Prepare for backporting of "Send small blobs inline (PR #8318)".

Author: hvlad

src/remote/inet.cpp

@@ -717,9 +717,11 @@ rem_port* INET_analyze(ClntAuthBlock* cBlock,
 		REMOTE_PROTOCOL(PROTOCOL_VERSION16, ptype_lazy_send, 7),
 		REMOTE_PROTOCOL(PROTOCOL_VERSION17, ptype_lazy_send, 8),
 		REMOTE_PROTOCOL(PROTOCOL_VERSION18, ptype_lazy_send, 9),
-		REMOTE_PROTOCOL(PROTOCOL_VERSION19, ptype_lazy_send, 10)
+		REMOTE_PROTOCOL(PROTOCOL_VERSION19, ptype_lazy_send, 10),
+		REMOTE_PROTOCOL(PROTOCOL_VERSION20, ptype_lazy_send, 11)
 	};
-	fb_assert(FB_NELEM(protocols_to_try) <= FB_NELEM(cnct->p_cnct_versions));
+	static_assert(FB_NELEM(protocols_to_try) <= MAX_CNCT_VERSIONS);
+
 	cnct->p_cnct_count = FB_NELEM(protocols_to_try);
 
 	for (size_t i = 0; i < cnct->p_cnct_count; i++) {

src/remote/os/win32/xnet.cpp

@@ -308,9 +308,11 @@ rem_port* XNET_analyze(ClntAuthBlock* cBlock,
 		REMOTE_PROTOCOL(PROTOCOL_VERSION16, ptype_batch_send, 7),
 		REMOTE_PROTOCOL(PROTOCOL_VERSION17, ptype_batch_send, 8),
 		REMOTE_PROTOCOL(PROTOCOL_VERSION18, ptype_batch_send, 9),
-		REMOTE_PROTOCOL(PROTOCOL_VERSION19, ptype_batch_send, 10)
+		REMOTE_PROTOCOL(PROTOCOL_VERSION19, ptype_batch_send, 10),
+		REMOTE_PROTOCOL(PROTOCOL_VERSION20, ptype_batch_send, 11)
 	};
-	fb_assert(FB_NELEM(protocols_to_try) <= FB_NELEM(cnct->p_cnct_versions));
+	static_assert(FB_NELEM(protocols_to_try) <= MAX_CNCT_VERSIONS);
+
 	cnct->p_cnct_count = FB_NELEM(protocols_to_try);
 
 	for (size_t i = 0; i < cnct->p_cnct_count; i++) {

src/remote/protocol.cpp

@@ -328,13 +328,12 @@ bool_t xdr_protocol(RemoteXdr* xdrs, PACKET* p)
 
 			MAP(xdr_cstring_const, connect->p_cnct_user_id);
 
-			const size_t CNCT_VERSIONS = FB_NELEM(connect->p_cnct_versions);
 			tail = connect->p_cnct_versions;
 			for (USHORT i = 0; i < connect->p_cnct_count; i++, tail++)
 			{
 				// ignore the rest of protocols in case of too many suggested versions
 				p_cnct::p_cnct_repeat dummy;
-				if (i >= CNCT_VERSIONS)
+				if (i >= MAX_CNCT_VERSIONS)
 				{
 					tail = &dummy;
 				}
@@ -347,9 +346,9 @@ bool_t xdr_protocol(RemoteXdr* xdrs, PACKET* p)
 			}
 
 			// ignore the rest of protocols in case of too many suggested versions
-			if (connect->p_cnct_count > CNCT_VERSIONS)
+			if (connect->p_cnct_count > MAX_CNCT_VERSIONS)
 			{
-				connect->p_cnct_count = CNCT_VERSIONS;
+				connect->p_cnct_count = MAX_CNCT_VERSIONS;
 			}
 
 			DEBUG_PRINTSIZE(xdrs, p->p_operation);
@@ -711,7 +710,7 @@ bool_t xdr_protocol(RemoteXdr* xdrs, PACKET* p)
 		// p_sqlst_buffer_length was USHORT in older versions
 		fixupLength(xdrs, prep_stmt->p_sqlst_buffer_length);
 
-		if (port->port_protocol >= PROTOCOL_VERSION19)
+		if (port->port_protocol >= PROTOCOL_PREPARE_FLAG)
 			MAP(xdr_short, reinterpret_cast<SSHORT&>(prep_stmt->p_sqlst_flags));
 
 		DEBUG_PRINTSIZE(xdrs, p->p_operation);

src/remote/protocol.h

@@ -108,12 +108,17 @@ const USHORT PROTOCOL_VERSION18 = (FB_PROTOCOL_FLAG | 18);
 const USHORT PROTOCOL_FETCH_SCROLL = PROTOCOL_VERSION18;
 
 // Protocol 19:
-//	- supports passing flags to IStatement::prepare
 //	- supports op_inline_blob
 
 const USHORT PROTOCOL_VERSION19 = (FB_PROTOCOL_FLAG | 19);
 const USHORT PROTOCOL_INLINE_BLOB = PROTOCOL_VERSION19;
 
+// Protocol 20:
+//	- supports passing flags to IStatement::prepare
+
+const USHORT PROTOCOL_VERSION20 = (FB_PROTOCOL_FLAG | 20);
+const USHORT PROTOCOL_PREPARE_FLAG = PROTOCOL_VERSION20;
+
 // Architecture types
 
 enum P_ARCH
@@ -380,6 +385,9 @@ typedef struct p_malloc
 
 // Connect Block (Client to server)
 
+// Servers before FB6 (PROTOCOL_VERSION20) uses only first 10 elements of p_cnct_versions
+constexpr size_t MAX_CNCT_VERSIONS = 11;
+
 typedef struct p_cnct
 {
 	USHORT	p_cnct_operation;			// unused
@@ -395,7 +403,7 @@ typedef struct p_cnct
 		USHORT	p_cnct_min_type;		// Minimum type (unused)
 		USHORT	p_cnct_max_type;		// Maximum type
 		USHORT	p_cnct_weight;			// Preference weight
-	}		p_cnct_versions[10];
+	}	p_cnct_versions[MAX_CNCT_VERSIONS];
 } P_CNCT;
 
 #ifdef ASYMMETRIC_PROTOCOLS_ONLY