lib/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         for include_file in includes:
 103             if not os.path.isabs(include_file):
 104                 include_file = find_file(
 105                     include_file,
 106                     relative=self.filename,
 107                     universe=self.universe
 108                 )
 109             if (include_file not in self.universe.files or not
 110                     self.universe.files[include_file].is_writeable()):
 111                 DataFile(include_file, self.universe)
 112
 113     def save(self):
 114         """Write the data, if necessary."""
 115         normal_umask = 0o0022
 116         private_umask = 0o0077
 117         private_file_mode = 0o0600
 118
 119         # when modified, writeable and has content or the file exists
 120         if self.modified and self.is_writeable() and (
 121            self.data or os.path.exists(self.filename)
 122            ):
 123
 124             # make parent directories if necessary
 125             if not os.path.exists(os.path.dirname(self.filename)):
 126                 old_umask = os.umask(normal_umask)
 127                 os.makedirs(os.path.dirname(self.filename))
 128                 os.umask(old_umask)
 129
 130             # backup the file
 131             if "__control__" in self.data and "backup_count" in self.data[
 132                     "__control__"]:
 133                 max_count = self.data["__control__"]["backup_count"]
 134             else:
 135                 max_count = self.universe.contents["mudpy.limit"].get(
 136                     "backups")
 137             if os.path.exists(self.filename) and max_count:
 138                 backups = []
 139                 for candidate in os.listdir(os.path.dirname(self.filename)):
 140                     if re.match(
 141                        os.path.basename(self.filename) +
 142                        """\.\d+$""", candidate
 143                        ):
 144                         backups.append(int(candidate.split(".")[-1]))
 145                 backups.sort()
 146                 backups.reverse()
 147                 for old_backup in backups:
 148                     if old_backup >= max_count - 1:
 149                         os.remove(self.filename + "." + str(old_backup))
 150                     elif not os.path.exists(
 151                         self.filename + "." + str(old_backup + 1)
 152                     ):
 153                         os.rename(
 154                             self.filename + "." + str(old_backup),
 155                             self.filename + "." + str(old_backup + 1)
 156                         )
 157                 if not os.path.exists(self.filename + ".0"):
 158                     os.rename(self.filename, self.filename + ".0")
 159
 160             # our data file
 161             if self.filename in self.universe.private_files:
 162                 old_umask = os.umask(private_umask)
 163                 file_descriptor = open(self.filename, "w")
 164                 if oct(stat.S_IMODE(os.stat(
 165                         self.filename)[stat.ST_MODE])) != private_file_mode:
 166                     # if it's marked private, chmod it appropriately
 167                     os.chmod(self.filename, private_file_mode)
 168             else:
 169                 old_umask = os.umask(normal_umask)
 170                 file_descriptor = open(self.filename, "w")
 171             os.umask(old_umask)
 172
 173             # write and close the file
 174             yaml.safe_dump(self.data, allow_unicode=True,
 175                            default_flow_style=False, stream=file_descriptor)
 176             file_descriptor.close()
 177
 178             # unset the modified flag
 179             self.modified = False
 180
 181     def is_writeable(self):
 182         """Returns True if the __control__ read_only is False."""
 183         try:
 184             return not self.data["__control__"].get("read_only", False)
 185         except KeyError:
 186             return True
 187
 188
 189 def find_file(
 190     file_name=None,
 191     root_path=None,
 192     search_path=None,
 193     default_dir=None,
 194     relative=None,
 195     universe=None
 196 ):
 197     """Return an absolute file path based on configuration."""
 198
 199     # make sure to get rid of any surrounding quotes first thing
 200     if file_name:
 201         file_name = file_name.strip("\"'")
 202
 203     # this is all unnecessary if it's already absolute
 204     if file_name and os.path.isabs(file_name):
 205         return os.path.realpath(file_name)
 206
 207     # if a universe was provided, try to get some defaults from there
 208     if universe:
 209
 210         if hasattr(
 211            universe,
 212            "contents"
 213            ) and "internal:storage" in universe.contents:
 214             storage = universe.categories["internal"]["storage"]
 215             if not root_path:
 216                 root_path = storage.get("root_path").strip("\"'")
 217             if not search_path:
 218                 search_path = storage.get("search_path")
 219             if not default_dir:
 220                 default_dir = storage.get("default_dir").strip("\"'")
 221
 222         # if there's only one file loaded, try to work around a chicken<egg
 223         elif hasattr(universe, "files") and len(
 224             universe.files
 225         ) == 1 and not universe.files[
 226                 list(universe.files.keys())[0]].is_writeable():
 227             data_file = universe.files[list(universe.files.keys())[0]].data
 228
 229             # try for a fallback default directory
 230             if not default_dir:
 231                 default_dir = data_file.get(
 232                     "internal:storage", "").get("default_dir", "")
 233
 234             # try for a fallback root path
 235             if not root_path:
 236                 root_path = data_file.get(
 237                     "internal:storage", "").get("root_path", "")
 238
 239             # try for a fallback search path
 240             if not search_path:
 241                 search_path = data_file.get(
 242                     "internal:storage", "").get("search_path", "")
 243
 244         # another fallback root path, this time from the universe startdir
 245         if not root_path and hasattr(universe, "startdir"):
 246             root_path = universe.startdir
 247
 248     # when no root path is specified, assume the current working directory
 249     if not root_path:
 250         root_path = os.getcwd()
 251
 252     # otherwise, make sure it's absolute
 253     elif not os.path.isabs(root_path):
 254         root_path = os.path.realpath(root_path)
 255
 256     # if there's no search path, just use the root path and etc
 257     if not search_path:
 258         search_path = [root_path, "etc"]
 259
 260     # work on a copy of the search path, to avoid modifying the caller's
 261     else:
 262         search_path = search_path[:]
 263
 264     # if there's no default path, use the last component of the search path
 265     if not default_dir:
 266         default_dir = search_path[-1]
 267
 268     # if an existing file or directory reference was supplied, prepend it
 269     if relative:
 270         relative = relative.strip("\"'")
 271         if os.path.isdir(relative):
 272             search_path = [relative] + search_path
 273         else:
 274             search_path = [os.path.dirname(relative)] + search_path
 275
 276     # make the search path entries absolute and throw away any dupes
 277     clean_search_path = []
 278     for each_path in search_path:
 279         each_path = each_path.strip("\"'")
 280         if not os.path.isabs(each_path):
 281             each_path = os.path.realpath(os.path.join(root_path, each_path))
 282         if each_path not in clean_search_path:
 283             clean_search_path.append(each_path)
 284
 285     # start hunting for the file now
 286     for each_path in clean_search_path:
 287
 288         # if the file exists and is readable, we're done
 289         if os.path.isfile(os.path.join(each_path, file_name)):
 290             file_name = os.path.realpath(os.path.join(each_path, file_name))
 291             break
 292
 293     # it didn't exist after all, so use the default path instead
 294     if not os.path.isabs(file_name):
 295         file_name = os.path.join(default_dir, file_name)
 296     if not os.path.isabs(file_name):
 297         file_name = os.path.join(root_path, file_name)
 298
 299     # and normalize it last thing before returning
 300     file_name = os.path.realpath(file_name)
 301
 302     # normalize the resulting file path and hand it back
 303     return file_name