Cleanup header files

- All now include maxscale/cdefs.h as the very first file.
- MXS_[BEGIN|END]_DECLS added to all C-headers.
  Strictly speaking not necessary for private headers, but
  does not hurt either.
- Include guards moved to the very top of the file.
- #pragma once added.

server/modules/routing/avro/avrorouter.h

@@ -1,3 +1,6 @@
+#pragma once
+#ifndef _MXS_AVRO_H
+#define _MXS_AVRO_H
 /*
  * Copyright (c) 2016 MariaDB Corporation Ab
  *
@@ -15,8 +18,7 @@
  * MaxScale AVRO router
  *
  */
-#ifndef _MXS_AVRO_H
-#define _MXS_AVRO_H
+#include <maxscale/cdefs.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <blr_constants.h>
@@ -35,6 +37,8 @@
 #include <sqlite3.h>
 #include <maxscale/protocol/mysql.h>
 
+MXS_BEGIN_DECLS
+
 /** SQLite3 version 3.7.14 introduced the new v2 close interface */
 #if SQLITE_VERSION_NUMBER < 3007014
 #define sqlite3_close_v2 sqlite3_close
@@ -312,4 +316,6 @@ extern void table_map_remap(uint8_t *ptr, uint8_t hdr_len, TABLE_MAP *map);
 #define AVRO_CS_BUSY             0x0001
 #define AVRO_WAIT_DATA           0x0002
 
+MXS_END_DECLS
+
 #endif

server/modules/routing/binlog/blr.h

@@ -1,3 +1,4 @@
+#pragma once
 #ifndef _BLR_H
 #define _BLR_H
 /*
@@ -37,6 +38,7 @@
  *
  * @endverbatim
  */
+#include <maxscale/cdefs.h>
 #include <maxscale/dcb.h>
 #include <maxscale/buffer.h>
 #include <pthread.h>
@@ -46,6 +48,8 @@
 #include <zlib.h>
 #include <maxscale/protocol/mysql.h>
 
+MXS_BEGIN_DECLS
+
 #define BINLOG_FNAMELEN         255
 #define BLR_PROTOCOL            "MySQLBackend"
 #define BINLOG_MAGIC            { 0xfe, 0x62, 0x69, 0x6e }
@@ -676,4 +680,6 @@ extern bool blr_send_event(blr_thread_role_t role,
                            REP_HEADER *hdr,
                            uint8_t *buf);
 
+MXS_END_DECLS
+
 #endif

server/modules/routing/maxinfo/maxinfo.h

@@ -1,3 +1,4 @@
+#pragma once
 #ifndef _MAXINFO_H
 #define _MAXINFO_H
 /*
@@ -12,10 +13,13 @@
  * of this software will be governed by version 2 or later of the General
  * Public License.
  */
+#include <maxscale/cdefs.h>
 #include <maxscale/service.h>
 #include <maxscale/session.h>
 #include <maxscale/spinlock.h>
 
+MXS_BEGIN_DECLS
+
 /**
  * @file maxinfo.h The MaxScale information schema provider
  *
@@ -138,4 +142,7 @@ extern void         maxinfo_send_parse_error(DCB *, char *, PARSE_ERROR);
 extern void     maxinfo_send_error(DCB *, int, char  *);
 extern RESULTSET    *maxinfo_variables();
 extern RESULTSET    *maxinfo_status();
+
+MXS_END_DECLS
+
 #endif

server/modules/routing/readconnroute/readconnection.h

@@ -1,3 +1,4 @@
+#pragma once
 #ifndef _READCONNECTION_H
 #define _READCONNECTION_H
 /*
@@ -25,8 +26,12 @@
  *
  * @endverbatim
  */
+
+#include <maxscale/cdefs.h>
 #include <maxscale/dcb.h>
 
+MXS_BEGIN_DECLS
+
 /**
  * Internal structure used to define the set of backend servers we are routing
  * connections to. This provides the storage for routing module specific data
@@ -84,4 +89,7 @@ typedef struct router_instance
     struct router_instance
         *next;
 } ROUTER_INSTANCE;
+
+MXS_END_DECLS
+
 #endif

server/modules/routing/readwritesplit/readwritesplit.h

@@ -1,3 +1,4 @@
+#pragma once
 #ifndef _RWSPLITROUTER_H
 #define _RWSPLITROUTER_H
 /*
@@ -24,10 +25,13 @@
  * @endverbatim
  */
 
