JSBigString implements jsi::Buffer (#54206)

Summary:
Pull Request resolved: #54206

We don't need `BigStringBuffer` as a separate abstraction when `JSBigString` implements almost exactly the same interface.

Changelog:

[General][Changed] BigStringBuffer is deprecated and will be removed in a future release - use JSBigString instead
[General][Breaking] JSBigString mutable data accessor has been renamed to mutableData

Reviewed By: Abbondanzo

Differential Revision: D84458636

fbshipit-source-id: f507fd4ff842301af3047afeccf853f30a2f72df

Author: javache

packages/react-native/ReactAndroid/src/main/jni/react/jni/JSLoader.cpp

@@ -72,7 +72,7 @@ loadScriptFromAssets(AAssetManager* manager, const std::string& assetName) {
       }
 
       auto buf = std::make_unique<JSBigBufferString>(script->size());
-      memcpy(buf->data(), script->c_str(), script->size());
+      memcpy(buf->mutableData(), script->c_str(), script->size());
       return buf;
     }
   }

packages/react-native/ReactCommon/cxxreact/JSBigString.h

@@ -10,6 +10,8 @@
 #include <memory>
 #include <string>
 
+#include <jsi/jsi.h>
+
 #ifndef RN_EXPORT
 #ifdef _MSC_VER
 #define RN_EXPORT
@@ -27,23 +29,30 @@ namespace facebook::react {
 // large string needs to be curried into a std::function<>, which must
 // by CopyConstructible.
 
-class JSBigString {
+class JSBigString : public facebook::jsi::Buffer {
  public:
   JSBigString() = default;
 
-  // Not copyable
+  // Not copyable or movable
   JSBigString(const JSBigString &) = delete;
   JSBigString &operator=(const JSBigString &) = delete;
+  JSBigString(JSBigString &&) = delete;
+  JSBigString &operator=(JSBigString &&) = delete;
 
-  virtual ~JSBigString() = default;
+  ~JSBigString() override = default;
 
   virtual bool isAscii() const = 0;
 
   // This needs to be a \0 terminated string
   virtual const char *c_str() const = 0;
 
   // Length of the c_str without the NULL byte.
-  virtual size_t size() const = 0;
+  size_t size() const override = 0;
+
+  const uint8_t *data() const final
+  {
+    return reinterpret_cast<const uint8_t *>(c_str());
+  }
 };
 
 // Concrete JSBigString implementation which holds a std::string
@@ -105,7 +114,7 @@ class RN_EXPORT JSBigBufferString : public JSBigString {
     return m_size;
   }
 
-  char *data()
+  char *mutableData()
   {
     return m_data;
   }

packages/react-native/ReactCommon/cxxreact/JSIndexedRAMBundle.cpp

@@ -60,8 +60,8 @@ void JSIndexedRAMBundle::init() {
       "header size must exactly match the input file format");
 
   readBundle(reinterpret_cast<char*>(header), sizeof(header));
-  const size_t numTableEntries = folly::Endian::little(header[1]);
-  const size_t startupCodeSize = folly::Endian::little(header[2]);
+  size_t numTableEntries = folly::Endian::little(header[1]);
+  std::streamsize startupCodeSize = folly::Endian::little(header[2]);
 
   // allocate memory for meta data and lookup table.
   m_table = ModuleTable(numTableEntries);
@@ -73,7 +73,7 @@ void JSIndexedRAMBundle::init() {
   // read the startup code
   m_startupCode = std::make_unique<JSBigBufferString>(startupCodeSize - 1);
 
-  readBundle(m_startupCode->data(), startupCodeSize - 1);
+  readBundle(m_startupCode->mutableData(), startupCodeSize - 1);
 }
 
 JSIndexedRAMBundle::Module JSIndexedRAMBundle::getModule(
@@ -109,8 +109,7 @@ std::string JSIndexedRAMBundle::getModuleCode(const uint32_t id) const {
   return ret;
 }
 
