Add minimal implementation of RuntimeScheduler::scheduleTask

Summary:
Changelog: [internal]

Add minimal implementation of schedule task. More features and proper scheduling will be added later.

Reviewed By: mdvacca

Differential Revision: D27622138

fbshipit-source-id: b2e4623d38e7217290a6a3c59ccc10a1c13e3a4f

Author: sammy-SC

ReactCommon/react/renderer/runtimescheduler/BUCK

@@ -49,5 +49,6 @@ rn_xplat_cxx_library(
     visibility = ["PUBLIC"],
     deps = [
         react_native_xplat_target("runtimeexecutor:runtimeexecutor"),
+        react_native_xplat_target("react/renderer/debug:debug"),
     ],
 )

ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler.cpp

@@ -7,4 +7,19 @@
 
 #include "RuntimeScheduler.h"
 
-namespace facebook::react {} // namespace facebook::react
+namespace facebook::react {
+
+RuntimeScheduler::RuntimeScheduler(RuntimeExecutor const &runtimeExecutor)
+    : runtimeExecutor_(runtimeExecutor) {}
+
+void RuntimeScheduler::scheduleTask(std::shared_ptr<Task> const &task) {
+  taskQueue_.push(task);
+
+  runtimeExecutor_([this](jsi::Runtime &runtime) {
+    auto topPriority = taskQueue_.top();
+    taskQueue_.pop();
+    (*topPriority)(runtime);
+  });
+}
+
+} // namespace facebook::react

ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler.h

@@ -7,10 +7,26 @@
 
 #pragma once
 
-namespace facebook {
-namespace react {
+#include <ReactCommon/RuntimeExecutor.h>
+#include <react/renderer/runtimescheduler/Task.h>
+#include <memory>
+#include <queue>
 
-class RuntimeScheduler final {};
+namespace facebook::react {
 
-} // namespace react
-} // namespace facebook
+class RuntimeScheduler final {
+ public:
+  RuntimeScheduler(RuntimeExecutor const &runtimeExecutor);
+
+  void scheduleTask(std::shared_ptr<Task> const &task);
+
+ private:
+  mutable std::priority_queue<
+      std::shared_ptr<Task>,
+      std::vector<std::shared_ptr<Task>>,
+      TaskPriorityComparer>
+      taskQueue_;
+  RuntimeExecutor const runtimeExecutor_;
+};
+
+} // namespace facebook::react

ReactCommon/react/renderer/runtimescheduler/RuntimeSchedulerBinding.cpp

@@ -8,20 +8,24 @@
 #include "RuntimeSchedulerBinding.h"
 #include "SchedulerPriority.h"
 
+#include <react/debug/react_native_assert.h>
 #include <memory>
 
 namespace facebook::react {
 
 std::shared_ptr<RuntimeSchedulerBinding>
-RuntimeSchedulerBinding::createAndInstallIfNeeded(jsi::Runtime &runtime) {
+RuntimeSchedulerBinding::createAndInstallIfNeeded(
+    jsi::Runtime &runtime,
+    RuntimeExecutor runtimeExecutor) {
   auto runtimeSchedulerModuleName = "nativeRuntimeScheduler";
 
   auto runtimeSchedulerValue =
       runtime.global().getProperty(runtime, runtimeSchedulerModuleName);
   if (runtimeSchedulerValue.isUndefined()) {
     // The global namespace does not have an instance of the binding;
     // we need to create, install and return it.
-    auto runtimeSchedulerBinding = std::make_shared<RuntimeSchedulerBinding>();
+    auto runtimeSchedulerBinding = std::make_shared<RuntimeSchedulerBinding>(
+        RuntimeScheduler(runtimeExecutor));
     auto object =
         jsi::Object::createFromHostObject(runtime, runtimeSchedulerBinding);
     runtime.global().setProperty(
@@ -35,11 +39,37 @@ RuntimeSchedulerBinding::createAndInstallIfNeeded(jsi::Runtime &runtime) {
   return runtimeSchedulerObject.getHostObject<RuntimeSchedulerBinding>(runtime);
 }
 
+RuntimeSchedulerBinding::RuntimeSchedulerBinding(
+    RuntimeScheduler runtimeScheduler)
+    : runtimeScheduler_(std::move(runtimeScheduler)) {}
+
 jsi::Value RuntimeSchedulerBinding::get(
     jsi::Runtime &runtime,
     jsi::PropNameID const &name) {
   auto propertyName = name.utf8(runtime);
 