+#include <maxscale/cdefs.h>
 #include <maxscale/dcb.h>
 #include <maxscale/hashtable.h>
 #include <math.h>
 
+MXS_BEGIN_DECLS
+
 #undef PREP_STMT_CACHING
 
 #if defined(PREP_STMT_CACHING)
@@ -356,5 +360,6 @@ typedef struct router_instance
 #define BACKEND_TYPE(b) (SERVER_IS_MASTER((b)->backend_server) ? BE_MASTER :    \
         (SERVER_IS_SLAVE((b)->backend_server) ? BE_SLAVE :  BE_UNDEFINED));
 
+MXS_END_DECLS
 
 #endif /*< _RWSPLITROUTER_H */

server/modules/routing/readwritesplit/rwsplit_internal.h

@@ -1,3 +1,6 @@
+#pragma once
+#ifndef _RWSPLIT_INTERNAL_H
+#define _RWSPLIT_INTERNAL_H
 /*
  * Copyright (c) 2016 MariaDB Corporation Ab
  *
@@ -18,15 +21,11 @@
  * Created on 08 August 2016, 11:54
  */
 
-#ifndef RWSPLIT_INTERNAL_H
-#define RWSPLIT_INTERNAL_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
+#include <maxscale/cdefs.h>
 #include <maxscale/query_classifier.h>
-    
+
+MXS_BEGIN_DECLS
+
 /* This needs to be removed along with dependency on it - see the 
  * rwsplit_tmp_table_multi functions
  */
@@ -145,5 +144,7 @@ qc_query_type_t determine_query_type(GWBUF *querybuf, int packet_type, bool non_
 }
 #endif
 
+MXS_END_DECLS
+
 #endif /* RWSPLIT_INTERNAL_H */
 

server/modules/routing/schemarouter/schemarouter.h

@@ -1,3 +1,4 @@
+#pragma once
 #ifndef _SCHEMAROUTER_H
 #define _SCHEMAROUTER_H
 /*
@@ -23,14 +24,15 @@
  *
  * @endverbatim
  */
-#ifndef PCRE2_CODE_UNIT_WIDTH
-#define PCRE2_CODE_UNIT_WIDTH 8
-#endif
 
+#include <maxscale/cdefs.h>
 #include <maxscale/dcb.h>
 #include <maxscale/hashtable.h>
 #include <maxscale/protocol/mysql.h>
-#include <pcre2.h>
+#include <maxscale/pcre2.h>
+
+MXS_BEGIN_DECLS
+
 /**
  * Bitmask values for the router session's initialization. These values are used
  * to prevent responses from internal commands being forwarded to the client.
@@ -377,4 +379,6 @@ typedef struct router_instance
 #define BACKEND_TYPE(b) (SERVER_IS_MASTER((b)->backend_server) ? BE_MASTER :    \
         (SERVER_IS_SLAVE((b)->backend_server) ? BE_SLAVE :  BE_UNDEFINED));
 
+MXS_END_DECLS
+
 #endif /*< _SCHEMAROUTER_H */

server/modules/routing/schemarouter/sharding_common.h

@@ -1,3 +1,6 @@
+#pragma once
+#ifndef _SHARDING_COMMON_HG
+#define _SHARDING_COMMON_HG
 /*
  * Copyright (c) 2016 MariaDB Corporation Ab
  *
@@ -11,9 +14,7 @@
  * Public License.
  */
 
-#ifndef _SHARDING_COMMON_HG
-#define _SHARDING_COMMON_HG
-
+#include <maxscale/cdefs.h>
 #include <my_config.h>
 #include <poll.h>
 #include <maxscale/buffer.h>
@@ -23,8 +24,12 @@
 #include <maxscale/log_manager.h>
 #include <maxscale/query_classifier.h>
 
+MXS_BEGIN_DECLS
+
 bool extract_database(GWBUF* buf, char* str);
 void create_error_reply(char* fail_str, DCB* dcb);
 bool change_current_db(char* dest, HASHTABLE* dbhash, GWBUF* buf);
 
+MXS_END_DECLS
+
 #endif