in ReactCommon/react/renderer/uimanager/UIManagerBinding.cpp [295:837]
jsi::Value UIManagerBinding::get(
jsi::Runtime &runtime,
jsi::PropNameID const &name) {
auto methodName = name.utf8(runtime);
SystraceSection s("UIManagerBinding::get", "name", methodName);
// Convert shared_ptr<UIManager> to a raw ptr
// Why? Because:
// 1) UIManagerBinding strongly retains UIManager. The JS VM
// strongly retains UIManagerBinding (through the JSI).
// These functions are JSI functions and are only called via
// the JS VM; if the JS VM is torn down, those functions can't
// execute and these lambdas won't execute.
// 2) The UIManager is only deallocated when all references to it
// are deallocated, including the UIManagerBinding. That only
// happens when the JS VM is deallocated. So, the raw pointer
// is safe.
//
// Even if it's safe, why not just use shared_ptr anyway as
// extra insurance?
// 1) Using shared_ptr or weak_ptr when they're not needed is
// a pessimisation. It's more instructions executed without
// any additional value in this case.
// 2) How and when exactly these lambdas is deallocated is
// complex. Adding shared_ptr to them which causes the UIManager
// to potentially live longer is unnecessary, complicated cognitive
// overhead.
// 3) There is a strong suspicion that retaining UIManager from
// these C++ lambdas, which are retained by an object that is held onto
// by the JSI, caused some crashes upon deallocation of the
// Scheduler and JS VM. This could happen if, for instance, C++
// semantics cause these lambda to not be deallocated until
// a CPU tick (or more) after the JS VM is deallocated.
UIManager *uiManager = uiManager_.get();
// Semantic: Creates a new node with given pieces.
if (methodName == "createNode") {
return jsi::Function::createFromHostFunction(
runtime,
name,
5,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto eventTarget =
eventTargetFromValue(runtime, arguments[4], arguments[0]);
if (!eventTarget) {
react_native_assert(false);
return jsi::Value::undefined();
}
return valueFromShadowNode(
runtime,
uiManager->createNode(
tagFromValue(arguments[0]),
stringFromValue(runtime, arguments[1]),
surfaceIdFromValue(runtime, arguments[2]),
RawProps(runtime, arguments[3]),
eventTarget));
});
}
// Semantic: Clones the node with *same* props and *same* children.
if (methodName == "cloneNode") {
return jsi::Function::createFromHostFunction(
runtime,
name,
1,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
return valueFromShadowNode(
runtime,
uiManager->cloneNode(shadowNodeFromValue(runtime, arguments[0])));
});
}
if (methodName == "setIsJSResponder") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
uiManager->setIsJSResponder(
shadowNodeFromValue(runtime, arguments[0]),
arguments[1].getBool(),
arguments[2].getBool());
return jsi::Value::undefined();
});
}
if (methodName == "findNodeAtPoint") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto node = shadowNodeFromValue(runtime, arguments[0]);
auto locationX = (Float)arguments[1].getNumber();
auto locationY = (Float)arguments[2].getNumber();
auto onSuccessFunction =
arguments[3].getObject(runtime).getFunction(runtime);
auto targetNode =
uiManager->findNodeAtPoint(node, Point{locationX, locationY});
auto &eventTarget = targetNode->getEventEmitter()->eventTarget_;
EventEmitter::DispatchMutex().lock();
eventTarget->retain(runtime);
auto instanceHandle = eventTarget->getInstanceHandle(runtime);
eventTarget->release(runtime);
EventEmitter::DispatchMutex().unlock();
onSuccessFunction.call(runtime, std::move(instanceHandle));
return jsi::Value::undefined();
});
}
// Semantic: Clones the node with *same* props and *empty* children.
if (methodName == "cloneNodeWithNewChildren") {
return jsi::Function::createFromHostFunction(
runtime,
name,
1,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
return valueFromShadowNode(
runtime,
uiManager->cloneNode(
shadowNodeFromValue(runtime, arguments[0]),
ShadowNode::emptySharedShadowNodeSharedList()));
});
}
// Semantic: Clones the node with *given* props and *same* children.
if (methodName == "cloneNodeWithNewProps") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto const &rawProps = RawProps(runtime, arguments[1]);
return valueFromShadowNode(
runtime,
uiManager->cloneNode(
shadowNodeFromValue(runtime, arguments[0]),
nullptr,
&rawProps));
});
}
// Semantic: Clones the node with *given* props and *empty* children.
