Why upgrade? I'm not a lawyer, but here's my take on the differences
to version 2:
* Software patents: better protection against abuse of patents to
prevent users from exercising the rights under the GPL. I doubt
we'll get hit with a patent suit, but it's a good move just on
general principles.
* License compatibility: compatible with more free licenses, i.e. can
"steal" more free software for use in Empire. I don't expect to steal
much, but it's nice to have the option.
* Definition of "source code": modernization of some details for today's
networked world, to make it easier to distribute the software. Not
really relevant to us now, as we normally distribute full source code.
* Tivoization: this is about putting GPL-licensed software in hardware,
then make the hardware refuse to run modified software. "Neat" trick
to effectively deny its users their rights under the GPL. Abuse was
"pioneered" by TiVo (popular digital video recorders). GPLv3 forbids
it. Unlikely to become a problem for us.
* Internationalization: more careful wording, to harden the license
outside the US. The lawyers tell us it better be done that way.
* License violations: friendlier way to deal with license violations.
This has come out of past experience enforcing the GPL.
* Additional permissions: Probably not relevant to us.
Also include myself in the list of principal authors.
Oops when a stale copy is written back, i.e. the processor was yielded
since the copy was made. Such bugs are difficult to spot. Sequence
numbers catch them when they do actual harm (they also catch different
bugs). Generation numbers catch them even when they don't.
New ef_generation to count generations. Call new ef_make_stale() to
increment it whenever the processor may be yielded.
New struct emptypedstr member generation. To conserve space, make it
a bit-field of twelve bits, i.e. generations are only recorded modulo
2^12. Make sure all members of unit empobj_storage share it. It is
only used in copies; its value on disk and in the cache is
meaningless. Copies with generation other than ef_generation are
stale. Stale copies that are a multiple of 2^12 generations old can't
be detected, but that is sufficiently improbable.
Set generation to ef_generation by calling new ef_mark_fresh() when
making copies in ef_read() and ef_blank(). nav_ship() and
fltp_to_list() make copies without going through ef_read(), and
therefore need to call ef_mark_fresh() as well. Also call it in
obj_changed() to make check_sect_ok() & friends freshen their argument
when it is unchanged.
New must_be_fresh() oopses when its argument is stale. Call it in
ef_write() to catch write back of stale copies.
check_loan_ok(), check_comm_ok() and check_trade_ok() should have been
changed to ignore timestamps when timestamps were added to their files
in commit a680c811, v4.3.12.
Move stuff to untangle the ugly cyclic dependencies between the
archives built for selected subdirectories of src/lib/:
* Move common/io.c to empthread/ because it requires empthread stuff
* Move parts of subs/nstr.c to common/nstreval.c to satisfy
common/ef_verify.o
* Move getstarg.c getstring.c onearg.c from gen/ to subs/ because they
require stuff from there
* Move bridgefall.c check.c damage.c empobj.c journal.c maps.c
sectdamage.c from common/ to subs/ because they require stuff from
there
* Move cnumb.c from subs/ to common/ to satisfy common/type.o
* Move log.c fsize.c from common/ to gen/ because they really belong
there
* Move emp_config.c mapdist.c from gen/ to common/ because they really
belong there, and require stuff from libglobal.a
Also package as/ as libas.a to satisfy common/path.o.
Remaining dependencies:
lib needs
--------------------------------------------
libas.a libglobal.a
libcommon.a libas.a libglobal.a libgen.a
libgen.a
libglobal.a
liblwp.a libgen.a
libw32.a[*] libgen.a
[*] Except for service.o, which can only be linked into the server
Link order now: liblwp.a libcommon.a libas.a libgen.a libglobal.a
libw32.a. The position of libw32.a is not quite right, but works
anyway.
