Adds mediapipe_core package

.github/workflows/main.yaml

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+name: Main Branch CI
+
+# Declare default permissions as read only.
+permissions: read-all
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main, ffi-wrapper, ffi-wrapper-core-pkg]
+  workflow_dispatch:
+  schedule:
+    - cron: "0 0 * * *" # Every day at midnight
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  flutter-tests:
+    name: Test mediapipe_core against ${{ matrix.flutter_version }}
+    runs-on: ${{ matrix.os }}
+    # Skip running job on forks
+    if: github.repository == 'google/flutter-mediapipe'
+    strategy:
+      fail-fast: false
+      matrix:
+        flutter_version: [stable, beta, master]
+        # TODO(craiglabenz): Add `ubuntu-latest` and `windows-latest` when those artifacts exist
+        os: [macos-latest]
+    steps:
+      - uses: actions/checkout@v4
+      - uses: subosito/flutter-action@v2
+        with:
+          channel: ${{ matrix.flutter_version }}
+      - run: ./tool/mediapipe_ci_script_${{ matrix.flutter_version }}.sh

Makefile

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+# Runs the utility to pull in all header files from `google/mediapipe`
+headers:
+	cd packages/build_cmd && dart bin/main.dart headers
+
+# Runs `ffigen` for all packages
+generate: generate_core generate_text
+
+# Runs `ffigen` for all packages, compiles the faked C artifacts, and runs all tests
+test: generate_text test_text generate_core test_core
+
+# Runs `ffigen` for all packages and all tests for all packages
+test_only: test_core test_text
+
+# Core ---
+
+# Runs `ffigen` for `mediapipe_core`
+generate_core:
+	cd packages/mediapipe-core && dart run ffigen --config=ffigen.yaml
+
+# Runs unit tests for `mediapipe_core`
+test_core:
+	cd packages/mediapipe-core && dart test
+
+# Text ---
+
+# Runs `ffigen` for `mediapipe_text`
+generate_text:
+	cd packages/mediapipe-task-text && dart run ffigen --config=ffigen.yaml
+
+# Compiles the faked C artifacts for testing
+compile_fake_text:
+	# Builds standalone executable
+	cd packages/mediapipe-task-text/test/c && gcc fake_text_classifier.c -o fake_text_classifier
+	# Builds what Flutter needs
+	cd packages/mediapipe-task-text/test/c && gcc -static -c -fPIC *.c -o fake_text_classifier.o
+	cd packages/mediapipe-task-text/test/c && gcc -shared -o fake_text_classifier.dylib fake_text_classifier.o 
+
+# Runs `ffigen` for `mediapipe_text` and all text tests
+test_text: compile_fake_text test_text_only
+
+# Runs all text tests
+test_text_only:
+	cd packages/mediapipe-task-text && flutter test

packages/analysis_options.yaml

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+include: package:lints/recommended.yaml
+
+linter:
+  rules:
+    - public_member_api_docs # see https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#documentation-dartdocs-javadocs-etc
+

packages/mediapipe-core/.gitignore

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+# https://dart.dev/guides/libraries/private-files
+# Created by `dart pub`
+.dart_tool/
+
+# Avoid committing pubspec.lock for library packages; see
+# https://dart.dev/guides/libraries/private-files#pubspeclock.
+pubspec.lock

packages/mediapipe-core/CHANGELOG.md

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+## 0.0.1
+
+- Initial version.

packages/mediapipe-core/README.md

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+# MediaPipe Core for Flutter
+
+![pub package](https://img.shields.io/pub/v/mediapipe_core)
+
+A Flutter plugin to use the MediaPipe Core API, which enables multiple Mediapipe tasks.
+
+To learn more about MediaPipe, please visit the [MediaPipe website](https://developers.google.com/mediapipe)
+
+## Getting Started
+
+To get started with MediaPipe, please [see the documentation](https://developers.google.com/mediapipe/solutions/guide).
+
+<!-- ASPIRATIONAL
+## Usage
+
+To use this plugin, please visit the [Core Usage documentation](https://github.com/google/flutter-mediapipe#Usage)
+-->
+
+## Issues and feedback
+
+Please file Flutter-MediaPipe specific issues, bugs, or feature requests in our [issue tracker](https://github.com/google/flutter-mediapipe/issues/new).
+
+Issues that are specific to Flutter can be filed in the [Flutter issue tracker](https://github.com/flutter/flutter/issues/new).
+
+To contribute a change to this plugin,
+please review our [contribution guide](https://github.com/google/flutter-mediapipe/blob/master/CONTRIBUTING.md)
+and open a [pull request](https://github.com/google/flutter-mediapipe/pulls).

