children gets large, to avoid severe platform realloc() degeneration
in extreme cases (like test_longexp).
Bugfix candidate.
This was doing extremely timid over-allocation, just rounding up to the
nearest multiple of 3. Now so long as the number of children is <= 128,
it rounds up to a multiple of 4 but via a much faster method. When the
number of children exceeds 128, though, and more space is needed, it
doubles the capacity. This is aggressive over-allocation.
SF patch <http://www.python.org/sf/578297> has Andrew MacIntyre using
PyMalloc in the parser to overcome platform malloc problems in
test_longexp on OS/2 EMX. Jack Jansen notes there that it didn't help
him on the Mac, because the Mac has problems with frequent ever-growing
reallocs, not just with gazillions of teensy mallocs. Win98 has no
visible problems with test_longexp, but I tried boosting the test-case
size and soon got "senseless" MemoryErrors out of it, and soon after
crashed the OS: as I've seen in many other contexts before, while the
Win98 realloc remains zippy in bad cases, it leads to extreme
fragmentation of user address space, to the point that the OS barfs.
I don't yet know whether this fixes Jack's Mac problems, but it does cure
Win98's problems when boosting the test case size. It also speeds
test_longexp in its unaltered state.
that have taken me "too long" to reverse-engineer over the years.
Vastly reduced the nesting level and redundancy of #ifdef-ery.
Took a light stab at repairing comments that are no longer true.
sys_gettotalrefcount(): Changed to enable under Py_REF_DEBUG.
It was enabled under Py_TRACE_REFS, which was much heavier than
necessary. sys.gettotalrefcount() is now available in a
Py_REF_DEBUG-only build.
If multiple header fields with the same name occur, they are combined
according to the rules in RFC 2616 sec 4.2:
Appending each subsequent field-value to the first, each separated by
a comma. The order in which header fields with the same field-name are
received is significant to the interpretation of the combined field
value.
mechanism is no longer evil: it no longer plays dangerous games with
the type pointer or refcounts, and objects in extension modules can play
along too without needing to edit the core first.
Rewrote all the comments to explain this, and (I hope) give clear
guidance to extension authors who do want to play along. Documented
all the functions. Added more asserts (it may no longer be evil, but
it's still dangerous <0.9 wink>). Rearranged the generated code to
make it clearer, and to tolerate either the presence or absence of a
semicolon after the macros. Rewrote _PyTrash_destroy_chain() to call
tp_dealloc directly; it was doing a Py_DECREF again, and that has all
sorts of obscure distorting effects in non-release builds (Py_DECREF
was already called on the object!). Removed Christian's little "embedded
change log" comments -- that's what checkin messages are for, and since
it was impossible to correlate the comments with the code that changed,
I found them merely distracting.
Section 19.6 of RFC 2616 (HTTP/1.1):
It is beyond the scope of a protocol specification to mandate
compliance with previous versions. HTTP/1.1 was deliberately
designed, however, to make supporting previous versions easy....
And we would expect HTTP/1.1 clients to:
- recognize the format of the Status-Line for HTTP/1.0 and 1.1
responses;
- understand any valid response in the format of HTTP/0.9, 1.0, or
1.1.
The changes to the code do handle response in the format of HTTP/0.9.
Some users may consider this a bug because all responses with a
sufficiently corrupted status line will look like an HTTP/0.9
response. These users can pass strict=1 to the HTTP constructors to
get a BadStatusLine exception instead.
While this is a new feature of sorts, it enhances the robustness of
the code (be tolerant in what you accept). Thus, I consider it a bug
fix candidate.
XXX strict needs to be documented.
binascii_crc32(): The previous patch forced this to return the same
result across platforms. This patch deals with that, on a 64-bit box,
the *entry* value may have "unexpected" bits in the high four bytes.
Bugfix candidate.
classdesc -- just use "..." with prose explaining the correspondence
between keyword args and instance attributes.
Document 'width' along with the other instance attributes.
Describe default values consistently.
Typo fixes.
\py@sigline macro will wrap the argument list so it will not extend into
the right margin.
Substantially based on a contribution from Dave Cole.
This addresses one of the comments in SF bug #574742.
binascii_crc32(): Make this return a signed 4-byte result across
platforms. The other way to make this platform-independent would be to
make it return an unsigned unbounded int, but the evidence suggests
other code out there treats it like a signed 4-byte int (e.g., existing
code writing the result with struct.pack "l" format).
Bugfix candidate.
This was mostly a matter of adding comments and light code rearrangement.
Upon untracking, gc_next is still set to NULL. It's a cheap way to
provoke memory faults if calling code is insane. It's also used in some
way by the trashcan mechanism.
object should now have a well-defined gc_refs value, with clear transitions
among gc_refs states. As a result, none of the visit_XYZ traversal
callbacks need to check IS_TRACKED() anymore, and those tests were removed.
(They were already looking for objects with specific gc_refs states, and
the gc_refs state of an untracked object can no longer match any other
gc_refs state by accident.)
Added more asserts.
I expect that the gc_next == NULL indicator for an untracked object is
now redundant and can also be removed, but I ran out of time for this.
in gc_refs, even at the cost of putting back a test+branch in
visit_decref.
The good news: since gc_refs became utterly tame then, it became
clear that another special value could be useful. The move_roots() and
move_root_reachable() passes have now been replaced by a single
move_unreachable() pass. Besides saving a pass over the generation, this
has a better effect: most of the time everything turns out to be
reachable, so we were breaking the generation list apart and moving it
into into the reachable list, one element at a time. Now the reachable
stuff stays in the generation list, and the unreachable stuff is moved
instead. This isn't quite as good as it sounds, since sometimes we
guess wrongly that a thing is unreachable, and have to move it back again.
Still, overall, it yields a significant (but not dramatic) boost in
collection speed.
1. You're not supposed to call this with a NULL argument, although the
docs could be clearer about that. The other visit_XYZ() functions
don't bother to check. This doesn't either now, although it does
assert non-NULL-ness now.
2. It doesn't matter whether the object is currently tracked, so don't
bother checking that either (if it isn't currently tracked, it may
have some nonsense value in gc_refs, but it doesn't hurt to
decrement gibberish, and it's cheaper to do so than to make everyone
test for trackedness).
It would be nice to get rid of the other tests on IS_TRACKED. Perhaps
trackedness should not be a matter of not being in any gc list, but
should be a matter of being in a new "untracked" gc list. This list
simply wouldn't be involved in the collection mechanism. A newly
created object would be put in the untracked list. Tracking would
simply unlink it and move it into the gen0 list. Untracking would do
the reverse. No test+branch needed then. visit_move() may be vulnerable
then, though, and I don't know how this would work with the trashcan.
Jack Jansen
Tim Peters
Jeremy Hylton
Kurt B. Kaiser
unknown
Michael W. Hudson
Greg Ward
Thomas Heller
Steve Holden
Fred Drake
Barry Warsaw
Mark Hammond