Save exported state across RuntimeAgent instances (#43098)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/43098

Changelog: [Internal]

Wraps Hermes's `CDPHandler::getState()` API in an engine-agnostic abstraction (`RuntimeAgentDelegate::getExportedState`).

An Agent's lifetime ends when its Target is destroyed, but it can occasionally be useful to persist some state for the "next" Target+Agent of the same type (in the same session) to read.

`RuntimeAgentDelegate` is polymorphic and can't just write arbitrary data to SessionState. Instead, it can now *export* a state object that we'll store and pass to the next `RuntimeTargetDelegate::createAgentDelegate` call.

Reviewed By: huntie

Differential Revision: D53919696

fbshipit-source-id: a8e9b921bc8fc2d195c5dddea9537e6ead3d0358

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

@@ -39,6 +39,7 @@ std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate>
 JSExecutor::createAgentDelegate(
     jsinspector_modern::FrontendChannel frontendChannel,
     jsinspector_modern::SessionState& sessionState,
+    std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate::ExportedState>,
     const jsinspector_modern::ExecutionContextDescription&
         executionContextDescription) {
   (void)executionContextDescription;

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

@@ -147,6 +147,8 @@ class RN_EXPORT JSExecutor : public jsinspector_modern::RuntimeTargetDelegate {
   createAgentDelegate(
       jsinspector_modern::FrontendChannel frontendChannel,
       jsinspector_modern::SessionState& sessionState,
+      std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const jsinspector_modern::ExecutionContextDescription&
           executionContextDescription) override;
 };

packages/react-native/ReactCommon/hermes/executor/HermesExecutorFactory.cpp

@@ -261,6 +261,8 @@ std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate>
 HermesExecutor::createAgentDelegate(
     jsinspector_modern::FrontendChannel frontendChannel,
     jsinspector_modern::SessionState& sessionState,
+    std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate::ExportedState>
+        previouslyExportedState,
     const jsinspector_modern::ExecutionContextDescription&
         executionContextDescription) {
   std::shared_ptr<HermesRuntime> hermesRuntimeShared(runtime_, &hermesRuntime_);
@@ -268,6 +270,7 @@ HermesExecutor::createAgentDelegate(
       new jsinspector_modern::HermesRuntimeAgentDelegate(
           frontendChannel,
           sessionState,
+          std::move(previouslyExportedState),
           executionContextDescription,
           hermesRuntimeShared,
           [jsQueueWeak = std::weak_ptr(jsQueue_),

packages/react-native/ReactCommon/hermes/executor/HermesExecutorFactory.h

@@ -58,6 +58,8 @@ class HermesExecutor : public JSIExecutor {
   createAgentDelegate(
       jsinspector_modern::FrontendChannel frontendChannel,
       jsinspector_modern::SessionState& sessionState,
+      std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const jsinspector_modern::ExecutionContextDescription&
           executionContextDescription) override;
 

packages/react-native/ReactCommon/hermes/inspector-modern/chrome/HermesRuntimeAgentDelegate.cpp

@@ -67,6 +67,26 @@ class HermesRuntimeAgentDelegate::Impl final : public RuntimeAgentDelegate {
   using HermesCDPHandler = hermes::inspector_modern::chrome::CDPHandler;
   using HermesExecutionContextDescription =
       hermes::inspector_modern::chrome::CDPHandlerExecutionContextDescription;
+  using HermesState = hermes::inspector_modern::chrome::State;
+
+  struct HermesStateWrapper : public ExportedState {
+    explicit HermesStateWrapper(std::unique_ptr<HermesState> state)
+        : state_(std::move(state)) {}
+
+    static std::unique_ptr<HermesState> unwrapDestructively(
+        ExportedState* wrapper) {
+      if (!wrapper) {
+        return nullptr;
+      }
+      if (auto* typedWrapper = dynamic_cast<HermesStateWrapper*>(wrapper)) {
+        return std::move(typedWrapper->state_);
+      }
+      return nullptr;
+    }
+
+   private:
+    std::unique_ptr<HermesState> state_;
+  };
 