packages/mediapipe-core/analysis_options.yaml

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+include: ../analysis_options.yaml
+
+analyzer:
+  exclude:
+    - "**/mediapipe_common_bindings.dart"

packages/mediapipe-core/ffigen.yaml

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+name: "MediaPipeCommonBindings"
+description: "Bindings for shared MediaPipe structs common across many tasks"
+output:
+  bindings: "lib/src/third_party/mediapipe/generated/mediapipe_common_bindings.dart"
+  symbol-file:
+    output: "package:mediapipe_core/generated/core_symbols.yaml"
+    import-path: "package:mediapipe_core/src/third_party/mediapipe/generated/mediapipe_common_bindings.dart"
+headers:
+  entry-points:
+    - "third_party/mediapipe/tasks/c/**"
+preamble: |
+  /* Copyright 2023 The MediaPipe Authors.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+  ==============================================================================*/
+ffi-native:

packages/mediapipe-core/lib/generated/core_symbols.yaml

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+format_version: 1.0.0
+files:
+  package:mediapipe_core/src/third_party/mediapipe/generated/mediapipe_common_bindings.dart:
+    used-config:
+      ffi-native: false
+    symbols:
+      c:@S@BaseOptions:
+        name: BaseOptions
+      c:@S@Category:
+        name: Category
+      c:@S@ClassificationResult:
+        name: ClassificationResult
+      c:@S@Classifications:
+        name: Classifications
+      c:@S@ClassifierOptions:
+        name: ClassifierOptions
+      c:@S@__darwin_pthread_handler_rec:
+        name: __darwin_pthread_handler_rec
+      c:@S@_opaque_pthread_attr_t:
+        name: _opaque_pthread_attr_t
+      c:@S@_opaque_pthread_cond_t:
+        name: _opaque_pthread_cond_t
+      c:@S@_opaque_pthread_condattr_t:
+        name: _opaque_pthread_condattr_t
+      c:@S@_opaque_pthread_mutex_t:
+        name: _opaque_pthread_mutex_t
+      c:@S@_opaque_pthread_mutexattr_t:
+        name: _opaque_pthread_mutexattr_t
+      c:@S@_opaque_pthread_once_t:
+        name: _opaque_pthread_once_t
+      c:@S@_opaque_pthread_rwlock_t:
+        name: _opaque_pthread_rwlock_t
+      c:@S@_opaque_pthread_rwlockattr_t:
+        name: _opaque_pthread_rwlockattr_t
+      c:@S@_opaque_pthread_t:
+        name: _opaque_pthread_t
+      c:@UA@__mbstate_t:
+        name: __mbstate_t

packages/mediapipe-core/lib/mediapipe_core.dart

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+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/// Package containing core dependencies for MediaPipe's text, vision, and
+/// audio-based tasks.
+library;
+
+export 'src/containers.dart' show Category, Classifications;
+export 'src/ffi_utils.dart';
+export 'src/task_options.dart' show BaseOptions, ClassifierOptions;

