Previously used check_cxx_source_compiles to attempt a
build to determine support for clang thread safety checks.
This change is to support static analysis of the leveldb source by
lgtm.com (using Semmle). It failed to build with the following error:
```
[2019-07-04 22:29:58] [build] c++: error: unrecognized command line option ‘-Wthread-safety’; did you mean ‘-fthread-jumps’?
[2019-07-04 22:30:02] [build] make[2]: *** [CMakeFiles/leveldb.dir/build.make:66: CMakeFiles/leveldb.dir/db/builder.cc.o] Error 1
```
PiperOrigin-RevId: 272275528
A recent change (4cb80b7ddc) to DBImpl::DeleteObsoleteFiles
unlocked DBImpl::mutex_ while deleting files to allow for
greater concurrency. This change improves on the prior in
a few areas:
1. The table is evicted from the table cache before unlocking
the mutex. This should only improve performance.
2. This implementation is slightly simpler, but at the cost of
a bit more memory usage.
3. A comment adding more detail as to why the mutex is being
unlocked and why it is safe to do so.
PiperOrigin-RevId: 253111645
mutex_ was already acquired before accessing DBImpl::versions_ in all
but one place: DBImpl::GetApproximateSizes. This change requires mutex_
to be held before accessing versions_.
PiperOrigin-RevId: 248390814
The previous attempt of having EnvPosix use O_CLOEXEC (close-on-exec()) when opening file descriptors added tests that relied on procfs, which is Linux-specific. These tests failed on macOS. Unfortunately, the test failures were not caught due to a (since fixed) error in our Travis CI configuration.
This CL re-structures the tests to only rely on POSIX features. Since there is no POSIX-compliant way to get a file name/path out of a file descriptor, this CL breaks up the O_CLOEXEC test into multiple tests, where each Env method that creates an FD gets its own test. This is intended to make it easier to find and fix errors in Env implementations.
This CL also fixes the implementation of NewLogger() to use O_CLOEXEC on macOS. The current implementation passes "we" to fopen(), but the macOS standard C library does not implement the "e" flag yet.
PiperOrigin-RevId: 247088953
Currently, the benchmark used to assess leveldb changes lives in db/. The codebase also contains two benchmarks against other database engines in doc/bench/. Moving all the benchmarks in one place opens up the way for extracting common code.
PiperOrigin-RevId: 246737541
1) Convert iterator-based for loops to C++11 foreach loops.
2) Convert "void operator=" to "T& operator=".
3) Switch from copy operators from private to public deleted.
4) Switch from empty ctors / dtors to "= default" where appropriate.
PiperOrigin-RevId: 246679195
Use clang-format to correct formatting to be in agreement with the [Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html). Doing this simplifies the process of accepting changes. Also fixed a few warnings flagged by clang-tidy.
PiperOrigin-RevId: 246350737
The Travis configuration:
1) Installs recent versions of clang and GCC.
2) Sets up the environment so that CMake picks up the installed
compilers. Previously, the pre-installed clang compiler was used
instead.
3) Requests a modern macOS image that has all the headers needed by GCC.
The CL also removes now-unnecessary old workarounds from the
Travis configuration.
PiperOrigin-RevId: 245831188
Windows linking visibility in shared libraries requires that inner classes are
specifically exported as visible, even if the containing class is exported.
PiperOrigin-RevId: 244886019
