mudpy/data.py

   1 """Data interface functions for the mudpy engine."""
   2
   3 # Copyright (c) 2004-2016 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 and their facets."""
  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, create elements and poplulate facets 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 node in list(self.data):
  88             if node == "__control__":
  89                 continue
  90             facet_pos = node.rfind(".") + 1
  91             if not facet_pos:
  92                 mudpy.misc.Element(node, self.universe, self.filename,
  93                                    old_style=True)
  94             else:
  95                 prefix = node[:facet_pos].strip(".")
  96                 try:
  97                     element = self.universe.contents[prefix]
  98                 except KeyError:
  99                     element = mudpy.misc.Element(prefix, self.universe,
 100                                                  self.filename)
 101                 element.set(node[facet_pos:], self.data[node])
 102                 if prefix.startswith("mudpy.movement."):
 103                     self.universe.directions.add(
 104                         prefix[prefix.rfind(".") + 1:])
 105         for include_file in includes:
 106             if not os.path.isabs(include_file):
 107                 include_file = find_file(
 108                     include_file,
 109                     relative=self.filename,
 110                     universe=self.universe
 111                 )
 112             if (include_file not in self.universe.files or not
 113                     self.universe.files[include_file].is_writeable()):
 114                 DataFile(include_file, self.universe)
 115
 116     def save(self):
 117         """Write the data, if necessary."""
 118         normal_umask = 0o0022
 119         private_umask = 0o0077
 120         private_file_mode = 0o0600
 121
 122         # when modified, writeable and has content or the file exists
 123         if self.modified and self.is_writeable() and (
 124            self.data or os.path.exists(self.filename)
 125            ):
 126
 127             # make parent directories if necessary
 128             if not os.path.exists(os.path.dirname(self.filename)):
 129                 old_umask = os.umask(normal_umask)
 130                 os.makedirs(os.path.dirname(self.filename))
 131                 os.umask(old_umask)
 132
 133             # backup the file
 134             if "__control__" in self.data and "backup_count" in self.data[
 135                     "__control__"]:
 136                 max_count = self.data["__control__"]["backup_count"]
 137             elif "mudpy.limit" in self.universe.contents:
 138                 max_count = self.universe.contents["mudpy.limit"].get(
 139                     "backups", 0)
 140             else:
 141                 max_count = 0
 142             if os.path.exists(self.filename) and max_count:
 143                 backups = []
 144                 for candidate in os.listdir(os.path.dirname(self.filename)):
 145                     if re.match(
 146                        os.path.basename(self.filename) +
 147                        r"""\.\d+$""", candidate
 148                        ):
 149                         backups.append(int(candidate.split(".")[-1]))
 150                 backups.sort()
 151                 backups.reverse()
 152                 for old_backup in backups:
 153                     if old_backup >= max_count - 1:
 154                         os.remove(self.filename + "." + str(old_backup))
 155                     elif not os.path.exists(
 156                         self.filename + "." + str(old_backup + 1)
 157                     ):
 158                         os.rename(
 159                             self.filename + "." + str(old_backup),
 160                             self.filename + "." + str(old_backup + 1)
 161                         )
 162                 if not os.path.exists(self.filename + ".0"):
 163                     os.rename(self.filename, self.filename + ".0")
 164
 165             # our data file
 166             if self.filename in self.universe.private_files:
 167                 old_umask = os.umask(private_umask)
 168                 file_descriptor = open(self.filename, "w")
 169                 if oct(stat.S_IMODE(os.stat(
 170                         self.filename)[stat.ST_MODE])) != private_file_mode:
 171                     # if it's marked private, chmod it appropriately
 172                     os.chmod(self.filename, private_file_mode)
 173             else:
 174                 old_umask = os.umask(normal_umask)
 175                 file_descriptor = open(self.filename, "w")
 176             os.umask(old_umask)
 177
 178             # write and close the file
 179             yaml.safe_dump(self.data, allow_unicode=True,
 180                            default_flow_style=False, stream=file_descriptor)
 181             file_descriptor.close()
 182
 183             # unset the modified flag
 184             self.modified = False
 185
 186     def is_writeable(self):
 187         """Returns True if the __control__ read_only is False."""
