storagewrapper.py

一个多点下载且源码公开的P2P软件

            self.data_flunked(length, index)
            self.inactive_requests[index] = 1
            self.amount_inactive += length
            self.stat_numflunked += 1

            self.failed_pieces[index] = {}
            allsenders = {}
            for d in self.download_history[index].values():
                allsenders[d] = 1
            if len(allsenders) == 1:
                culprit = allsenders.keys()[0]
                if culprit is not None:
                    culprit.failed(index, bump = True)
                del self.failed_pieces[index] # found the culprit already
            
            return False

        self.have[index] = True
        self.inactive_requests[index] = None
        self.waschecked[index] = True
        self.amount_left -= length
        self.stat_numdownloaded += 1

        for d in self.download_history[index].values():
            if d is not None:
                d.good(index)
        del self.download_history[index]
        if self.failed_pieces.has_key(index):
            for d in self.failed_pieces[index].keys():
                if d is not None:
                    d.failed(index)
            del self.failed_pieces[index]

        if self.amount_left == 0:
            self.finished()
        return True


    def request_lost(self, index, begin, length):
        assert not (begin, length) in self.inactive_requests[index]
        insort(self.inactive_requests[index], (begin, length))
        self.amount_inactive += length
        self.numactive[index] -= 1
        if not self.numactive[index]:
            del self.stat_active[index]
            if self.stat_new.has_key(index):
                del self.stat_new[index]


    def get_piece(self, index, begin, length):
        if not self.have[index]:
            return None
        data = None
        if not self.waschecked[index]:
            data = self.read_raw(self.places[index], 0, self._piecelen(index))
            if data is None:
                return None
            if sha(data[:]).digest() != self.hashes[index]:
                self.failed('told file complete on start-up, but piece failed hash check')
                return None
            self.waschecked[index] = True
            if length == -1 and begin == 0:
                return data     # optimization
        if length == -1:
            if begin > self._piecelen(index):
                return None
            length = self._piecelen(index)-begin
            if begin == 0:
                return self.read_raw(self.places[index], 0, length)
        elif begin + length > self._piecelen(index):
            return None
        if data is not None:
            s = data[begin:begin+length]
            data.release()
            return s
        data = self.read_raw(self.places[index], begin, length)
        if data is None:
            return None
        s = data.getarray()
        data.release()
        return s

    def read_raw(self, piece, begin, length, flush_first = False):
        try:
            return self.storage.read(self.piece_size * piece + begin,
                                                     length, flush_first)
        except IOError, e:
            self.failed('IO Error: ' + str(e))
            return None


    def set_file_readonly(self, n):
        try:
            self.storage.set_readonly(n)
        except IOError, e:
            self.failed('IO Error: ' + str(e))
        except OSError, e:
            self.failed('OS Error: ' + str(e))


    def has_data(self, index):
        return index not in self.holes and index not in self.blocked_holes

    def doublecheck_data(self, pieces_to_check):
        if not self.double_check:
            return
        sources = []
        for p,v in self.places.items():
            if pieces_to_check.has_key(v):
                sources.append(p)
        assert len(sources) == len(pieces_to_check)
        sources.sort()
        for index in sources:
            if self.have[index]:
                piece = self.read_raw(self.places[index],0,self._piecelen(index),
                                       flush_first = True )
                if piece is None:
                    return False
                if sha(piece[:]).digest() != self.hashes[index]:
                    self.failed('download corrupted; please restart and resume')
                    return False
                piece.release()
        return True


    def reblock(self, new_blocked):
        # assume downloads have already been canceled and chunks made inactive
        for i in xrange(len(new_blocked)):
            if new_blocked[i] and not self.blocked[i]:
                length = self._piecelen(i)
                self.amount_desired -= length
                if self.have[i]:
                    self.amount_obtained -= length
                    continue
                if self.inactive_requests[i] == 1:
                    self.amount_inactive -= length
                    continue
                inactive = 0
                for nb, nl in self.inactive_requests[i]:
                    inactive += nl
                self.amount_inactive -= inactive
                self.amount_obtained -= length - inactive
                
            if self.blocked[i] and not new_blocked[i]:
                length = self._piecelen(i)
                self.amount_desired += length
                if self.have[i]:
                    self.amount_obtained += length
                    continue
                if self.inactive_requests[i] == 1:
                    self.amount_inactive += length
                    continue
                inactive = 0
                for nb, nl in self.inactive_requests[i]:
                    inactive += nl
                self.amount_inactive += inactive
                self.amount_obtained += length - inactive

        self.blocked = new_blocked

        self.blocked_movein = Olist()
        self.blocked_moveout = Olist()
        for p,v in self.places.items():
            if p != v:
                if self.blocked[p] and not self.blocked[v]:
                    self.blocked_movein.add(p)
                elif self.blocked[v] and not self.blocked[p]:
                    self.blocked_moveout.add(p)

        self.holes.extend(self.blocked_holes)    # reset holes list
        self.holes.sort()
        self.blocked_holes = []


