lib/mudpy/data.py

   1 """Data interface functions for the mudpy engine."""
   2
   3 # Copyright (c) 2004-2015 Jeremy Stanley <fungi@yuggoth.org>. Permission
   4 # to use, copy, modify, and distribute this software is granted under
   5 # terms provided in the LICENSE file distributed with this software.
   6
   7 import os
   8 import re
   9 import stat
  10
  11 import mudpy
  12 import yaml
  13
  14
  15 class DataFile:
  16
  17     """A file containing universe elements."""
  18
  19     def __init__(self, filename, universe):
  20         self.filename = filename
  21         self.universe = universe
  22         self.data = {}
  23         self.load()
  24
  25     def load(self):
  26         """Read a file and create elements accordingly."""
  27         self.modified = False
  28         try:
  29             self.data = yaml.safe_load(open(self.filename))
  30         except FileNotFoundError:
  31             # it's normal if the file is one which doesn't exist yet
  32             log_entry = ("File %s is unavailable." % self.filename, 6)
  33             try:
  34                 mudpy.misc.log(*log_entry)
  35             except NameError:
  36                 # happens when we're not far enough along in the init process
  37                 self.universe.setup_loglines.append(log_entry)
  38         if not hasattr(self.universe, "files"):
  39             self.universe.files = {}
  40         self.universe.files[self.filename] = self
  41         includes = []
  42         if "__control__" in self.data:
  43             if "include_files" in self.data["__control__"]:
  44                 for included in self.data["__control__"]["include_files"]:
  45                     included = find_file(
  46                         included,
  47                         relative=self.filename,
  48                         universe=self.universe)
  49                     if included not in includes:
  50                         includes.append(included)
  51             if "include_dirs" in self.data["__control__"]:
  52                 for included in [
  53                     os.path.join(x, "__init__.yaml") for x in
  54                         self.data["__control__"]["include_dirs"]
  55                 ]:
  56                     included = find_file(
  57                         included,
  58                         relative=self.filename,
  59                         universe=self.universe
  60                     )
  61                     if included not in includes:
  62                         includes.append(included)
  63             if "default_files" in self.data["__control__"]:
  64                 origins = self.data["__control__"]["default_files"]
  65                 for key in origins.keys():
  66                     origins[key] = find_file(
  67                         origins[key],
  68                         relative=self.filename,
  69                         universe=self.universe
  70                     )
  71                     if origins[key] not in includes:
  72                         includes.append(origins[key])
  73                     self.universe.default_origins[key] = origins[key]
  74                     if key not in self.universe.categories:
  75                         self.universe.categories[key] = {}
  76             if "private_files" in self.data["__control__"]:
  77                 for item in self.data["__control__"]["private_files"]:
  78                     item = find_file(
  79                         item,
  80                         relative=self.filename,
  81                         universe=self.universe
  82                     )
  83                     if item not in includes:
  84                         includes.append(item)
  85                     if item not in self.universe.private_files:
  86                         self.universe.private_files.append(item)
  87         for element in self.data:
  88             if element != "__control__":
  89                 mudpy.misc.Element(element, self.universe, self.filename)
  90         for include_file in includes:
  91             if not os.path.isabs(include_file):
  92                 include_file = find_file(
  93                     include_file,
  94                     relative=self.filename,
  95                     universe=self.universe
  96                 )
  97             if (include_file not in self.universe.files or not
  98                     self.universe.files[include_file].is_writeable()):
  99                 DataFile(include_file, self.universe)
 100
 101     def save(self):
 102         """Write the data, if necessary."""
 103         normal_umask = 0o0022
 104         private_umask = 0o0077
 105         private_file_mode = 0o0600
 106
 107         # when modified, writeable and has content or the file exists
 108         if self.modified and self.is_writeable() and (
 109            self.data or os.path.exists(self.filename)
 110            ):
 111
 112             # make parent directories if necessary
 113             if not os.path.exists(os.path.dirname(self.filename)):
 114                 old_umask = os.umask(normal_umask)
 115                 os.makedirs(os.path.dirname(self.filename))
 116                 os.umask(old_umask)
 117
 118             # backup the file
 119             if "__control__" in self.data and "backup_count" in self.data[
 120                     "__control__"]:
 121                 max_count = self.data["__control__"]["backup_count"]
 122             else:
 123                 max_count = self.universe.categories[
 124                     "internal"
 125                 ][
 126                     "limits"
 127                 ].get("default_backup_count")
 128             if os.path.exists(self.filename) and max_count:
 129                 backups = []
 130                 for candidate in os.listdir(os.path.dirname(self.filename)):
 131                     if re.match(
 132                        os.path.basename(self.filename) +
 133                        """\.\d+$""", candidate
 134                        ):
 135                         backups.append(int(candidate.split(".")[-1]))
 136                 backups.sort()
 137                 backups.reverse()
 138                 for old_backup in backups:
 139                     if old_backup >= max_count - 1:
 140                         os.remove(self.filename + "." + str(old_backup))
 141                     elif not os.path.exists(
 142                         self.filename + "." + str(old_backup + 1)
 143                     ):
 144                         os.rename(
 145                             self.filename + "." + str(old_backup),
 146                             self.filename + "." + str(old_backup + 1)
 147                         )
 148                 if not os.path.exists(self.filename + ".0"):
 149                     os.rename(self.filename, self.filename + ".0")
 150
 151             # our data file
 152             if self.filename in self.universe.private_files:
 153                 old_umask = os.umask(private_umask)
 154                 file_descriptor = open(self.filename, "w")
 155                 if oct(stat.S_IMODE(os.stat(
 156                         self.filename)[stat.ST_MODE])) != private_file_mode:
 157                     # if it's marked private, chmod it appropriately
 158                     os.chmod(self.filename, private_file_mode)
 159             else:
 160                 old_umask = os.umask(normal_umask)
 161                 file_descriptor = open(self.filename, "w")
 162             os.umask(old_umask)
 163
 164             # write and close the file
 165             yaml.safe_dump(self.data, allow_unicode=True,
 166                            default_flow_style=False, stream=file_descriptor)
 167             file_descriptor.close()
 168
 169             # unset the modified flag
 170             self.modified = False
 171
 172     def is_writeable(self):
 173         """Returns True if the __control__ read_only is False."""