+  if (propertyName == "unstable_scheduleCallback") {
+    return jsi::Function::createFromHostFunction(
+        runtime,
+        name,
+        3,
+        [this](
+            jsi::Runtime &runtime,
+            jsi::Value const &,
+            jsi::Value const *arguments,
+            size_t) noexcept -> jsi::Value {
+          SchedulerPriority priority = fromRawValue(arguments[0].getNumber());
+          auto callback = arguments[1].getObject(runtime).getFunction(runtime);
+          react_native_assert(arguments[2].isUndefined());
+
+          auto task = std::make_shared<Task>(priority, std::move(callback));
+          runtimeScheduler_.scheduleTask(task);
+
+          // TODO: return reference to the task.
+          return jsi::Value::undefined();
+        });
+  }
+
   if (propertyName == "unstable_ImmediatePriority") {
     return jsi::Value(runtime, serialize(SchedulerPriority::ImmediatePriority));
   }

ReactCommon/react/renderer/runtimescheduler/RuntimeSchedulerBinding.h

@@ -8,6 +8,7 @@
 #pragma once
 
 #include <jsi/jsi.h>
+#include <react/renderer/runtimescheduler/RuntimeScheduler.h>
 
 namespace facebook::react {
 
@@ -16,20 +17,25 @@ namespace facebook::react {
  */
 class RuntimeSchedulerBinding : public jsi::HostObject {
  public:
+  RuntimeSchedulerBinding(RuntimeScheduler runtimeScheduler);
+
   /*
    * Installs RuntimeSchedulerBinding into JavaScript runtime if needed.
    * Creates and sets `RuntimeSchedulerBinding` into the global namespace.
    * In case if the global namespace already has a `RuntimeSchedulerBinding`
-   * installed, returns that. Thread synchronization must be enforced
-   * externally.
+   * installed, returns that.
    */
   static std::shared_ptr<RuntimeSchedulerBinding> createAndInstallIfNeeded(
-      jsi::Runtime &runtime);
+      jsi::Runtime &runtime,
+      RuntimeExecutor runtimeExecutor);
 
   /*
    * `jsi::HostObject` specific overloads.
    */
   jsi::Value get(jsi::Runtime &runtime, jsi::PropNameID const &name) override;
+
+ private:
+  RuntimeScheduler runtimeScheduler_;
 };
 
 } // namespace facebook::react

ReactCommon/react/renderer/runtimescheduler/SchedulerPriority.h

@@ -7,6 +7,8 @@
 
 #pragma once
 
+#include <react/debug/react_native_assert.h>
+
 namespace facebook::react {
 
 enum class SchedulerPriority : int {
@@ -23,4 +25,22 @@ static constexpr std::underlying_type<SchedulerPriority>::type serialize(
       schedulerPriority);
 }
 
+static inline SchedulerPriority fromRawValue(double value) {
+  switch ((int)value) {
+    case 1:
+      return SchedulerPriority::ImmediatePriority;
+    case 2:
+      return SchedulerPriority::UserBlockingPriority;
+    case 3:
+      return SchedulerPriority::NormalPriority;
+    case 4:
+      return SchedulerPriority::LowPriority;
+    case 5:
+      return SchedulerPriority::IdlePriority;
+    default:
+      react_native_assert(false && "Unsupported SchedulerPriority value");
+      return SchedulerPriority::NormalPriority;
+  }
+}
+
 } // namespace facebook::react

ReactCommon/react/renderer/runtimescheduler/Task.cpp

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "RuntimeScheduler.h"
+
+namespace facebook::react {
+
+Task::Task(SchedulerPriority priority, jsi::Function callback)
+    : priority_(priority), callback_(std::move(callback)) {}
+
+SchedulerPriority Task::getPriority() const {
+  return priority_;
+}
+
+void Task::operator()(jsi::Runtime &runtime) const {
+  callback_.call(runtime, {});
+}
+
+} // namespace facebook::react

ReactCommon/react/renderer/runtimescheduler/Task.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <jsi/jsi.h>
+#include <react/renderer/runtimescheduler/SchedulerPriority.h>
+
+namespace facebook::react {
+
+class Task final {
+ public:
+  Task(SchedulerPriority priority, jsi::Function callback);
+
+  SchedulerPriority priority_;
+  jsi::Function callback_;
+
+  SchedulerPriority getPriority() const;
+
+  void operator()(jsi::Runtime &runtime) const;
+};
+
+class TaskPriorityComparer {
+ public:
+  inline bool operator()(
+      std::shared_ptr<Task> const &lhs,
+      std::shared_ptr<Task> const &rhs) {
+    return lhs->getPriority() > rhs->getPriority();
+  }
+};
+
+} // namespace facebook::react

ReactCommon/react/renderer/scheduler/Scheduler.cpp

@@ -99,7 +99,8 @@ Scheduler::Scheduler(
     auto uiManagerBinding = UIManagerBinding::createAndInstallIfNeeded(runtime);
     uiManagerBinding->attach(uiManager);
     if (enableRuntimeScheduler) {
-      RuntimeSchedulerBinding::createAndInstallIfNeeded(runtime);
+      RuntimeSchedulerBinding::createAndInstallIfNeeded(
+          runtime, runtimeExecutor_);
     }
   });