-void JSIndexedRAMBundle::readBundle(char* buffer, const std::streamsize bytes)
-    const {
+void JSIndexedRAMBundle::readBundle(char* buffer, std::streamsize bytes) const {
   if (!m_bundle->read(buffer, bytes)) {
     if ((m_bundle->rdstate() & std::ios::eofbit) != 0) {
       throw std::ios_base::failure("Unexpected end of RAM Bundle file");

packages/react-native/ReactCommon/jsiexecutor/jsireact/JSIExecutor.cpp

@@ -168,8 +168,7 @@ void JSIExecutor::loadBundle(
     ReactMarker::logTaggedMarker(
         ReactMarker::RUN_JS_BUNDLE_START, scriptName.c_str());
   }
-  runtime_->evaluateJavaScript(
-      std::make_unique<BigStringBuffer>(std::move(script)), sourceURL);
+  runtime_->evaluateJavaScript(std::move(script), sourceURL);
   flush();
   if (hasLogger) {
     ReactMarker::logTaggedMarker(
@@ -212,7 +211,7 @@ void JSIExecutor::registerBundle(
           "Empty bundle registered with ID " + tag + " from " + bundlePath);
     }
     runtime_->evaluateJavaScript(
-        std::make_unique<BigStringBuffer>(std::move(script)),
+        std::move(script),
         JSExecutor::getSyntheticBundlePath(bundleId, bundlePath));
   }
   ReactMarker::logTaggedMarker(

packages/react-native/ReactCommon/jsiexecutor/jsireact/JSIExecutor.h

@@ -49,7 +49,7 @@ namespace facebook::react {
 using JSIScopedTimeoutInvoker =
     std::function<void(const std::function<void()> &invokee, std::function<std::string()> errorMessageProducer)>;
 
-class BigStringBuffer : public jsi::Buffer {
+class [[deprecated("JSBigString implements jsi::Buffer directly")]] BigStringBuffer : public jsi::Buffer {
  public:
   BigStringBuffer(std::unique_ptr<const JSBigString> script) : script_(std::move(script)) {}
 
@@ -60,7 +60,7 @@ class BigStringBuffer : public jsi::Buffer {
 
   const uint8_t *data() const override
   {
-    return reinterpret_cast<const uint8_t *>(script_->c_str());
+    return script_->data();
   }
 
  private:

packages/react-native/ReactCommon/react/runtime/ReactInstance.cpp

@@ -221,7 +221,7 @@ void ReactInstance::loadScript(
     const std::string& sourceURL,
     std::function<void(jsi::Runtime& runtime)>&& beforeLoad,
     std::function<void(jsi::Runtime& runtime)>&& afterLoad) {
-  auto buffer = std::make_shared<BigStringBuffer>(std::move(script));
+  std::shared_ptr<const jsi::Buffer> buffer(std::move(script));
   std::string scriptName = simpleBasename(sourceURL);
 
   runtimeScheduler_->scheduleWork([this,
@@ -232,7 +232,7 @@ void ReactInstance::loadScript(
                                        std::weak_ptr<BufferedRuntimeExecutor>(
                                            bufferedRuntimeExecutor_),
                                    beforeLoad,
-                                   afterLoad](jsi::Runtime& runtime) {
+                                   afterLoad](jsi::Runtime& runtime) mutable {
     if (beforeLoad) {
       beforeLoad(runtime);
     }
@@ -357,7 +357,6 @@ void ReactInstance::registerSegment(
       throw std::invalid_argument(
           "Empty segment registered with ID " + tag + " from " + segmentPath);
     }
-    auto buffer = std::make_shared<BigStringBuffer>(std::move(script));
 
     bool hasLogger(ReactMarker::logTaggedMarkerBridgelessImpl != nullptr);
     if (hasLogger) {
@@ -369,7 +368,8 @@ void ReactInstance::registerSegment(
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
     runtime.evaluateJavaScript(
-        buffer, JSExecutor::getSyntheticBundlePath(segmentId, segmentPath));
+        std::move(script),
+        JSExecutor::getSyntheticBundlePath(segmentId, segmentPath));
 #pragma clang diagnostic pop
     LOG(WARNING) << "Finished evaluating segment " << segmentId
                  << " in ReactInstance::registerSegment";