Add support for C bindings to the compaction V2 filter mechanism.

Test Plan: make c_test && ./c_test

Some fixes after merge.
Fix typo, add missing inclusion of state void* in invocation of
create_compaction_filter_v2_.
Merge pull request #226 from bbiao/master

fix various 'comparison of integers of different signs' compiling errors...
Merge pull request #224 from cockroachdb/spencerkimball/compaction-filter-v2-c-bindings

Add support for C bindings to the compaction V2 filter mechanism.
Fix c_test
Fix leak in c_test
Fix db_test and DBIter

Summary: Fix old issue with DBTest.Randomized with BlockBasedTableWithWholeKeyHashIndex + added printing in DBTest.Randomized.

Test Plan: make all check

Reviewers: zagfox, igor, ljin, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21003
Fix SIGSEGV in travis

Summary:
Travis build was failing a lot. For example see https://travis-ci.org/facebook/rocksdb/builds/31425845

This fixes it.

Also, please don't put any code after SignalAll :)

Test Plan: no more SIGSEGV

Reviewers: yhchiang, sdong, ljin

Reviewed By: ljin

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D21417
Need to schedule compactions when manual compaction finishes

Summary: If there is an outstanding compaction scheduled but at the time a manual compaction is triggered, the manual compaction will preempt. In the end of the manual compaction, we should try to schedule compactions to make sure those preempted ones are not skipped.

Test Plan: make all check

Reviewers: yhchiang, ljin

Reviewed By: ljin

Subscribers: leveldb, dhruba, igor

Differential Revision: https://reviews.facebook.net/D21321
Include candidate files under options.db_log_dir in FindObsoleteFiles()

Summary: In FindObsoleteFiles(), we don't scan db_log_dir. Add it.

Test Plan: make all check

Reviewers: ljin, igor, yhchiang

Reviewed By: yhchiang

Subscribers: leveldb, yhchiang

Differential Revision: https://reviews.facebook.net/D21429
Changes to support unity build:
* Script for building the unity.cc file via Makefile
* Unity executable Makefile target for testing builds
* Source code changes to fix compilation of unity build
check prefix_size when using hash search in db_bench

Summary:
1. Check prefix_size when enable use_hash_search in db_bench
2. Remove include/statistics.h in db_bench

Test Plan: ./db_bench --use_hash_search=1

Reviewers: ljin, yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21375
Merge pull request #228 from miguelportilla/develop

Changes to support unity build:

Script for building the unity.cc file via Makefile
Unity executable Makefile target for testing builds
Source code changes to fix compilation of unity build
make statistics ToString function empty instead of pure virtual

Summary: as title

Test Plan: make release

Reviewers: yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21549
Integrating Cuckoo Hash SST Table format into RocksDB

Summary:
Contains the following changes:
- Implementation of cuckoo_table_factory
- Adding cuckoo table into AdaptiveTableFactory
- Adding cuckoo_table_db_test, similar to lines of plain_table_db_test
- Minor fixes to Reader: When a key is found in the table, return the key found instead of the search key.
- Minor fixes to Builder: Add table properties that are required by Version::UpdateTemporaryStats() during Get operation. Don't define curr_node as a reference variable as the memory locations may get reassigned during tree.push_back operation, leading to invalid memory access.

Test Plan:
cuckoo_table_reader_test --enable_perf
cuckoo_table_builder_test
cuckoo_table_db_test
make check all
make valgrind_check
make asan_check

Reviewers: sdong, igor, yhchiang, ljin

Reviewed By: ljin

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21219
Flush only one column family

Summary:
Currently DBImpl::Flush() triggers flushes in all column families.
Instead we need to trigger just the column family specified.

Test Plan: make all check

Reviewers: igor, ljin, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D20841
Add scope guard

Summary: Small change: replace mutex_.Lock/mutex_.Unlock() with scope guard

Test Plan: make all check

Reviewers: igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21609
set bytes_per_sync to 1MB if rate limiter is enabled

Summary: as title

Test Plan: make all check

Reviewers: igor, yhchiang, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21201
remove tailing_iter.h/cc

Summary: as title

Test Plan:
make all check
ran db_bench and saw seek stats at the end

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: leveldb

Differential Revision: https://reviews.facebook.net/D21651
Fixed a signed-unsigned comparison error in db_test

Summary:
Fixed a signed-unsigned comparison error in db_test

Test Plan:
make db_test