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   1  <?php
   2  /**
   3   * WordPress Query API
   4   *
   5   * The query API attempts to get which part of WordPress the user is on. It
   6   * also provides functionality for getting URL query information.
   7   *
   8   * @link https://developer.wordpress.org/themes/basics/the-loop/ More information on The Loop.
   9   *
  10   * @package WordPress
  11   * @subpackage Query
  12   */
  13  
  14  /**
  15   * Retrieves the value of a query variable in the WP_Query class.
  16   *
  17   * @since 1.5.0
  18   * @since 3.9.0 The `$default` argument was introduced.
  19   *
  20   * @global WP_Query $wp_query WordPress Query object.
  21   *
  22   * @param string $var       The variable key to retrieve.
  23   * @param mixed  $default   Optional. Value to return if the query variable is not set. Default empty.
  24   * @return mixed Contents of the query variable.
  25   */
  26  function get_query_var( $var, $default = '' ) {
  27      global $wp_query;
  28      return $wp_query->get( $var, $default );
  29  }
  30  
  31  /**
  32   * Retrieves the currently queried object.
  33   *
  34   * Wrapper for WP_Query::get_queried_object().
  35   *
  36   * @since 3.1.0
  37   *
  38   * @global WP_Query $wp_query WordPress Query object.
  39   *
  40   * @return WP_Term|WP_Post_Type|WP_Post|WP_User|null The queried object.
  41   */
  42  function get_queried_object() {
  43      global $wp_query;
  44      return $wp_query->get_queried_object();
  45  }
  46  
  47  /**
  48   * Retrieves the ID of the currently queried object.
  49   *
  50   * Wrapper for WP_Query::get_queried_object_id().
  51   *
  52   * @since 3.1.0
  53   *
  54   * @global WP_Query $wp_query WordPress Query object.
  55   *
  56   * @return int ID of the queried object.
  57   */
  58  function get_queried_object_id() {
  59      global $wp_query;
  60      return $wp_query->get_queried_object_id();
  61  }
  62  
  63  /**
  64   * Sets the value of a query variable in the WP_Query class.
  65   *
  66   * @since 2.2.0
  67   *
  68   * @global WP_Query $wp_query WordPress Query object.
  69   *
  70   * @param string $var   Query variable key.
  71   * @param mixed  $value Query variable value.
  72   */
  73  function set_query_var( $var, $value ) {
  74      global $wp_query;
  75      $wp_query->set( $var, $value );
  76  }
  77  
  78  /**
  79   * Sets up The Loop with query parameters.
  80   *
  81   * Note: This function will completely override the main query and isn't intended for use
  82   * by plugins or themes. Its overly-simplistic approach to modifying the main query can be
  83   * problematic and should be avoided wherever possible. In most cases, there are better,
  84   * more performant options for modifying the main query such as via the {@see 'pre_get_posts'}
  85   * action within WP_Query.
  86   *
  87   * This must not be used within the WordPress Loop.
  88   *
  89   * @since 1.5.0
  90   *
  91   * @global WP_Query $wp_query WordPress Query object.
  92   *
  93   * @param array|string $query Array or string of WP_Query arguments.
  94   * @return WP_Post[]|int[] Array of post objects or post IDs.
  95   */
  96  function query_posts( $query ) {
  97      $GLOBALS['wp_query'] = new WP_Query();
  98      return $GLOBALS['wp_query']->query( $query );
  99  }
 100  
 101  /**
 102   * Destroys the previous query and sets up a new query.
 103   *
 104   * This should be used after query_posts() and before another query_posts().
 105   * This will remove obscure bugs that occur when the previous WP_Query object
 106   * is not destroyed properly before another is set up.
 107   *
 108   * @since 2.3.0
 109   *
 110   * @global WP_Query $wp_query     WordPress Query object.
 111   * @global WP_Query $wp_the_query Copy of the global WP_Query instance created during wp_reset_query().
 112   */
 113  function wp_reset_query() {
 114      $GLOBALS['wp_query'] = $GLOBALS['wp_the_query'];
 115      wp_reset_postdata();
 116  }
 117  
 118  /**
 119   * After looping through a separate query, this function restores
 120   * the $post global to the current post in the main query.
 121   *
 122   * @since 3.0.0
 123   *
 124   * @global WP_Query $wp_query WordPress Query object.
 125   */
 126  function wp_reset_postdata() {
 127      global $wp_query;
 128  
 129      if ( isset( $wp_query ) ) {
 130          $wp_query->reset_postdata();
 131      }
 132  }
 133  
 134  /*
 135   * Query type checks.
 136   */
 137  
 138  /**
 139   * Determines whether the query is for an existing archive page.
 140   *
 141   * Archive pages include category, tag, author, date, custom post type,
 142   * and custom taxonomy based archives.
