Reduced code duplication when creating rock db file.
Initial Large Rock implmentation.

Needs polishing, a better replacement policy, and rebuild fixes.
xmemset was removed from Squid sources recently
Use newly added slot-size cache_dir parameter instead of abusing max-size.

Use unique suffixes for inode and free slot index names.
Use unique map/index paths not only when creating their shared memory segments
but also when opening those segments.
Maximum number of slots is the maximum number of entries rather than
maximum number of bytes.

Renamed loaded member to processed, to avoid name clash with a local counter.
Prevent Rock Store map entries being locked for reading forever.

The map entries were locked to serve a hit but the client side carelessly
discarded the attached StoreEntry object when the hit had to be ignored.
Discarded StoreEntry object was left idle because it was never [un]locked.
Fixed SMP cache manager request handling.

Same as trunk r12564.
Provide a safer version of a "is set" operator and
its explicitly named equivalent.
Debug push and pop operations.
Split lock() into "just lock" and "update entry reference time" interfaces.
Improved entry lock/unlock debugging.

Several modern store entry users need to lock the entry for storage rather
then to update entry's reference time. There is an old XXX describing the
corresponding API bug that merges the two distinct operations. This change
does not modify existing code, but allows new code to use new/fixed API
instead of changing an essentially private entry lock counter.
Adjusted StoreIOState::write() API to allow callers detect write errors.

The errors are reported without these changes, but only via callbacks, some of
which may be asynchronous. Callers such as doPages() would keep calling
write() after the failure. It is probably best to quit early instead of
ignoring "post-error" state in StoreIOState::write().

Added StoreIOState::write() API description.
Do not reject size-less entries in storeRebuildParseEntry(). Deal with
entry size in the caller.

Some callers can handle entries that had unknown (at swapout start time) sizes.

Added rebuild debugging.
Fixed job entering/leaving search patterns in job tracing scripts.

Same as trunk r12530.
Fixed job entering/leaving search patterns in job tracing scripts.

Same as trunk r12530.
Added patterns for finding Ipc::StoreMap entries.
Use size_t instead of int32_t for blob sizes
because MemBlob only stores in-memory things and does not use negative sizes.
Working Large Rock implementation, including concurrent store "rebuild"
and a simple "scan" replacement policy.

Needs polishing and possibly a swap.state equivalent for faster rebuild.
Synced with Ipc::StoreMap API changes. No functionality changes expected.
Moved StoreMapSlice declaration and ctor definition into StoreMap.h
as too small/trivial to warrant dedicated source files.