Added temporary storage for subtransactions.

src/ZODB/TmpStore.py

+##############################################################################
+# 
+# Zope Public License (ZPL) Version 1.0
+# -------------------------------------
+# 
+# Copyright (c) Digital Creations.  All rights reserved.
+# 
+# This license has been certified as Open Source(tm).
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+# 
+# 1. Redistributions in source code must retain the above copyright
+#    notice, this list of conditions, and the following disclaimer.
+# 
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions, and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 
+# 3. Digital Creations requests that attribution be given to Zope
+#    in any manner possible. Zope includes a "Powered by Zope"
+#    button that is installed by default. While it is not a license
+#    violation to remove this button, it is requested that the
+#    attribution remain. A significant investment has been put
+#    into Zope, and this effort will continue if the Zope community
+#    continues to grow. This is one way to assure that growth.
+# 
+# 4. All advertising materials and documentation mentioning
+#    features derived from or use of this software must display
+#    the following acknowledgement:
+# 
+#      "This product includes software developed by Digital Creations
+#      for use in the Z Object Publishing Environment
+#      (http://www.zope.org/)."
+# 
+#    In the event that the product being advertised includes an
+#    intact Zope distribution (with copyright and license included)
+#    then this clause is waived.
+# 
+# 5. Names associated with Zope or Digital Creations must not be used to
+#    endorse or promote products derived from this software without
+#    prior written permission from Digital Creations.
+# 
+# 6. Modified redistributions of any form whatsoever must retain
+#    the following acknowledgment:
+# 
+#      "This product includes software developed by Digital Creations
+#      for use in the Z Object Publishing Environment
+#      (http://www.zope.org/)."
+# 
+#    Intact (re-)distributions of any official Zope release do not
+#    require an external acknowledgement.
+# 
+# 7. Modifications are encouraged but must be packaged separately as
+#    patches to official Zope releases.  Distributions that do not
+#    clearly separate the patches from the original work must be clearly
+#    labeled as unofficial distributions.  Modifications which do not
+#    carry the name Zope may be packaged in any form, as long as they
+#    conform to all of the clauses above.
+# 
+# 
+# Disclaimer
+# 
+#   THIS SOFTWARE IS PROVIDED BY DIGITAL CREATIONS ``AS IS'' AND ANY
+#   EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+#   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+#   PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL DIGITAL CREATIONS OR ITS
+#   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+#   USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+#   ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+#   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+#   OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+#   SUCH DAMAGE.
+# 
+# 
+# This software consists of contributions made by Digital Creations and
+# many individuals on behalf of Digital Creations.  Specific
+# attributions are listed in the accompanying credits file.
+# 
+##############################################################################
+
+import POSException
+from utils import p64, u64
+
+class TmpStore:
+    _transaction=_isCommitting=None
+
+    def __init__(self, base_version, file=None):
+        if file is None:
+            import tempfile
+            file=tempfile.TemporaryFile()
+
+        self._file=file
+        self._index={}
+        self._pos=self._tpos=0
+        self._bver=base_version
+        self._tindex=[]
+        self._db=None
+
+    def __del__(self): self.close()
+
+    def close(self):
+        self._file.close()
+        del self._file
+        del self._index
+        del self._db
+
+    def getName(self): return self._db.getName()
+    def getSize(self): return self._pos
+
+    def load(self, oid, version):
+        #if version is not self: raise KeyError, oid
+        pos=self._index.get(oid, None)
+        if pos is None:
+            return self._storage.load(oid, self._bver)
+        file=self._file
+        file.seek(pos)
+        h=file.read(24)
+        if h[:8] != oid:
+            raise POSException.StorageSystemError, 'Bad temporary storage'
+        return file.read(u64(h[16:])), h[8:16]
+        
+    def modifiedInVersion(self, oid):
+        if self._index.has_key(oid): return 1
+        return self._db._storage.modifiedInVersion(oid)
+
+    def new_oid(self): return self._db._storage.new_oid()
+
+    def registerDB(self, db, limit):
+        self._db=db
+        self._storage=db._storage
+
+    def store(self, oid, serial, data, version, transaction):
+        if transaction is not self._transaction:
+            raise POSException.StorageTransactionError(self, transaction)
+        file=self._file
+        pos=self._pos
+        file.seek(pos)
+        l=len(data)
+        file.write(oid+serial+p64(l))
+        file.write(data)
+        self._tindex.append((oid,pos))
+        self._pos=pos+l+24
+        return serial
+        
+    def tpc_abort(self, transaction):
+        if transaction is not self._transaction: return
+        del self._tindex[:]
+        self._transaction=None
+        self._pos=self._tpos
+
+    def tpc_begin(self, transaction):
+        if self._transaction is transaction: return
+        self._transaction=transaction
+        del self._tindex[:]   # Just to be sure!
+        self._pos=self._tpos
+
+    def tpc_finish(self, transaction, f=None):
+        if transaction is not self._transaction: return
+        if f is not None: f()
+        index=self._index
+        tindex=self._tindex
+        for oid, pos in tindex: index[oid]=pos
+        del tindex[:]
+        self._tpos=self._pos
+
+    def undoLog(self, first, last, filter=None): return ()
+    
+    def versionEmpty(self, version):
+        if version is self: return len(self._index)