thodg/libgit2/tests

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  • Show log

    Commit

  • Hash : 208f1d7a
    Author : Patrick Steinhardt
    Date : 2019-09-19T12:46:37

    buffer: fix infinite loop when growing buffers When growing buffers, we repeatedly multiply the currently allocated number of bytes by 1.5 until it exceeds the requested number of bytes. This has two major problems: 1. If the current number of bytes is tiny and one wishes to resize to a comparatively huge number of bytes, then we may need to loop thousands of times. 2. If resizing to a value close to `SIZE_MAX` (which would fail anyway), then we probably hit an infinite loop as multiplying the current amount of bytes will repeatedly result in integer overflows. When reallocating buffers, one typically chooses values close to 1.5 to enable re-use of resulting memory holes in later reallocations. But because of this, it really only makes sense to use a factor of 1.5 _once_, but not looping until we finally are able to fit it. Thus, we can completely avoid the loop and just opt for the much simpler algorithm of multiplying with 1.5 once and, if the result doesn't fit, just use the target size. This avoids both problems of looping extensively and hitting overflows. This commit also adds a test that would've previously resulted in an infinite loop.

  • README.md

  • Writing Clar tests for libgit2

    For information on the Clar testing framework and a detailed introduction please visit:

    https://github.com/vmg/clar

    • Write your modules and tests. Use good, meaningful names.

    • Make sure you actually build the tests by setting: 

        cmake -DBUILD_CLAR=ON build/

    • Test: 

        ./build/libgit2_clar

    • Make sure everything is fine.

    • Send your pull request. That’s it.

    Memory leak checks

    These are automatically run as part of CI, but if you want to check locally:

    Linux

    Uses valgrind:

    $ cmake -DBUILD_CLAR=ON -DVALGRIND=ON ..
$ cmake --build .
$ valgrind --leak-check=full --show-reachable=yes --num-callers=50 --suppressions=../libgit2_clar.supp \
  ./libgit2_clar

    macOS

    Uses leaks, which requires XCode installed:

    $ MallocStackLogging=1 MallocScribble=1 MallocLogFile=/dev/null CLAR_AT_EXIT="leaks -quiet \$PPID" \
  ./libgit2_clar

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