react-native-executorch/lib/module/controllers/BaseOCRController.js

An easy way to run AI models in React Native with ExecuTorch

"use strict";

import { Logger } from '../common/Logger';
import { symbols } from '../constants/ocr/symbols';
import { RnExecutorchErrorCode } from '../errors/ErrorCodes';
import { RnExecutorchError, parseUnknownError } from '../errors/errorUtils';
import { isPixelData } from '../modules/computer_vision/VisionModule';
import { ResourceFetcher } from '../utils/ResourceFetcher';
export class BaseOCRController {
  isReady = false;
  isGenerating = false;
  error = null;
  constructor({
    isReadyCallback = _isReady => {},
    isGeneratingCallback = _isGenerating => {},
    errorCallback = _error => {}
  } = {}) {
    this.isReadyCallback = isReadyCallback;
    this.isGeneratingCallback = isGeneratingCallback;
    this.errorCallback = errorCallback;
  }
  internalLoad = async (detectorSource, recognizerSource, language, onDownloadProgressCallback, extraParams) => {
    try {
      if (!detectorSource || !recognizerSource) return;
      if (!symbols[language]) {
        throw new RnExecutorchError(RnExecutorchErrorCode.LanguageNotSupported, 'The provided language for OCR is not supported. Please try using other language.');
      }
      this.isReady = false;
      this.isReadyCallback(false);
      const paths = await ResourceFetcher.fetch(onDownloadProgressCallback, detectorSource, recognizerSource);
      if (paths === null || paths.length < 2) {
        throw new RnExecutorchError(RnExecutorchErrorCode.DownloadInterrupted, 'The download has been interrupted. As a result, not every file was downloaded. Please retry the download.');
      }
      this.nativeModule = await this.loadNativeModule(paths[0], paths[1], language, extraParams);
      this.isReady = true;
      this.isReadyCallback(this.isReady);
    } catch (e) {
      if (e && typeof e === 'object' && 'code' in e && e.code === RnExecutorchErrorCode.ResourceFetcherAdapterNotInitialized) {
        Logger.error('Load failed:', e);
      } else if (this.errorCallback) {
        this.errorCallback(parseUnknownError(e));
      } else {
        throw parseUnknownError(e);
      }
    }
  };
  get runOnFrame() {
    if (!this.isReady) {
      throw new RnExecutorchError(RnExecutorchErrorCode.ModuleNotLoaded, 'The model is currently not loaded. Please load the model before calling runOnFrame().');
    }
    const nativeGenerateFromFrame = this.nativeModule.generateFromFrame;
    return (frame, isFrontCamera) => {
      'worklet';

      let nativeBuffer = null;
      try {
        nativeBuffer = frame.getNativeBuffer();
        const frameData = {
          nativeBuffer: nativeBuffer.pointer,
          orientation: frame.orientation,
          isMirrored: isFrontCamera
        };
        return nativeGenerateFromFrame(frameData);
      } finally {
        if (nativeBuffer?.release) {
          nativeBuffer.release();
        }
      }
    };
  }
  forward = async input => {
    if (!this.isReady) {
      throw new RnExecutorchError(RnExecutorchErrorCode.ModuleNotLoaded, 'The model is currently not loaded. Please load the model before calling forward().');
    }
    if (this.isGenerating) {
      throw new RnExecutorchError(RnExecutorchErrorCode.ModelGenerating, 'The model is currently generating. Please wait until previous model run is complete.');
    }
    try {
      this.isGenerating = true;
      this.isGeneratingCallback(this.isGenerating);
      if (typeof input === 'string') {
        return await this.nativeModule.generateFromString(input);
      } else if (isPixelData(input)) {
        return await this.nativeModule.generateFromPixels(input);
      } else {
        throw new RnExecutorchError(RnExecutorchErrorCode.InvalidArgument, 'Invalid input: expected string path or PixelData object. For VisionCamera frames, use runOnFrame instead.');
      }
    } catch (e) {
      throw parseUnknownError(e);
    } finally {
      this.isGenerating = false;
      this.isGeneratingCallback(this.isGenerating);
    }
  };
  delete() {
    if (this.isGenerating) {
      throw new RnExecutorchError(RnExecutorchErrorCode.ModelGenerating, 'The model is currently generating. Please wait until previous model run is complete.');
    }
    if (this.nativeModule) {
      this.nativeModule.unload();
    }
    this.isReadyCallback(false);
    this.isGeneratingCallback(false);
  }
}
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