--all-commands", action="store_true", dest="show_all_commands", help="Print all available commands"),
174        ]
175        AbstractDeclarativeCommand.__init__(self, options)
176        self.show_all_commands = False # A hack used to pass --all-commands to _help_epilog even though it's called by the OptionParser.
177
178    def _help_epilog(self):
179        # Only show commands which are relevant to this checkout's SCM system.  Might this be confusing to some users?
180        if self.show_all_commands:
181            epilog = "All %prog commands:\n"
182            relevant_commands = self._tool.commands[:]
183        else:
184            epilog = "Common %prog commands:\n"
185            relevant_commands = filter(self._tool.should_show_in_main_help, self._tool.commands)
186        longest_name_length = max(map(lambda command: len(command.name), relevant_commands))
187        relevant_commands.sort(lambda a, b: cmp(a.name, b.name))
188        command_help_texts = map(lambda command: "   %s   %s\n" % (command.name.ljust(longest_name_length), command.help_text), relevant_commands)
189        epilog += "%s\n" % "".join(command_help_texts)
190        epilog += "See '%prog help --all-commands' to list all commands.\n"
191        epilog += "See '%prog help COMMAND' for more information on a specific command.\n"
192        return epilog.replace("%prog", self._tool.name()) # Use of %prog here mimics OptionParser.expand_prog_name().
193
194    # FIXME: This is a hack so that we don't show --all-commands as a global option:
195    def _remove_help_options(self):
196        for option in self.options:
197            self.option_parser.remove_option(option.get_opt_string())
198
199    def execute(self, options, args, tool):
200        if args:
201            command = self._tool.command_by_name(args[0])
202            if command:
203                print command.standalone_help()
204                return 0
205
206        self.show_all_commands = options.show_all_commands
207        self._remove_help_options()
208        self.option_parser.print_help()
209        return 0
210
211
212class MultiCommandTool(object):
213    global_options = None
214
215    def __init__(self, name=None, commands=None):
216        self._name = name or OptionParser(prog=name).get_prog_name() # OptionParser has nice logic for fetching the name.
217        # Allow the unit tests to disable command auto-discovery.
218        self.commands = commands or [cls() for cls in self._find_all_commands() if cls.name]
219        self.help_command = self.command_by_name(HelpCommand.name)
220        # Require a help command, even if the manual test list doesn't include one.
221        if not self.help_command:
222            self.help_command = HelpCommand()
223            self.commands.append(self.help_command)
224        for command in self.commands:
225            command.bind_to_tool(self)
226
227    @classmethod
228    def _add_all_subclasses(cls, class_to_crawl, seen_classes):
229        for subclass in class_to_crawl.__subclasses__():
230            if subclass not in seen_classes:
231                seen_classes.add(subclass)
232                cls._add_all_subclasses(subclass, seen_classes)
233
234    @classmethod
235    def _find_all_commands(cls):
236        commands = set()
237        cls._add_all_subclasses(Command, commands)
238        return sorted(commands)
239
240    def name(self):
241        return self._name
242
243    def _create_option_parser(self):
244        usage = "Usage: %prog [options] COMMAND [ARGS]"
245        return HelpPrintingOptionParser(epilog_method=self.help_command._help_epilog, prog=self.name(), usage=usage)
246
247    @staticmethod
248    def _split_command_name_from_args(args):
249        # Assume the first argument which doesn't start with "-" is the command name.
250        command_index = 0
251        for arg in args:
252            if arg[0] != "-":
253                break
254            command_index += 1
255        else:
256            return (None, args[:])
257
258        command = args[command_index]
259        return (command, args[:command_index] + args[command_index + 1:])
260
261    def command_by_name(self, command_name):
262        for command in self.commands:
263            if command_name == command.name:
264                return command
265        return None
266
267    def path(self):
268        raise NotImplementedError, "subclasses must implement"
269
270    def command_completed(self):
271        pass
272
273    def should_show_in_main_help(self, command):
274        return command.show_in_main_help
275
276    def should_execute_command(self, command):
277        return True
278
279    def _add_global_options(self, option_parser):
280        global_options = self.global_options or []
281        for option in global_options:
282            option_parser.add_option(option)
283
284    def handle_global_options(self, options):
285        pass
286
287    def main(self, argv=sys.argv):
288        (command_name, args) = self._split_command_name_from_args(argv[1:])
289
290        option_parser = self._create_option_parser()
291        self._add_global_options(option_parser)
292
293        command = self.command_by_name(command_name) or self.help_command
294        if not command:
295            option_parser.error("%s is not a recognized command" % command_name)
296
297        command.set_option_parser(option_parser)
298        (options, args) = command.parse_args(args)
299        self.handle_global_options(options)
300
301        (should_execute, failure_reason) = self.should_execute_command(command)
302        if not should_execute:
303            log(failure_reason)
304            return 0 # FIXME: Should this really be 0?
305
306        while True:
307            try:
308                result = command.check_arguments_and_execute(options, args, self)
309                break
310            except TryAgain, e:
311                pass
312
313        self.command_completed()
314        return result
315