leptonica-plumbing

Crate to expose a safe version of the leptonica-sys api.

This is designed to expose the C API of leptonica in a safe manner.

Adding value by deviating from the API is a non-goal. That is left to libraries that build on top of leptonica-plumbing.

Motivation

I'm a maintainer of both leptess and tesseract-rs.

I noticed that there was a lot of duplication in how they interact with both leptonica-sys and tesseract-sys. Having multiple layers of abstraction in leptess and tesseract-rs made it hard to reason about their memory safety.

Having a safety layer that stays simple improves the correctness and maintainability of the above libraries.

Testing

To test for memory leaks, test with valgrind.

cargo test --release && valgrind --leak-check=yes --error-exitcode=1 --leak-check=full --show-leak-kinds=all "$(find target/*/deps/ -executable -name 'leptonica_plumbing-*')"

You may find that leptonica always leaks 16B of memory.

To test with a manually compiled Leptonica, test with additional environment variables

LD_LIBRARY_PATH="$(pwd)/../../DanBloomberg/leptonica/local/lib" PKG_CONFIG_PATH="$(pwd)/../../DanBloomberg/leptonica/local/lib/pkgconfig" cargo test

The two can be combined

LD_LIBRARY_PATH="$(pwd)/../../DanBloomberg/leptonica/local/lib" PKG_CONFIG_PATH="$(pwd)/../../DanBloomberg/leptonica/local/lib/pkgconfig" bash -c 'cargo test --release && valgrind --leak-check=yes --error-exitcode=1 --leak-check=full --show-leak-kinds=all "$(find target/*/deps/ -executable -name 'leptonica_plumbing-*')"'