 174         try:
 175             return not self.data["__control__"].get("read_only", False)
 176         except KeyError:
 177             return True
 178
 179
 180 def find_file(
 181     file_name=None,
 182     root_path=None,
 183     search_path=None,
 184     default_dir=None,
 185     relative=None,
 186     universe=None
 187 ):
 188     """Return an absolute file path based on configuration."""
 189
 190     # make sure to get rid of any surrounding quotes first thing
 191     if file_name:
 192         file_name = file_name.strip("\"'")
 193
 194     # this is all unnecessary if it's already absolute
 195     if file_name and os.path.isabs(file_name):
 196         return os.path.realpath(file_name)
 197
 198     # if a universe was provided, try to get some defaults from there
 199     if universe:
 200
 201         if hasattr(
 202            universe,
 203            "contents"
 204            ) and "internal:storage" in universe.contents:
 205             storage = universe.categories["internal"]["storage"]
 206             if not root_path:
 207                 root_path = storage.get("root_path").strip("\"'")
 208             if not search_path:
 209                 search_path = storage.get("search_path")
 210             if not default_dir:
 211                 default_dir = storage.get("default_dir").strip("\"'")
 212
 213         # if there's only one file loaded, try to work around a chicken<egg
 214         elif hasattr(universe, "files") and len(
 215             universe.files
 216         ) == 1 and not universe.files[
 217                 list(universe.files.keys())[0]].is_writeable():
 218             data_file = universe.files[list(universe.files.keys())[0]].data
 219
 220             # try for a fallback default directory
 221             if not default_dir:
 222                 default_dir = data_file.get(
 223                     "internal:storage", "").get("default_dir", "")
 224
 225             # try for a fallback root path
 226             if not root_path:
 227                 root_path = data_file.get(
 228                     "internal:storage", "").get("root_path", "")
 229
 230             # try for a fallback search path
 231             if not search_path:
 232                 search_path = data_file.get(
 233                     "internal:storage", "").get("search_path", "")
 234
 235         # another fallback root path, this time from the universe startdir
 236         if not root_path and hasattr(universe, "startdir"):
 237             root_path = universe.startdir
 238
 239     # when no root path is specified, assume the current working directory
 240     if not root_path:
 241         root_path = os.getcwd()
 242
 243     # otherwise, make sure it's absolute
 244     elif not os.path.isabs(root_path):
 245         root_path = os.path.realpath(root_path)
 246
 247     # if there's no search path, just use the root path and etc
 248     if not search_path:
 249         search_path = [root_path, "etc"]
 250
 251     # work on a copy of the search path, to avoid modifying the caller's
 252     else:
 253         search_path = search_path[:]
 254
 255     # if there's no default path, use the last element of the search path
 256     if not default_dir:
 257         default_dir = search_path[-1]
 258
 259     # if an existing file or directory reference was supplied, prepend it
 260     if relative:
 261         relative = relative.strip("\"'")
 262         if os.path.isdir(relative):
 263             search_path = [relative] + search_path
 264         else:
 265             search_path = [os.path.dirname(relative)] + search_path
 266
 267     # make the search path entries absolute and throw away any dupes
 268     clean_search_path = []
 269     for each_path in search_path:
 270         each_path = each_path.strip("\"'")
 271         if not os.path.isabs(each_path):
 272             each_path = os.path.realpath(os.path.join(root_path, each_path))
 273         if each_path not in clean_search_path:
 274             clean_search_path.append(each_path)
 275
 276     # start hunting for the file now
 277     for each_path in clean_search_path:
 278
 279         # if the file exists and is readable, we're done
 280         if os.path.isfile(os.path.join(each_path, file_name)):
 281             file_name = os.path.realpath(os.path.join(each_path, file_name))
 282             break
 283
 284     # it didn't exist after all, so use the default path instead
 285     if not os.path.isabs(file_name):
 286         file_name = os.path.join(default_dir, file_name)
 287     if not os.path.isabs(file_name):
 288         file_name = os.path.join(root_path, file_name)
 289
 290     # and normalize it last thing before returning
 291     file_name = os.path.realpath(file_name)
 292
 293     # normalize the resulting file path and hand it back
 294     return file_name