 143   *
 144   * For more information on this and similar theme functions, check out
 145   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 146   * Conditional Tags} article in the Theme Developer Handbook.
 147   *
 148   * @since 1.5.0
 149   *
 150   * @see is_category()
 151   * @see is_tag()
 152   * @see is_author()
 153   * @see is_date()
 154   * @see is_post_type_archive()
 155   * @see is_tax()
 156   * @global WP_Query $wp_query WordPress Query object.
 157   *
 158   * @return bool Whether the query is for an existing archive page.
 159   */
 160  function is_archive() {
 161      global $wp_query;
 162  
 163      if ( ! isset( $wp_query ) ) {
 164          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 165          return false;
 166      }
 167  
 168      return $wp_query->is_archive();
 169  }
 170  
 171  /**
 172   * Determines whether the query is for an existing post type archive page.
 173   *
 174   * For more information on this and similar theme functions, check out
 175   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 176   * Conditional Tags} article in the Theme Developer Handbook.
 177   *
 178   * @since 3.1.0
 179   *
 180   * @global WP_Query $wp_query WordPress Query object.
 181   *
 182   * @param string|string[] $post_types Optional. Post type or array of posts types
 183   *                                    to check against. Default empty.
 184   * @return bool Whether the query is for an existing post type archive page.
 185   */
 186  function is_post_type_archive( $post_types = '' ) {
 187      global $wp_query;
 188  
 189      if ( ! isset( $wp_query ) ) {
 190          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 191          return false;
 192      }
 193  
 194      return $wp_query->is_post_type_archive( $post_types );
 195  }
 196  
 197  /**
 198   * Determines whether the query is for an existing attachment page.
 199   *
 200   * For more information on this and similar theme functions, check out
 201   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 202   * Conditional Tags} article in the Theme Developer Handbook.
 203   *
 204   * @since 2.0.0
 205   *
 206   * @global WP_Query $wp_query WordPress Query object.
 207   *
 208   * @param int|string|int[]|string[] $attachment Optional. Attachment ID, title, slug, or array of such
 209   *                                              to check against. Default empty.
 210   * @return bool Whether the query is for an existing attachment page.
 211   */
 212  function is_attachment( $attachment = '' ) {
 213      global $wp_query;
 214  
 215      if ( ! isset( $wp_query ) ) {
 216          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 217          return false;
 218      }
 219  
 220      return $wp_query->is_attachment( $attachment );
 221  }
 222  
 223  /**
 224   * Determines whether the query is for an existing author archive page.
 225   *
 226   * If the $author parameter is specified, this function will additionally
 227   * check if the query is for one of the authors specified.
 228   *
 229   * For more information on this and similar theme functions, check out
 230   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 231   * Conditional Tags} article in the Theme Developer Handbook.
 232   *
 233   * @since 1.5.0
 234   *
 235   * @global WP_Query $wp_query WordPress Query object.
 236   *
 237   * @param int|string|int[]|string[] $author Optional. User ID, nickname, nicename, or array of such
 238   *                                          to check against. Default empty.
 239   * @return bool Whether the query is for an existing author archive page.
 240   */
 241  function is_author( $author = '' ) {
 242      global $wp_query;
 243  
 244      if ( ! isset( $wp_query ) ) {
 245          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 246          return false;
 247      }
 248  
 249      return $wp_query->is_author( $author );
 250  }
 251  
 252  /**
 253   * Determines whether the query is for an existing category archive page.
 254   *
 255   * If the $category parameter is specified, this function will additionally
 256   * check if the query is for one of the categories specified.
 257   *
 258   * For more information on this and similar theme functions, check out
 259   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 260   * Conditional Tags} article in the Theme Developer Handbook.
 261   *
 262   * @since 1.5.0
 263   *
 264   * @global WP_Query $wp_query WordPress Query object.
 265   *
 266   * @param int|string|int[]|string[] $category Optional. Category ID, name, slug, or array of such
 267   *                                            to check against. Default empty.
 268   * @return bool Whether the query is for an existing category archive page.
 269   */
 270  function is_category( $category = '' ) {
 271      global $wp_query;
 272  
 273      if ( ! isset( $wp_query ) ) {
 274          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 275          return false;
 276      }
 277  
 278      return $wp_query->is_category( $category );
 279  }
 280  
 281  /**
 282   * Determines whether the query is for an existing tag archive page.
 283   *
 284   * If the $tag parameter is specified, this function will additionally
 285   * check if the query is for one of the tags specified.
 286   *
 287   * For more information on this and similar theme functions, check out
 288   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 289   * Conditional Tags} article in the Theme Developer Handbook.
 290   *
 291   * @since 2.3.0
 292   *
 293   * @global WP_Query $wp_query WordPress Query object.
