runtime read of json layer state

src/app/RuntimeLayerControllerBuild.cpp

@@ -1,9 +1,12 @@
 #include "RuntimeLayerController.h"
 
 #include "AppConfigProvider.h"
+#include "RuntimeJson.h"
 #include "../logging/Logger.h"
 
 #include <filesystem>
+#include <fstream>
+#include <sstream>
 
 namespace RenderCadenceCompositor
 {
@@ -30,6 +33,9 @@ bool RuntimeLayerController::LoadSupportedShaderCatalog(const std::string& shade
 
 void RuntimeLayerController::InitializeLayerModel(std::string& runtimeShaderId)
 {
+	if (InitializeLayerModelFromRuntimeState())
+		return;
+
 	std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
 	std::string error;
 	if (!mRuntimeLayerModel.InitializeSingleLayer(mShaderCatalog, runtimeShaderId, error))
@@ -40,6 +46,43 @@ void RuntimeLayerController::InitializeLayerModel(std::string& runtimeShaderId)
 	}
 }
 
+bool RuntimeLayerController::InitializeLayerModelFromRuntimeState()
+{
+	const std::filesystem::path runtimeStatePath = FindRepoPath("runtime/runtime_state.json");
+	if (runtimeStatePath.empty())
+		return false;
+
+	std::ifstream input(runtimeStatePath, std::ios::binary);
+	if (!input)
+	{
+		LogWarning("runtime-state", "Could not open runtime state file: " + runtimeStatePath.string());
+		return false;
+	}
+
+	std::ostringstream buffer;
+	buffer << input.rdbuf();
+
+	JsonValue runtimeState;
+	std::string error;
+	if (!ParseJson(buffer.str(), runtimeState, error))
+	{
+		LogWarning("runtime-state", "Could not parse runtime state file: " + error);
+		return false;
+	}
+
+	{
+		std::lock_guard<std::mutex> lock(mRuntimeLayerMutex);
+		if (!mRuntimeLayerModel.InitializeFromRuntimeState(mShaderCatalog, runtimeState, error))
+		{
+			LogWarning("runtime-state", "Could not restore runtime state: " + error);
+			return false;
+		}
+	}
+
+	Log("runtime-state", "Restored runtime layer stack from " + runtimeStatePath.string() + ".");
+	return true;
+}
+
 void RuntimeLayerController::StartLayerShaderBuild(const std::string& layerId, const std::string& shaderId)
 {
 	CleanupRetiredShaderBuilds();