git_remote_helpers/fastimport/processor.py

   1 # Copyright (C) 2008 Canonical Ltd
   2 #
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 2 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program; if not, write to the Free Software
  15 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16
  17 """Processor of import commands.
  18
  19 This module provides core processing functionality including an abstract class
  20 for basing real processors on. See the processors package for examples.
  21 """
  22
  23 import sys
  24 import time
  25 import logging
  26
  27 from git_remote_helpers.fastimport import errors
  28
  29 log = logging.getLogger(__name__)
  30
  31
  32 class ImportProcessor(object):
  33     """Base class for import processors.
  34
  35     Subclasses should override the pre_*, post_* and *_handler
  36     methods as appropriate.
  37     """
  38
  39     known_params = []
  40
  41     def __init__(self, params=None, verbose=False, outf=None):
  42         if outf is None:
  43             self.outf = sys.stdout
  44         else:
  45             self.outf = outf
  46         self.verbose = verbose
  47         if params is None:
  48             self.params = {}
  49         else:
  50             self.params = params
  51             self.validate_parameters()
  52
  53         # Handlers can set this to request exiting cleanly without
  54         # iterating through the remaining commands
  55         self.finished = False
  56
  57     def validate_parameters(self):
  58         """Validate that the parameters are correctly specified."""
  59         for p in self.params:
  60             if p not in self.known_params:
  61                 raise errors.UnknownParameter(p, self.known_params)
  62
  63     def process(self, commands):
  64         """Process a stream of fast-import commands from a parser.
  65
  66         :param commands: a sequence of commands.ImportCommand objects
  67         """
  68         self.pre_process()
  69         for cmd in commands:
  70             try:
  71                 handler = self.__class__.__dict__[cmd.name + "_handler"]
  72             except KeyError:
  73                 raise errors.MissingHandler(cmd.name)
  74             else:
  75                 self.pre_handler(cmd)
  76                 handler(self, cmd)
  77                 self.post_handler(cmd)
  78             if self.finished:
  79                 break
  80         self.post_process()
  81
  82     def pre_process(self):
  83         """Hook for logic at start of processing.
  84
  85         Called just before process() starts iterating over its sequence
  86         of commands.
  87         """
  88         pass
  89
  90     def post_process(self):
  91         """Hook for logic at end of successful processing.
  92
  93         Called after process() finishes successfully iterating over its
  94         sequence of commands (i.e. not called if an exception is raised
  95         while processing commands).
  96         """
  97         pass
  98
  99     def pre_handler(self, cmd):
 100         """Hook for logic before each handler starts."""
 101         pass
 102
 103     def post_handler(self, cmd):
 104         """Hook for logic after each handler finishes."""
 105         pass
 106
 107     def progress_handler(self, cmd):
 108         """Process a ProgressCommand."""
 109         raise NotImplementedError(self.progress_handler)
 110
 111     def blob_handler(self, cmd):
 112         """Process a BlobCommand."""
 113         raise NotImplementedError(self.blob_handler)
 114
 115     def checkpoint_handler(self, cmd):
 116         """Process a CheckpointCommand."""
 117         raise NotImplementedError(self.checkpoint_handler)
 118
 119     def commit_handler(self, cmd):
 120         """Process a CommitCommand."""
 121         raise NotImplementedError(self.commit_handler)
 122
 123     def reset_handler(self, cmd):
 124         """Process a ResetCommand."""
 125         raise NotImplementedError(self.reset_handler)
 126
 127     def tag_handler(self, cmd):
 128         """Process a TagCommand."""
 129         raise NotImplementedError(self.tag_handler)
 130
 131     def feature_handler(self, cmd):
 132         """Process a FeatureCommand."""
 133         raise NotImplementedError(self.feature_handler)
 134
 135
 136 class CommitHandler(object):
 137     """Base class for commit handling.
 138
 139     Subclasses should override the pre_*, post_* and *_handler
 140     methods as appropriate.
 141     """
 142
 143     def __init__(self, command):
 144         self.command = command
 145
 146     def process(self):
 147         self.pre_process_files()
 148         for fc in self.command.file_cmds:
 149             try:
 150                 handler = self.__class__.__dict__[fc.name[4:] + "_handler"]
 151             except KeyError:
 152                 raise errors.MissingHandler(fc.name)
 153             else:
 154                 handler(self, fc)
 155         self.post_process_files()
 156
 157     def _log(self, level, msg, *args):
 158         log.log(level, msg + " (%s)", *(args + (self.command.id,)))
 159
 160     # Logging methods: unused in this library, but used by
 161     # bzr-fastimport.  Could be useful for other subclasses.
 162
 163     def note(self, msg, *args):
 164         """log.info() with context about the command"""
 165         self._log(logging.INFO, msg, *args)
 166
 167     def warning(self, msg, *args):
 168         """log.warning() with context about the command"""
 169         self._log(logging.WARNING, msg, *args)
 170
 171     def debug(self, msg, *args):
 172         """log.debug() with context about the command"""
 173         self._log(logging.DEBUG, msg, *args)
 174
 175     def pre_process_files(self):
 176         """Prepare for committing."""
 177         pass
 178
 179     def post_process_files(self):
 180         """Save the revision."""
 181         pass
 182
 183     def modify_handler(self, filecmd):
 184         """Handle a filemodify command."""
 185         raise NotImplementedError(self.modify_handler)
 186
 187     def delete_handler(self, filecmd):
 188         """Handle a filedelete command."""
 189         raise NotImplementedError(self.delete_handler)
 190
 191     def copy_handler(self, filecmd):
 192         """Handle a filecopy command."""
 193         raise NotImplementedError(self.copy_handler)
 194
 195     def rename_handler(self, filecmd):
 196         """Handle a filerename command."""
 197         raise NotImplementedError(self.rename_handler)
 198
 199     def deleteall_handler(self, filecmd):
 200         """Handle a filedeleteall command."""
 201         raise NotImplementedError(self.deleteall_handler)
 202
 203
 204 def parseMany(filenames, parser_factory, processor):
 205     """Parse multiple input files, sending the results all to
 206     'processor'.  parser_factory must be a callable that takes one input
 207     file and returns an ImportParser instance, e.g. the ImportParser
 208     class object itself.  Each file in 'filenames' is opened, parsed,
 209     and closed in turn.  For filename \"-\", reads stdin.
 210     """
 211     for filename in filenames:
 212         if filename == "-":
 213             infile = sys.stdin
 214         else:
 215             infile = open(filename, "rb")
 216
 217         try:
 218             parser = parser_factory(infile)
 219             processor.process(parser.parse())
 220         finally:
 221             if filename != "-":
 222                 infile.close()