mDNSMacOSX/mdns_objects/mdns_set.c

   1 /*
   2  * Copyright (c) 2020 Apple Inc. All rights reserved.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     https://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include "mdns_set.h"
  18 #include "mdns_helpers.h"
  19 #include "mdns_objects.h"
  20
  21 #include <CoreUtils/CoreUtils.h>
  22
  23 //======================================================================================================================
  24 // MARK: - Set Kind Definition
  25
  26 typedef struct _subset_s * _subset_t;
  27
  28 struct mdns_set_s {
  29         struct mdns_object_s    base;   // Object base.
  30         _subset_t                               list;   // Subset list.
  31 };
  32
  33 MDNS_OBJECT_SUBKIND_DEFINE(set);
  34
  35 //======================================================================================================================
  36 // MARK: - Internal Data Structures
  37
  38 typedef struct _item_s * _item_t;
  39 struct _item_s {
  40         _item_t                 next;   // Next item in list.
  41         mdns_object_t   object; // Object.
  42 };
  43
  44 struct _subset_s {
  45         _subset_t       next;   // Next subset in list.
  46         uintptr_t       ident;  // Subset ID.
  47         _item_t         list;   // Querier list.
  48         size_t          count;  // Item count.
  49 };
  50
  51 //======================================================================================================================
  52 // MARK: - Internal Helper Function Prototypes
  53
  54 static _subset_t
  55 _subset_create(uintptr_t subset_id);
  56
  57 static void
  58 _subset_free(_subset_t subset);
  59 #define _subset_forget(X) ForgetCustom(X, _subset_free)
  60
  61 static _item_t
  62 _item_create(mdns_object_t object);
  63
  64 static void
  65 _item_free(_item_t item);
  66 #define _item_forget(X) ForgetCustom(X, _item_free)
  67
  68 //======================================================================================================================
  69 // MARK: - Set Public Methods
  70
  71 mdns_set_t
  72 mdns_set_create(void)
  73 {
  74         return _mdns_set_alloc();
  75 }
  76
  77 //======================================================================================================================
  78
  79 OSStatus
  80 mdns_set_add(const mdns_set_t me, const uintptr_t subset_id, const mdns_object_t object)
  81 {
  82         _subset_t *subset_ptr;
  83         _subset_t subset;
  84         for (subset_ptr = &me->list; (subset = *subset_ptr) != NULL; subset_ptr = &subset->next) {
  85                 if (subset->ident == subset_id) {
  86                         break;
  87                 }
  88         }
  89         OSStatus err;
  90         _subset_t new_subset = NULL;
  91         if (!subset) {
  92                 new_subset = _subset_create(subset_id);
  93                 require_action_quiet(new_subset, exit, err = kNoMemoryErr);
  94                 subset = new_subset;
  95         }
  96         _item_t *item_ptr;
  97         _item_t item;
  98         for (item_ptr = &subset->list; (item = *item_ptr) != NULL; item_ptr = &item->next) {
  99                 if (item->object == object) {
 100                         break;
 101                 }
 102         }
 103         require_action_quiet(!item, exit, err = kNoErr);
 104
 105         item = _item_create(object);
 106         require_action_quiet(item, exit, err = kNoMemoryErr);
 107
 108         *item_ptr = item;
 109         item = NULL;
 110         ++subset->count;
 111         if (new_subset) {
 112                 *subset_ptr = new_subset;
 113                 new_subset = NULL;
 114         }
 115         err = kNoErr;
 116
 117 exit:
 118         _subset_forget(&new_subset);
 119         return err;
 120 }
 121
 122 //======================================================================================================================
 123
 124 OSStatus
 125 mdns_set_remove(const mdns_set_t me, const uintptr_t subset_id, const mdns_object_t object)
 126 {
 127         _subset_t *subset_ptr;
 128         _subset_t subset;
 129         for (subset_ptr = &me->list; (subset = *subset_ptr) != NULL; subset_ptr = &subset->next) {
 130                 if (subset->ident == subset_id) {
 131                         break;
 132                 }
 133         }
 134         OSStatus err;
 135         require_action_quiet(subset, exit, err = kNotFoundErr);
 136
 137         _item_t *item_ptr;
 138         _item_t item;
 139         for (item_ptr = &subset->list; (item = *item_ptr) != NULL; item_ptr = &item->next) {