 294   *
 295   * @param int|string|int[]|string[] $tag Optional. Tag ID, name, slug, or array of such
 296   *                                       to check against. Default empty.
 297   * @return bool Whether the query is for an existing tag archive page.
 298   */
 299  function is_tag( $tag = '' ) {
 300      global $wp_query;
 301  
 302      if ( ! isset( $wp_query ) ) {
 303          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 304          return false;
 305      }
 306  
 307      return $wp_query->is_tag( $tag );
 308  }
 309  
 310  /**
 311   * Determines whether the query is for an existing custom taxonomy archive page.
 312   *
 313   * If the $taxonomy parameter is specified, this function will additionally
 314   * check if the query is for that specific $taxonomy.
 315   *
 316   * If the $term parameter is specified in addition to the $taxonomy parameter,
 317   * this function will additionally check if the query is for one of the terms
 318   * specified.
 319   *
 320   * For more information on this and similar theme functions, check out
 321   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 322   * Conditional Tags} article in the Theme Developer Handbook.
 323   *
 324   * @since 2.5.0
 325   *
 326   * @global WP_Query $wp_query WordPress Query object.
 327   *
 328   * @param string|string[]           $taxonomy Optional. Taxonomy slug or slugs to check against.
 329   *                                            Default empty.
 330   * @param int|string|int[]|string[] $term     Optional. Term ID, name, slug, or array of such
 331   *                                            to check against. Default empty.
 332   * @return bool Whether the query is for an existing custom taxonomy archive page.
 333   *              True for custom taxonomy archive pages, false for built-in taxonomies
 334   *              (category and tag archives).
 335   */
 336  function is_tax( $taxonomy = '', $term = '' ) {
 337      global $wp_query;
 338  
 339      if ( ! isset( $wp_query ) ) {
 340          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 341          return false;
 342      }
 343  
 344      return $wp_query->is_tax( $taxonomy, $term );
 345  }
 346  
 347  /**
 348   * Determines whether the query is for an existing date archive.
 349   *
 350   * For more information on this and similar theme functions, check out
 351   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 352   * Conditional Tags} article in the Theme Developer Handbook.
 353   *
 354   * @since 1.5.0
 355   *
 356   * @global WP_Query $wp_query WordPress Query object.
 357   *
 358   * @return bool Whether the query is for an existing date archive.
 359   */
 360  function is_date() {
 361      global $wp_query;
 362  
 363      if ( ! isset( $wp_query ) ) {
 364          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 365          return false;
 366      }
 367  
 368      return $wp_query->is_date();
 369  }
 370  
 371  /**
 372   * Determines whether the query is for an existing day archive.
 373   *
 374   * A conditional check to test whether the page is a date-based archive page displaying posts for the current day.
 375   *
 376   * For more information on this and similar theme functions, check out
 377   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 378   * Conditional Tags} article in the Theme Developer Handbook.
 379   *
 380   * @since 1.5.0
 381   *
 382   * @global WP_Query $wp_query WordPress Query object.
 383   *
 384   * @return bool Whether the query is for an existing day archive.
 385   */
 386  function is_day() {
 387      global $wp_query;
 388  
 389      if ( ! isset( $wp_query ) ) {
 390          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 391          return false;
 392      }
 393  
 394      return $wp_query->is_day();
 395  }
 396  
 397  /**
 398   * Determines whether the query is for a feed.
 399   *
 400   * For more information on this and similar theme functions, check out
 401   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 402   * Conditional Tags} article in the Theme Developer Handbook.
 403   *
 404   * @since 1.5.0
 405   *
 406   * @global WP_Query $wp_query WordPress Query object.
 407   *
 408   * @param string|string[] $feeds Optional. Feed type or array of feed types
 409   *                                         to check against. Default empty.
 410   * @return bool Whether the query is for a feed.
 411   */
 412  function is_feed( $feeds = '' ) {
 413      global $wp_query;
 414  
 415      if ( ! isset( $wp_query ) ) {
 416          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 417          return false;
 418      }
 419  
 420      return $wp_query->is_feed( $feeds );
 421  }
 422  
 423  /**
 424   * Is the query for a comments feed?
 425   *
 426   * @since 3.0.0
 427   *
 428   * @global WP_Query $wp_query WordPress Query object.
 429   *
 430   * @return bool Whether the query is for a comments feed.
 431   */
 432  function is_comment_feed() {
 433      global $wp_query;
 434  
 435      if ( ! isset( $wp_query ) ) {
 436          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 437          return false;
 438      }
 439  
 440      return $wp_query->is_comment_feed();
 441  }
 442  
 443  /**
 444   * Determines whether the query is for the front page of the site.
 445   *
 446   * This is for what is displayed at your site's main URL.
 447   *
 448   * Depends on the site's "Front page displays" Reading Settings 'show_on_front' and 'page_on_front'.
