index.py

   1 import os, stat, time, struct, tempfile
   2 from helpers import *
   3
   4 EMPTY_SHA = '\0'*20
   5 FAKE_SHA = '\x01'*20
   6 INDEX_HDR = 'BUPI\0\0\0\2'
   7 INDEX_SIG = '!IIIIIQII20sHII'
   8 ENTLEN = struct.calcsize(INDEX_SIG)
   9 FOOTER_SIG = '!Q'
  10 FOOTLEN = struct.calcsize(FOOTER_SIG)
  11
  12 IX_EXISTS = 0x8000
  13 IX_HASHVALID = 0x4000
  14
  15 class Error(Exception):
  16     pass
  17
  18
  19 class Level:
  20     def __init__(self, ename, parent):
  21         self.parent = parent
  22         self.ename = ename
  23         self.list = []
  24         self.count = 0
  25
  26     def write(self, f):
  27         (ofs,n) = (f.tell(), len(self.list))
  28         if self.list:
  29             count = len(self.list)
  30             #log('popping %r with %d entries\n'
  31             #    % (''.join(self.ename), count))
  32             for e in self.list:
  33                 e.write(f)
  34             if self.parent:
  35                 self.parent.count += count + self.count
  36         return (ofs,n)
  37
  38
  39 def _golevel(level, f, ename, newentry):
  40     # close nodes back up the tree
  41     assert(level)
  42     while ename[:len(level.ename)] != level.ename:
  43         n = BlankNewEntry(level.ename[-1])
  44         (n.children_ofs,n.children_n) = level.write(f)
  45         level.parent.list.append(n)
  46         level = level.parent
  47
  48     # create nodes down the tree
  49     while len(level.ename) < len(ename):
  50         level = Level(ename[:len(level.ename)+1], level)
  51
  52     # are we in precisely the right place?
  53     assert(ename == level.ename)
  54     n = newentry or BlankNewEntry(ename and level.ename[-1] or None)
  55     (n.children_ofs,n.children_n) = level.write(f)
  56     if level.parent:
  57         level.parent.list.append(n)
  58     level = level.parent
  59
  60     return level
  61
  62
  63 class Entry:
  64     def __init__(self, basename, name):
  65         self.basename = str(basename)
  66         self.name = str(name)
  67         self.children_ofs = 0
  68         self.children_n = 0
  69
  70     def __repr__(self):
  71         return ("(%s,0x%04x,%d,%d,%d,%d,%d,0x%04x,0x%08x/%d)"
  72                 % (self.name, self.dev,
  73                    self.ctime, self.mtime, self.uid, self.gid,
  74                    self.size, self.flags, self.children_ofs, self.children_n))
  75
  76     def packed(self):
  77         return struct.pack(INDEX_SIG,
  78                            self.dev, self.ctime, self.mtime,
  79                            self.uid, self.gid, self.size, self.mode,
  80                            self.gitmode, self.sha, self.flags,
  81                            self.children_ofs, self.children_n)
  82
  83     def from_stat(self, st, tstart):
  84         old = (self.dev, self.ctime, self.mtime,
  85                self.uid, self.gid, self.size, self.flags & IX_EXISTS)
  86         new = (st.st_dev, int(st.st_ctime), int(st.st_mtime),
  87                st.st_uid, st.st_gid, st.st_size, IX_EXISTS)
  88         self.dev = st.st_dev
  89         self.ctime = int(st.st_ctime)
  90         self.mtime = int(st.st_mtime)
  91         self.uid = st.st_uid
  92         self.gid = st.st_gid
  93         self.size = st.st_size
  94         self.mode = st.st_mode
  95         self.flags |= IX_EXISTS
  96         if int(st.st_ctime) >= tstart or old != new:
  97             self.flags &= ~IX_HASHVALID
  98             self.set_dirty()
  99
 100     def validate(self, sha):
 101         assert(sha)
 102         self.sha = sha
 103         self.flags |= IX_HASHVALID
 104
 105     def set_deleted(self):
 106         self.flags &= ~(IX_EXISTS | IX_HASHVALID)
 107         self.set_dirty()
 108
 109     def set_dirty(self):
 110         pass # FIXME
 111
 112     def __cmp__(a, b):
 113         return cmp(a.name, b.name)
 114
 115     def write(self, f):
 116         f.write(self.basename + '\0' + self.packed())
 117
 118
 119 class NewEntry(Entry):
 120     def __init__(self, basename, name, dev, ctime, mtime, uid, gid,
 121                  size, mode, gitmode, sha, flags, children_ofs, children_n):
 122         Entry.__init__(self, basename, name)
 123         (self.dev, self.ctime, self.mtime, self.uid, self.gid,
 124          self.size, self.mode, self.gitmode, self.sha,