  public:
   /**
@@ -75,6 +95,10 @@ class HermesRuntimeAgentDelegate::Impl final : public RuntimeAgentDelegate {
    * \param sessionState The state of the current CDP session. This will only
    * be accessed on the main thread (during the constructor, in handleRequest,
    * etc).
+   * \param previouslyExportedState The exported state from a previous instance
+   * of RuntimeAgentDelegate (NOT necessarily HermesRuntimeAgentDelegate). This
+   * may be nullptr, and if not nullptr it may be of any concrete type that
+   * implements RuntimeAgentDelegate::ExportedState.
    * \param executionContextDescription A description of the execution context
    * represented by this runtime. This is used for disambiguating the
    * source/destination of CDP messages when there are multiple runtimes
@@ -87,6 +111,8 @@ class HermesRuntimeAgentDelegate::Impl final : public RuntimeAgentDelegate {
   Impl(
       FrontendChannel frontendChannel,
       SessionState& sessionState,
+      std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const ExecutionContextDescription& executionContextDescription,
       std::shared_ptr<hermes::HermesRuntime> runtime,
       RuntimeExecutor runtimeExecutor)
@@ -96,7 +122,9 @@ class HermesRuntimeAgentDelegate::Impl final : public RuntimeAgentDelegate {
                 runtimeExecutor),
             /* waitForDebugger */ false,
             /* enableConsoleAPICapturing */ false,
-            /* state */ nullptr,
+            /* state */
+            HermesStateWrapper::unwrapDestructively(
+                previouslyExportedState.get()),
             {.isRuntimeDomainEnabled = sessionState.isRuntimeDomainEnabled},
             HermesExecutionContextDescription{
                 .id = executionContextDescription.id,
@@ -139,6 +167,10 @@ class HermesRuntimeAgentDelegate::Impl final : public RuntimeAgentDelegate {
     return true;
   }
 
+  virtual std::unique_ptr<ExportedState> getExportedState() override {
+    return std::make_unique<HermesStateWrapper>(hermes_->getState());
+  }
+
  private:
   std::shared_ptr<HermesCDPHandler> hermes_;
 };
@@ -155,6 +187,7 @@ class HermesRuntimeAgentDelegate::Impl final
   Impl(
       FrontendChannel frontendChannel,
       SessionState& sessionState,
+      std::unique_ptr<RuntimeAgentDelegate::ExportedState>,
       const ExecutionContextDescription&,
       std::shared_ptr<hermes::HermesRuntime> runtime,
       RuntimeExecutor)
@@ -169,12 +202,15 @@ class HermesRuntimeAgentDelegate::Impl final
 HermesRuntimeAgentDelegate::HermesRuntimeAgentDelegate(
     FrontendChannel frontendChannel,
     SessionState& sessionState,
+    std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+        previouslyExportedState,
     const ExecutionContextDescription& executionContextDescription,
     std::shared_ptr<hermes::HermesRuntime> runtime,
     RuntimeExecutor runtimeExecutor)
     : impl_(std::make_unique<Impl>(
           std::move(frontendChannel),
           sessionState,
+          std::move(previouslyExportedState),
           executionContextDescription,
           std::move(runtime),
           std::move(runtimeExecutor))) {}
@@ -184,4 +220,9 @@ bool HermesRuntimeAgentDelegate::handleRequest(
   return impl_->handleRequest(req);
 }
 
+std::unique_ptr<HermesRuntimeAgentDelegate::ExportedState>
+HermesRuntimeAgentDelegate::getExportedState() {
+  return impl_->getExportedState();
+}
+
 } // namespace facebook::react::jsinspector_modern

packages/react-native/ReactCommon/hermes/inspector-modern/chrome/HermesRuntimeAgentDelegate.h

@@ -26,6 +26,10 @@ class HermesRuntimeAgentDelegate : public RuntimeAgentDelegate {
    * \param sessionState The state of the current CDP session. This will only
    * be accessed on the main thread (during the constructor, in handleRequest,
    * etc).
+   * \param previouslyExportedState The exported state from a previous instance
+   * of RuntimeAgentDelegate (NOT necessarily HermesRuntimeAgentDelegate). This
+   * may be nullptr, and if not nullptr it may be of any concrete type that
+   * implements RuntimeAgentDelegate::ExportedState.
    * \param executionContextDescription A description of the execution context
    * represented by this runtime. This is used for disambiguating the
    * source/destination of CDP messages when there are multiple runtimes
@@ -38,6 +42,8 @@ class HermesRuntimeAgentDelegate : public RuntimeAgentDelegate {
   HermesRuntimeAgentDelegate(
       FrontendChannel frontendChannel,
       SessionState& sessionState,
+      std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const ExecutionContextDescription& executionContextDescription,
       std::shared_ptr<hermes::HermesRuntime> runtime,
       RuntimeExecutor runtimeExecutor);
@@ -52,6 +58,8 @@ class HermesRuntimeAgentDelegate : public RuntimeAgentDelegate {
    */
   bool handleRequest(const cdp::PreparsedRequest& req) override;
 