if (methodName == "cloneNodeWithNewChildrenAndProps") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto const &rawProps = RawProps(runtime, arguments[1]);
return valueFromShadowNode(
runtime,
uiManager->cloneNode(
shadowNodeFromValue(runtime, arguments[0]),
ShadowNode::emptySharedShadowNodeSharedList(),
&rawProps));
});
}
if (methodName == "appendChild") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
uiManager->appendChild(
shadowNodeFromValue(runtime, arguments[0]),
shadowNodeFromValue(runtime, arguments[1]));
return jsi::Value::undefined();
});
}
if (methodName == "createChildSet") {
return jsi::Function::createFromHostFunction(
runtime,
name,
1,
[](jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto shadowNodeList =
std::make_shared<SharedShadowNodeList>(SharedShadowNodeList({}));
return valueFromShadowNodeList(runtime, shadowNodeList);
});
}
if (methodName == "appendChildToSet") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[](jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto shadowNodeList = shadowNodeListFromValue(runtime, arguments[0]);
auto shadowNode = shadowNodeFromValue(runtime, arguments[1]);
shadowNodeList->push_back(shadowNode);
return jsi::Value::undefined();
});
}
if (methodName == "completeRoot") {
if (uiManager->backgroundExecutor_) {
std::weak_ptr<UIManager> weakUIManager = uiManager_;
// Enhanced version of the method that uses `backgroundExecutor` and
// captures a shared pointer to `UIManager`.
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[weakUIManager, uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto surfaceId = surfaceIdFromValue(runtime, arguments[0]);
auto weakShadowNodeList =
weakShadowNodeListFromValue(runtime, arguments[1]);
static std::atomic_uint_fast8_t completeRootEventCounter{0};
static std::atomic_uint_fast32_t mostRecentSurfaceId{0};
completeRootEventCounter += 1;
mostRecentSurfaceId = surfaceId;
uiManager->backgroundExecutor_(
[weakUIManager,
weakShadowNodeList,
surfaceId,
eventCount = completeRootEventCounter.load()] {
auto shouldYield = [=]() -> bool {
// If `completeRootEventCounter` was incremented, another
// `completeSurface` call has been scheduled and current
// `completeSurface` should yield to it.
return completeRootEventCounter > eventCount &&
mostRecentSurfaceId == surfaceId;
};
auto shadowNodeList =
shadowNodeListFromWeakList(weakShadowNodeList);
auto strongUIManager = weakUIManager.lock();
if (shadowNodeList && strongUIManager) {
strongUIManager->completeSurface(
surfaceId, shadowNodeList, {true, shouldYield});
}
});
return jsi::Value::undefined();
});
} else {
// Basic version of the method that does *not* use `backgroundExecutor`
// and does *not* capture a shared pointer to `UIManager`.
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
uiManager->completeSurface(
surfaceIdFromValue(runtime, arguments[0]),
shadowNodeListFromValue(runtime, arguments[1]),
{true, {}});
return jsi::Value::undefined();
});
}
}
if (methodName == "registerEventHandler") {
return jsi::Function::createFromHostFunction(
runtime,
name,
1,
[this](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto eventHandler =
arguments[0].getObject(runtime).getFunction(runtime);
eventHandler_ =
std::make_unique<EventHandlerWrapper>(std::move(eventHandler));
return jsi::Value::undefined();
});
}
if (methodName == "getRelativeLayoutMetrics") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto layoutMetrics = uiManager->getRelativeLayoutMetrics(
*shadowNodeFromValue(runtime, arguments[0]),
shadowNodeFromValue(runtime, arguments[1]).get(),
{/* .includeTransform = */ true});
auto frame = layoutMetrics.frame;
auto result = jsi::Object(runtime);
result.setProperty(runtime, "left", frame.origin.x);
result.setProperty(runtime, "top", frame.origin.y);
result.setProperty(runtime, "width", frame.size.width);
result.setProperty(runtime, "height", frame.size.height);
return result;
});
}
if (methodName == "dispatchCommand") {
return jsi::Function::createFromHostFunction(
runtime,
name,
3,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto shadowNode = shadowNodeFromValue(runtime, arguments[0]);
if (shadowNode) {
uiManager->dispatchCommand(
shadowNodeFromValue(runtime, arguments[0]),
stringFromValue(runtime, arguments[1]),