 449   *
 450   * If you set a static page for the front page of your site, this function will return
 451   * true when viewing that page.
 452   *
 453   * Otherwise the same as @see is_home()
 454   *
 455   * For more information on this and similar theme functions, check out
 456   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 457   * Conditional Tags} article in the Theme Developer Handbook.
 458   *
 459   * @since 2.5.0
 460   *
 461   * @global WP_Query $wp_query WordPress Query object.
 462   *
 463   * @return bool Whether the query is for the front page of the site.
 464   */
 465  function is_front_page() {
 466      global $wp_query;
 467  
 468      if ( ! isset( $wp_query ) ) {
 469          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 470          return false;
 471      }
 472  
 473      return $wp_query->is_front_page();
 474  }
 475  
 476  /**
 477   * Determines whether the query is for the blog homepage.
 478   *
 479   * The blog homepage is the page that shows the time-based blog content of the site.
 480   *
 481   * is_home() is dependent on the site's "Front page displays" Reading Settings 'show_on_front'
 482   * and 'page_for_posts'.
 483   *
 484   * If a static page is set for the front page of the site, this function will return true only
 485   * on the page you set as the "Posts page".
 486   *
 487   * For more information on this and similar theme functions, check out
 488   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 489   * Conditional Tags} article in the Theme Developer Handbook.
 490   *
 491   * @since 1.5.0
 492   *
 493   * @see is_front_page()
 494   * @global WP_Query $wp_query WordPress Query object.
 495   *
 496   * @return bool Whether the query is for the blog homepage.
 497   */
 498  function is_home() {
 499      global $wp_query;
 500  
 501      if ( ! isset( $wp_query ) ) {
 502          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 503          return false;
 504      }
 505  
 506      return $wp_query->is_home();
 507  }
 508  
 509  /**
 510   * Determines whether the query is for the Privacy Policy page.
 511   *
 512   * The Privacy Policy page is the page that shows the Privacy Policy content of the site.
 513   *
 514   * is_privacy_policy() is dependent on the site's "Change your Privacy Policy page" Privacy Settings 'wp_page_for_privacy_policy'.
 515   *
 516   * This function will return true only on the page you set as the "Privacy Policy page".
 517   *
 518   * For more information on this and similar theme functions, check out
 519   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 520   * Conditional Tags} article in the Theme Developer Handbook.
 521   *
 522   * @since 5.2.0
 523   *
 524   * @global WP_Query $wp_query WordPress Query object.
 525   *
 526   * @return bool Whether the query is for the Privacy Policy page.
 527   */
 528  function is_privacy_policy() {
 529      global $wp_query;
 530  
 531      if ( ! isset( $wp_query ) ) {
 532          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 533          return false;
 534      }
 535  
 536      return $wp_query->is_privacy_policy();
 537  }
 538  
 539  /**
 540   * Determines whether the query is for an existing month archive.
 541   *
 542   * For more information on this and similar theme functions, check out
 543   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 544   * Conditional Tags} article in the Theme Developer Handbook.
 545   *
 546   * @since 1.5.0
 547   *
 548   * @global WP_Query $wp_query WordPress Query object.
 549   *
 550   * @return bool Whether the query is for an existing month archive.
 551   */
 552  function is_month() {
 553      global $wp_query;
 554  
 555      if ( ! isset( $wp_query ) ) {
 556          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 557          return false;
 558      }
 559  
 560      return $wp_query->is_month();
 561  }
 562  
 563  /**
 564   * Determines whether the query is for an existing single page.
 565   *
 566   * If the $page parameter is specified, this function will additionally
 567   * check if the query is for one of the pages specified.
 568   *
 569   * For more information on this and similar theme functions, check out
 570   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 571   * Conditional Tags} article in the Theme Developer Handbook.
 572   *
 573   * @since 1.5.0
 574   *
 575   * @see is_single()
 576   * @see is_singular()
 577   * @global WP_Query $wp_query WordPress Query object.
 578   *
 579   * @param int|string|int[]|string[] $page Optional. Page ID, title, slug, or array of such
 580   *                                        to check against. Default empty.
 581   * @return bool Whether the query is for an existing single page.
 582   */
 583  function is_page( $page = '' ) {
 584      global $wp_query;
 585  
 586      if ( ! isset( $wp_query ) ) {
 587          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 588          return false;
 589      }
 590  
 591      return $wp_query->is_page( $page );
 592  }
 593  
 594  /**
 595   * Determines whether the query is for a paged result and not for the first page.
 596   *
 597   * For more information on this and similar theme functions, check out
 598   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 599   * Conditional Tags} article in the Theme Developer Handbook.
 600   *
 601   * @since 1.5.0
 602   *
 603   * @global WP_Query $wp_query WordPress Query object.
 604   *
 605   * @return bool Whether the query is for a paged result.
