Move headers from server/include to include/maxscale

- Headers now to be included as <maxscale/xyz.h>
- First step, no cleanup of headers has been made. Only moving
  from one place to another + necessary modifications.

include/maxscale/filter.h

@@ -0,0 +1,119 @@
+#ifndef _FILTER_H
+#define _FILTER_H
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl.
+ *
+ * Change Date: 2019-07-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+
+/**
+ * @file filter.h -  The filter interface mechanisms
+ *
+ * Revision History
+ *
+ * Date         Who                     Description
+ * 27/05/2014   Mark Riddoch            Initial implementation
+ *
+ */
+#include <maxscale/dcb.h>
+#include <maxscale/session.h>
+#include <maxscale/buffer.h>
+#include <stdint.h>
+
+/**
+ * The FILTER handle points to module specific data, so the best we can do
+ * is to make it a void * externally.
+ */
+typedef void *FILTER;
+
+/**
+ * The structure used to pass name, value pairs to the filter instances
+ */
+typedef struct
+{
+    char    *name;          /**< Name of the parameter */
+    char    *value;         /**< Value of the parameter */
+} FILTER_PARAMETER;
+
+/**
+ * @verbatim
+ * The "module object" structure for a query router module
+ *
+ * The entry points are:
+ *      createInstance          Called by the service to create a new
+ *                              instance of the filter
+ *      newSession              Called to create a new user session
+ *                              within the filter
+ *      closeSession            Called when a session is closed
+ *      freeSession             Called when a session is freed
+ *      setDownstream           Sets the downstream component of the
+ *                              filter pipline
+ *      routeQuery              Called on each query that requires
+ *                              routing
+ *      clientReply             Called for each reply packet
+ *      diagnostics             Called to force the filter to print
+ *                              diagnostic output
+ *
+ * @endverbatim
+ *
+ * @see load_module
+ */
+typedef struct filter_object
+{
+    FILTER *(*createInstance)(const char *name,
+                              char **options,
+                              FILTER_PARAMETER **params);
+    void   *(*newSession)(FILTER *instance, SESSION *session);
+    void   (*closeSession)(FILTER *instance, void *fsession);
+    void   (*freeSession)(FILTER *instance, void *fsession);
+    void   (*setDownstream)(FILTER *instance, void *fsession, DOWNSTREAM *downstream);
+    void   (*setUpstream)(FILTER *instance, void *fsession, UPSTREAM *downstream);
+    int    (*routeQuery)(FILTER *instance, void *fsession, GWBUF *queue);
+    int    (*clientReply)(FILTER *instance, void *fsession, GWBUF *queue);
+    void   (*diagnostics)(FILTER *instance, void *fsession, DCB *dcb);
+} FILTER_OBJECT;
+
+/**
+ * The filter API version. If the FILTER_OBJECT structure or the filter API
+ * is changed these values must be updated in line with the rules in the
+ * file modinfo.h.
+ */
+#define FILTER_VERSION  {2, 1, 0}
+/**
+ * The definition of a filter from the configuration file.
+ * This is basically the link between a plugin to load and the
+ * optons to pass to that plugin.
+ */
+typedef struct filter_def
+{
+    char *name;                    /**< The Filter name */
+    char *module;                  /**< The module to load */
+    char **options;                /**< The options set for this filter */
+    FILTER_PARAMETER **parameters; /**< The filter parameters */
+    FILTER filter;                 /**< The runtime filter */
+    FILTER_OBJECT *obj;            /**< The "MODULE_OBJECT" for the filter */
+    SPINLOCK spin;                 /**< Spinlock to protect the filter definition */
+    struct filter_def *next;       /**< Next filter in the chain of all filters */
+} FILTER_DEF;
+
+FILTER_DEF *filter_alloc(char *, char *);
+void filter_free(FILTER_DEF *);
+bool filter_load(FILTER_DEF* filter);
+FILTER_DEF *filter_find(char *);
+void filterAddOption(FILTER_DEF *, char *);
+void filterAddParameter(FILTER_DEF *, char *, char *);
+DOWNSTREAM *filterApply(FILTER_DEF *, SESSION *, DOWNSTREAM *);
+UPSTREAM *filterUpstream(FILTER_DEF *, void *, UPSTREAM *);
+int filter_standard_parameter(char *);
+void dprintAllFilters(DCB *);
+void dprintFilter(DCB *, FILTER_DEF *);
+void dListFilters(DCB *);
+
+#endif