[Checkins]
SVN: ZODB/branches/jim-storage-api-cleanup/src/ZODB/BaseStorage.py
Updated to work with new model in which storages that don't support
Jim Fulton
jim at zope.com
Thu Apr 26 15:35:42 EDT 2007
Log message for revision 74813:
Updated to work with new model in which storages that don't support
undo don't have to provide any undo messages.
Changed:
U ZODB/branches/jim-storage-api-cleanup/src/ZODB/BaseStorage.py
-=-
Modified: ZODB/branches/jim-storage-api-cleanup/src/ZODB/BaseStorage.py
===================================================================
--- ZODB/branches/jim-storage-api-cleanup/src/ZODB/BaseStorage.py 2007-04-26 19:01:08 UTC (rev 74812)
+++ ZODB/branches/jim-storage-api-cleanup/src/ZODB/BaseStorage.py 2007-04-26 19:35:41 UTC (rev 74813)
@@ -54,21 +54,7 @@
If it stores multiple revisions, it should implement
loadSerial()
loadBefore()
- iterator()
- If the subclass wants to implement undo, it should implement the
- multiple revision methods and:
- undo()
- undoInfo()
- undoLog()
-
- If the subclass wants to implement versions, it must implement:
- abortVersion()
- commitVersion()
- modifiedInVersion()
- versionEmpty()
- versions()
-
Each storage will have two locks that are accessed via lock
acquire and release methods bound to the instance. (Yuck.)
_lock_acquire / _lock_release (reentrant)
@@ -112,12 +98,6 @@
else:
self._oid = oid
- def close(self):
- pass
-
- def cleanup(self):
- pass
-
def sortKey(self):
"""Return a string that can be used to sort storage instances.
@@ -186,7 +166,7 @@
def _abort(self):
"""Subclasses should redefine this to supply abort actions"""
- raise NotImplementedError
+ pass
def tpc_begin(self, transaction, tid=None, status=' '):
if self._is_read_only:
@@ -230,7 +210,7 @@
def _begin(self, tid, u, d, e):
"""Subclasses should redefine this to supply transaction start actions.
"""
- raise NotImplementedError
+ pass
def tpc_vote(self, transaction):
self._lock_acquire()
@@ -244,7 +224,7 @@
def _vote(self):
"""Subclasses should redefine this to supply transaction vote actions.
"""
- raise NotImplementedError
+ pass
def tpc_finish(self, transaction, f=None):
# It's important that the storage calls the function we pass
@@ -279,7 +259,14 @@
def getTid(self, oid):
self._lock_acquire()
try:
- v = self.modifiedInVersion(oid)
+ v = ''
+ try:
+ supportsVersions = self.supportsVersions
+ except AttributeError:
+ pass
+ else:
+ if supportsVersions():
+ v = self.modifiedInVersion(oid)
pickledata, serial = self.load(oid, v)
return serial
finally:
@@ -291,120 +278,78 @@
def loadBefore(self, oid, tid):
"""Return most recent revision of oid before tid committed."""
+ return None
- # Unsure: Is it okay for loadBefore() to return current data?
- # There doesn't seem to be a good reason to forbid it, even
- # though the typical use of this method will never find
- # current data. But maybe we should call it loadByTid()?
-
- n = 2
- start_time = None
- end_time = None
- while start_time is None:
- # The history() approach is a hack, because the dict
- # returned by history() doesn't contain a tid. It
- # contains a serialno, which is often the same, but isn't
- # required to be. We'll pretend it is for now.
-
- # A second problem is that history() doesn't say anything
- # about whether the transaction status. If it falls before
- # the pack time, we can't honor the MVCC request.
-
- # Note: history() returns the most recent record first.
-
- # TODO: The filter argument to history() only appears to be
- # supported by FileStorage. Perhaps it shouldn't be used.
- L = self.history(oid, "", n, lambda d: not d["version"])
- if not L:
- return
- for d in L:
- if d["serial"] < tid:
- start_time = d["serial"]
- break
- else:
- end_time = d["serial"]
- if len(L) < n:
- break
- n *= 2
- if start_time is None:
- return None
- data = self.loadSerial(oid, start_time)
- return data, start_time, end_time
-
- def getExtensionMethods(self):
- """getExtensionMethods
-
- This returns a dictionary whose keys are names of extra methods
- provided by this storage. Storage proxies (such as ZEO) should
- call this method to determine the extra methods that they need
- to proxy in addition to the standard storage methods.
