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Reserve less memory for json (#3289)

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Jesse Hills 2022-03-23 09:46:25 +13:00
parent 0729ed538e
commit 4e4a512107
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GPG key ID: BEAAE804EFD8E83A
1 changed files with 43 additions and 17 deletions
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50
esphome/components/json/json_util.cpp
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@ -16,16 +16,24 @@ static const char *const TAG = "json";
static std::vector<char> global_json_build_buffer; // NOLINT static std::vector<char> global_json_build_buffer; // NOLINT
std::string build_json(const json_build_t &f) { std::string build_json(const json_build_t &f) {
// Here we are allocating as much heap memory as available minus 2kb to be safe // Here we are allocating up to 5kb of memory,
// with the heap size minus 2kb to be safe if less than 5kb
// as we can not have a true dynamic sized document. // as we can not have a true dynamic sized document.
// The excess memory is freed below with `shrinkToFit()` // The excess memory is freed below with `shrinkToFit()`
#ifdef USE_ESP8266 #ifdef USE_ESP8266
const size_t free_heap = ESP.getMaxFreeBlockSize() - 2048; // NOLINT(readability-static-accessed-through-instance) const size_t free_heap = ESP.getMaxFreeBlockSize(); // NOLINT(readability-static-accessed-through-instance)
#elif defined(USE_ESP32) #elif defined(USE_ESP32)
const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL) - 2048; const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL);
#endif #endif
DynamicJsonDocument json_document(free_heap); const size_t request_size = std::min(free_heap - 2048, (size_t) 5120);
DynamicJsonDocument json_document(request_size);
if (json_document.memoryPool().buffer() == nullptr) {
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>(); JsonObject root = json_document.to<JsonObject>();
f(root); f(root);
json_document.shrinkToFit(); json_document.shrinkToFit();
@ -36,27 +44,45 @@ std::string build_json(const json_build_t &f) {
} }
void parse_json(const std::string &data, const json_parse_t &f) { void parse_json(const std::string &data, const json_parse_t &f) {
// Here we are allocating as much heap memory as available minus 2kb to be safe // Here we are allocating 1.5 times the data size,
// with the heap size minus 2kb to be safe if less than that
// as we can not have a true dynamic sized document. // as we can not have a true dynamic sized document.
// The excess memory is freed below with `shrinkToFit()` // The excess memory is freed below with `shrinkToFit()`
#ifdef USE_ESP8266 #ifdef USE_ESP8266
const size_t free_heap = ESP.getMaxFreeBlockSize() - 2048; // NOLINT(readability-static-accessed-through-instance) const size_t free_heap = ESP.getMaxFreeBlockSize(); // NOLINT(readability-static-accessed-through-instance)
#elif defined(USE_ESP32) #elif defined(USE_ESP32)
const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL) - 2048; const size_t free_heap = heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL);
#endif #endif
bool pass = false;
do {
const size_t request_size = std::min(free_heap - 2048, (size_t)(data.size() * 1.5));
DynamicJsonDocument json_document(free_heap); DynamicJsonDocument json_document(request_size);
if (json_document.memoryPool().buffer() == nullptr) {
ESP_LOGE(TAG, "Could not allocate memory for JSON document! Requested %u bytes, free heap: %u", request_size,
free_heap);
return;
}
DeserializationError err = deserializeJson(json_document, data); DeserializationError err = deserializeJson(json_document, data);
json_document.shrinkToFit(); json_document.shrinkToFit();
JsonObject root = json_document.as<JsonObject>(); JsonObject root = json_document.as<JsonObject>();
if (err) { if (err == DeserializationError::Ok) {
ESP_LOGW(TAG, "Parsing JSON failed."); pass = true;
f(root);
} else if (err == DeserializationError::NoMemory) {
if (request_size * 2 >= free_heap) {
ESP_LOGE(TAG, "Can not allocate more memory for deserialization. Consider making source string smaller");
return; return;
} }
ESP_LOGW(TAG, "Increasing memory allocation.");
f(root); continue;
} else {
ESP_LOGE(TAG, "JSON parse error: %s", err.c_str());
return;
}
} while (!pass);
} }
} // namespace json } // namespace json