FrameHostObject.cpp

#import "FrameHostObject.h"
#import <Foundation/Foundation.h>
#import <jsi/jsi.h>

// This method returns all of keys
std::vector<jsi::PropNameID> FrameHostObject::getPropertyNames(jsi::Runtime& rt) {
  std::vector<jsi::PropNameID> result;
  result.push_back(jsi::PropNameID::forUtf8(rt, std::string("toString")));
  result.push_back(jsi::PropNameID::forUtf8(rt, std::string("isValid")));
  result.push_back(jsi::PropNameID::forUtf8(rt, std::string("width")));
  result.push_back(jsi::PropNameID::forUtf8(rt, std::string("height")));
  result.push_back(jsi::PropNameID::forUtf8(rt, std::string("bytesPerRow")));
  result.push_back(jsi::PropNameID::forUtf8(rt, std::string("planesCount")));
  result.push_back(jsi::PropNameID::forUtf8(rt, std::string("close")));
  return result;
}

// Returns a value based on propName'e
jsi::Value FrameHostObject::get(jsi::Runtime& runtime, const jsi::PropNameID& propName) {
  auto name = propName.utf8(runtime);
  // ...
  
  // Returns frame height
  if (name == "height") {
    this->assertIsFrameStrong(runtime, name);
    auto imageBuffer = CMSampleBufferGetImageBuffer(frame.buffer);
    auto height = CVPixelBufferGetHeight(imageBuffer);
    return jsi::Value((double) height);
  }

  // For returning a function, we need to create host function as follows:
  if (name == "close") {
    auto close = [this] (jsi::Runtime& runtime, const jsi::Value&, const jsi::Value*, size_t) -> jsi::Value {
      if (this->frame == nil) {
        throw jsi::JSError(runtime, "Trying to close an already closed frame! Did you call frame.close() twice?");
      }
      this->close();
      return jsi::Value::undefined();
    };
    return jsi::Function::createFromHostFunction(runtime, jsi::PropNameID::forUtf8(runtime, "close"), 0, close);
  }

  //...

  return jsi::Value::undefined();
}