/*
  Copyright (c) 2012 Frank Lahm <franklahm@gmail.com>

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
*/

/*!
  @file
  Typesafe, dynamic object store based on talloc

  Usage:


  Define some terminal types:

  A key/value store aka dictionary that supports retrieving elements by key
    typedef dict_t DALLOC_CTX;

  An ordered set that can store different objects which can be retrieved by number
    typedef set_t DALLOC_CTX;


  Create an dalloc object and add elementes of different type

  Allocate a new talloc context
    TALLOC_CTX *mem_ctx = talloc_new(NULL);
  Create a new dalloc object
    DALLOC_CTX *d = talloc_zero(mem_ctx, DALLOC_CTX);

  Store an int value in the object
    uint64_t i = 1;
    dalloc_add_copy(d, &i, uint64_t);

  Store a string
    char *str = dalloc_strdup(d, "hello world");
    dalloc_add(d, str, char *);

  Add a nested object, you later can't fetch this directly
    DALLOC_CTX *nested = talloc_zero(d, DALLOC_CTX);
    dalloc_add(d, nested, DALLOC_CTX);

  Add an int value to the nested object, this can be fetched
    i = 2;
    dalloc_add_copy(nested, &i, uint64_t);

  Add a nested set
    set_t *set = talloc_zero(nested, set_t);
    dalloc_add(nested, set, set_t);

  Add an int value to the set
    i = 3;
    dalloc_add_copy(set, &i, uint64_t);

  Add a dictionary (key/value store)
    dict_t *dict = talloc_zero(nested, dict_t);
    dalloc_add(nested, dict, dict_t);

  Store a string as key in the dict
    str = dalloc_strdup(d, "key");
    dalloc_add(dict, str, char *);

  Add a value for the key
    i = 4;
    dalloc_add_copy(dict, &i, uint64_t);


  Fetching value references

  You can fetch anything that is not a DALLOC_CTXs, because passing
  "DALLOC_CTXs" as type to the functions dalloc_get() and dalloc_value_for_key()
  tells the function to step into that object and expect more arguments that specify
  which element to fetch.

  Get reference to an objects element by position
    uint64_t *p = dalloc_get(d, "uint64_t", 0);
  p now points to the first int with a value of 1

  Get reference to the "hello world" string
    str = dalloc_get(d, "char *", 1);

  You can't fetch a pure DALLOC_CTX
    nested = dalloc_get(d, "DALLOC_CTX", 2);
  But you can do this
    p = dalloc_get(d, "DALLOC_CTX", 2, "uint64_t", 0);
  p now points to the value 2

  You can fetch types that are typedefd DALLOC_CTXs
    set = dalloc_get(d, "DALLOC_CTX", 2, "set_t", 1);

  Fetch int from set, note that you must use DALLOC_CTX as type for the set
    p = dalloc_get(d, "DALLOC_CTX", 2, "DALLOC_CTX", 1, "uint64_t", 0);
  p points to 3

  Fetch value by key from dictionary
    p = dalloc_value_for_key(d, "DALLOC_CTX", 2, "DALLOC_CTX", 2, "key");
  p now point to 4
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */

#include <errno.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>

#include <talloc.h>

#include <atalk/errchk.h>
#include <atalk/util.h>
#include <atalk/logger.h>
#include <atalk/dalloc.h>

/* Use dalloc_add_copy() macro, not this function */
int dalloc_add_talloc_chunk(DALLOC_CTX *dd, void *talloc_chunk, void *obj,
                            size_t size)
{
    if (talloc_chunk) {
        /* Called from dalloc_add_copy() macro */
        dd->dd_talloc_array = talloc_realloc(dd,
                                             dd->dd_talloc_array,
                                             void *,
                                             talloc_array_length(dd->dd_talloc_array) + 1);
        memcpy(talloc_chunk, obj, size);
        dd->dd_talloc_array[talloc_array_length(dd->dd_talloc_array) - 1] =
            talloc_chunk;
    } else {
        /* Called from dalloc_add() macro */
        dd->dd_talloc_array = talloc_realloc(dd,
                                             dd->dd_talloc_array,
                                             void *,
                                             talloc_array_length(dd->dd_talloc_array) + 1);
        dd->dd_talloc_array[talloc_array_length(dd->dd_talloc_array) - 1] = obj;
    }