 606   */
 607  function is_paged() {
 608      global $wp_query;
 609  
 610      if ( ! isset( $wp_query ) ) {
 611          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 612          return false;
 613      }
 614  
 615      return $wp_query->is_paged();
 616  }
 617  
 618  /**
 619   * Determines whether the query is for a post or page preview.
 620   *
 621   * For more information on this and similar theme functions, check out
 622   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 623   * Conditional Tags} article in the Theme Developer Handbook.
 624   *
 625   * @since 2.0.0
 626   *
 627   * @global WP_Query $wp_query WordPress Query object.
 628   *
 629   * @return bool Whether the query is for a post or page preview.
 630   */
 631  function is_preview() {
 632      global $wp_query;
 633  
 634      if ( ! isset( $wp_query ) ) {
 635          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 636          return false;
 637      }
 638  
 639      return $wp_query->is_preview();
 640  }
 641  
 642  /**
 643   * Is the query for the robots.txt file?
 644   *
 645   * @since 2.1.0
 646   *
 647   * @global WP_Query $wp_query WordPress Query object.
 648   *
 649   * @return bool Whether the query is for the robots.txt file.
 650   */
 651  function is_robots() {
 652      global $wp_query;
 653  
 654      if ( ! isset( $wp_query ) ) {
 655          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 656          return false;
 657      }
 658  
 659      return $wp_query->is_robots();
 660  }
 661  
 662  /**
 663   * Is the query for the favicon.ico file?
 664   *
 665   * @since 5.4.0
 666   *
 667   * @global WP_Query $wp_query WordPress Query object.
 668   *
 669   * @return bool Whether the query is for the favicon.ico file.
 670   */
 671  function is_favicon() {
 672      global $wp_query;
 673  
 674      if ( ! isset( $wp_query ) ) {
 675          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 676          return false;
 677      }
 678  
 679      return $wp_query->is_favicon();
 680  }
 681  
 682  /**
 683   * Determines whether the query is for a search.
 684   *
 685   * For more information on this and similar theme functions, check out
 686   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 687   * Conditional Tags} article in the Theme Developer Handbook.
 688   *
 689   * @since 1.5.0
 690   *
 691   * @global WP_Query $wp_query WordPress Query object.
 692   *
 693   * @return bool Whether the query is for a search.
 694   */
 695  function is_search() {
 696      global $wp_query;
 697  
 698      if ( ! isset( $wp_query ) ) {
 699          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 700          return false;
 701      }
 702  
 703      return $wp_query->is_search();
 704  }
 705  
 706  /**
 707   * Determines whether the query is for an existing single post.
 708   *
 709   * Works for any post type, except attachments and pages
 710   *
 711   * If the $post parameter is specified, this function will additionally
 712   * check if the query is for one of the Posts specified.
 713   *
 714   * For more information on this and similar theme functions, check out
 715   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 716   * Conditional Tags} article in the Theme Developer Handbook.
 717   *
 718   * @since 1.5.0
 719   *
 720   * @see is_page()
 721   * @see is_singular()
 722   * @global WP_Query $wp_query WordPress Query object.
 723   *
 724   * @param int|string|int[]|string[] $post Optional. Post ID, title, slug, or array of such
 725   *                                        to check against. Default empty.
 726   * @return bool Whether the query is for an existing single post.
 727   */
 728  function is_single( $post = '' ) {
 729      global $wp_query;
 730  
 731      if ( ! isset( $wp_query ) ) {
 732          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 733          return false;
 734      }
 735  
 736      return $wp_query->is_single( $post );
 737  }
 738  
 739  /**
 740   * Determines whether the query is for an existing single post of any post type
 741   * (post, attachment, page, custom post types).
 742   *
 743   * If the $post_types parameter is specified, this function will additionally
 744   * check if the query is for one of the Posts Types specified.
 745   *
 746   * For more information on this and similar theme functions, check out
 747   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 748   * Conditional Tags} article in the Theme Developer Handbook.
 749   *
 750   * @since 1.5.0
 751   *
 752   * @see is_page()
 753   * @see is_single()
 754   * @global WP_Query $wp_query WordPress Query object.
 755   *
 756   * @param string|string[] $post_types Optional. Post type or array of post types
 757   *                                    to check against. Default empty.
 758   * @return bool Whether the query is for an existing single post
 759   *              or any of the given post types.
 760   */
 761  function is_singular( $post_types = '' ) {
 762      global $wp_query;
 763  
 764      if ( ! isset( $wp_query ) ) {
 765          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 766          return false;
 767      }
 768  
 769      return $wp_query->is_singular( $post_types );
 770  }
 771  
 772  /**
 773   * Determines whether the query is for a specific time.
 774   *
 775   * For more information on this and similar theme functions, check out
 776   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 777   * Conditional Tags} article in the Theme Developer Handbook.
