Add default getStringData/getPropNameIdData implementation (#47530)

Summary:

Adds the default implementation for `getStringData`/`getPropNameIdData`
for VMs that do not provide their own implementation

Changelog: [Internal]

Differential Revision: D65638889

packages/react-native/ReactCommon/jsi/jsi/decorator.h

@@ -232,6 +232,22 @@ class RuntimeDecorator : public Base, private jsi::Instrumentation {
     return plain_.utf16(sym);
   }
 
+  void getStringData(
+      const jsi::String& str,
+      const void* ctx,
+      void (*cb)(const void* ctx, bool ascii, const void* data, size_t num))
+      override {
+    plain_.getStringData(str, ctx, cb);
+  }
+
+  void getPropNameIdData(
+      const jsi::PropNameID& sym,
+      const void* ctx,
+      void (*cb)(const void* ctx, bool ascii, const void* data, size_t num))
+      override {
+    plain_.getPropNameIdData(sym, ctx, cb);
+  }
+
   Object createObject() override {
     return plain_.createObject();
   };
@@ -690,6 +706,24 @@ class WithRuntimeDecorator : public RuntimeDecorator<Plain, Base> {
     return RD::utf16(sym);
   }
 
+  void getStringData(
+      const jsi::String& str,
+      const void* ctx,
+      void (*cb)(const void* ctx, bool ascii, const void* data, size_t num))
+      override {
+    Around around{with_};
+    RD::getStringData(str, ctx, cb);
+  }
+
+  void getPropNameIdData(
+      const jsi::PropNameID& sym,
+      const void* ctx,
+      void (*cb)(const void* ctx, bool ascii, const void* data, size_t num))
+      override {
+    Around around{with_};
+    RD::getPropNameIdData(sym, ctx, cb);
+  }
+
   Value createValueFromJsonUtf8(const uint8_t* json, size_t length) override {
     Around around{with_};
     return RD::createValueFromJsonUtf8(json, length);

packages/react-native/ReactCommon/jsi/jsi/jsi.cpp

@@ -258,6 +258,22 @@ std::u16string Runtime::utf16(const String& str) {
   return convertUTF8ToUTF16(utf8Str);
 }
 
+void Runtime::getStringData(
+    const jsi::String& str,
+    const void* ctx,
+    void (*cb)(const void* ctx, bool ascii, const void* data, size_t num)) {
+  auto utf16Str = utf16(str);
+  cb(ctx, false, utf16Str.data(), utf16Str.size());
+}
+
+void Runtime::getPropNameIdData(
+    const jsi::PropNameID& sym,
+    const void* ctx,
+    void (*cb)(const void* ctx, bool ascii, const void* data, size_t num)) {
+  auto utf16Str = utf16(sym);
+  cb(ctx, false, utf16Str.data(), utf16Str.size());
+}
+
 Pointer& Pointer::operator=(Pointer&& other) noexcept {
   if (ptr_) {
     ptr_->invalidate();

packages/react-native/ReactCommon/jsi/jsi/jsi.h

@@ -402,6 +402,24 @@ class JSI_EXPORT Runtime {
   virtual std::u16string utf16(const String& str);
   virtual std::u16string utf16(const PropNameID& sym);
 
+  /// Invokes the provided callback \p cb with the String content as either
+  /// ASCII or UTF16 String. It's possible for the callback to be called
+  /// multiple times, potentially with different types of String.
+  virtual void getStringData(
+      const jsi::String& str,
+      const void* ctx,
+      void (*cb)(const void* ctx, bool ascii, const void* data, size_t num));
+
+  /// Invokes the provided callback \p cb with the PropNameID content as either
+  /// ASCII or UTF16 String. It's possible for the callback to be called
+  /// multiple times, potentially with different types of String.  It's possible
+  /// for the callback to be called multiple times, potentially with different
+  /// types of String.
+  virtual void getPropNameIdData(
+      const jsi::PropNameID& sym,
+      const void* ctx,
+      void (*cb)(const void* ctx, bool ascii, const void* data, size_t num));
+
   // These exist so derived classes can access the private parts of
   // Value, Symbol, String, and Object, which are all friends of Runtime.
   template <typename T>
@@ -509,6 +527,20 @@ class JSI_EXPORT PropNameID : public Pointer {
     return runtime.utf16(*this);
   }
 
+  /// Invokes the user provided callback to process the content in PropNameId.
+  /// The callback must take in three arguments: bool ascii, const void* data,
+  /// and size_t num, respectively. The callback is responsible for handling
+  /// both ASCII and UTF16 string.
+  template <typename CB>
+  void getPropNameIdData(Runtime& runtime, const CB& cb) const {
+    runtime.getPropNameIdData(
+        *this,
+        &cb,
+        [](const void* ctx, bool ascii, const void* data, size_t num) {
+          (*((const CB*)ctx))(ascii, data, num);
+        });
+  }
+
   static bool compare(
       Runtime& runtime,
       const jsi::PropNameID& a,
@@ -664,6 +696,21 @@ class JSI_EXPORT String : public Pointer {
     return runtime.utf16(*this);
   }
 
+  /// Invokes the user provided callback to process content in String. The
+  /// callback must take in three arguments: bool ascii, const void* data, and
+  /// size_t num, respectively. The callback is responsible for handling both
+  /// ASCII and UTF16 string.  It's possible for the callback to be called
+  /// multiple times, potentially with different types of String.
+  template <typename CB>
+  void getStringData(Runtime& runtime, const CB& cb) const {
+    runtime.getStringData(
+        *this,
+        &cb,
+        [](const void* ctx, bool ascii, const void* data, size_t num) {
+          (*((const CB*)ctx))(ascii, data, num);
+        });
+  }
+
   friend class Runtime;
   friend class Value;
 };

packages/react-native/ReactCommon/jsi/jsi/test/testlib.cpp

@@ -1635,6 +1635,40 @@ TEST_P(JSITest, UTF16Test) {
   EXPECT_EQ(str.utf16(rd), u"\uFFFD\u007A");
 }
 
+TEST_P(JSITest, GetStringDataTest) {
+  // This Runtime Decorator is used to test the default getStringData
+  // implementation for VMs that do not provide their own implementation
+  class RD : public RuntimeDecorator<Runtime, Runtime> {
+   public:
+    RD(Runtime& rt) : RuntimeDecorator(rt) {}
+
+    void getStringData(
+        const String& str,
+        const void* ctx,
+        void (*cb)(const void* ctx, bool ascii, const void* data, size_t num))
+        override {
+      Runtime::getStringData(str, ctx, cb);
+    }
+  };
+
+  RD rd = RD(rt);
+  String str = String::createFromUtf8(rd, "hello👋");
+
+  std::u16string buf;
+  auto cb = [&buf](bool ascii, const void* data, size_t num) {
+    auto begin = (const char16_t*)data;
+    auto end = begin + num;
+    while (begin < end) {
+      auto curr = begin[0];
+      buf.push_back(curr);
+      begin++;
+    }
+  };
+
+  str.getStringData(rd, cb);
+  EXPECT_EQ(buf, str.utf16(rd));
+}
+
 INSTANTIATE_TEST_CASE_P(
     Runtimes,
     JSITest,