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12 commits

Author SHA1 Message Date
Steven Moreland
1a055a8957 RefBase.cpp remove unused include typeinfo
Test: pass
Change-Id: Iec9b9e1e9b6c974124b2043f550fb110cc22846d
2017-02-15 19:04:40 -08:00
Colin Cross
1811d156e9 Fix more system/core/include warnings
The warnings in these files were hidden by -isystem
framework/native/include.

Bug: 31752268
Test: m -j
Change-Id: I2a54376aea380ee24e6483fb7d35fdfe8991c490
2016-09-27 16:21:12 -07:00
Colin Cross
17b5b82d64 Fix warnings in libutils headers
system/core/include is included in the global include path using
-isystem, which hides all warnings.  Fix warnings in libutils
headers in preparation for moving from -isystem to -I.

- Fix implicit cast from int64_t to long in Condition.h.  Remove
  the __LP64__ check and always compare against LONG_MAX before
  casting.
- Fix implicit cast from size_t to ssize_t in KeyedVector.h
- Fix -Wshadow-field-in-constructor warnings in Looper.h and RefBase.h
- Move destructors for MessageHandler and LooperCallback to Looper.cpp
  and ReferenceRenamer and VirtualLightRefBase to RefBase.cpp to prevent
  vtables in every compilation unit.
- Declare template variables in Singleton.h
- Fix old-style casts in StrongPointer.h and TypeHelpers.h
- Use template metaprogramming in TypeHelpers.h to avoid warnings on
  memmove on non-trivial types.
- Add an assignment operator to key_value_pair_t to complete
  rule-of-three
- Use memcpy instead of dereferencing a reinterpret_casted pointer to
  treat the bits of a float or double as int32_t or int64_t
- Escape unicode sequences inside doxygen comments between \code and
  \endcode
- Remove WIN32 ZD definition in Compat.h, %zd works fine with mingw
- Fix WIN32 printf warnings in Filemap.cpp
- Initialize mNullValue with 0 in LruCache.h, some of the tests use a
  non-pointer type for TValue.

Test: m -j native
Bug: 31492149
Change-Id: I385a05a3ca01258e44fe3b37ef77e4aaff547b26
2016-09-22 13:03:15 -07:00
Hans Boehm
23c857ebd6 Make RefBase more robust and debuggable
This prevents two different kinds of client errors from causing
undetected memory corruption, and helps with the detection of others:

1. We no longer deallocate objects when the weak count goes to zero
and there have been no strong references.  This otherwise causes
us to return a garbage object from a constructor if the constructor
allocates and deallocates a weak pointer to this. And we do know
that clients allocate such weak pointers in constructors and their
lifetime is hard to trace.

2. We abort if a RefBase object is explicitly destroyed while
the weak count is nonzero.  Otherwise a subsequent decrement
would cause a write to potentially reallocated memory.

3. We check counter values returned by atomic decrements for
plausibility, and fail immediately if they are not plausible.

We unconditionally log any cases in which 1 changes behavior
from before. We abort in cases in which 2 changes behavior, since
those reflect clear bugs.
In case 1, a log message now indicates a possible leak. We have
not seen such a message in practice.

The third point introduces a small amount of overhead into the
reference count decrement path. But this should be negligible
compared to the actual decrement cost.

Add a test for promote/attemptIncStrong that tries to check for
both (1) above and concurrent operation of attemptIncStrong.

Add some additional warnings and explanations to the RefBase
documentation.

Bug: 30503444
Bug: 30292291
Bug: 30292538

Change-Id: Ida92b9a2e247f543a948a75d221fbc0038dea66c
2016-08-13 11:17:51 -07:00
Hans Boehm
9ba7192c1f Improve RefBase documentation, especially for clients.
Add basic interface documentation to RefBase.h.

Much, but not all, of this is cut-and-pasted from an email message
from Mathias Agopian. The rest is reconstructed from the code.

Delete some, now redundant, text from Refbase.cpp, and add a bit
more about the implementation strategy.

Some minor fixes to internal comments.

Bug: 30292291
Change-Id: I56518ae5553bc6de0cc2331778e7fcf2e6c4fd87
2016-08-09 15:12:19 -07:00
Hans Boehm
7f27cbc3f4 Fix race bug in attemptIncStrong
The compensating onLastStrongRef call could be made even when there
was no onIncStrongAttempted call to compensate for.  This
happened in the OBJECT_LIFETIME_STRONG case when e.g. curCount
was initially zero, but was concurrently incremented by another
thread.

I believe the old code was also incorrect in the
curCount = INITIAL_STRONG_VALUE + 1 case,
which seems to be possible under unlikely conditions.
In that case, I believe the compensating call IS needed.
Thus the condition was also changed.

Bug: 30503444
Change-Id: I44bcbcbb1264e4b52b6d3750dc39b041c4140381
2016-07-29 14:39:10 -07:00
Hans Boehm
e263e6c633 Fix memory order and race bugs in Refbase.h & RefBase.cpp
Convert to use std::atomic directly.

Consistently use relaxed ordering for increments, release ordering
for decrements, and an added acquire fence when the count goes to
zero.

Fix what looks like another race in attemptIncStrong:
It seems entirely possible that the final adjustment for
INITIAL_STRONG_VALUE would see e.g. INITIAL_STRONG_VALUE + 1,
since we could be running in the middle of another initial
increment.

Attempt to somewhat document what this actually does, and
what's expected from the client. Hide the documentation in
the .cpp file for now.

Remove a confusing redundant test in decWeak. OBJECT_LIFETIME_STRONG
and OBJECT_LIFETIME_WEAK are the only options, in spite of some
of the original comments.

It's conceivable that either of these issues has resulted in
actual crashes, though I would guess the probability is small.
It's hard enough to reason about this code without the bugs.

Bug: 28705989
Change-Id: I4107a56c3fc0fdb7ee17fc8a8f0dd7fb128af9d8
2016-05-17 16:11:11 -07:00
Chih-Hung Hsieh
1c563d96f0 Fix google-explicit-constructor warnings.
Bug: 28341362
Change-Id: I4504e98a8db31e0edcbe63c23f9af43eb13e9d86
2016-04-29 15:44:04 -07:00
George Burgess IV
e7aa2b2c83 Cleanup uses of sprintf so we can deprecate it.
Also cleans up two instances of open() with useless mode params, and
changes a few uses of snprintf to use sizeof(buffer) instead of
hardcoded buffer sizes.

Change-Id: If11591003d910c995e72ad8f75afd072c255a3c5
2016-03-07 18:40:40 -08:00
Mark Salyzyn
5bed803664 libutils: turn on -Werror
- Deal with some -Wunused issues
- Override PRI macros (windows)
- Revert use of PRI macros on off64_t (linux)
- Deal with a gnu++11 complaince issue

Change-Id: Ie66751293bd84477a5a6dfd8a57e700a16e36964
2014-06-02 15:57:50 -07:00
Ian McKellar
55e0f1c8bd Fix stack trace logging in RefBase.
This was broken about 5 months ago in change I78435ed49aa196a0efb45bf9b2d58b62c41737d3.
See: https://goto.google.com/jhtss

Change-Id: Icc32993552efed3015bc1b79a7bd872d7510e020
2014-04-01 15:02:57 -07:00
Alex Ray
d98e07fdf9 move libs/utils to libutils
Change-Id: I6cf4268599460791414882f91eeb88a992fbd29d
2013-08-02 14:40:08 -07:00
Renamed from libs/utils/RefBase.cpp (Browse further)