- Fix MDEV-13136: enhance CREATE SERVER MyServerName

FOREIGN DATA WRAPPER to work with CONNECT engine
  modified:   storage/connect/tabjdbc.cpp

- Add a function to retrieve User variable value (DEVELOPMENT only)
  modified:   storage/connect/ha_connect.cc
  modified:   storage/connect/jsonudf.cpp
  modified:   storage/connect/jsonudf.h
  modified:   storage/connect/tabjdbc.cpp

storage/connect/ha_connect.cc

@@ -204,6 +204,26 @@ pthread_mutex_t parmut;
 pthread_mutex_t usrmut;
 pthread_mutex_t tblmut;
 
+#if defined(DEVELOPMENT)
+char *GetUserVariable(PGLOBAL g, const uchar *varname);
+
+char *GetUserVariable(PGLOBAL g, const uchar *varname)
+{
+	char buf[1024];
+	bool b;
+	THD *thd = current_thd;
+	CHARSET_INFO *cs = system_charset_info;
+	String *str = NULL, tmp(buf, sizeof(buf), cs);
+	HASH uvars = thd->user_vars;
+	user_var_entry *uvar = (user_var_entry*)my_hash_search(&uvars, varname, 0);
+
+	if (uvar)
+		str = uvar->val_str(&b, &tmp, NOT_FIXED_DEC);
+
+	return str ? PlugDup(g, str->ptr()) : NULL;
+}; // end of GetUserVariable
+#endif   // DEVELOPMENT
+
 /***********************************************************************/
 /*  Utility functions.                                                 */
 /***********************************************************************/

storage/connect/jsonudf.cpp

@@ -1666,7 +1666,8 @@ static PCSZ MakeKey(PGLOBAL g, UDF_ARGS *args, int i)
 	if (args->arg_count > (unsigned)i) {
 		int     j = 0, n = args->attribute_lengths[i];
 		my_bool b;  // true if attribute is zero terminated
-		PSZ     p, s = args->attributes[i];
+		PSZ     p;
+		PCSZ    s = args->attributes[i];
 
 		if (s && *s && (n || *s == '\'')) {
 			if ((b = (!n || !s[n])))
@@ -5805,6 +5806,52 @@ char *envar(UDF_INIT *initid, UDF_ARGS *args, char *result,
 	return str;
 } // end of envar
 
+#if defined(DEVELOPMENT)
+extern char *GetUserVariable(PGLOBAL g, const uchar *varname);
+
+/*********************************************************************************/
+/*  Utility function returning a user variable value.                            */
+/*********************************************************************************/
+my_bool uvar_init(UDF_INIT *initid, UDF_ARGS *args, char *message)
+{
+	unsigned long reslen, memlen;
+
+	if (args->arg_count != 1) {
+		strcpy(message, "Unique argument must be a user variable name");
+		return true;
+	} else
+		CalcLen(args, false, reslen, memlen, true);
+
+	initid->maybe_null = true;
+	return JsonInit(initid, args, message, true, reslen, memlen, 2048);
+} // end of uvar_init
+
+char *uvar(UDF_INIT *initid, UDF_ARGS *args, char *result,
+	unsigned long *res_length, char *is_null, char *)
+{
+	char   *str, varname[256];
+	PGLOBAL g = (PGLOBAL)initid->ptr;
+	int     n = MY_MIN(args->lengths[0], sizeof(varname) - 1);
+
+	PlugSubSet(g->Sarea, g->Sarea_Size);
+	memcpy(varname, args->args[0], n);
+	varname[n] = 0;
+
+	if (!(str = GetUserVariable(g, (const uchar*)&varname))) {
+		*res_length = 0;
+		*is_null = 1;
+	} else
+		*res_length = strlen(str);
+
+	return str;
+} // end of uvar
+
+void uvar_deinit(UDF_INIT* initid)
+{
+	JsonFreeMem((PGLOBAL)initid->ptr);
+} // end of uvar_deinit
+#endif   // DEVELOPMENT
+
 /*********************************************************************************/
 /*  Returns the distinct number of B occurences in A.                            */
 /*********************************************************************************/

storage/connect/jsonudf.h

@@ -238,6 +238,11 @@ extern "C" {
 	DllExport my_bool envar_init(UDF_INIT*, UDF_ARGS*, char*);
 	DllExport char *envar(UDF_EXEC_ARGS);
 
