Allocate OIDs to new objects in the PSpace

The following methods on a PSpace allow for making new IPersistable objects persist. An IPersistable has an OID allocated if and only if it persists on secondary storage.

$adt+ PSpace
{
    ...
    void MakeObjectPersist(OidLow affiliateOidLow, ptr<IPersistable> po);
    OID AllocateOid(OidHigh oidHigh, bool useIncrementalOidAllocations);
    OidHigh GetOidHighForOidAllocations() const;
    void SetOidHighForOidAllocations(OidHigh oidHigh, bool useIncrementalOidAllocations);
    bool MakeObjectPersistWithGivenOID(ptr<IPersistable> po, OID oid, bool trace);
    void DeclareReachable(ptr<const IPersistable> parent, ptr<const IPersistable> child, bool trace);
    void MakeReachableObjectsPersist(ptr<IPersistable> po);
};

Only the thread with write access to the PSpace is allowed to allocate OIDs to objects. Therefore in the following functions we don't need to be concerned with multiple threads.

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void MakeObjectPersist(OidLow affiliateOidLow, ptr<IPersistable> po)

po must not have an OID already. po is allocated an oid affiliated with affiliateOidLow and added to the PSpace. No trace is performed (i.e. to allocate oids to objects reachable from po). Must be called by a thread that has an exclusive lock on the associated CSpace.

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OID AllocateOid(OidHigh oidHigh, bool useIncrementalOidAllocations)

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OidHigh GetOidHighForOidAllocations() const
void SetOidHighForOidAllocations(OidHigh oidHigh, bool useIncrementalOidAllocations)

We provide the means for the OidHigh used for OID allocations to be temporarily overidden. A thread achieves that by pushing a new OidHigh and later popping it.

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bool MakeObjectPersistWithGivenOID(ptr<IPersistable> po, OID oid, bool trace)

po must not have an OID allocated. Allocates oid to po, and runs a trace from po to allocate any additional OIDs as required. If trace is true then use IObjectVisitor to recursively allocate OIDs to IPersistable objects. Must be called by a thread that has an exclusive lock on the associated CSpace. Returns false if there is already an object in the ROT with the given oid.

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void DeclareReachable(ptr<const IPersistable> parent, ptr<const IPersistable> child, bool trace)

Must be called by a thread that has an exclusive lock on the associated CSpace Declare the fact that child has become reachable from parent. This will run a full trace from child, allocating an OID to child and any additional objects reachable from child. Must be called by a thread that has an exclusive lock on the associated CSpace

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void MakeReachableObjectsPersist(ptr<IPersistable> po)

Make all objects reachable from po persist. Assumes po is already persistent. Must be called by a thread that has an exclusive lock on the associated CSpace.