From 7cd4126d52d788d8bfc40c4f5e4d7a4d1d2350e9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Kristan?= <blaz@kristan-sp.si>
Date: Sat, 6 Jan 2024 17:01:34 +0100
Subject: [PATCH] Merge pull request #3648 from
 willmmiles/json-response-locking

Expand JSON buffer lock scope to entire web reply
---
 wled00/fcn_declare.h | 16 ++++++++++++++++
 wled00/json.cpp      | 22 +++++++++++++++++++---
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/wled00/fcn_declare.h b/wled00/fcn_declare.h
index f46c7cce97..ab29dd8d21 100644
--- a/wled00/fcn_declare.h
+++ b/wled00/fcn_declare.h
@@ -373,6 +373,22 @@ um_data_t* simulateSound(uint8_t simulationId);
 CRGB getCRGBForBand(int x, uint8_t *fftResult, int pal); //WLEDMM netmindz ar palette
 char *cleanUpName(char *in); // to clean up a name that was read from file
 
+// RAII guard class for the JSON Buffer lock
+// Modeled after std::lock_guard
+class JSONBufferGuard {
+  bool holding_lock;
+  public:
+    inline JSONBufferGuard(uint8_t module=255) : holding_lock(requestJSONBufferLock(module)) {};
+    inline ~JSONBufferGuard() { if (holding_lock) releaseJSONBufferLock(); };
+    inline JSONBufferGuard(const JSONBufferGuard&) = delete; // Noncopyable
+    inline JSONBufferGuard& operator=(const JSONBufferGuard&) = delete;
+    inline JSONBufferGuard(JSONBufferGuard&& r) : holding_lock(r.holding_lock) { r.holding_lock = false; };  // but movable
+    inline JSONBufferGuard& operator=(JSONBufferGuard&& r) { holding_lock |= r.holding_lock; r.holding_lock = false; return *this; };
+    inline bool owns_lock() const { return holding_lock; }
+    explicit inline operator bool() const { return owns_lock(); };
+    inline void release() { if (holding_lock) releaseJSONBufferLock(); holding_lock = false; }
+};
+
 #ifdef WLED_ADD_EEPROM_SUPPORT
 //wled_eeprom.cpp
 void applyMacro(byte index);
diff --git a/wled00/json.cpp b/wled00/json.cpp
index b481d7b8f2..212482b012 100644
--- a/wled00/json.cpp
+++ b/wled00/json.cpp
@@ -9,6 +9,7 @@
 #define JSON_PATH_PALETTES   5
 #define JSON_PATH_FXDATA     6
 #define JSON_PATH_NETWORKS   7
+#define JSON_PATH_EFFECTS    8
 
 // begin WLEDMM
 #ifdef ARDUINO_ARCH_ESP32
@@ -1392,6 +1393,17 @@ void serializeModeNames(JsonArray arr) {
   }
 }
 
+
+// Global buffer locking response helper class
+class GlobalBufferAsyncJsonResponse: public JSONBufferGuard, public AsyncJsonResponse {
+  public:
+  inline GlobalBufferAsyncJsonResponse(bool isArray) : JSONBufferGuard(17), AsyncJsonResponse(&doc, isArray) {};
+  virtual ~GlobalBufferAsyncJsonResponse() {};
+
+  // Other members are inherited
+};
+
+
 void serveJson(AsyncWebServerRequest* request)
 {
   byte subJson = 0;
@@ -1400,6 +1412,7 @@ void serveJson(AsyncWebServerRequest* request)
   else if (url.indexOf("info")  > 0) subJson = JSON_PATH_INFO;
   else if (url.indexOf("si")    > 0) subJson = JSON_PATH_STATE_INFO;
   else if (url.indexOf("nodes") > 0) subJson = JSON_PATH_NODES;
+  else if (url.indexOf("eff")   > 0) subJson = JSON_PATH_EFFECTS;
   else if (url.indexOf("palx")  > 0) subJson = JSON_PATH_PALETTES;
   else if (url.indexOf("fxda")  > 0) subJson = JSON_PATH_FXDATA;
   else if (url.indexOf("net") > 0) subJson = JSON_PATH_NETWORKS;
@@ -1435,11 +1448,12 @@ void serveJson(AsyncWebServerRequest* request)
     return;
   }
 
-  if (!requestJSONBufferLock(17)) {
+  GlobalBufferAsyncJsonResponse *response = new GlobalBufferAsyncJsonResponse(subJson==JSON_PATH_FXDATA || subJson==JSON_PATH_EFFECTS); // will clear and convert JsonDocument into JsonArray if necessary
+  if (!response->owns_lock()) {
     request->send(503, "application/json", F("{\"error\":3}"));
+    delete response;
     return;
   }
-  AsyncJsonResponse *response = new AsyncJsonResponse(&doc, subJson==6);
 
   JsonVariant lDoc = response->getRoot();
 
@@ -1453,6 +1467,9 @@ void serveJson(AsyncWebServerRequest* request)
       serializeNodes(lDoc); break;
     case JSON_PATH_PALETTES:
       serializePalettes(lDoc, request); break;
+      //serializePalettes(lDoc, request->hasParam("page") ? request->getParam("page")->value().toInt() : 0); break;
+    case JSON_PATH_EFFECTS:
+      serializeModeNames(lDoc); break;
     case JSON_PATH_FXDATA:
       serializeModeData(lDoc.as<JsonArray>()); break;
     case JSON_PATH_NETWORKS:
@@ -1475,7 +1492,6 @@ void serveJson(AsyncWebServerRequest* request)
 
   response->setLength();
   request->send(response);
-  releaseJSONBufferLock();
 }
 
 #ifdef WLED_ENABLE_JSONLIVE