    '''
    Pickled data format:

    d['pieces'] = either a string containing a bitfield of complete pieces,
                    or the numeric value "1" signifying a seed.  If it is
                    a seed, d['places'] and d['partials'] should be empty
                    and needn't even exist.
    d['partials'] = [ piece, [ offset, length... ]... ]
                    a list of partial data that had been previously
                    downloaded, plus the given offsets.  Adjacent partials
                    are merged so as to save space, and so that if the
                    request size changes then new requests can be
                    calculated more efficiently.
    d['places'] = [ piece, place, {,piece, place ...} ]
                    the piece index, and the place it's stored.
                    If d['pieces'] specifies a complete piece or d['partials']
                    specifies a set of partials for a piece which has no
                    entry in d['places'], it can be assumed that
                    place[index] = index.  A place specified with no
                    corresponding data in d['pieces'] or d['partials']
                    indicates allocated space with no valid data, and is
                    reserved so it doesn't need to be hash-checked.
    '''
    def pickle(self):
        if self.have.complete():
            return {'pieces': 1}
        pieces = Bitfield(len(self.hashes))
        places = []
        partials = []
        for p in xrange(len(self.hashes)):
            if self.blocked[p] or not self.places.has_key(p):
                continue
            h = self.have[p]
            pieces[p] = h
            pp = self.dirty.get(p)
            if not h and not pp:  # no data
                places.extend([self.places[p],self.places[p]])
            elif self.places[p] != p:
                places.extend([p, self.places[p]])
            if h or not pp:
                continue
            pp.sort()
            r = []
            while len(pp) > 1:
                if pp[0][0]+pp[0][1] == pp[1][0]:
                    pp[0] = list(pp[0])
                    pp[0][1] += pp[1][1]
                    del pp[1]
                else:
                    r.extend(pp[0])
                    del pp[0]
            r.extend(pp[0])
            partials.extend([p,r])
        return {'pieces': pieces.tostring(), 'places': places, 'partials': partials}


    def unpickle(self, data, valid_places):
        got = {}
        places = {}
        dirty = {}
        download_history = {}
        stat_active = {}
        stat_numfound = self.stat_numfound
        amount_obtained = self.amount_obtained
        amount_inactive = self.amount_inactive
        amount_left = self.amount_left
        inactive_requests = [x for x in self.inactive_requests]
        restored_partials = []

        try:
            if data['pieces'] == 1:     # a seed
                assert not data.get('places',None)
                assert not data.get('partials',None)
                have = Bitfield(len(self.hashes))
                for i in xrange(len(self.hashes)):
                    have[i] = True
                assert have.complete()
                _places = []
                _partials = []
            else:
                have = Bitfield(len(self.hashes), data['pieces'])
                _places = data['places']
                assert len(_places) % 2 == 0
                _places = [_places[x:x+2] for x in xrange(0,len(_places),2)]
                _partials = data['partials']
                assert len(_partials) % 2 == 0
                _partials = [_partials[x:x+2] for x in xrange(0,len(_partials),2)]
                
            for index, place in _places:
                if place not in valid_places:
                    continue
                assert not got.has_key(index)
                assert not got.has_key(place)
                places[index] = place
                got[index] = 1
                got[place] = 1

            for index in xrange(len(self.hashes)):
                if have[index]:
                    if not places.has_key(index):
                        if index not in valid_places:
                            have[index] = False
                            continue
                        assert not got.has_key(index)
                        places[index] = index
                        got[index] = 1
                    length = self._piecelen(index)
                    amount_obtained += length
                    stat_numfound += 1
                    amount_inactive -= length
                    amount_left -= length
                    inactive_requests[index] = None

            for index, plist in _partials:
                assert not dirty.has_key(index)
                assert not have[index]
                if not places.has_key(index):
                    if index not in valid_places:
                        continue
                    assert not got.has_key(index)
                    places[index] = index
                    got[index] = 1
                assert len(plist) % 2 == 0
                plist = [plist[x:x+2] for x in xrange(0,len(plist),2)]
                dirty[index] = plist
                stat_active[index] = 1
                download_history[index] = {}
                # invert given partials
                length = self._piecelen(index)
                l = []
                if plist[0][0] > 0:
                    l.append((0,plist[0][0]))
                for i in xrange(len(plist)-1):
                    end = plist[i][0]+plist[i][1]
                    assert not end > plist[i+1][0]
                    l.append((end,plist[i+1][0]-end))
                end = plist[-1][0]+plist[-1][1]
                assert not end > length
                if end < length:
                    l.append((end,length-end))
                # split them to request_size
                ll = []
                amount_obtained += length
                amount_inactive -= length
                for nb, nl in l:
                    while nl > 0:
                        r = min(nl,self.request_size)
                        ll.append((nb,r))
                        amount_inactive += r
                        amount_obtained -= r
                        nb += self.request_size
                        nl -= self.request_size
                inactive_requests[index] = ll
                restored_partials.append(index)

            assert amount_obtained + amount_inactive == self.amount_desired
        except:
#            print_exc()
            return []   # invalid data, discard everything

        self.have = have
        self.places = places
        self.dirty = dirty
        self.download_history = download_history
        self.stat_active = stat_active
        self.stat_numfound = stat_numfound
        self.amount_obtained = amount_obtained
        self.amount_inactive = amount_inactive
        self.amount_left = amount_left
        self.inactive_requests = inactive_requests
                
        return restored_partials