NativeBackend class

High-level wrapper around the RunAnywhere native C API.

This class provides a Dart-friendly interface to native backends, handling memory management and type conversions.

The new architecture supports multiple backends:

LlamaCPP: LLM text generation
ONNX: STT, TTS, VAD

Architecture Note

RACommons provides the generic component APIs (rac_llm_component_*, rac_stt_component_*, etc.)
Backend libraries (LlamaCPP, ONNX) register themselves with RACommons

For LlamaCPP, component functions are loaded from RACommons, matching the pattern used in Swift's CppBridge and React Native's C++ bridges.

Usage

// For LlamaCPP
final llamacpp = NativeBackend.llamacpp();
llamacpp.initialize();
llamacpp.loadModel('/path/to/model.gguf');
final result = llamacpp.generate('Hello, world!');
llamacpp.dispose();

// For ONNX
final onnx = NativeBackend.onnx();
onnx.initialize();
onnx.loadSttModel('/path/to/whisper');
final text = onnx.transcribe(audioSamples);
onnx.dispose();

Constructors

NativeBackend(): Create a NativeBackend using RACommons for all component operations.
factory
NativeBackend.llamacpp(): Create a NativeBackend for LLM operations.
factory
NativeBackend.onnx(): Create a NativeBackend for STT/TTS/VAD operations.
factory

Properties

backendName → String: Get the backend type.
no setter
handle → RacHandle?: Get the backend handle (for advanced operations).
no setter
hashCode → int: The hash code for this object.
no setterinherited
isInitialized → bool: Check if the backend is initialized.
no setter
isSttModelLoaded → bool: Check if an STT model is loaded.
no setter
isTextModelLoaded → bool: Check if a text model is loaded.
no setter
isTtsModelLoaded → bool: Check if a TTS model is loaded.
no setter
isVadModelLoaded → bool: Check if a VAD model is loaded.
no setter
runtimeType → Type: A representation of the runtime type of the object.
no setterinherited
sttSupportsStreaming → bool: Check if STT supports streaming.
no setter
version → String: Get the library version.
no setter

Methods

cancelTextGeneration() → void: Cancel ongoing text generation.
create(String backendName, {Map<String, dynamic>? config}) → void: Create and initialize the backend.
dispose() → void: Destroy the backend and release resources.
generate(String prompt, {String? systemPrompt, int maxTokens = 512, double temperature = 0.7}) → Map<String, dynamic>: Generate text (non-streaming).
getAvailableBackends() → List<String>: Get list of available backend names.
getBackendInfo() → Map<String, dynamic>: Get backend info as a map.
getTtsVoices() → List<String>: Get available TTS voices.
initialize() → void: Initialize the backend (simplified for new architecture).
loadSttModel(String modelPath, {String modelType = 'whisper', Map<String, dynamic>? config}) → void: Load an STT model.
loadTextModel(String modelPath, {Map<String, dynamic>? config}) → void: Load a text generation model (LLM).
loadTtsModel(String modelPath, {String modelType = 'vits', Map<String, dynamic>? config}) → void: Load a TTS model.
loadVadModel(String? modelPath, {Map<String, dynamic>? config}) → void: Load a VAD model.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
processVad(Float32List samples, {int sampleRate = 16000}) → Map<String, dynamic>: Process audio for voice activity detection.
supportsCapability(int capability) → bool: Check if backend supports a specific capability.
synthesize(String text, {String? voiceId, double speed = 1.0, double pitch = 0.0}) → Map<String, dynamic>: Synthesize speech from text.
toString() → String: A string representation of this object.
inherited
transcribe(Float32List samples, {int sampleRate = 16000, String? language}) → Map<String, dynamic>: Transcribe audio samples (batch mode).
unloadSttModel() → void: Unload the STT model.
unloadTextModel() → void: Unload the text model.
unloadTtsModel() → void: Unload the TTS model.
unloadVadModel() → void: Unload the VAD model.

Operators

operator ==(Object other) → bool: The equality operator.
inherited

Static Methods

tryCreate() → NativeBackend?: Try to create a native backend, returning null if it fails.