raheelh fdf8599aaa Fix a crash in String::changeBuffer() ...

Calling String::reserve() causes a crash if String object was in invalidated state. Per the comment on the method's declaration in ESP_SSD1306.h, This method was supposed to recover invalidated strings. This change fixes the edge case bug in String::changeBuffer() which is the root cause of the crash exposed from String::reserve().

Following test code was used to reproduce the problem and also to validate the fix:

String result;
while(true){
  char c = 'A';
  result += c; // the loop will cause malloc() to fail at some point.
  if (result.c_str()==0)
  {
    Serial.println("String INVALIDATED!!!!!");
    result.reserve(0);   // before fix, this would crash.
    Serial.println("Trying to empty....");
    result=""; 
    Serial.println("Emptied!!!!");
    break;
  } 
}

2016-02-22 22:57:21 -06:00

..

esp8266

Fix a crash in String::changeBuffer()

2016-02-22 22:57:21 -06:00