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Remove temporary buffer in ConfigFile.ino (#8298)

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When reading from a `Stream`, like `File`, using a temporary buffer is counterproductive because it complexifies the code and increases memory usage.
It's also a source of confusion because it can create dangling pointers in the `JsonDocument`.
The only benefit of using a buffer is the reading speed, but I don't think speed is the focus in this example; if it were, it would use a buffer in `saveConfig()` too.
This commit is contained in:
Benoît Blanchon 2021-09-16 11:23:08 +02:00 committed by GitHub
parent 211606fe9c
commit 612e7ffd7f
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1 changed files with 4 additions and 15 deletions
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19
libraries/esp8266/examples/ConfigFile/ConfigFile.ino
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@ -11,6 +11,9 @@
#include "FS.h"
#include <LittleFS.h>
// more and possibly updated information can be found at:
// https://arduinojson.org/v6/example/config/
bool loadConfig() {
File configFile = LittleFS.open("/config.json", "r");
if (!configFile) {
@ -18,22 +21,8 @@ bool loadConfig() {
return false;
}
size_t size = configFile.size();
if (size > 1024) {
Serial.println("Config file size is too large");
return false;
}
// Allocate a buffer to store contents of the file.
std::unique_ptr<char[]> buf(new char[size]);
// We don't use String here because ArduinoJson library requires the input
// buffer to be mutable. If you don't use ArduinoJson, you may as well
// use configFile.readString instead.
configFile.readBytes(buf.get(), size);
StaticJsonDocument<200> doc;
auto error = deserializeJson(doc, buf.get());
auto error = deserializeJson(doc, configFile);
if (error) {
Serial.println("Failed to parse config file");
return false;