 778   *
 779   * @since 1.5.0
 780   *
 781   * @global WP_Query $wp_query WordPress Query object.
 782   *
 783   * @return bool Whether the query is for a specific time.
 784   */
 785  function is_time() {
 786      global $wp_query;
 787  
 788      if ( ! isset( $wp_query ) ) {
 789          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 790          return false;
 791      }
 792  
 793      return $wp_query->is_time();
 794  }
 795  
 796  /**
 797   * Determines whether the query is for a trackback endpoint call.
 798   *
 799   * For more information on this and similar theme functions, check out
 800   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 801   * Conditional Tags} article in the Theme Developer Handbook.
 802   *
 803   * @since 1.5.0
 804   *
 805   * @global WP_Query $wp_query WordPress Query object.
 806   *
 807   * @return bool Whether the query is for a trackback endpoint call.
 808   */
 809  function is_trackback() {
 810      global $wp_query;
 811  
 812      if ( ! isset( $wp_query ) ) {
 813          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 814          return false;
 815      }
 816  
 817      return $wp_query->is_trackback();
 818  }
 819  
 820  /**
 821   * Determines whether the query is for an existing year archive.
 822   *
 823   * For more information on this and similar theme functions, check out
 824   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 825   * Conditional Tags} article in the Theme Developer Handbook.
 826   *
 827   * @since 1.5.0
 828   *
 829   * @global WP_Query $wp_query WordPress Query object.
 830   *
 831   * @return bool Whether the query is for an existing year archive.
 832   */
 833  function is_year() {
 834      global $wp_query;
 835  
 836      if ( ! isset( $wp_query ) ) {
 837          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 838          return false;
 839      }
 840  
 841      return $wp_query->is_year();
 842  }
 843  
 844  /**
 845   * Determines whether the query has resulted in a 404 (returns no results).
 846   *
 847   * For more information on this and similar theme functions, check out
 848   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 849   * Conditional Tags} article in the Theme Developer Handbook.
 850   *
 851   * @since 1.5.0
 852   *
 853   * @global WP_Query $wp_query WordPress Query object.
 854   *
 855   * @return bool Whether the query is a 404 error.
 856   */
 857  function is_404() {
 858      global $wp_query;
 859  
 860      if ( ! isset( $wp_query ) ) {
 861          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 862          return false;
 863      }
 864  
 865      return $wp_query->is_404();
 866  }
 867  
 868  /**
 869   * Is the query for an embedded post?
 870   *
 871   * @since 4.4.0
 872   *
 873   * @global WP_Query $wp_query WordPress Query object.
 874   *
 875   * @return bool Whether the query is for an embedded post.
 876   */
 877  function is_embed() {
 878      global $wp_query;
 879  
 880      if ( ! isset( $wp_query ) ) {
 881          _doing_it_wrong( __FUNCTION__, __( 'Conditional query tags do not work before the query is run. Before then, they always return false.' ), '3.1.0' );
 882          return false;
 883      }
 884  
 885      return $wp_query->is_embed();
 886  }
 887  
 888  /**
 889   * Determines whether the query is the main query.
 890   *
 891   * For more information on this and similar theme functions, check out
 892   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 893   * Conditional Tags} article in the Theme Developer Handbook.
 894   *
 895   * @since 3.3.0
 896   *
 897   * @global WP_Query $wp_query WordPress Query object.
 898   *
 899   * @return bool Whether the query is the main query.
 900   */
 901  function is_main_query() {
 902      global $wp_query;
 903  
 904      if ( 'pre_get_posts' === current_filter() ) {
 905          _doing_it_wrong(
 906              __FUNCTION__,
 907              sprintf(
 908                  /* translators: 1: pre_get_posts, 2: WP_Query->is_main_query(), 3: is_main_query(), 4: Documentation URL. */
 909                  __( 'In %1$s, use the %2$s method, not the %3$s function. See %4$s.' ),
 910                  '<code>pre_get_posts</code>',
 911                  '<code>WP_Query->is_main_query()</code>',
 912                  '<code>is_main_query()</code>',
 913                  __( 'https://developer.wordpress.org/reference/functions/is_main_query/' )
 914              ),
 915              '3.7.0'
 916          );
 917      }
 918  
 919      return $wp_query->is_main_query();
 920  }
 921  
 922  /*
 923   * The Loop. Post loop control.
 924   */
 925  
 926  /**
 927   * Determines whether current WordPress query has posts to loop over.
 928   *
 929   * @since 1.5.0
 930   *
 931   * @global WP_Query $wp_query WordPress Query object.
 932   *
 933   * @return bool True if posts are available, false if end of the loop.
 934   */
 935  function have_posts() {
 936      global $wp_query;
 937      return $wp_query->have_posts();
 938  }
 939  
 940  /**
 941   * Determines whether the caller is in the Loop.
