Dart build system?

README.md

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

$ 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

$ dnb --platform=macos rebuild # Specify a specific platform

Platforms:

• windows
• macos
• linux
• android
• ios
• fuchsia
• unknown

Definitions on-the-fly

$ 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.

dnb.yaml

targets:
  sample_extension: # add_library(sample_extension ...)
    sources:
      - lib/src/sample_extension.cc
      
# Note: If `sources` is a List, instead of the form {paths: [...], globs: [...]},
# then it is assumed that all members of the list provided are paths.
#
# So effectively, this configuration above is {paths: ["lib/src/sample_extension.cc"]}.

kitchen_sink.macos.yaml

targets:
  name: sample_extension
  flags:
    - "-undefined dynamic_lookup" # This will actually be defined by default
  definitions:
    DEBUG:
    MAC:
    ARCH: "$ENV{ARCH}"
  environment:
    CC: gcc-7
    CXX: g++-7

kitchen_sink.yaml

targets:
  name: sample_extension
  output_directory: lib/src # Default
  sources:
    glob_recurse: true # Default
    paths:
      - lib/src/sample_extension.cc
    globs:
      - lib/src/*.cc
  includes:
    before:
      - foo.cmake
    after:
      - bar.cmake
  subdirectories:
    before:
      - third_party
      - "${SOME_VARIABLE_FROM_THE_CACHE}"
    after:
      - fourth_party
  dependencies:
    - MY_EXTERNAL_PROJECT
    - ANOTHER_TARGET_DEFINED_IN_THIS_FILE
  scripts: # You can only run Dart files as scripts. This is by design.
    before:
      - tool/foo.dart
    after:
      - tool/bar.dart
debug: # Specify debug-only info
  sample_extension:
    definitions:
      DEBUG: 
release:
  sample_extension:
    definitions:
      NDEBUG:
      find_libraries:
        - foo # Produces FOO_DIR, FOO_LIBRARIES, FOO_INCLUDE_DIRS
      include_directories:
        - "${foo_INCLUDE_DIRS}"
        - bar/baz
      link_directories:
        - cv
        - ffi
      link_libraries:
        - some_lib
        - "-framework CoreFoundation"
        - "${FOO_LIBRARIES}"

sample_extension.cc

#include <dart_api.h> // `dnb` finds the SDK `include/` dir and configures CMake accordingly.

Dart_Handle sample_extension_init(Dart_Handle parent_library) {
  // ...
}

Note: There should be an option to specify which directory the CMakeLists.txt file should be generated in.