[MERGE] SourceLayout: acl/, take1

SourceLayout: acl/, take 1

Moved src/ACL* and a few related files into src/acl/.
Renamed ACL source files from ACLFoo.{cc,cci,h} to Foo.{cc,cci,h}.

Added acl/ libraries, reorganized auth/ libraries, and split
ACLChecklist class to avoid circular dependencies among libraries.

Many targets in src/Makefile.am depended on selected ACL*cc and related
sources. These targets depend on acl/* libraries now. As a part of this
cleanup, the number of ufsdump sources went from about 160 to about 20.

No functionality changes were intended. Source code changes were kept to
the minimum. All my build tests are successful, including "make
distcheck". However, since I had to move a lot of files, move some code
pieces, and split ACLChecklist, it is possible that some targets will no
longer build in some environments and some authentication code will
break. Please test.

For details, please see individual commit messages below.

Thank you,

Alex.
bb:approve

---------------- change log ------------------
* Moved src/ACL* and a few related files into src/acl/.
  Renamed ACL source files from ACLFoo.{cc,cci,h} to Foo.{cc,cci,h}.
 
  Many targets in src/Makefile.am depended on selected ACL ACL*cc and
related
  sources. These targets depend on acl/* libraries now.

* Extracted transaction state storage and related checks from
ACLChecklist into
  ACLFilledChecklist.
 
  ACLChecklist contained many data members representing the state of the
current
  transaction (in a broad sense). These members and related methods depended
  on complex types such as HttpRequest and ConnStateData. Any Squid code
using
  ACLChecklist (and there is a lot of that code) was, hence, dependent
on these
  types. These dependencies caused, among other things, huge SOURCES
lists in
  src/Makefile.am, often for trivial targets such as ufsdump and test cases.
 
  ACLChecklist is an abstract class now (to make sure we do not accidentally
  create it). ACLChecklist has only one kid: ACLFilledChecklist. The
Filled()
  global function can be used to cast ACLChecklist* to ACLFilledChecklist*.
  Since all ACLChecklist objects have to be ACLFilledChecklist objects,
the cast
  is fast and safe. The cast allows us to avoid bloating ACLChecklist with
  virtual methods that only make sense in ACLFilledChecklist context.
 
  ACLFilledChecklist now contains state-specific members while ACLChecklist
  contains basic check list logic. The code that organizes or passes through
  ACL checks does not need to be exposed to ACLFilledChecklist and the data
  types it depends on.
 
  Furthermore, ACLFilledChecklist should not contain complicated checks
either.
  It should focus on maintaining the state. The checks should go into
specific
  ACLs. Otherwise, complex checks cause dependency cycles with higher-level
  libraries that provide code for those checks and yet depend on having
access
  to ACLFilledChecklist to implement specific ACLs. Currently, only the
  authenticated() method got moved to auth/Acl.{cc,h} to break the circular
  dependency between acl/libs and auth/libs. More work in that direction
will
  probably be required as we move more src/* code into libraries.
 
  ACLFilledChecklist constructor replaces aclChecklistCreate global. This
  simplifies the initiating code of all fast ACL checks: the checks no
longer
  need to do manual state locking, duplicating aclChecklistCreate code.

* Split auth/libauth into two libraries:
 
    - auth/libauth containing core authentication code (used, in part,
      by the acl/libstate library) and not using acl/ libraries; and
    - auth/libacls containing authentication-related ACL code (used to build
      executables) and using acl/libstate.
 
  The split was necessary to prevent circular dependencies among acl/
and auth/
  libraries.
 
  Added conditionally built libraries to libauth, eliminating the need for
  AUTH_LIBS_TO_ADD. Use libtool to build those libraries.

* Moved authenticated() method from ACL[Filled]Checklist into
auth/Acl.{cc,h} to
  break the circular dependency between acl/libs and auth/libs.

* Split ACL.{cc,h} and src/acl_noncore.cc into acl/Acl and acl/Gadgets,
moving
  high-level global functions into Gadgets and leaving basic API types
in Acl.
 
  Moved horrific acl_access::containsPURGE into aclPurgeMethodInUse to avoid
  exposing basic ACL API to "strategy" templates and HTTP-specific PURGE
method.
  The aclPurgeMethodInUse global lives in acl/libacls, which is a top-level
  library that already contains a lot of data-specific code.

* Synced #includes after moving files around.
 
  Use newly added ACLFilledChecklist for fast ACL checks. Its
constructor locks
  request and accessList, simplifying the caller code.
 
  Use newly added ACLFilledChecklist for state-specific ACL code. Also, the
  ACLChecklist::authenticated() method is now an AuthenticateAcl global
  function. See ACLFilledChecklist addition log for rationale.

* Removed some 140 SOURCEs of ufsdump, adding a few stubs. The program
seems to
  work on simple ufs cache files.
 
  urlCanonical is currently an always-asserting stub. I am not sure what
pulls
  in urlCanonical. I know storeKeyPublicByRequest* require it, but I am
not sure
  which source requires storeKeyPublicByRequest. If the stub assertion
fails on
  some cache files, we will need to pull more sources or re-implement
  urlCanonical.
 
  The more sources are moved into libraries, the more difficult it may be to
  write isolated, compact test cases or tools because test case stubs and
  customizations may start to conflict with names defined in the
libraries and
  because pulling in a whole library might require defining more stubs.
It is
  not clear yet how real this concern is in general, but a lot of acl/
  SourceLayout time was spent on making ufsdump build...

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