 942   *
 943   * For more information on this and similar theme functions, check out
 944   * the {@link https://developer.wordpress.org/themes/basics/conditional-tags/
 945   * Conditional Tags} article in the Theme Developer Handbook.
 946   *
 947   * @since 2.0.0
 948   *
 949   * @global WP_Query $wp_query WordPress Query object.
 950   *
 951   * @return bool True if caller is within loop, false if loop hasn't started or ended.
 952   */
 953  function in_the_loop() {
 954      global $wp_query;
 955      return $wp_query->in_the_loop;
 956  }
 957  
 958  /**
 959   * Rewind the loop posts.
 960   *
 961   * @since 1.5.0
 962   *
 963   * @global WP_Query $wp_query WordPress Query object.
 964   */
 965  function rewind_posts() {
 966      global $wp_query;
 967      $wp_query->rewind_posts();
 968  }
 969  
 970  /**
 971   * Iterate the post index in the loop.
 972   *
 973   * @since 1.5.0
 974   *
 975   * @global WP_Query $wp_query WordPress Query object.
 976   */
 977  function the_post() {
 978      global $wp_query;
 979      $wp_query->the_post();
 980  }
 981  
 982  /*
 983   * Comments loop.
 984   */
 985  
 986  /**
 987   * Determines whether current WordPress query has comments to loop over.
 988   *
 989   * @since 2.2.0
 990   *
 991   * @global WP_Query $wp_query WordPress Query object.
 992   *
 993   * @return bool True if comments are available, false if no more comments.
 994   */
 995  function have_comments() {
 996      global $wp_query;
 997      return $wp_query->have_comments();
 998  }
 999  
1000  /**
1001   * Iterate comment index in the comment loop.
1002   *
1003   * @since 2.2.0
1004   *
1005   * @global WP_Query $wp_query WordPress Query object.
1006   *
1007   * @return null
1008   */
1009  function the_comment() {
1010      global $wp_query;
1011      return $wp_query->the_comment();
1012  }
1013  
1014  /**
1015   * Redirect old slugs to the correct permalink.
1016   *
1017   * Attempts to find the current slug from the past slugs.
1018   *
1019   * @since 2.1.0
1020   */
1021  function wp_old_slug_redirect() {
1022      if ( is_404() && '' !== get_query_var( 'name' ) ) {
1023          // Guess the current post type based on the query vars.
1024          if ( get_query_var( 'post_type' ) ) {
1025              $post_type = get_query_var( 'post_type' );
1026          } elseif ( get_query_var( 'attachment' ) ) {
1027              $post_type = 'attachment';
1028          } elseif ( get_query_var( 'pagename' ) ) {
1029              $post_type = 'page';
1030          } else {
1031              $post_type = 'post';
1032          }
1033  
1034          if ( is_array( $post_type ) ) {
1035              if ( count( $post_type ) > 1 ) {
1036                  return;
1037              }
1038              $post_type = reset( $post_type );
1039          }
1040  
1041          // Do not attempt redirect for hierarchical post types.
1042          if ( is_post_type_hierarchical( $post_type ) ) {
1043              return;
1044          }
1045  
1046          $id = _find_post_by_old_slug( $post_type );
1047  
1048          if ( ! $id ) {
1049              $id = _find_post_by_old_date( $post_type );
1050          }
1051  
1052          /**
1053           * Filters the old slug redirect post ID.
1054           *
1055           * @since 4.9.3
1056           *
1057           * @param int $id The redirect post ID.
1058           */
1059          $id = apply_filters( 'old_slug_redirect_post_id', $id );
1060  
1061          if ( ! $id ) {
1062              return;
1063          }
1064  
1065          $link = get_permalink( $id );
1066  
1067          if ( get_query_var( 'paged' ) > 1 ) {
1068              $link = user_trailingslashit( trailingslashit( $link ) . 'page/' . get_query_var( 'paged' ) );
1069          } elseif ( is_embed() ) {
1070              $link = user_trailingslashit( trailingslashit( $link ) . 'embed' );
1071          }
1072  
1073          /**
1074           * Filters the old slug redirect URL.
1075           *
1076           * @since 4.4.0
1077           *
1078           * @param string $link The redirect URL.
1079           */
1080          $link = apply_filters( 'old_slug_redirect_url', $link );
1081  
1082          if ( ! $link ) {
1083              return;
1084          }
1085  
1086          wp_redirect( $link, 301 ); // Permanent redirect.
1087          exit;
1088      }
1089  }
1090  
1091  /**
1092   * Find the post ID for redirecting an old slug.
1093   *
1094   * @since 4.9.3
1095   * @access private
1096   *
1097   * @see wp_old_slug_redirect()
1098   * @global wpdb $wpdb WordPress database abstraction object.