+  virtual std::unique_ptr<ExportedState> getExportedState() override;
+
  private:
   // We use the private implementation idiom to keep HERMES_ENABLE_DEBUGGER
   // checks out of the header.

packages/react-native/ReactCommon/jsinspector-modern/RuntimeAgent.cpp

@@ -6,6 +6,7 @@
  */
 
 #include "RuntimeAgent.h"
+#include "SessionState.h"
 
 namespace facebook::react::jsinspector_modern {
 
@@ -120,4 +121,18 @@ void RuntimeAgent::notifyBindingCalled(
               "name", bindingName)("payload", payload))));
 }
 
+RuntimeAgent::ExportedState RuntimeAgent::getExportedState() {
+  return {
+      .delegateState = delegate_ ? delegate_->getExportedState() : nullptr,
+  };
+}
+
+RuntimeAgent::~RuntimeAgent() {
+  // TODO: Eventually, there may be more than one Runtime per Page, and we'll
+  // need to store multiple agent states here accordingly. For now let's do
+  // the simple thing and assume (as we do elsewhere) that only one Runtime
+  // per Page can exist at a time.
+  sessionState_.lastRuntimeAgentExportedState = getExportedState();
+}
+
 } // namespace facebook::react::jsinspector_modern

packages/react-native/ReactCommon/jsinspector-modern/RuntimeAgent.h

@@ -10,13 +10,13 @@
 #include "InspectorInterfaces.h"
 #include "RuntimeAgentDelegate.h"
 #include "RuntimeTarget.h"
-#include "SessionState.h"
 
 #include <jsinspector-modern/Parsing.h>
 
 namespace facebook::react::jsinspector_modern {
 
 class RuntimeTargetController;
+struct SessionState;
 
 /**
  * An Agent that handles requests from the Chrome DevTools Protocol
@@ -48,6 +48,8 @@ class RuntimeAgent final {
       SessionState& sessionState,
       std::unique_ptr<RuntimeAgentDelegate> delegate);
 
+  ~RuntimeAgent();
+
   /**
    * Handle a CDP request. The response will be sent over the provided
    * \c FrontendChannel synchronously or asynchronously. Performs any
@@ -69,6 +71,17 @@ class RuntimeAgent final {
       const std::string& bindingName,
       const std::string& payload);
 
+  struct ExportedState {
+    std::unique_ptr<RuntimeAgentDelegate::ExportedState> delegateState;
+  };
+
+  /**
+   * Export the RuntimeAgent's state, if available. This will be called
+   * shortly before the RuntimeAgent is destroyed to preserve state that may be
+   * needed when constructin a new RuntimeAgent.
+   */
+  ExportedState getExportedState();
+
  private:
   FrontendChannel frontendChannel_;
   RuntimeTargetController& targetController_;

packages/react-native/ReactCommon/jsinspector-modern/RuntimeAgentDelegate.h

@@ -19,6 +19,11 @@ namespace facebook::react::jsinspector_modern {
  */
 class RuntimeAgentDelegate {
  public:
+  class ExportedState {
+   public:
+    virtual ~ExportedState() = default;
+  };
+
   virtual ~RuntimeAgentDelegate() = default;
 
   /**
@@ -30,6 +35,17 @@ class RuntimeAgentDelegate {
    * agent expects another agent to respond to the request instead.
    */
   virtual bool handleRequest(const cdp::PreparsedRequest& req) = 0;
+
+  /**
+   * Export RuntimeAgentDelegate-specific state that should persist across
+   * consecutive RuntimeTargets in this session.
+   * If the RuntimeTarget is destroyed and later logically replaced by a new
+   * one (e.g. as part of an Instance reload), the state returned here will be
+   * passed to \ref RuntimeTargetDelegate::createAgentDelegate.
+   */
+  inline virtual std::unique_ptr<ExportedState> getExportedState() {
+    return std::make_unique<ExportedState>();
+  }
 };
 
