# DNB
This is a prototype of a CMake-based build tool for Dart native extensions.
Combined with `scripts`, this would be comparable to `node-gyp`, but with actual
Windows support, and no Python dependency.

DNB is designed to ensure portability across various platforms where Dart runs.

# Examples explained
Note: In real projects, filenames would be `dnb.yaml`, `dnb.macos.yaml`, etc.

## `dnb.yaml`
This file would be used to build a hypothetical Dart native extension named `sample_extension`.
The extension would build to `lib/src/libsample_extension.so` (or `.dll`, `.dylib`, etc.).

In a real project, `dnb.yaml` would be a sibling to `pubspec.yaml`.

## Kitchen sink
The files `kitchen_sink.yaml` and `kitchen_sink.macos.yaml` contain every feature planned thusfar.
Most projects will only need to use a small subset of the features, so it will be simple to produce portable
native extensions without too much ugly configuration.

# Usage
```bash
$ dnb --help
$ dnb init # Create a minimal `dnb.yaml` (virtually the same as the one in the example)
$ dnb configure # Generate CMakeLists.txt, run "cmake ."
$ dnb build # Run "cmake --build . -- -j <num_cores>"
$ dnb clean # Run "cmake --build . --target clean"
$ dnb rebuild # Delete CMakeCache.txt, `configure`, then `build`
$ dnb boilerplate foo_extension > lib/src/foo_extension.cc # Generate extension boilerplate C/C++ code
$ dnb -j 4 --target rebuild my_extension # Specify `-j` arg to pass to CMake
$ dnb --cmake="/path/to/cmake" rebuild # Override CMake executable path
$ dnb --watch rebuild # Watch dnb.yaml for changes
$ dnb --debug rebuild # Enable debug-specific flags. Default is release
```

Ultimately, the command end-users will need to run is `dnb rebuild`.

## Cross-compiling
```bash
$ dnb --platform=macos rebuild # Specify a specific platform
```

Platforms:
* `windows`
* `macos`
* `linux`
* `android`
* `ios`
* `fuchsia`
* `unknown`

## Definitions on-the-fly
```bash
$ dnb --define foo=bar --define baz
$ dnb -dfoo=bar -dbaz
```

# Default definitions
* `DART_SHARED_LIB`: Always defined
* `DART_PACKAGE_NAME`: The name of the package
* `DART_PACKAGE_VERSION`: The package's version string. Defaults to `0.0.0`
* `DEBUG`: defined when `--debug` is present
* `NDEBUG`, `RELEASE`: defined by default. Undefined when `--debug` is present.

# Environment variables
* `DART_SDK`: Defined to the path to your Dart SDK.