 125          self.flags, self.children_ofs, self.children_n
 126          ) = (dev, int(ctime), int(mtime), uid, gid,
 127               size, mode, gitmode, sha, flags, children_ofs, children_n)
 128
 129
 130 class BlankNewEntry(NewEntry):
 131     def __init__(self, basename):
 132         NewEntry.__init__(self, basename, basename,
 133                           0, 0, 0, 0, 0, 0, 0,
 134                           0, EMPTY_SHA, 0, 0, 0)
 135
 136
 137 class ExistingEntry(Entry):
 138     def __init__(self, basename, name, m, ofs):
 139         Entry.__init__(self, basename, name)
 140         self._m = m
 141         self._ofs = ofs
 142         (self.dev, self.ctime, self.mtime, self.uid, self.gid,
 143          self.size, self.mode, self.gitmode, self.sha,
 144          self.flags, self.children_ofs, self.children_n
 145          ) = struct.unpack(INDEX_SIG, str(buffer(m, ofs, ENTLEN)))
 146
 147     def repack(self):
 148         self._m[self._ofs:self._ofs+ENTLEN] = self.packed()
 149
 150     def iter(self, name=None):
 151         dname = name
 152         if dname and not dname.endswith('/'):
 153             dname += '/'
 154         ofs = self.children_ofs
 155         assert(ofs <= len(self._m))
 156         assert(self.children_n < 1000000)
 157         for i in xrange(self.children_n):
 158             eon = self._m.find('\0', ofs)
 159             assert(eon >= 0)
 160             assert(eon >= ofs)
 161             assert(eon > ofs)
 162             basename = str(buffer(self._m, ofs, eon-ofs))
 163             child = ExistingEntry(basename, self.name + basename,
 164                                   self._m, eon+1)
 165             if (not dname
 166                  or child.name.startswith(dname)
 167                  or child.name.endswith('/') and dname.startswith(child.name)):
 168                 for e in child.iter(name=name):
 169                     yield e
 170             if not name or child.name == name or child.name.startswith(dname):
 171                 yield child
 172             ofs = eon + 1 + ENTLEN
 173
 174     def __iter__(self):
 175         return self.iter()
 176
 177
 178 class Reader:
 179     def __init__(self, filename):
 180         self.filename = filename
 181         self.m = ''
 182         self.writable = False
 183         self.count = 0
 184         f = None
 185         try:
 186             f = open(filename, 'r+')
 187         except IOError, e:
 188             if e.errno == errno.ENOENT:
 189                 pass
 190             else:
 191                 raise
 192         if f:
 193             b = f.read(len(INDEX_HDR))
 194             if b != INDEX_HDR:
 195                 log('warning: %s: header: expected %r, got %r'
 196                                  % (filename, INDEX_HDR, b))
 197             else:
 198                 st = os.fstat(f.fileno())
 199                 if st.st_size:
 200                     self.m = mmap_readwrite(f)
 201                     self.writable = True
 202                     self.count = struct.unpack(FOOTER_SIG,
 203                           str(buffer(self.m, st.st_size-FOOTLEN, FOOTLEN)))[0]
 204
 205     def __del__(self):
 206         self.close()
 207
 208     def __len__(self):
 209         return int(self.count)
 210
 211     def forward_iter(self):
 212         ofs = len(INDEX_HDR)
 213         while ofs+ENTLEN <= len(self.m)-FOOTLEN:
 214             eon = self.m.find('\0', ofs)
 215             assert(eon >= 0)
 216             assert(eon >= ofs)
 217             assert(eon > ofs)
 218             basename = str(buffer(self.m, ofs, eon-ofs))
 219             yield ExistingEntry(basename, basename, self.m, eon+1)
 220             ofs = eon + 1 + ENTLEN
 221
 222     def iter(self, name=None):
 223         if len(self.m) > len(INDEX_HDR)+ENTLEN:
 224             dname = name
 225             if dname and not dname.endswith('/'):
 226                 dname += '/'
 227             root = ExistingEntry('/', '/', self.m, len(self.m)-FOOTLEN-ENTLEN)
 228             for sub in root.iter(name=name):
 229                 yield sub
 230             if not dname or dname == root.name:
 231                 yield root
 232
 233     def __iter__(self):
 234         return self.iter()
 235
 236     def exists(self):
 237         return self.m
 238