 } // namespace facebook::react::jsinspector_modern

packages/react-native/ReactCommon/jsinspector-modern/RuntimeTarget.cpp

@@ -5,6 +5,8 @@
  * LICENSE file in the root directory of this source tree.
  */
 
+#include "SessionState.h"
+
 #include <jsinspector-modern/RuntimeTarget.h>
 
 using namespace facebook::jsi;
@@ -33,13 +35,18 @@ RuntimeTarget::RuntimeTarget(
 std::shared_ptr<RuntimeAgent> RuntimeTarget::createAgent(
     FrontendChannel channel,
     SessionState& sessionState) {
+  auto runtimeAgentState =
+      std::move(sessionState.lastRuntimeAgentExportedState);
   auto runtimeAgent = std::make_shared<RuntimeAgent>(
       channel,
       controller_,
       executionContextDescription_,
       sessionState,
       delegate_.createAgentDelegate(
-          channel, sessionState, executionContextDescription_));
+          channel,
+          sessionState,
+          std::move(runtimeAgentState.delegateState),
+          executionContextDescription_));
   agents_.insert(runtimeAgent);
   return runtimeAgent;
 }

packages/react-native/ReactCommon/jsinspector-modern/RuntimeTarget.h

@@ -13,7 +13,6 @@
 #include "InspectorInterfaces.h"
 #include "RuntimeAgent.h"
 #include "ScopedExecutor.h"
-#include "SessionState.h"
 #include "WeakList.h"
 
 #include <memory>
@@ -35,6 +34,7 @@ namespace facebook::react::jsinspector_modern {
 class RuntimeAgent;
 class RuntimeAgentDelegate;
 class RuntimeTarget;
+struct SessionState;
 
 /**
  * Receives events from a RuntimeTarget. This is a shared interface that
@@ -47,6 +47,8 @@ class RuntimeTargetDelegate {
   virtual std::unique_ptr<RuntimeAgentDelegate> createAgentDelegate(
       FrontendChannel channel,
       SessionState& sessionState,
+      std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const ExecutionContextDescription& executionContextDescription) = 0;
 };
 

packages/react-native/ReactCommon/jsinspector-modern/SessionState.h

@@ -8,6 +8,7 @@
 #pragma once
 
 #include "ExecutionContext.h"
+#include "RuntimeAgent.h"
 
 #include <string>
 #include <string_view>
@@ -34,6 +35,12 @@ struct SessionState {
   std::unordered_map<std::string, ExecutionContextSelectorSet>
       subscribedBindings;
 
+  /**
+   * Stores the state object exported from the last main RuntimeAgent, if any,
+   * before it was destroyed.
+   */
+  RuntimeAgent::ExportedState lastRuntimeAgentExportedState;
+
   // Here, we will eventually allow RuntimeAgents to store their own arbitrary
   // state (e.g. some sort of K/V storage of folly::dynamic?)
 

packages/react-native/ReactCommon/jsinspector-modern/tests/InspectorMocks.h

@@ -131,6 +131,8 @@ class MockRuntimeTargetDelegate : public RuntimeTargetDelegate {
       createAgentDelegate,
       (FrontendChannel channel,
        SessionState& sessionState,
+       std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+           previouslyExportedState,
        const ExecutionContextDescription&),
       (override));
 };
@@ -140,6 +142,7 @@ class MockRuntimeAgentDelegate : public RuntimeAgentDelegate {
   inline MockRuntimeAgentDelegate(
       FrontendChannel frontendChannel,
       SessionState& sessionState,
+      std::unique_ptr<RuntimeAgentDelegate::ExportedState>,
       const ExecutionContextDescription& executionContextDescription)
       : frontendChannel(std::move(frontendChannel)),
         sessionState(sessionState),

packages/react-native/ReactCommon/jsinspector-modern/tests/PageTargetTest.cpp

@@ -31,10 +31,11 @@ class PageTargetTest : public Test {
 
  protected:
   PageTargetTest() {
-    EXPECT_CALL(runtimeTargetDelegate_, createAgentDelegate(_, _, _))
+    EXPECT_CALL(runtimeTargetDelegate_, createAgentDelegate(_, _, _, _))
         .WillRepeatedly(runtimeAgentDelegates_.lazily_make_unique<
                         FrontendChannel,
                         SessionState&,
+                        std::unique_ptr<RuntimeAgentDelegate::ExportedState>,
                         const ExecutionContextDescription&>());
   }
 
@@ -444,7 +445,7 @@ TEST_F(PageTargetProtocolTest, MessageRoutingWhileNoRuntimeAgentDelegate) {
 TEST_F(PageTargetProtocolTest, InstanceWithNullRuntimeAgentDelegate) {
   InSequence s;
 
