json.c

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/*
 * This file is part of the Fun programming language.
 * https://fun-lang.xyz/
 *
 * Copyright 2025 Johannes Findeisen <you@hanez.org>
 * Licensed under the terms of the Apache-2.0 license.
 * https://opensource.org/license/apache-2-0
 */
 
/**
 * @file json.c
 * @brief JSON extension helpers and VM opcode cases (conditional build).
 *
 * Provides conversions between json-c objects and the Fun Value type and
 * supplies VM opcode case implementations when FUN_WITH_JSON is enabled.
 * This unit may be included or compiled conditionally based on build flags.
 */
 
/* json-c helpers and VM opcode cases (included from vm.c) */
 
#ifdef FUN_WITH_JSON
#include "value.h"
#include "vm.h"
 
#include <json-c/json.h>
#include <string.h>
 
/* --- Conversion helpers between json-c and Fun Value --- */
/**
 * @brief Convert a json-c object into a Fun Value.
 *
 * Maps json-c primitive and compound types to the closest Fun Value
 * representation.
 * - null -> Nil
 * - boolean -> Bool
 * - number (int/double) -> Int/Float
 * - string -> String
 * - array -> Array (recursively converted)
 * - object -> Map<string,any> (values recursively converted)
 *
 * @param j Pointer to a json_object; may be NULL.
 * @return A Value representing the converted JSON data. Ownership of the
 *         returned Value belongs to the caller and must be freed with
 *         free_value() when no longer needed.
 */
static Value json_to_fun(json_object *j) {
  if (!j) return make_nil();
  enum json_type t = json_object_get_type(j);
  switch (t) {
  case json_type_null:
    return make_nil();
  case json_type_boolean:
    return make_bool(json_object_get_boolean(j));
  case json_type_double:
    return make_float(json_object_get_double(j));
  case json_type_int:
    return make_int((int64_t)json_object_get_int64(j));
  case json_type_string:
    return make_string(json_object_get_string(j));
  case json_type_array: {
    size_t n = json_object_array_length(j);
    if (n == 0) {
      return make_array_from_values(NULL, 0);
    }
    Value *vals = (Value *)malloc(sizeof(Value) * n);
    if (!vals) return make_array_from_values(NULL, 0);
    for (size_t i = 0; i < n; ++i) {
      json_object *item = json_object_array_get_idx(j, (int)i);
      vals[i] = json_to_fun(item);
    }
    Value arr = make_array_from_values(vals, (int)n);
    for (size_t i = 0; i < n; ++i)
      free_value(vals[i]);
    free(vals);
    return arr;
  }
  case json_type_object: {
    Value map = make_map_empty();
    json_object_object_foreach(j, key, val) {
      (void)map_set(&map, key, json_to_fun(val));
    }
    return map;
  }
  default:
    return make_nil();
  }
}
 
/**
 * @brief Convert a Fun Value into a json-c object.
 *
 * Produces a newly-allocated json_object tree representing the supplied
 * Value. Unsupported Fun types are stringified using a placeholder.
 *
 * @param v Pointer to the source Value. Must not be NULL.
 * @return Newly created json_object* on success. The caller owns the
 *         returned object and must release it with json_object_put().
 */
static json_object *fun_to_json(const Value *v) {
  switch (v->type) {
  case VAL_NIL:
    return json_object_new_null();
  case VAL_BOOL:
    return json_object_new_boolean(v->i ? 1 : 0);
  case VAL_INT:
    return json_object_new_int64(v->i);
  case VAL_FLOAT:
    return json_object_new_double(v->d);
  case VAL_STRING:
    return json_object_new_string(v->s ? v->s : "");
  case VAL_ARRAY: {
    json_object *arr = json_object_new_array();
    int n = array_length(v);
    for (int i = 0; i < n; ++i) {
      Value item;
      if (array_get_copy(v, i, &item)) {
        json_object_array_add(arr, fun_to_json(&item));
        free_value(item);
      } else {
        json_object_array_add(arr, json_object_new_null());
      }
    }
    return arr;
  }
  case VAL_MAP: {
    json_object *obj = json_object_new_object();
    /* We don't have an iterator API; use keys() helper */
    Value keys = map_keys_array(v);
    int kn = array_length(&keys);
    for (int i = 0; i < kn; ++i) {
      Value k;
      if (!array_get_copy(&keys, i, &k)) continue;
      if (k.type == VAL_STRING && k.s) {
        Value val;
        if (map_get_copy(v, k.s, &val)) {
          json_object_object_add(obj, k.s, fun_to_json(&val));
          free_value(val);
        } else {
          json_object_object_add(obj, k.s, json_object_new_null());
        }
      }
      free_value(k);
    }
    free_value(keys);
    return obj;
  }
  default:
    /* Fallback: stringify unsupported types */
    return json_object_new_string("<unsupported>");
  }
}
#endif