 188         try:
 189             return not self.data["__control__"].get("read_only", False)
 190         except KeyError:
 191             return True
 192
 193
 194 def find_file(
 195     file_name=None,
 196     prefix=None,
 197     relative=None,
 198     search=None,
 199     stash=None,
 200     universe=None
 201 ):
 202     """Return an absolute file path based on configuration."""
 203
 204     # this is all unnecessary if it's already absolute
 205     if file_name and os.path.isabs(file_name):
 206         return os.path.realpath(file_name)
 207
 208     # if a universe was provided, try to get some defaults from there
 209     if universe:
 210
 211         if hasattr(
 212                 universe, "contents") and "mudpy.filing" in universe.contents:
 213             filing = universe.contents["mudpy.filing"]
 214             if not prefix:
 215                 prefix = filing.get("prefix")
 216             if not search:
 217                 search = filing.get("search")
 218             if not stash:
 219                 stash = filing.get("stash")
 220
 221         # if there's only one file loaded, try to work around a chicken<egg
 222         elif hasattr(universe, "files") and len(
 223             universe.files
 224         ) == 1 and not universe.files[
 225                 list(universe.files.keys())[0]].is_writeable():
 226             data_file = universe.files[list(universe.files.keys())[0]].data
 227
 228             # try for a fallback default directory
 229             if not stash:
 230                 stash = data_file.get(".mudpy.filing.stash", "")
 231
 232             # try for a fallback root path
 233             if not prefix:
 234                 prefix = data_file.get(".mudpy.filing.prefix", "")
 235
 236             # try for a fallback search path
 237             if not search:
 238                 search = data_file.get(".mudpy.filing.search", "")
 239
 240         # another fallback root path, this time from the universe startdir
 241         if hasattr(universe, "startdir"):
 242             if not prefix:
 243                 prefix = universe.startdir
 244             elif not os.path.isabs(prefix):
 245                 prefix = os.path.join(universe.startdir, prefix)
 246
 247     # when no root path is specified, assume the current working directory
 248     if not prefix:
 249         prefix = os.getcwd()
 250
 251     # make sure it's absolute
 252     prefix = os.path.realpath(prefix)
 253
 254     # if there's no search path, just use the root path and etc
 255     if not search:
 256         search = [prefix, "etc"]
 257
 258     # work on a copy of the search path, to avoid modifying the caller's
 259     else:
 260         search = search[:]
 261
 262     # if there's no default path, use the last component of the search path
 263     if not stash:
 264         stash = search[-1]
 265
 266     # if an existing file or directory reference was supplied, prepend it
 267     if relative:
 268         if os.path.isdir(relative):
 269             search = [relative] + search
 270         else:
 271             search = [os.path.dirname(relative)] + search
 272
 273     # make the search path entries absolute and throw away any dupes
 274     clean_search = []
 275     for each_path in search:
 276         if not os.path.isabs(each_path):
 277             each_path = os.path.realpath(os.path.join(prefix, each_path))
 278         if each_path not in clean_search:
 279             clean_search.append(each_path)
 280
 281     # start hunting for the file now
 282     for each_path in clean_search:
 283
 284         # if the file exists and is readable, we're done
 285         if os.path.isfile(os.path.join(each_path, file_name)):
 286             file_name = os.path.realpath(os.path.join(each_path, file_name))
 287             break
 288
 289     # it didn't exist after all, so use the default path instead
 290     if not os.path.isabs(file_name):
 291         file_name = os.path.join(stash, file_name)
 292     if not os.path.isabs(file_name):
 293         file_name = os.path.join(prefix, file_name)
 294
 295     # and normalize it last thing before returning
 296     file_name = os.path.realpath(file_name)
 297
 298     # normalize the resulting file path and hand it back
 299     return file_name