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| 1 | +#$Id: _anydbm.py,v 1.1 2001-07-23 07:15:57 richard Exp $ |
| 2 | + |
| 3 | +import anydbm, os, cPickle |
| 4 | +from roundup import hyperdb, date |
| 5 | + |
| 6 | +# |
| 7 | +# Now the database |
| 8 | +# |
| 9 | +class Database(hyperdb.Database): |
| 10 | + """A database for storing records containing flexible data types.""" |
| 11 | + |
| 12 | + def __init__(self, storagelocator, journaltag=None): |
| 13 | + """Open a hyperdatabase given a specifier to some storage. |
| 14 | +
|
| 15 | + The meaning of 'storagelocator' depends on the particular |
| 16 | + implementation of the hyperdatabase. It could be a file name, |
| 17 | + a directory path, a socket descriptor for a connection to a |
| 18 | + database over the network, etc. |
| 19 | +
|
| 20 | + The 'journaltag' is a token that will be attached to the journal |
| 21 | + entries for any edits done on the database. If 'journaltag' is |
| 22 | + None, the database is opened in read-only mode: the Class.create(), |
| 23 | + Class.set(), and Class.retire() methods are disabled. |
| 24 | + """ |
| 25 | + self.dir, self.journaltag = storagelocator, journaltag |
| 26 | + self.classes = {} |
| 27 | + |
| 28 | + # |
| 29 | + # Classes |
| 30 | + # |
| 31 | + def __getattr__(self, classname): |
| 32 | + """A convenient way of calling self.getclass(classname).""" |
| 33 | + return self.classes[classname] |
| 34 | + |
| 35 | + def addclass(self, cl): |
| 36 | + cn = cl.classname |
| 37 | + if self.classes.has_key(cn): |
| 38 | + raise ValueError, cn |
| 39 | + self.classes[cn] = cl |
| 40 | + |
| 41 | + def getclasses(self): |
| 42 | + """Return a list of the names of all existing classes.""" |
| 43 | + l = self.classes.keys() |
| 44 | + l.sort() |
| 45 | + return l |
| 46 | + |
| 47 | + def getclass(self, classname): |
| 48 | + """Get the Class object representing a particular class. |
| 49 | +
|
| 50 | + If 'classname' is not a valid class name, a KeyError is raised. |
| 51 | + """ |
| 52 | + return self.classes[classname] |
| 53 | + |
| 54 | + # |
| 55 | + # Class DBs |
| 56 | + # |
| 57 | + def clear(self): |
| 58 | + for cn in self.classes.keys(): |
| 59 | + db = os.path.join(self.dir, 'nodes.%s'%cn) |
| 60 | + anydbm.open(db, 'n') |
| 61 | + db = os.path.join(self.dir, 'journals.%s'%cn) |
| 62 | + anydbm.open(db, 'n') |
| 63 | + |
| 64 | + def getclassdb(self, classname, mode='r'): |
| 65 | + ''' grab a connection to the class db that will be used for |
| 66 | + multiple actions |
| 67 | + ''' |
| 68 | + path = os.path.join(os.getcwd(), self.dir, 'nodes.%s'%classname) |
| 69 | + return anydbm.open(path, mode) |
| 70 | + |
| 71 | + def addnode(self, classname, nodeid, node): |
| 72 | + ''' add the specified node to its class's db |
| 73 | + ''' |
| 74 | + db = self.getclassdb(classname, 'c') |
| 75 | + db[nodeid] = cPickle.dumps(node, 1) |
| 76 | + db.close() |
| 77 | + setnode = addnode |
| 78 | + |
| 79 | + def getnode(self, classname, nodeid, cldb=None): |
| 80 | + ''' add the specified node to its class's db |
| 81 | + ''' |
| 82 | + db = cldb or self.getclassdb(classname) |
| 83 | + if not db.has_key(nodeid): |
| 84 | + raise IndexError, nodeid |
| 85 | + res = cPickle.loads(db[nodeid]) |
| 86 | + if not cldb: db.close() |
| 87 | + return res |
| 88 | + |
| 89 | + def hasnode(self, classname, nodeid, cldb=None): |
| 90 | + ''' add the specified node to its class's db |
| 91 | + ''' |
| 92 | + db = cldb or self.getclassdb(classname) |
| 93 | + res = db.has_key(nodeid) |
| 94 | + if not cldb: db.close() |
| 95 | + return res |
| 96 | + |
| 97 | + def countnodes(self, classname, cldb=None): |
| 98 | + db = cldb or self.getclassdb(classname) |
| 99 | + return len(db.keys()) |
| 100 | + if not cldb: db.close() |
| 101 | + return res |
| 102 | + |
| 103 | + def getnodeids(self, classname, cldb=None): |
| 104 | + db = cldb or self.getclassdb(classname) |
| 105 | + res = db.keys() |
| 106 | + if not cldb: db.close() |
| 107 | + return res |
| 108 | + |
| 109 | + # |
| 110 | + # Journal |
| 111 | + # |
| 112 | + def addjournal(self, classname, nodeid, action, params): |
| 113 | + ''' Journal the Action |
| 114 | + 'action' may be: |
| 115 | +
|
| 116 | + 'create' or 'set' -- 'params' is a dictionary of property values |
| 117 | + 'link' or 'unlink' -- 'params' is (classname, nodeid, propname) |
| 118 | + 'retire' -- 'params' is None |
| 119 | + ''' |
| 120 | + entry = (nodeid, date.Date(), self.journaltag, action, params) |
| 121 | + db = anydbm.open(os.path.join(self.dir, 'journals.%s'%classname), 'c') |
| 122 | + if db.has_key(nodeid): |
| 123 | + s = db[nodeid] |
| 124 | + l = cPickle.loads(db[nodeid]) |
| 125 | + l.append(entry) |
| 126 | + else: |
| 127 | + l = [entry] |
| 128 | + db[nodeid] = cPickle.dumps(l) |
| 129 | + db.close() |
| 130 | + |
| 131 | + def getjournal(self, classname, nodeid): |
| 132 | + ''' get the journal for id |
| 133 | + ''' |
| 134 | + db = anydbm.open(os.path.join(self.dir, 'journals.%s'%classname), 'r') |
| 135 | + res = cPickle.loads(db[nodeid]) |
| 136 | + db.close() |
| 137 | + return res |
| 138 | + |
| 139 | + def close(self): |
| 140 | + ''' Close the Database - we must release the circular refs so that |
| 141 | + we can be del'ed and the underlying anydbm connections closed |
| 142 | + cleanly. |
| 143 | + ''' |
| 144 | + self.classes = None |
| 145 | + |
| 146 | + |
| 147 | + # |
| 148 | + # Basic transaction support |
| 149 | + # |
| 150 | + # TODO: well, write these methods (and then use them in other code) |
| 151 | + def register_action(self): |
| 152 | + ''' Register an action to the transaction undo log |
| 153 | + ''' |
| 154 | + |
| 155 | + def commit(self): |
| 156 | + ''' Commit the current transaction, start a new one |
| 157 | + ''' |
| 158 | + |
| 159 | + def rollback(self): |
| 160 | + ''' Reverse all actions from the current transaction |
| 161 | + ''' |
| 162 | + |
| 163 | +# |
| 164 | +#$Log: not supported by cvs2svn $ |
| 165 | +# |
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