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database/apache/include/ap_slotmem.h

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+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SLOTMEM_H
+#define SLOTMEM_H
+
+/* Memory handler for a shared memory divided in slot.
+ */
+/**
+ * @file  ap_slotmem.h
+ * @brief Memory Slot Extension Storage Module for Apache
+ *
+ * @defgroup MEM mem
+ * @ingroup  APACHE_MODS
+ * @{
+ */
+
+#include "httpd.h"
+#include "http_config.h"
+#include "http_log.h"
+#include "ap_provider.h"
+
+#include "apr.h"
+#include "apr_strings.h"
+#include "apr_pools.h"
+#include "apr_shm.h"
+#include "apr_global_mutex.h"
+#include "apr_file_io.h"
+#include "apr_md5.h"
+
+#if APR_HAVE_UNISTD_H
+#include <unistd.h>         /* for getpid() */
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define AP_SLOTMEM_PROVIDER_GROUP "slotmem"
+#define AP_SLOTMEM_PROVIDER_VERSION "0"
+
+typedef unsigned int ap_slotmem_type_t;
+
+/*
+ * Values for ap_slotmem_type_t::
+ *
+ * AP_SLOTMEM_TYPE_PERSIST: For transitory providers, persist
+ *    the data on the file-system
+ *
+ * AP_SLOTMEM_TYPE_NOTMPSAFE:
+ *
+ * AP_SLOTMEM_TYPE_PREALLOC: Access to slots require they be grabbed 1st
+ *
+ * AP_SLOTMEM_TYPE_CLEARINUSE: If persisting, clear 'inuse' array before
+ *    storing
+ */
+#define AP_SLOTMEM_TYPE_PERSIST      (1 << 0)
+#define AP_SLOTMEM_TYPE_NOTMPSAFE    (1 << 1)
+#define AP_SLOTMEM_TYPE_PREGRAB      (1 << 2)
+#define AP_SLOTMEM_TYPE_CLEARINUSE   (1 << 3)
+
+typedef struct ap_slotmem_instance_t ap_slotmem_instance_t;
+
+/**
+ * callback function used for slotmem doall.
+ * @param mem is the memory associated with a worker.
+ * @param data is what is passed to slotmem.
+ * @param pool is pool used
+ * @return APR_SUCCESS if all went well
+ */
+typedef apr_status_t ap_slotmem_callback_fn_t(void* mem, void *data, apr_pool_t *pool);
+
+struct ap_slotmem_provider_t {
+    /*
+     * Name of the provider method
+     */
+    const char *name;
+    /**
+     * call the callback on all worker slots
+     * @param s ap_slotmem_instance_t to use.
+     * @param funct callback function to call for each element.
+     * @param data parameter for the callback function.
+     * @param pool is pool used
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* doall)(ap_slotmem_instance_t *s, ap_slotmem_callback_fn_t *func, void *data, apr_pool_t *pool);
+    /**
+     * create a new slotmem with each item size is item_size.
+     * This would create shared memory, basically.
+     * @param inst where to store pointer to slotmem
+     * @param name a key used for debugging and in mod_status output or allow another process to share this space.
+     * @param item_size size of each item
+     * @param item_num number of item to create.
+     * @param type type of slotmem.
+     * @param pool is pool used
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* create)(ap_slotmem_instance_t **inst, const char *name, apr_size_t item_size, unsigned int item_num, ap_slotmem_type_t type, apr_pool_t *pool);
+    /**
+     * attach to an existing slotmem.
+     * This would attach to  shared memory, basically.
+     * @param inst where to store pointer to slotmem
+     * @param name a key used for debugging and in mod_status output or allow another process to share this space.
+     * @param item_size size of each item
+     * @param item_num max number of item.
+     * @param pool is pool to memory allocate.
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* attach)(ap_slotmem_instance_t **inst, const char *name, apr_size_t *item_size, unsigned int *item_num, apr_pool_t *pool);
+    /**
+     * get the memory ptr associated with this worker slot.
+     * @param s ap_slotmem_instance_t to use.
+     * @param item_id item to return for 0 to item_num
+     * @param mem address to store the pointer to the slot
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* dptr)(ap_slotmem_instance_t *s, unsigned int item_id, void**mem);
+    /**
+     * get/read the data associated with this worker slot.
+     * @param s ap_slotmem_instance_t to use.
+     * @param item_id item to return for 0 to item_num
+     * @param dest address to store the data
+     * @param dest_len length of dataset to retrieve
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* get)(ap_slotmem_instance_t *s, unsigned int item_id, unsigned char *dest, apr_size_t dest_len);
+    /**
+     * put/write the data associated with this worker slot.
+     * @param s ap_slotmem_instance_t to use.
+     * @param item_id item to return for 0 to item_num
+     * @param src address of the data to store in the slot
+     * @param src_len length of dataset to store in the slot
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* put)(ap_slotmem_instance_t *slot, unsigned int item_id, unsigned char *src, apr_size_t src_len);
+    /**
+     * return number of slots allocated for this entry.
+     * @param s ap_slotmem_instance_t to use.
+     * @return number of slots
+     */
+    unsigned int (* num_slots)(ap_slotmem_instance_t *s);
+    /**
+     * return number of free (not used) slots allocated for this entry.
+     * Valid for slots which are AP_SLOTMEM_TYPE_PREGRAB as well as
+     * any which use get/release.
+     * @param s ap_slotmem_instance_t to use.
+     * @return number of slots
+     */
+    unsigned int (* num_free_slots)(ap_slotmem_instance_t *s);
+    /**
+     * return slot size allocated for this entry.
+     * @param s ap_slotmem_instance_t to use.
+     * @return size of slot
+     */
+    apr_size_t (* slot_size)(ap_slotmem_instance_t *s);
+    /**
+     * grab (or alloc) a free slot
+     * @param s ap_slotmem_instance_t to use.
+     * @param item_id ptr to the available slot id and marked as in-use
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* grab)(ap_slotmem_instance_t *s, unsigned int *item_id);
+    /**
+     * release (or free) the slot associated with this item_id
+     * @param s ap_slotmem_instance_t to use.
+     * @param item_id slot id to free and mark as no longer in-use
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* release)(ap_slotmem_instance_t *s, unsigned int item_id);
+    /**
+     * forced grab (or alloc) a slot associated with this item_id
+     * @param s ap_slotmem_instance_t to use.
+     * @param item_id to the specified slot id and marked as in-use
+     * @return APR_SUCCESS if all went well
+     */
+    apr_status_t (* fgrab)(ap_slotmem_instance_t *s, unsigned int item_id);
+};
+
+typedef struct ap_slotmem_provider_t ap_slotmem_provider_t;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/** @} */