add or improve some debug messages (#6508)

Author: d-a-v

cores/esp8266/StreamString.cpp

@@ -32,6 +32,7 @@ size_t StreamString::write(const uint8_t *data, size_t size) {
             *(wbuffer() + newlen) = 0x00; // add null for string end
             return size;
         }
+        DEBUGV(":stream2string: OOM (%d->%d)\n", length(), newlen+1);
     }
     return 0;
 }

libraries/ESP8266HTTPClient/src/ESP8266HTTPClient.cpp

@@ -1007,7 +1007,7 @@ const String& HTTPClient::getString(void)
 
     _payload.reset(new StreamString());
 
-    if(_size) {
+    if(_size > 0) {
         // try to reserve needed memmory
         if(!_payload->reserve((_size + 1))) {
             DEBUG_HTTPCLIENT("[HTTP-Client][getString] not enough memory to reserve a string! need: %d\n", (_size + 1));
@@ -1456,10 +1456,10 @@ int HTTPClient::writeToStreamDataBlock(Stream * stream, int size)
 
     free(buff);
 
-    DEBUG_HTTPCLIENT("[HTTP-Client][writeToStreamDataBlock] connection closed or file end (written: %d).\n", bytesWritten);
+    DEBUG_HTTPCLIENT("[HTTP-Client][writeToStreamDataBlock] end of chunk or data (transferred: %d).\n", bytesWritten);
 
     if((size > 0) && (size != bytesWritten)) {
-        DEBUG_HTTPCLIENT("[HTTP-Client][writeToStreamDataBlock] bytesWritten %d and size %d mismatch!.\n", bytesWritten, size);
+        DEBUG_HTTPCLIENT("[HTTP-Client][writeToStreamDataBlock] transferred size %d and request size %d mismatch!.\n", bytesWritten, size);
         return HTTPC_ERROR_STREAM_WRITE;
     }