packages/mediapipe-core/lib/src/containers.dart

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+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import 'package:mediapipe_core/mediapipe_core.dart';
+import 'third_party/mediapipe/generated/mediapipe_common_bindings.dart'
+    as bindings;
+
+/// Dart representation of MediaPipe's "Category" concept.
+///
+/// Category is a util class, that contains a [categoryName], its [displayName],
+/// a float value as [score], and the [index] of the label in the corresponding
+/// label file. Typically it's used as result of classification or detection
+/// tasks.
+///
+/// See more:
+///  * [MediaPipe's Category documentation](https://developers.google.com/mediapipe/api/solutions/java/com/google/mediapipe/tasks/components/containers/Category)
+class Category {
+  /// Generative constructor that creates a [Category] instance.
+  const Category({
+    required this.index,
+    required this.score,
+    required this.categoryName,
+    required this.displayName,
+  });
+
+  /// The index of the label in the corresponding label file.
+  final int index;
+
+  /// The probability score of this label category.
+  final double score;
+
+  /// The label of this category object.
+  final String? categoryName;
+
+  /// The display name of the label, which may be translated for different locales.
+  final String? displayName;
+
+  /// Accepts a pointer to a list of structs, and a count representing the length
+  /// of the list, and returns a list of pure-Dart [Category] instances.
+  static List<Category> fromStructs(
+    Pointer<bindings.Category> structs,
+    int count,
+  ) {
+    final categories = <Category>[];
+    for (int i = 0; i < count; i++) {
+      categories.add(fromStruct(structs[i]));
+    }
+    return categories;
+  }
+
+  /// Accepts a pointer to a single struct and returns a pure-Dart [Category] instance.
+  static Category fromStruct(bindings.Category struct) {
+    return Category(
+      index: struct.index,
+      score: struct.score,
+      categoryName: toDartString(struct.category_name),
+      displayName: toDartString(struct.display_name),
+    );
+  }
+
+  /// Releases all C memory associated with a list of [bindings.Category] pointers.
+  /// This method is important to call after calling [Category.fromStructs] to
+  /// convert that C memory into pure-Dart objects.
+  static void freeStructs(Pointer<bindings.Category> structs, int count) {
+    int index = 0;
+    while (index < count) {
+      bindings.Category obj = structs[index];
+      calloc.free(obj.category_name);
+      calloc.free(obj.display_name);
+      index++;
+    }
+    calloc.free(structs);
+  }
+
+  @override
+  String toString() => 'Category(index=$index, score=$score, '
+      'categoryName=$categoryName, displayName=$displayName)';
+}
+
+/// Dart representation of MediaPipe's "Classifications" concept.
+///
+/// Represents the list of classification for a given classifier head.
+/// Typically used as a result for classification tasks.
+///
+/// See also:
+///  * [MediaPipe's Classifications documentation](https://developers.google.com/mediapipe/api/solutions/java/com/google/mediapipe/tasks/components/containers/Classifications)
+class Classifications {
+  /// Generative constructor that creates a [Classifications] instance.
+  const Classifications({
+    required this.categories,
+    required this.headIndex,
+    required this.headName,
+  });
+
+  /// A list of [Category] objects which contain the actual classification
+  /// information, including human-readable labels and probability scores.
+  final List<Category> categories;
+
+  /// The index of the classifier head these entries refer to.
+  final int headIndex;
+
+  /// The optional name of the classifier head, which is the corresponding
+  /// tensor metadata name.
+  final String? headName;
+
+  /// Accepts a pointer to a list of structs, and a count representing the length
+  /// of the list, and returns a list of pure-Dart [Classifications] instances.
+  static List<Classifications> fromStructs(
+    Pointer<bindings.Classifications> structs,
+    int count,
+  ) {
+    final classifications = <Classifications>[];
+    for (int i = 0; i < count; i++) {
+      classifications.add(fromStruct(structs[i]));
+    }
+    return classifications;
+  }
+
+  /// Accepts a pointer to a single struct and returns a pure-Dart [Classifications]
+  /// instance.
+  static Classifications fromStruct(bindings.Classifications struct) {
+    return Classifications(
+      categories: Category.fromStructs(
+        struct.categories,
+        struct.categories_count,
+      ),
+      headIndex: struct.head_index,
+      headName: toDartString(struct.head_name),
+    );
+  }
+
+  /// Releases all C memory associated with a list of [bindings.Classifications]
+  /// pointers. This method is important to call after calling [Classifications.fromStructs]
+  /// to convert that C memory into pure-Dart objects.
+  static void freeStructs(
+    Pointer<bindings.Classifications> structs,
+    int count,
+  ) {
+    int index = 0;
+    while (index < count) {
+      bindings.Classifications obj = structs[index];
+      Category.freeStructs(obj.categories, obj.categories_count);
+      calloc.free(obj.head_name);
+      index++;
+    }
+    calloc.free(structs);
+  }
+
+  /// Convenience getter for the first [Category] out of the [categories] list.
+  Category? get firstCategory =>
+      categories.isNotEmpty ? categories.first : null;
+
+  @override
+  String toString() {
+    final categoryStrings = categories.map((cat) => cat.toString()).join(', ');
+    return 'Classification(categories=[$categoryStrings], '
+        'headIndex=$headIndex, headName=$headName)';
+  }
+}