Method quickPeek

src/main/java/com/google/gson/stream/JsonReader.java:354–396

Ensures that a token is ready. After this call either token or value will be non-null. To ensure token has a definitive value, use #peek()

()

   * value, use {@link #peek()}
   */
  private JsonToken quickPeek() throws IOException {
    if (hasToken) {
      return token;
    }

    switch (peekStack()) {
    case EMPTY_DOCUMENT:
      if (lenient) {
        consumeNonExecutePrefix();
      }
      replaceTop(JsonScope.NONEMPTY_DOCUMENT);
      JsonToken firstToken = nextValue();
      if (!lenient && firstToken != JsonToken.BEGIN_ARRAY && firstToken != JsonToken.BEGIN_OBJECT) {
        syntaxError("Expected JSON document to start with '[' or '{'");
      }
      return firstToken;
    case EMPTY_ARRAY:
      return nextInArray(true);
    case NONEMPTY_ARRAY:
      return nextInArray(false);
    case EMPTY_OBJECT:
      return nextInObject(true);
    case DANGLING_NAME:
      return objectValue();
    case NONEMPTY_OBJECT:
      return nextInObject(false);
    case NONEMPTY_DOCUMENT:
      try {
        JsonToken token = nextValue();
        if (lenient) {
          return token;
        }
        throw syntaxError("Expected EOF");
      } catch (EOFException e) {
        hasToken = true; // TODO: avoid throwing here?
        return token = JsonToken.END_DOCUMENT;
      }
    case CLOSED:
      throw new IllegalStateException("JsonReader is closed");
    default:
      throw new AssertionError();
    }
  }

  /**
   * Consumes the non-execute prefix if it exists.