| Replace V with Nim 472eb49 nandithebull 20h ago | 1 | /// Idiomatic Dart surface over the Nim library. |
| 2 | /// |
| 3 | /// Callers never see a Pointer, and never own Nim memory: every string that |
| 4 | /// crosses the boundary is copied into Dart and the Nim allocation is released |
| 5 | /// before the call returns. |
| 6 | /// |
| 7 | /// Two backends implement the same signatures — `dart:ffi` against the native |
| 8 | /// shared library, and `dart:js_interop` against the emscripten build — and |
| 9 | /// the conditional import below picks one at compile time. Callers see no |
| 10 | /// difference beyond [supportsIsolateParallelism]. |
| 11 | library nimflutter_ffi; |
| 12 | |
| 13 | import 'dart:typed_data'; |
| 14 | |
| 15 | import 'src/backend_native.dart' |
| 16 | if (dart.library.js_interop) 'src/backend_web.dart' as backend; |
| 17 | import 'src/fractal_view.dart'; |
| 18 | |
| 19 | export 'src/fractal_view.dart' show FractalView; |
| 20 | |
| 21 | /// Which bridge this build is using, for display. 'dart:ffi' or 'wasm'. |
| 22 | const String backendName = backend.backendName; |
| 23 | |
| 24 | /// Whether bands can genuinely run at the same time. |
| 25 | /// |
| 26 | /// False on web: the emscripten module is single-threaded, so a split still |
| 27 | /// produces the identical frame but renders it sequentially. |
| 28 | const bool supportsIsolateParallelism = backend.supportsIsolateParallelism; |
| 29 | |
| 30 | /// Whether the bridge is ready to take calls. |
| 31 | bool get isInitialized => backend.isInitialized; |
| 32 | |
| 33 | /// Prepares the bridge, and the only form that works on every backend. |
| 34 | /// |
| 35 | /// Native initialisation is synchronous, but loading a wasm module is not, so |
| 36 | /// the async form is the common denominator. Await this once at startup. |
| 37 | Future<void> initialize() => backend.initialize(); |
| 38 | |
| 39 | /// Synchronous initialisation. Native-only: on web this throws unless |
| 40 | /// [initialize] has already completed, because the module cannot be loaded |
| 41 | /// synchronously. |
| 42 | void ensureInitialized() => backend.ensureInitialized(); |
| 43 | |
| 44 | /// Adds two integers in Nim. The trivial case, useful as a liveness check. |
| 45 | int add(int a, int b) => backend.add(a, b); |
| 46 | |
| 47 | /// Round-trips a string through Nim. |
| 48 | /// |
| 49 | /// Nim allocates the result on the shared heap; this copies it into a Dart |
| 50 | /// [String] and frees the Nim allocation before returning, so there is nothing |
| 51 | /// for the caller to release. |
| 52 | String greet(String name) => backend.greet(name); |
| 53 | |
| 54 | /// Runs [greet] off the calling isolate where the backend supports it. |
| 55 | Future<String> greetAsync(String name) => backend.greetAsync(name); |
| 56 | |
| 57 | /// Renders rows [y0, y1) of [view] into a fresh RGBA byte buffer. |
| 58 | /// |
| 59 | /// The buffer is allocated on the Dart side and filled in place by Nim, so no |
| 60 | /// Nim memory is created and nothing needs freeing. |
| 61 | Uint8List renderBand(FractalView view, int y0, int y1) => |
| 62 | backend.renderBand(view, y0, y1); |
| 63 | |
| 64 | /// Renders the whole of [view] on the calling isolate. |
| 65 | Uint8List render(FractalView view) => renderBand(view, 0, view.height); |
| 66 | |
| 67 | /// Renders [view] as [tiles] horizontal bands. |
| 68 | /// |
| 69 | /// Bands are independent by construction — each call writes only its own rows |
| 70 | /// — so on native this is real parallelism across isolates. On web it is the |
| 71 | /// same split run sequentially; see [supportsIsolateParallelism]. |
| 72 | Future<Uint8List> renderParallel(FractalView view, {int tiles = 4}) => |
| 73 | backend.renderParallel(view, tiles); |