 140                 if (item->object == object) {
 141                         break;
 142                 }
 143         }
 144         require_action_quiet(item, exit, err = kNotFoundErr);
 145
 146         *item_ptr = item->next;
 147         --subset->count;
 148         _item_forget(&item);
 149         if (!subset->list) {
 150                 *subset_ptr = subset->next;
 151                 _subset_forget(&subset);
 152         }
 153         err = kNoErr;
 154
 155 exit:
 156         return err;
 157 }
 158
 159 //======================================================================================================================
 160
 161 size_t
 162 mdns_set_get_count(const mdns_set_t me, const uintptr_t subset_id)
 163 {
 164         _subset_t subset;
 165         for (subset = me->list; subset; subset = subset->next) {
 166                 if (subset->ident == subset_id) {
 167                         return subset->count;
 168                 }
 169         }
 170         return 0;
 171 }
 172
 173 //======================================================================================================================
 174
 175 void
 176 mdns_set_iterate(const mdns_set_t me, const uintptr_t subset_id, mdns_set_applier_t applier)
 177 {
 178         _subset_t subset = me->list;
 179         while (subset && (subset->ident != subset_id)) {
 180                 subset = subset->next;
 181         }
 182         require_quiet(subset, exit);
 183
 184         for (_item_t item = subset->list; item; item = item->next) {
 185                 const bool stop = applier(item->object);
 186                 if (stop) {
 187                         break;
 188                 }
 189         }
 190
 191 exit:
 192         return;
 193 }
 194
 195 //======================================================================================================================
 196 // MARK: - Set Private Methods
 197
 198 static char *
 199 _mdns_set_copy_description(const mdns_set_t me, __unused const bool debug, __unused const bool privacy)
 200 {
 201         char *                          description     = NULL;
 202         char                            buffer[128];
 203         char *                          dst                     = buffer;
 204         const char * const      lim                     = &buffer[countof(buffer)];
 205         int                                     n;
 206
 207         *dst = '\0';
 208         n = mdns_snprintf_add(&dst, lim, "<%s: %p>: ", me->base.kind->name, me);
 209         require_quiet(n >= 0, exit);
 210
 211         description = strdup(buffer);
 212
 213 exit:
 214         return description;
 215 }
 216 //======================================================================================================================
 217
 218 static void
 219 _mdns_set_finalize(const mdns_set_t me)
 220 {
 221         _subset_t subset;
 222         while ((subset = me->list) != NULL) {
 223                 me->list = subset->next;
 224                 _subset_free(subset);
 225         }
 226 }
 227
 228 //======================================================================================================================
 229 // MARK: - Internal Helper Functions
 230
 231 static _subset_t
 232 _subset_create(const uintptr_t subset_id)
 233 {
 234         const _subset_t obj = (_subset_t)calloc(1, sizeof(*obj));
 235         require_quiet(obj, exit);
 236
 237         obj->ident = subset_id;
 238
 239 exit:
 240         return obj;
 241 }
 242
 243 //======================================================================================================================
 244
 245 static void
 246 _subset_free(const _subset_t me)
 247 {
 248         me->next = NULL;
 249         _item_t item;
 250         while ((item = me->list) != NULL) {
 251                 me->list = item->next;
 252                 _item_free(item);
 253         }
 254         free(me);
 255 }
 256
 257 //======================================================================================================================
 258
 259 static _item_t
 260 _item_create(mdns_object_t object)
 261 {
 262         const _item_t obj = (_item_t)calloc(1, sizeof(*obj));
 263         require_quiet(obj, exit);
 264
 265         obj->object = object;
 266         mdns_retain(obj->object);
 267
 268 exit:
 269         return obj;
 270 }
 271
 272 //======================================================================================================================
 273
 274 static void
 275 _item_free(const _item_t me)
 276 {
 277         me->next = NULL;
 278         mdns_forget(&me->object);
 279         free(me);
 280 }