    return 0;
}

/*
 * Get pointer to value from a DALLOC object
 *
 * Returns pointer to object from a DALLOC object. Nested object interation
 * is supported by using the type string "DALLOC_CTX". Any other type string
 * designates the requested objects type.
 */
void *dalloc_get(const DALLOC_CTX *d, ...)
{
    EC_INIT;
    void *p = NULL;
    va_list args;
    const char *type;
    int elem;
    va_start(args, d);
    type = va_arg(args, const char *);

    while (STRCMP(type, ==, "DALLOC_CTX")) {
        elem = va_arg(args, int);

        if (elem >= talloc_array_length(d->dd_talloc_array)) {
            LOG(log_error, logtype_sl, "dalloc_get(%s): bound check error: %d >= %d",
                type, elem >= talloc_array_length(d->dd_talloc_array));
            EC_FAIL;
        }

        d = d->dd_talloc_array[elem];
        type = va_arg(args, const char *);
    }

    elem = va_arg(args, int);

    if (elem >= talloc_array_length(d->dd_talloc_array)) {
        LOG(log_error, logtype_sl, "dalloc_get(%s): bound check error: %d >= %d",
            type, elem,  talloc_array_length(d->dd_talloc_array));
        EC_FAIL;
    }

    if (!(p = talloc_check_name(d->dd_talloc_array[elem], type))) {
        LOG(log_error, logtype_sl, "dalloc_get(%d/%s): type mismatch: %s",
            type, elem, talloc_get_name(d->dd_talloc_array[elem]));
    }

    va_end(args);
EC_CLEANUP:

    if (ret != 0) {
        p = NULL;
    }

    return p;
}

void *dalloc_value_for_key(const DALLOC_CTX *d, ...)
{
    EC_INIT;
    void *p = NULL;
    va_list args;
    const char *type = NULL;
    int elem;
    va_start(args, d);
    type = va_arg(args, const char *);

    while (STRCMP(type, ==, "DALLOC_CTX")) {
        elem = va_arg(args, int);
        AFP_ASSERT(elem < talloc_array_length(d->dd_talloc_array))
        d = d->dd_talloc_array[elem];
        type = va_arg(args, const char *);
    }

    for (elem = 0; elem + 1 < talloc_array_length(d->dd_talloc_array); elem += 2) {
        if (STRCMP(talloc_get_name(d->dd_talloc_array[elem]), !=, "char *")) {
            LOG(log_error, logtype_default, "dalloc_value_for_key: key not a string: %s",
                talloc_get_name(d->dd_talloc_array[elem]));
            EC_FAIL;
        }

        if (STRCMP((char *)d->dd_talloc_array[elem], ==, type)) {
            p = d->dd_talloc_array[elem + 1];
            break;
        }
    }

    if (p == NULL) {
        EC_FAIL;
    }

    type = va_arg(args, const char *);

    if (STRCMP(talloc_get_name(p), !=, type)) {
        p = NULL;
    }

EC_CLEANUP:
    va_end(args);

    if (ret != 0) {
        p = NULL;
    }

    return p;
}

char *dalloc_strdup(const void *ctx, const char *string)
{
    EC_INIT;
    char *p;
    EC_NULL(p = talloc_strdup(ctx, string));
    talloc_set_name(p, "char *");
EC_CLEANUP:

    if (ret != 0) {
        if (p) {
            talloc_free(p);
        }

        p = NULL;
    }

    return p;
}

char *dalloc_strndup(const void *ctx, const char *string, size_t n)
{
    EC_INIT;
    char *p;
    EC_NULL(p = talloc_strndup(ctx, string, n));
    talloc_set_name(p, "char *");
EC_CLEANUP:

    if (ret != 0) {
        if (p) {
            talloc_free(p);
        }

        p = NULL;
    }

    return p;
}
