guardia-messenger/node_modules/expo-modules-core/common/cpp/JSIUtils.cpp

// Copyright 2022-present 650 Industries. All rights reserved.

#include <sstream>
#include "JSIUtils.h"

namespace expo::common {

jsi::Function createClass(jsi::Runtime &runtime, const char *name, ClassConstructor constructor) {
  std::string nativeConstructorKey("__native_constructor__");

  // Create a string buffer of the source code to evaluate.
  std::stringstream source;
  source << "(function " << name << "(...args) { return this." << nativeConstructorKey << "(...args); })";
  std::shared_ptr<jsi::StringBuffer> sourceBuffer = std::make_shared<jsi::StringBuffer>(source.str());

  // Evaluate the code and obtain returned value (the constructor function).
  jsi::Object klass = runtime.evaluateJavaScript(sourceBuffer, "").asObject(runtime);

  // Set the native constructor in the prototype.
  jsi::Object prototype = klass.getPropertyAsObject(runtime, "prototype");
  jsi::PropNameID nativeConstructorPropId = jsi::PropNameID::forAscii(runtime, nativeConstructorKey);
  jsi::Function nativeConstructor = jsi::Function::createFromHostFunction(
    runtime,
    nativeConstructorPropId,
    // The paramCount is not obligatory to match, it only affects the `length` property of the function.
    0,
    [constructor](jsi::Runtime &runtime, const jsi::Value &thisValue, const jsi::Value *args, size_t count) -> jsi::Value {
      if (constructor) {
        return constructor(runtime, thisValue, args, count);
      }
      return jsi::Value(runtime, thisValue);
    });

  jsi::Object descriptor(runtime);
  descriptor.setProperty(runtime, "value", jsi::Value(runtime, nativeConstructor));

  defineProperty(runtime, &prototype, nativeConstructorKey.c_str(), std::move(descriptor));

  return klass.asFunction(runtime);
}

jsi::Function createInheritingClass(jsi::Runtime &runtime, const char *className, jsi::Function &baseClass, ClassConstructor constructor) {
  jsi::PropNameID prototypePropNameId = jsi::PropNameID::forAscii(runtime, "prototype", 9);
  jsi::Object baseClassPrototype = baseClass
    .getProperty(runtime, prototypePropNameId)
    .asObject(runtime);

  jsi::Function klass = createClass(runtime, className, constructor);
  jsi::Object klassPrototype = klass.getProperty(runtime, prototypePropNameId).asObject(runtime);

  klassPrototype.setProperty(runtime, "__proto__", baseClassPrototype);

  return klass;
}

jsi::Object createObjectWithPrototype(jsi::Runtime &runtime, jsi::Object *prototype) {
  // Get the "Object" class.
  jsi::Object objectClass = runtime
    .global()
    .getPropertyAsObject(runtime, "Object");

  // Call "Object.create(prototype)" to create an object with the given prototype without calling the constructor.
  jsi::Object object = objectClass
    .getPropertyAsFunction(runtime, "create")
    .callWithThis(runtime, objectClass, {
      jsi::Value(runtime, *prototype)
    })
    .asObject(runtime);

  return object;
}

std::vector<jsi::PropNameID> jsiArrayToPropNameIdsVector(jsi::Runtime &runtime, const jsi::Array &array) {
  size_t size = array.size(runtime);
  std::vector<jsi::PropNameID> vector;

  vector.reserve(size);

  for (size_t i = 0; i < size; i++) {
    jsi::String name = array.getValueAtIndex(runtime, i).getString(runtime);
    vector.push_back(jsi::PropNameID::forString(runtime, name));
  }
  return vector;
}

void defineProperty(jsi::Runtime &runtime, jsi::Object *object, const char *name, const PropertyDescriptor descriptor) {
  jsi::Object jsDescriptor(runtime);

  // These three flags are all `false` by default, so set the property only when `true`.
  if (descriptor.configurable) {
    jsDescriptor.setProperty(runtime, "configurable", jsi::Value(true));
  }
  if (descriptor.enumerable) {
    jsDescriptor.setProperty(runtime, "enumerable", jsi::Value(true));
  }
  if (descriptor.writable) {
    jsDescriptor.setProperty(runtime, "writable", jsi::Value(true));
  }

  if (descriptor.get) {
    jsi::PropNameID getPropName = jsi::PropNameID::forAscii(runtime, "get", 3);
    jsi::Function get = jsi::Function::createFromHostFunction(
      runtime,
      getPropName,
      0,
      [getter = descriptor.get](jsi::Runtime &runtime, const jsi::Value &thisValue, const jsi::Value *args, size_t count) -> jsi::Value {
        return getter(runtime, thisValue.asObject(runtime));
      });

    jsDescriptor.setProperty(runtime, getPropName, get);
  }
  if (descriptor.set) {
    jsi::PropNameID setPropName = jsi::PropNameID::forAscii(runtime, "set", 3);
    jsi::Function set = jsi::Function::createFromHostFunction(
      runtime,
      setPropName,
      1,
      [setter = descriptor.set](jsi::Runtime &runtime, const jsi::Value &thisValue, const jsi::Value *args, size_t count) -> jsi::Value {
        setter(runtime, thisValue.asObject(runtime), jsi::Value(runtime, args[0]));
        return jsi::Value::undefined();
      });

    jsDescriptor.setProperty(runtime, setPropName, set);
  }
  if (!descriptor.value.isUndefined()) {
    jsi::PropNameID valuePropName = jsi::PropNameID::forAscii(runtime, "value", 5);
    jsDescriptor.setProperty(runtime, valuePropName, descriptor.value);
  }

  defineProperty(runtime, object, name, std::move(jsDescriptor));
}

void defineProperty(jsi::Runtime &runtime, jsi::Object *object, const char *name, jsi::Object descriptor) {
  jsi::Object global = runtime.global();
  jsi::Object objectClass = global.getPropertyAsObject(runtime, "Object");
  jsi::Function definePropertyFunction = objectClass.getPropertyAsFunction(runtime, "defineProperty");

  // This call is basically the same as `Object.defineProperty(object, name, descriptor)` in JS
  definePropertyFunction.callWithThis(runtime, objectClass, {
    jsi::Value(runtime, *object),
    jsi::String::createFromUtf8(runtime, name),
    std::move(descriptor),
  });
}

} // namespace expo::common