react-native code-gen > C++ TurboModules struct support (#35265)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/35265

This adds a templating layer for C++ TurboModules to automatically generate struct templates from TurboModule specs.

You have to define concrete types for those templates to use them in your C++ TurboModule.

E.g. for the JS flow type:
```
export type ObjectStruct = {|
  a: number,
  b: string,
  c?: ?string,
|};
```
code-gen will now generate the following template code:
```
#pragma mark - NativeCxxModuleExampleCxxBaseObjectStruct

template <typename P0, typename P1, typename P2>
struct NativeCxxModuleExampleCxxBaseObjectStruct {
  P0 a;
  P1 b;
  P2 c;
  bool operator==(const NativeCxxModuleExampleCxxBaseObjectStruct &other) const {
    return a == other.a && b == other.b && c == other.c;
  }
};

template <typename P0, typename P1, typename P2>
struct NativeCxxModuleExampleCxxBaseObjectStructBridging {
  static NativeCxxModuleExampleCxxBaseObjectStruct<P0, P1, P2> fromJs(
      jsi::Runtime &rt,
      const jsi::Object &value,
      const std::shared_ptr<CallInvoker> &jsInvoker) {
    NativeCxxModuleExampleCxxBaseObjectStruct<P0, P1, P2> result{
      bridging::fromJs<P0>(rt, value.getProperty(rt, "a"), jsInvoker),
      bridging::fromJs<P1>(rt, value.getProperty(rt, "b"), jsInvoker),
      bridging::fromJs<P2>(rt, value.getProperty(rt, "c"), jsInvoker)};
    return result;
  }

  static jsi::Object toJs(
      jsi::Runtime &rt,
      const NativeCxxModuleExampleCxxBaseObjectStruct<P0, P1, P2> &value) {
    auto result = facebook::jsi::Object(rt);
    result.setProperty(rt, "a", bridging::toJs(rt, value.a));
    result.setProperty(rt, "b", bridging::toJs(rt, value.b));
    if (value.c) {
      result.setProperty(rt, "c", bridging::toJs(rt, value.c.value()));
    }
    return result;
  }
};
```
and you can use it in our C++ TurboModule for example as:
```
using ObjectStruct = NativeCxxModuleExampleCxxBaseObjectStruct<
    int32_t,
    std::string,
    std::optional<std::string>>;

template <>
struct Bridging<ObjectStruct>
    : NativeCxxModuleExampleCxxBaseObjectStructBridging<
          int32_t,
          std::string,
          std::optional<std::string>> {};
```
or as
```
using ObjectStruct = NativeCxxModuleExampleCxxBaseObjectStruct<
    float,
    folly::StringPiece,
    std::optional<std::string>>;

template <>
struct Bridging<ObjectStruct>
    : NativeCxxModuleExampleCxxBaseObjectStructBridging<
          float,
          folly::StringPiece,
          std::optional<std::string>> {};
```
Or as
...

Changelog: [Internal]

Reviewed By: rshest

Differential Revision: D41133761

fbshipit-source-id: fdf36e51073cb46c5234f6121842c79a884899c7

Libraries/WebPerformance/NativePerformanceObserver.h

@@ -13,10 +13,34 @@
 #include <optional>
 #include <string>
 #include <vector>
-#include "NativePerformanceObserver_RawPerformanceEntry.h"
 
 namespace facebook::react {
 
+#pragma mark - Structs
+
+using RawPerformanceEntry = NativePerformanceObserverCxxBaseRawPerformanceEntry<
+    std::string,
+    int32_t,
+    double,
+    double,
+    // For "event" entries only:
+    std::optional<double>,
+    std::optional<double>,
+    std::optional<double>>;
+
+template <>
+struct Bridging<RawPerformanceEntry>
+    : NativePerformanceObserverCxxBaseRawPerformanceEntryBridging<
+          std::string,
+          int32_t,
+          double,
+          double,
+          std::optional<double>,
+          std::optional<double>,
+          std::optional<double>> {};
+
+#pragma mark - implementation
+
 class NativePerformanceObserver
     : public NativePerformanceObserverCxxSpec<NativePerformanceObserver>,
       std::enable_shared_from_this<NativePerformanceObserver> {