+#if defined(DEVELOPMENT)
+	DllExport my_bool uvar_init(UDF_INIT*, UDF_ARGS*, char*);
+	DllExport char *uvar(UDF_EXEC_ARGS);
+#endif   // DEVELOPMENT
+
 	DllExport my_bool countin_init(UDF_INIT*, UDF_ARGS*, char*);
 	DllExport long long countin(UDF_EXEC_ARGS);
 } // extern "C"

storage/connect/tabjdbc.cpp

@@ -72,7 +72,6 @@
 #include "tabext.h"
 #include "tabjdbc.h"
 #include "tabmul.h"
-//#include "reldef.h"
 #include "tabcol.h"
 #include "valblk.h"
 #include "ha_connect.h"
@@ -89,6 +88,9 @@ extern int num_read, num_there, num_eq[2];                // Statistics
 /*  External function.                                                 */
 /***********************************************************************/
 bool ExactInfo(void);
+#if defined(DEVELOPMENT)
+extern char *GetUserVariable(PGLOBAL g, const uchar *varname);
+#endif  // DEVELOPMENT
 
 /* -------------------------- Class JDBCDEF -------------------------- */
 
@@ -147,10 +149,6 @@ int JDBCDEF::ParseURL(PGLOBAL g, char *url, bool b)
 				return RC_FX;
 
 			Tabname = p;
-//  } else if (b) {
-//	  // Otherwise, straight server name, 
-//	  Tabname = GetStringCatInfo(g, "Name", NULL);
-//	  Tabname = GetStringCatInfo(g, "Tabname", Tabname);
 		} // endif
 
 		if (trace(1))
@@ -165,6 +163,11 @@ int JDBCDEF::ParseURL(PGLOBAL g, char *url, bool b)
 			return RC_FX;
 		} // endif server
 
+#if defined(DEVELOPMENT)
+		if (*server->host == '@') {
+			Url = GetUserVariable(g, (const uchar*)&server->host[1]);
+		} else
+#endif // 0
 		if (strncmp(server->host, "jdbc:", 5)) {
 			// Now make the required URL
 			Url = (PSZ)PlugSubAlloc(g, NULL, 0);
@@ -191,6 +194,9 @@ int JDBCDEF::ParseURL(PGLOBAL g, char *url, bool b)
 		if (!Password && server->password)
 			Password = PlugDup(g, server->password);
 
+		Driver = PlugDup(g, GetListOption(g, "Driver", server->owner, NULL));
+		Wrapname = PlugDup(g, GetListOption(g, "Wrapper", server->owner, NULL));
+		Memory = atoi(GetListOption(g, "Memory", server->owner, "0"));
 		return RC_NF;
 	} // endif
 
@@ -208,7 +214,6 @@ bool JDBCDEF::DefineAM(PGLOBAL g, LPCSTR am, int poff)
 	if (EXTDEF::DefineAM(g, am, poff))
 		return true;
 
-	Driver = GetStringCatInfo(g, "Driver", NULL);
 	Desc = Url = GetStringCatInfo(g, "Connect", NULL);
 
 	if (!Url && !Catfunc) {
@@ -228,7 +233,10 @@ bool JDBCDEF::DefineAM(PGLOBAL g, LPCSTR am, int poff)
 			return true;
 		} // endif rc
 
-	Wrapname = GetStringCatInfo(g, "Wrapper", NULL);
+	// Default values may have been set in ParseURL
+	Memory = GetIntCatInfo("Memory", Memory);
+	Driver = GetStringCatInfo(g, "Driver", Driver);
+	Wrapname = GetStringCatInfo(g, "Wrapper", Wrapname);
 	return false;
 } // end of DefineAM