commandArgsFromValue(runtime, arguments[2]));
}
return jsi::Value::undefined();
});
}
// Legacy API
if (methodName == "measureLayout") {
return jsi::Function::createFromHostFunction(
runtime,
name,
4,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto layoutMetrics = uiManager->getRelativeLayoutMetrics(
*shadowNodeFromValue(runtime, arguments[0]),
shadowNodeFromValue(runtime, arguments[1]).get(),
{/* .includeTransform = */ false});
if (layoutMetrics == EmptyLayoutMetrics) {
auto onFailFunction =
arguments[2].getObject(runtime).getFunction(runtime);
onFailFunction.call(runtime);
return jsi::Value::undefined();
}
auto onSuccessFunction =
arguments[3].getObject(runtime).getFunction(runtime);
auto frame = layoutMetrics.frame;
onSuccessFunction.call(
runtime,
{jsi::Value{runtime, (double)frame.origin.x},
jsi::Value{runtime, (double)frame.origin.y},
jsi::Value{runtime, (double)frame.size.width},
jsi::Value{runtime, (double)frame.size.height}});
return jsi::Value::undefined();
});
}
if (methodName == "measure") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto shadowNode = shadowNodeFromValue(runtime, arguments[0]);
auto layoutMetrics = uiManager->getRelativeLayoutMetrics(
*shadowNode, nullptr, {/* .includeTransform = */ true});
auto onSuccessFunction =
arguments[1].getObject(runtime).getFunction(runtime);
if (layoutMetrics == EmptyLayoutMetrics) {
onSuccessFunction.call(runtime, {0, 0, 0, 0, 0, 0});
return jsi::Value::undefined();
}
auto newestCloneOfShadowNode =
uiManager->getNewestCloneOfShadowNode(*shadowNode);
auto layoutableShadowNode = traitCast<LayoutableShadowNode const *>(
newestCloneOfShadowNode.get());
Point originRelativeToParent = layoutableShadowNode
? layoutableShadowNode->getLayoutMetrics().frame.origin
: Point();
auto frame = layoutMetrics.frame;
onSuccessFunction.call(
runtime,
{jsi::Value{runtime, (double)originRelativeToParent.x},
jsi::Value{runtime, (double)originRelativeToParent.y},
jsi::Value{runtime, (double)frame.size.width},
jsi::Value{runtime, (double)frame.size.height},
jsi::Value{runtime, (double)frame.origin.x},
jsi::Value{runtime, (double)frame.origin.y}});
return jsi::Value::undefined();
});
}
if (methodName == "measureInWindow") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
auto layoutMetrics = uiManager->getRelativeLayoutMetrics(
*shadowNodeFromValue(runtime, arguments[0]),
nullptr,
{/* .includeTransform = */ true,
/* includeViewportOffset = */ true});
auto onSuccessFunction =
arguments[1].getObject(runtime).getFunction(runtime);
if (layoutMetrics == EmptyLayoutMetrics) {
onSuccessFunction.call(runtime, {0, 0, 0, 0});
return jsi::Value::undefined();
}
auto frame = layoutMetrics.frame;
onSuccessFunction.call(
runtime,
{jsi::Value{runtime, (double)frame.origin.x},
jsi::Value{runtime, (double)frame.origin.y},
jsi::Value{runtime, (double)frame.size.width},
jsi::Value{runtime, (double)frame.size.height}});
return jsi::Value::undefined();
});
}
if (methodName == "sendAccessibilityEvent") {
return jsi::Function::createFromHostFunction(
runtime,
name,
2,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
uiManager->sendAccessibilityEvent(
shadowNodeFromValue(runtime, arguments[0]),
stringFromValue(runtime, arguments[1]));
return jsi::Value::undefined();
});
}
if (methodName == "configureNextLayoutAnimation") {
return jsi::Function::createFromHostFunction(
runtime,
name,
3,
[uiManager](
jsi::Runtime &runtime,
jsi::Value const &thisValue,
jsi::Value const *arguments,
size_t count) noexcept -> jsi::Value {
uiManager->configureNextLayoutAnimation(
runtime,
// TODO: pass in JSI value instead of folly::dynamic to RawValue
RawValue(commandArgsFromValue(runtime, arguments[0])),
arguments[1],
arguments[2]);
return jsi::Value::undefined();
});
}
if (methodName == "unstable_getCurrentEventPriority") {
return jsi::Function::createFromHostFunction(
runtime,
name,
0,
[this](
jsi::Runtime &,
jsi::Value const &,
jsi::Value const *,
size_t) noexcept -> jsi::Value {
return jsi::Value(serialize(currentEventPriority_));
});
}
if (methodName == "unstable_DefaultEventPriority") {
return jsi::Value(serialize(ReactEventPriority::Default));
}
if (methodName == "unstable_DiscreteEventPriority") {
return jsi::Value(serialize(ReactEventPriority::Discrete));
}
return jsi::Value::undefined();
}