-  EXPECT_CALL(runtimeTargetDelegate_, createAgentDelegate(_, _, _))
+  EXPECT_CALL(runtimeTargetDelegate_, createAgentDelegate(_, _, _, _))
       .WillRepeatedly(ReturnNull());
 
   auto& instanceTarget = page_->registerInstance(instanceTargetDelegate_);

packages/react-native/ReactCommon/jsinspector-modern/tests/engines/JsiIntegrationTestGenericEngineAdapter.cpp

@@ -24,6 +24,7 @@ std::unique_ptr<RuntimeAgentDelegate>
 JsiIntegrationTestGenericEngineAdapter::createAgentDelegate(
     FrontendChannel frontendChannel,
     SessionState& sessionState,
+    std::unique_ptr<RuntimeAgentDelegate::ExportedState>,
     const ExecutionContextDescription&) {
   return std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate>(
       new FallbackRuntimeAgentDelegate(

packages/react-native/ReactCommon/jsinspector-modern/tests/engines/JsiIntegrationTestGenericEngineAdapter.h

@@ -28,6 +28,8 @@ class JsiIntegrationTestGenericEngineAdapter : public RuntimeTargetDelegate {
   virtual std::unique_ptr<RuntimeAgentDelegate> createAgentDelegate(
       FrontendChannel frontendChannel,
       SessionState& sessionState,
+      std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const ExecutionContextDescription& executionContextDescription) override;
 
   jsi::Runtime& getRuntime() const noexcept;

packages/react-native/ReactCommon/jsinspector-modern/tests/engines/JsiIntegrationTestHermesEngineAdapter.cpp

@@ -23,11 +23,14 @@ std::unique_ptr<RuntimeAgentDelegate>
 JsiIntegrationTestHermesEngineAdapter::createAgentDelegate(
     FrontendChannel frontendChannel,
     SessionState& sessionState,
+    std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+        previouslyExportedState,
     const ExecutionContextDescription& executionContextDescription) {
   return std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate>(
       new HermesRuntimeAgentDelegate(
           frontendChannel,
           sessionState,
+          std::move(previouslyExportedState),
           executionContextDescription,
           runtime_,
           getRuntimeExecutor()));

packages/react-native/ReactCommon/jsinspector-modern/tests/engines/JsiIntegrationTestHermesEngineAdapter.h

@@ -28,6 +28,8 @@ class JsiIntegrationTestHermesEngineAdapter : public RuntimeTargetDelegate {
   virtual std::unique_ptr<RuntimeAgentDelegate> createAgentDelegate(
       FrontendChannel frontendChannel,
       SessionState& sessionState,
+      std::unique_ptr<RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const ExecutionContextDescription& executionContextDescription) override;
 
   jsi::Runtime& getRuntime() const noexcept;

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

@@ -22,6 +22,7 @@ std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate>
 JSIRuntimeHolder::createAgentDelegate(
     jsinspector_modern::FrontendChannel frontendChannel,
     jsinspector_modern::SessionState& sessionState,
+    std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate::ExportedState>,
     const jsinspector_modern::ExecutionContextDescription&
         executionContextDescription) {
   (void)executionContextDescription;

packages/react-native/ReactCommon/react/runtime/JSRuntimeFactory.h

@@ -44,6 +44,8 @@ class JSIRuntimeHolder : public JSRuntime {
   std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate> createAgentDelegate(
       jsinspector_modern::FrontendChannel frontendChannel,
       jsinspector_modern::SessionState& sessionState,
+      std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const jsinspector_modern::ExecutionContextDescription&
           executionContextDescription) override;
 

packages/react-native/ReactCommon/react/runtime/hermes/HermesInstance.cpp

@@ -107,12 +107,15 @@ class HermesJSRuntime : public JSRuntime {
   std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate> createAgentDelegate(
       jsinspector_modern::FrontendChannel frontendChannel,
       jsinspector_modern::SessionState& sessionState,
+      std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate::ExportedState>
+          previouslyExportedState,
       const jsinspector_modern::ExecutionContextDescription&
           executionContextDescription) override {
     return std::unique_ptr<jsinspector_modern::RuntimeAgentDelegate>(
         new jsinspector_modern::HermesRuntimeAgentDelegate(
             frontendChannel,
             sessionState,
+            std::move(previouslyExportedState),
             executionContextDescription,
             runtime_,
             [msgQueueThreadWeak = std::weak_ptr(msgQueueThread_),