expand oracle null handling compatability by offering the ability to convert

NULLs into empty strings as well as the other way around.  It still doesn't
help a great deal in the long run, but at least the option is there.

Make sure hash tables are nulled out to avoid double freeing them.

ext/pdo/pdo.c

@@ -346,7 +346,11 @@ PHP_MINIT_FUNCTION(pdo)
 	REGISTER_LONG_CONSTANT("PDO_CASE_NATURAL",	(long)PDO_CASE_NATURAL,		CONST_CS|CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("PDO_CASE_LOWER",	(long)PDO_CASE_LOWER,		CONST_CS|CONST_PERSISTENT);
 	REGISTER_LONG_CONSTANT("PDO_CASE_UPPER",	(long)PDO_CASE_UPPER,		CONST_CS|CONST_PERSISTENT);
-		
+
+	REGISTER_LONG_CONSTANT("PDO_NULL_NATURAL",	(long)PDO_NULL_NATURAL,		CONST_CS|CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("PDO_NULL_EMPTY_STRING",	(long)PDO_NULL_EMPTY_STRING,		CONST_CS|CONST_PERSISTENT);
+	REGISTER_LONG_CONSTANT("PDO_NULL_TO_STRING",	(long)PDO_NULL_TO_STRING,		CONST_CS|CONST_PERSISTENT);
+			
 	REGISTER_STRING_CONSTANT("PDO_ERR_NONE",	PDO_ERR_NONE,		CONST_CS|CONST_PERSISTENT);
 
 	REGISTER_LONG_CONSTANT("PDO_FETCH_ORI_NEXT", (long)PDO_FETCH_ORI_NEXT, CONST_CS|CONST_PERSISTENT);

ext/pdo/pdo_dbh.c

@@ -691,7 +691,7 @@ static PHP_METHOD(PDO, setAttribute)
 
 		case PDO_ATTR_ORACLE_NULLS:
 			convert_to_long(value);
-			dbh->oracle_nulls = Z_LVAL_P(value) ? 1 : 0;
+			dbh->oracle_nulls = Z_LVAL_P(value);
 			RETURN_TRUE;
 
 		case PDO_ATTR_STRINGIFY_FETCHES:
@@ -746,7 +746,7 @@ static PHP_METHOD(PDO, getAttribute)
 			RETURN_LONG(dbh->desired_case);
 
 		case PDO_ATTR_ORACLE_NULLS:
-			RETURN_BOOL(dbh->oracle_nulls);
+			RETURN_LONG(dbh->oracle_nulls);
 
 		case PDO_ATTR_ERRMODE:
 			RETURN_LONG(dbh->error_mode);

ext/pdo/pdo_stmt.c

@@ -476,7 +476,7 @@ static inline void fetch_value(pdo_stmt_t *stmt, zval *dest, int colno TSRMLS_DC
 			break;
 		
 		case PDO_PARAM_STR:
-			if (value && !(value_len == 0 && stmt->dbh->oracle_nulls)) {
+			if (value && !(value_len == 0 && stmt->dbh->oracle_nulls == PDO_NULL_EMPTY_STRING)) {
 				ZVAL_STRINGL(dest, value, value_len, !caller_frees);
 				if (caller_frees) {
 					caller_frees = 0;
@@ -499,6 +499,10 @@ static inline void fetch_value(pdo_stmt_t *stmt, zval *dest, int colno TSRMLS_DC
 				break;
 		}
 	}
+
+	if (Z_TYPE_P(dest) == IS_NULL && stmt->dbh->oracle_nulls == PDO_NULL_TO_STRING) {
+		ZVAL_EMPTY_STRING(dest);
+	}
 }
 /* }}} */
 
@@ -1898,14 +1902,17 @@ static void free_statement(pdo_stmt_t *stmt TSRMLS_DC)
 	if (stmt->bound_params) {
 		zend_hash_destroy(stmt->bound_params);
 		FREE_HASHTABLE(stmt->bound_params);
+		stmt->bound_params = NULL;
 	}
 	if (stmt->bound_param_map) {
 		zend_hash_destroy(stmt->bound_param_map);
 		FREE_HASHTABLE(stmt->bound_param_map);
+		stmt->bound_param_map = NULL;
 	}
 	if (stmt->bound_columns) {
 		zend_hash_destroy(stmt->bound_columns);
 		FREE_HASHTABLE(stmt->bound_columns);
+		stmt->bound_columns = NULL;
 	}
 
 	if (stmt->methods && stmt->methods->dtor) {

ext/pdo/php_pdo_driver.h

@@ -44,7 +44,7 @@ PDO_API char *php_pdo_int64_to_str(pdo_int64_t i64 TSRMLS_DC);
 # define FALSE 0
 #endif
 
-#define PDO_DRIVER_API	20050709
+#define PDO_DRIVER_API	20050711
 
 enum pdo_param_type {
 	PDO_PARAM_NULL,
@@ -174,6 +174,13 @@ enum pdo_case_conversion {
 	PDO_CASE_LOWER
 };
 
+/* oracle interop settings */
+enum pdo_null_handling {
+	PDO_NULL_NATURAL = 0,
+	PDO_NULL_EMPTY_STRING = 1,
+	PDO_NULL_TO_STRING = 2,
+};
+
 /* {{{ utils for reading attributes set as driver_options */
 static inline long pdo_attr_lval(zval *options, enum pdo_fetch_type option_name, long defval TSRMLS_DC)
 {
@@ -437,15 +444,15 @@ struct _pdo_dbh_t {
 	/* max length a single character can become after correct quoting */
 	unsigned max_escaped_char_length:3;
 
-	/* when set, convert empty strings to NULL */
-	unsigned oracle_nulls:1;
+	/* oracle compat; see enum pdo_null_handling */
+	unsigned oracle_nulls:2;
 
 	/* when set, convert int/floats to strings */
 	unsigned stringify:1;
 
 	/* the sum of the number of bits here and the bit fields preceeding should
 	 * equal 32 */
-	unsigned _reserved_flags:22;
+	unsigned _reserved_flags:21;
 
 	/* data source string used to open this handle */
 	const char *data_source;