/**
 * 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 APACHE_HTRACE_SPAN_H
#define APACHE_HTRACE_SPAN_H

/**
 * @file span.h
 *
 * Functions related to HTrace spans and trace scopes.
 *
 * This is an internal header, not intended for external use.
 */

#include <stdint.h>

struct htracer;

struct htrace_span {
    /**
     * The name of this trace scope.
     * Dynamically allocated.  Will never be NULL.
     */
    char *desc;

    /**
     * The beginning time in wall-clock milliseconds.
     */
    uint64_t begin_ms;

    /**
     * The end time in wall-clock milliseconds.
     */
    uint64_t end_ms;

    /**
     * The span id.
     */
    uint64_t span_id;

    /**
     * The process ID of this trace scope.
     * Dynamically allocated.  May be null.
     */
    char *prid;

    /**
     * The number of parents.
     */
    int num_parents;

    union {
        /**
         * If there is 1 parent, this is the parent ID.
         */
        uint64_t single;

        /**
         * If there are multiple parents, this is a pointer to a dynamically
         * allocated array of parent IDs.
         */
        uint64_t *list;
    } parent;
};

/**
 * Allocate an htrace span.
 *
 * @param desc          The span name to use.  Will be deep-copied.
 * @param begin_ms      The value to use for begin_ms.
 * @param span_id       The span ID to use.
 *
 * @return              NULL on OOM; the span otherwise.
 */
struct htrace_span *htrace_span_alloc(const char *desc,
                uint64_t begin_ms, uint64_t span_id);

/**
 * Free the memory associated with an htrace span.
 *
 * @param span          The span to free.
 */
void htrace_span_free(struct htrace_span *span);

/**
 * Sort and deduplicate the parents array within the span.
 *
 * @param span          The span to process.
 */
void htrace_span_sort_and_dedupe_parents(struct htrace_span *span);

/**
 * Escape a JSON string.  Specifically, put backslashes before double quotes and
 * other backslashes.
 *
 * @param in            The string to escape.
 *
 * @param out           The escaped string.  Malloced. NULL on OOM.
 */
char *json_escape(const char *in);

/**
 * Get the buffer size that would be needed to serialize this span to a buffer.
 *
 * @param span          The span.
 *
 * @return              The buffer size in bytes.  This will never be less
 *                          than 1.
 */
int span_json_size(const struct htrace_span *span);

/**
 * Get the buffer size that would be needed to serialize this span to a buffer.
 *
 * @param span          The span.
 *
 * @return              The buffer size in bytes.
 */
void span_json_sprintf(const struct htrace_span *span, int max, void *buf);

#endif

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