- Nuke empty_string. It is a reminanent from the time where RETURN_FALSE()

  used to return "" and not bool(false). It's not worth keeping it because
  STR_FREE() and zval_dtor() always have to check for it and it slows down
  the general case. In addition, it seems that empty_string has been abused
  quite a lot, and was used not only for setting zval's but generally in
  PHP code instead of "", which wasn't the intention. Last but not least,
  nuking empty_string should improve stability as I doubt every place
  correctly checked if they are not mistakenly erealloc()'ing it or
  calling efree() on it.
  NOTE: Some code is probably broken. Each extension maintainer should
  check and see that my changes are OK. Also, I haven't had time to touch
  PECL yet. Will try and do it tomorrow.

1 files changed, 6 insertions, 13 deletions

diff --git a/Zend/zend_operators.c b/Zend/zend_operators.c
index 96217df5b1..8ef15ba102 100644
--- a/Zend/zend_operators.c
+++ b/Zend/zend_operators.c
@@ -510,7 +510,7 @@ ZEND_API void _convert_to_string(zval *op ZEND_FILE_LINE_DC)
 
 	switch (op->type) {
 		case IS_NULL:
-			op->value.str.val = empty_string;
+			op->value.str.val = STR_EMPTY_ALLOC();
 			op->value.str.len = 0;
 			break;
 		case IS_STRING:
@@ -520,7 +520,7 @@ ZEND_API void _convert_to_string(zval *op ZEND_FILE_LINE_DC)
 				op->value.str.val = estrndup_rel("1", 1);
 				op->value.str.len = 1;
 			} else {
-				op->value.str.val = empty_string;
+				op->value.str.val = STR_EMPTY_ALLOC();
 				op->value.str.len = 0;
 			}
 			break;
@@ -1130,11 +1130,8 @@ ZEND_API int add_char_to_string(zval *result, zval *op1, zval *op2)
 ZEND_API int add_string_to_string(zval *result, zval *op1, zval *op2)
 {
 	int length = op1->value.str.len + op2->value.str.len;
-	if (op1->value.str.val == empty_string) {
-		result->value.str.val = (char *) emalloc(length+1);
-	} else {
-		result->value.str.val = (char *) erealloc(op1->value.str.val, length+1);
-	}
+
+	result->value.str.val = (char *) erealloc(op1->value.str.val, length+1);
     memcpy(result->value.str.val+op1->value.str.len, op2->value.str.val, op2->value.str.len);
     result->value.str.val[length] = 0;
 	result->value.str.len = length;
@@ -1167,12 +1164,8 @@ ZEND_API int concat_function(zval *result, zval *op1, zval *op2 TSRMLS_DC)
 	if (result==op1) {	/* special case, perform operations on result */
 		uint res_len = op1->value.str.len + op2->value.str.len;
 		
-		if (result->value.str.len == 0) { /* handle empty_string */
-			STR_FREE(result->value.str.val);
-			result->value.str.val = emalloc(res_len+1);
-		} else {
-			result->value.str.val = erealloc(result->value.str.val, res_len+1);
-		}
+		result->value.str.val = erealloc(result->value.str.val, res_len+1);
+
 		memcpy(result->value.str.val+result->value.str.len, op2->value.str.val, op2->value.str.len);
 		result->value.str.val[res_len]=0;
 		result->value.str.len = res_len;