1099   *
1100   * @param string $post_type The current post type based on the query vars.
1101   * @return int The Post ID.
1102   */
1103  function _find_post_by_old_slug( $post_type ) {
1104      global $wpdb;
1105  
1106      $query = $wpdb->prepare( "SELECT post_id FROM $wpdb->postmeta, $wpdb->posts WHERE ID = post_id AND post_type = %s AND meta_key = '_wp_old_slug' AND meta_value = %s", $post_type, get_query_var( 'name' ) );
1107  
1108      // If year, monthnum, or day have been specified, make our query more precise
1109      // just in case there are multiple identical _wp_old_slug values.
1110      if ( get_query_var( 'year' ) ) {
1111          $query .= $wpdb->prepare( ' AND YEAR(post_date) = %d', get_query_var( 'year' ) );
1112      }
1113      if ( get_query_var( 'monthnum' ) ) {
1114          $query .= $wpdb->prepare( ' AND MONTH(post_date) = %d', get_query_var( 'monthnum' ) );
1115      }
1116      if ( get_query_var( 'day' ) ) {
1117          $query .= $wpdb->prepare( ' AND DAYOFMONTH(post_date) = %d', get_query_var( 'day' ) );
1118      }
1119  
1120      $id = (int) $wpdb->get_var( $query );
1121  
1122      return $id;
1123  }
1124  
1125  /**
1126   * Find the post ID for redirecting an old date.
1127   *
1128   * @since 4.9.3
1129   * @access private
1130   *
1131   * @see wp_old_slug_redirect()
1132   * @global wpdb $wpdb WordPress database abstraction object.
1133   *
1134   * @param string $post_type The current post type based on the query vars.
1135   * @return int The Post ID.
1136   */
1137  function _find_post_by_old_date( $post_type ) {
1138      global $wpdb;
1139  
1140      $date_query = '';
1141      if ( get_query_var( 'year' ) ) {
1142          $date_query .= $wpdb->prepare( ' AND YEAR(pm_date.meta_value) = %d', get_query_var( 'year' ) );
1143      }
1144      if ( get_query_var( 'monthnum' ) ) {
1145          $date_query .= $wpdb->prepare( ' AND MONTH(pm_date.meta_value) = %d', get_query_var( 'monthnum' ) );
1146      }
1147      if ( get_query_var( 'day' ) ) {
1148          $date_query .= $wpdb->prepare( ' AND DAYOFMONTH(pm_date.meta_value) = %d', get_query_var( 'day' ) );
1149      }
1150  
1151      $id = 0;
1152      if ( $date_query ) {
1153          $id = (int) $wpdb->get_var( $wpdb->prepare( "SELECT post_id FROM $wpdb->postmeta AS pm_date, $wpdb->posts WHERE ID = post_id AND post_type = %s AND meta_key = '_wp_old_date' AND post_name = %s" . $date_query, $post_type, get_query_var( 'name' ) ) );
1154  
1155          if ( ! $id ) {
1156              // Check to see if an old slug matches the old date.
1157              $id = (int) $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts, $wpdb->postmeta AS pm_slug, $wpdb->postmeta AS pm_date WHERE ID = pm_slug.post_id AND ID = pm_date.post_id AND post_type = %s AND pm_slug.meta_key = '_wp_old_slug' AND pm_slug.meta_value = %s AND pm_date.meta_key = '_wp_old_date'" . $date_query, $post_type, get_query_var( 'name' ) ) );
1158          }
1159      }
1160  
1161      return $id;
1162  }
1163  
1164  /**
1165   * Set up global post data.
1166   *
1167   * @since 1.5.0
1168   * @since 4.4.0 Added the ability to pass a post ID to `$post`.
1169   *
1170   * @global WP_Query $wp_query WordPress Query object.
1171   *
1172   * @param WP_Post|object|int $post WP_Post instance or Post ID/object.
1173   * @return bool True when finished.
1174   */
1175  function setup_postdata( $post ) {
1176      global $wp_query;
1177  
1178      if ( ! empty( $wp_query ) && $wp_query instanceof WP_Query ) {
1179          return $wp_query->setup_postdata( $post );
1180      }
1181  
1182      return false;
1183  }
1184  
1185  /**
1186   * Generates post data.
1187   *
1188   * @since 5.2.0
1189   *
1190   * @global WP_Query $wp_query WordPress Query object.
1191   *
1192   * @param WP_Post|object|int $post WP_Post instance or Post ID/object.
1193   * @return array|false Elements of post, or false on failure.
1194   */
1195  function generate_postdata( $post ) {
1196      global $wp_query;
1197  
1198      if ( ! empty( $wp_query ) && $wp_query instanceof WP_Query ) {
1199          return $wp_query->generate_postdata( $post );
1200      }
1201  
1202      return false;
1203  }