- Dictionary values should be None; this will be a handy place
- for extra marshalling information, should we need it
- """
- return {}
-
def copyTransactionsFrom(self, other, verbose=0):
"""Copy transactions from another storage.
This is typically used for converting data from one storage to
another. `other` must have an .iterator() method.
"""
- _ts=None
- ok=1
- preindex={};
- preget=preindex.get # waaaa
- # restore() is a new storage API method which has an identical
- # signature to store() except that it does not return anything.
- # Semantically, restore() is also identical to store() except that it
- # doesn't do the ConflictError or VersionLockError consistency
- # checks. The reason to use restore() over store() in this method is
- # that store() cannot be used to copy transactions spanning a version
- # commit or abort, or over transactional undos.
- #
- # We'll use restore() if it's available, otherwise we'll fall back to
- # using store(). However, if we use store, then
- # copyTransactionsFrom() may fail with VersionLockError or
- # ConflictError.
- restoring = hasattr(self, 'restore')
- fiter = other.iterator()
- for transaction in fiter:
- tid=transaction.tid
- if _ts is None:
- _ts=TimeStamp(tid)
+ copy(other, self, verbose)
+
+def copy(source, dest, verbose=0):
+ """Copy transactions from a source to a destination storage
+
+ This is typically used for converting data from one storage to
+ another. `source` must have an .iterator() method.
+ """
+ _ts = None
+ ok = 1
+ preindex = {};
+ preget = preindex.get
+ # restore() is a new storage API method which has an identical
+ # signature to store() except that it does not return anything.
+ # Semantically, restore() is also identical to store() except that it
+ # doesn't do the ConflictError or VersionLockError consistency
+ # checks. The reason to use restore() over store() in this method is
+ # that store() cannot be used to copy transactions spanning a version
+ # commit or abort, or over transactional undos.
+ #
+ # We'll use restore() if it's available, otherwise we'll fall back to
+ # using store(). However, if we use store, then
+ # copyTransactionsFrom() may fail with VersionLockError or
+ # ConflictError.
+ restoring = hasattr(dest, 'restore')
+ fiter = source.iterator()
+ for transaction in fiter:
+ tid = transaction.tid
+ if _ts is None:
+ _ts = TimeStamp(tid)
+ else:
+ t = TimeStamp(tid)
+ if t <= _ts:
+ if ok: print ('Time stamps out of order %s, %s' % (_ts, t))
+ ok = 0
+ _ts = t.laterThan(_ts)
+ tid = `_ts`
else:
- t=TimeStamp(tid)
- if t <= _ts:
- if ok: print ('Time stamps out of order %s, %s' % (_ts, t))
- ok=0
- _ts=t.laterThan(_ts)
- tid=`_ts`
- else:
- _ts = t
- if not ok:
- print ('Time stamps back in order %s' % (t))
- ok=1
+ _ts = t
+ if not ok:
+ print ('Time stamps back in order %s' % (t))
+ ok = 1
+ if verbose:
+ print _ts
+
+ dest.tpc_begin(transaction, tid, transaction.status)
+ for r in transaction:
+ oid = r.oid
if verbose:
- print _ts
+ print oid_repr(oid), r.version, len(r.data)
+ if restoring:
+ dest.restore(oid, r.tid, r.data, r.version,
+ r.data_txn, transaction)
+ else:
+ pre = preget(oid, None)
+ s = dest.store(oid, pre, r.data, r.version, transaction)
+ preindex[oid] = s
- self.tpc_begin(transaction, tid, transaction.status)
- for r in transaction:
- oid=r.oid
- if verbose:
- print oid_repr(oid), r.version, len(r.data)
- if restoring:
- self.restore(oid, r.tid, r.data, r.version,
- r.data_txn, transaction)
- else:
- pre=preget(oid, None)
- s=self.store(oid, pre, r.data, r.version, transaction)
- preindex[oid]=s
+ dest.tpc_vote(transaction)
+ dest.tpc_finish(transaction)
- self.tpc_vote(transaction)
- self.tpc_finish(transaction)
+ fiter.close()
- fiter.close()
-
class TransactionRecord:
"""Abstract base class for iterator protocol"""
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