 239     def save(self):
 240         if self.writable and self.m:
 241             self.m.flush()
 242
 243     def close(self):
 244         self.save()
 245         if self.writable and self.m:
 246             self.m = None
 247             self.writable = False
 248
 249     def filter(self, prefixes):
 250         for (rp, path) in reduce_paths(prefixes):
 251             for e in self.iter(rp):
 252                 assert(e.name.startswith(rp))
 253                 name = path + e.name[len(rp):]
 254                 yield (name, e)
 255
 256
 257 class Writer:
 258     def __init__(self, filename):
 259         self.rootlevel = self.level = Level([], None)
 260         self.f = None
 261         self.count = 0
 262         self.lastfile = None
 263         self.filename = None
 264         self.filename = filename = realpath(filename)
 265         (dir,name) = os.path.split(filename)
 266         (ffd,self.tmpname) = tempfile.mkstemp('.tmp', filename, dir)
 267         self.f = os.fdopen(ffd, 'wb', 65536)
 268         self.f.write(INDEX_HDR)
 269
 270     def __del__(self):
 271         self.abort()
 272
 273     def abort(self):
 274         f = self.f
 275         self.f = None
 276         if f:
 277             f.close()
 278             os.unlink(self.tmpname)
 279
 280     def flush(self):
 281         if self.level:
 282             self.level = _golevel(self.level, self.f, [], None)
 283             self.count = self.rootlevel.count
 284             if self.count:
 285                 self.count += 1
 286             self.f.write(struct.pack(FOOTER_SIG, self.count))
 287             self.f.flush()
 288         assert(self.level == None)
 289
 290     def close(self):
 291         self.flush()
 292         f = self.f
 293         self.f = None
 294         if f:
 295             f.close()
 296             os.rename(self.tmpname, self.filename)
 297
 298     def _add(self, ename, entry):
 299         if self.lastfile and self.lastfile <= ename:
 300             raise Error('%r must come before %r'
 301                              % (''.join(e.name), ''.join(self.lastfile)))
 302             self.lastfile = e.name
 303         self.level = _golevel(self.level, self.f, ename, entry)
 304
 305     def add(self, name, st, hashgen = None):
 306         endswith = name.endswith('/')
 307         ename = pathsplit(name)
 308         basename = ename[-1]
 309         #log('add: %r %r\n' % (basename, name))
 310         flags = IX_EXISTS
 311         sha = None
 312         if hashgen:
 313             (gitmode, sha) = hashgen(name)
 314             flags |= IX_HASHVALID
 315         else:
 316             (gitmode, sha) = (0, EMPTY_SHA)
 317         if st:
 318             isdir = stat.S_ISDIR(st.st_mode)
 319             assert(isdir == endswith)
 320             e = NewEntry(basename, name, st.st_dev, int(st.st_ctime),
 321                          int(st.st_mtime), st.st_uid, st.st_gid,
 322                          st.st_size, st.st_mode, gitmode, sha, flags,
 323                          0, 0)
 324         else:
 325             assert(endswith)
 326             e = BlankNewEntry(basename)
 327             e.gitmode = gitmode
 328             e.sha = sha
 329             e.flags = flags
 330         self._add(ename, e)
 331
 332     def add_ixentry(self, e):
 333         e.children_ofs = e.children_n = 0
 334         self._add(pathsplit(e.name), e)
 335
 336     def new_reader(self):
 337         self.flush()
 338         return Reader(self.tmpname)
 339
 340
 341 def reduce_paths(paths):
 342     xpaths = []
 343     for p in paths:
 344         rp = realpath(p)
 345         try:
 346             st = os.lstat(rp)
 347             if stat.S_ISDIR(st.st_mode):
 348                 rp = slashappend(rp)
 349                 p = slashappend(p)
 350         except OSError, e:
 351             if e.errno != errno.ENOENT:
 352                 raise
 353         xpaths.append((rp, p))
 354     xpaths.sort()
 355
 356     paths = []
 357     prev = None
 358     for (rp, p) in xpaths:
 359         if prev and (prev == rp
 360                      or (prev.endswith('/') and rp.startswith(prev))):
 361             continue # already superceded by previous path
 362         paths.append((rp, p))
 363         prev = rp
 364     paths.sort(reverse=True)
 365     return paths
 366