query_classifier.cc:skygw_get_canonical: if the item to be replaced is an empty string "", it is processed differently from the other cases due to difficulties to get wanted result by adding special rule for that to regex.

query_classifier.h: added parsing information structure to query classifier away from buffer.h.
buffer.c:introduced a buffer object which includes object pointer and a clean-up call-back function. Buffer objects form a list which is cleaned up by the last referrer of the buffer, as a part of gwbuf_free. Buffer object list is protected by a spinlock gwbuf_lock.
	Also added identifier type, bufobj_id_t which is enumerated type and currently includes one value only, GWBUF_PARSING_INFO. Added also a bitfield for information about the buffer. It currently has one type only, GWBUF_INFO_PARSED indicating that buffer content is parsed and there is buffer object of type GWBUF_PARSING_INFO.
skygw_utils.cc:replace_literal:changed regexec matching to case insensitive because user-defined literals are sometimes converted to upper-case ones.

server/include/buffer.h

@@ -42,6 +42,8 @@
  * @endverbatim
  */
 #include <skygw_debug.h>
+#include <spinlock.h>
+
 
 EXTERN_C_BLOCK_BEGIN
 
@@ -74,18 +76,33 @@ typedef struct  {
 	int		refcount;		/*< Reference count on the buffer */
 } SHARED_BUF;
 
+typedef enum
+{       
+        GWBUF_INFO_NONE         = 0x0,
+        GWBUF_INFO_PARSED       = 0x1
+} gwbuf_info_t;
 
-typedef struct parsing_info_st {
-#if defined(SS_DEBUG)
-        skygw_chk_t pi_chk_top;     
-#endif
-        void* pi_handle;                        /*< parsing info object pointer */
-        char* pi_query_plain_str;               /*< query as plain string */
-        void (*pi_done_fp)(void *);             /*< clean-up function for parsing info */
-#if defined(SS_DEBUG)
-        skygw_chk_t pi_chk_tail;
-#endif
-} parsing_info_t;
+#define GWBUF_IS_PARSED(b)      (b->gwbuf_info & GWBUF_INFO_PARSED)
+
+/**
+ * A structure for cleaning up memory allocations of structures which are 
+ * referred to by GWBUF and deallocated in gwbuf_free but GWBUF doesn't
+ * know what they are.
+ * All functions on the list are executed before freeing memory of GWBUF struct.
+ */
+typedef enum 
+{
+        GWBUF_PARSING_INFO
+} bufobj_id_t;
+
+typedef struct buffer_object_st buffer_object_t;
+
+struct buffer_object_st {
+        bufobj_id_t      bo_id;
+        void*            bo_data;
+        void            (*bo_donefun_fp)(void *);
+        buffer_object_t* bo_next;
+};
 
 
 /**
@@ -97,11 +114,13 @@ typedef struct parsing_info_st {
  * be copied within the gateway.
  */
 typedef struct gwbuf {
+        SPINLOCK        gwbuf_lock;
 	struct gwbuf	*next;	/*< Next buffer in a linked chain of buffers */
 	void		*start;	/*< Start of the valid data */
 	void		*end;	/*< First byte after the valid data */
 	SHARED_BUF	*sbuf;  /*< The shared buffer with the real data */
-	void            *gwbuf_parsing_info; /*< parsing info object pointer */
+        buffer_object_t *gwbuf_bufobj; /*< List of objects referred to by GWBUF */
+        gwbuf_info_t    gwbuf_info; /*< Info bits */
 	gwbuf_type_t    gwbuf_type; /*< buffer's data type information */
 } GWBUF;
 
@@ -136,8 +155,12 @@ extern unsigned int	gwbuf_length(GWBUF *head);
 extern GWBUF            *gwbuf_clone_portion(GWBUF *head, size_t offset, size_t len);
 extern GWBUF            *gwbuf_clone_transform(GWBUF *head, gwbuf_type_t type);
 extern void             gwbuf_set_type(GWBUF *head, gwbuf_type_t type);
-void*                   gwbuf_get_parsing_info(GWBUF* buf);
 
+void                    gwbuf_add_buffer_object(GWBUF* buf,
+                                                bufobj_id_t id,
+                                                void*  data,
+                                                void (*donefun_fp)(void *));
+void*                   gwbuf_get_buffer_object_data(GWBUF* buf, bufobj_id_t id);
 
 EXTERN_C_BLOCK_END