Allocate smaller amount of buffer for JSON (esphome#3384)

jamesduke · Apr 14, 2022 · 93b628d · 93b628d
1 parent 6bac551
commit 93b628d
Showing 1 changed file with 7 additions and 7 deletions.
diff --git a/esphome/components/json/json_util.cpp b/esphome/components/json/json_util.cpp
@@ -23,21 +23,21 @@ std::string build_json(const json_build_t &f) {
 #ifdef USE_ESP8266
   const size_t free_heap = ESP.getMaxFreeBlockSize();  // NOLINT(readability-static-accessed-through-instance)
 #elif defined(USE_ESP32)
-  const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL);
+  const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT);
 #endif
 
-  const size_t request_size = std::min(free_heap - 2048, (size_t) 5120);
+  const size_t request_size = std::min(free_heap, (size_t) 512);
 
   DynamicJsonDocument json_document(request_size);
-  if (json_document.memoryPool().buffer() == nullptr) {
+  if (json_document.capacity() == 0) {
     ESP_LOGE(TAG, "Could not allocate memory for JSON document! Requested %u bytes, largest free heap block: %u bytes",
              request_size, free_heap);
     return "{}";
   }
   JsonObject root = json_document.to<JsonObject>();
   f(root);
   json_document.shrinkToFit();
-
+  ESP_LOGV(TAG, "Size after shrink %u bytes", json_document.capacity());
   std::string output;
   serializeJson(json_document, output);
   return output;
@@ -51,13 +51,13 @@ void parse_json(const std::string &data, const json_parse_t &f) {
 #ifdef USE_ESP8266
   const size_t free_heap = ESP.getMaxFreeBlockSize();  // NOLINT(readability-static-accessed-through-instance)
 #elif defined(USE_ESP32)
-  const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL);
+  const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_8BIT);
 #endif
   bool pass = false;
-  size_t request_size = std::min(free_heap - 2048, (size_t)(data.size() * 1.5));
+  size_t request_size = std::min(free_heap, (size_t)(data.size() * 1.5));
   do {
     DynamicJsonDocument json_document(request_size);
-    if (json_document.memoryPool().buffer() == nullptr) {
+    if (json_document.capacity() == 0) {
       ESP_LOGE(TAG, "Could not allocate memory for JSON document! Requested %u bytes, free heap: %u", request_size,
                free_heap);
       return;