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   1  <?php
   2  
   3  /**
   4  * @package   s9e\TextFormatter
   5  * @copyright Copyright (c) 2010-2021 The s9e authors
   6  * @license   http://www.opensource.org/licenses/mit-license.php The MIT License
   7  */
   8  namespace s9e\TextFormatter\Parser;
   9  
  10  class Tag
  11  {
  12      /**
  13      * Tag type: start tag
  14      */
  15      const START_TAG = 1;
  16  
  17      /**
  18      * Tag type: end tag
  19      */
  20      const END_TAG = 2;
  21  
  22      /**
  23      * Tag type: self-closing tag
  24      */
  25      const SELF_CLOSING_TAG = self::START_TAG | self::END_TAG;
  26  
  27      /**
  28      * @var array Dictionary of attributes
  29      */
  30      protected $attributes = [];
  31  
  32      /**
  33      * @var array List of tags that are invalidated when this tag is invalidated
  34      */
  35      protected $cascade = [];
  36  
  37      /**
  38      * @var Tag End tag that unconditionally ends this start tag
  39      */
  40      protected $endTag = null;
  41  
  42      /**
  43      * @var integer Bitfield of boolean rules that apply to this tag
  44      */
  45      protected $flags = 0;
  46  
  47      /**
  48      * @var bool Whether this tag is be invalid
  49      */
  50      protected $invalid = false;
  51  
  52      /**
  53      * @var integer Length of text consumed by this tag
  54      */
  55      protected $len;
  56  
  57      /**
  58      * @var string Name of this tag
  59      */
  60      protected $name;
  61  
  62      /**
  63      * @var integer Position of this tag in the text
  64      */
  65      protected $pos;
  66  
  67      /**
  68      * @var integer Tiebreaker used when sorting identical tags
  69      */
  70      protected $sortPriority;
  71  
  72      /**
  73      * @var Tag Start tag that is unconditionally closed this end tag
  74      */
  75      protected $startTag = null;
  76  
  77      /**
  78      * @var integer Tag type
  79      */
  80      protected $type;
  81  
  82      /**
  83      * Constructor
  84      *
  85      * @param  integer $type     Tag's type
  86      * @param  string  $name     Name of the tag
  87      * @param  integer $pos      Position of the tag in the text
  88      * @param  integer $len      Length of text consumed by the tag
  89      * @param  integer $priority This tag's sorting tiebreaker
  90      */
  91  	public function __construct($type, $name, $pos, $len, $priority = 0)
  92      {
  93          $this->type = (int) $type;
  94          $this->name = $name;
  95          $this->pos  = (int) $pos;
  96          $this->len  = (int) $len;
  97          $this->sortPriority = (int) $priority;
  98      }
  99  
 100      //==========================================================================
 101      // Actions
 102      //==========================================================================
 103  
 104      /**
 105      * Add a set of flags to this tag's
 106      *
 107      * @param  integer $flags
 108      * @return void
 109      */
 110  	public function addFlags($flags)
 111      {
 112          $this->flags |= $flags;
 113      }
 114  
 115      /**
 116      * Set given tag to be invalidated if this tag is invalidated
 117      *
 118      * @param  Tag  $tag
 119      * @return void
 120      */
 121  	public function cascadeInvalidationTo(Tag $tag)
 122      {
 123          $this->cascade[] = $tag;
 124  
 125          // If this tag is already invalid, cascade it now
 126          if ($this->invalid)
 127          {
 128              $tag->invalidate();
 129          }
 130      }
 131  
 132      /**
 133      * Invalidate this tag, as well as tags bound to this tag
 134      *
 135      * @return void
 136      */
 137  	public function invalidate()
 138      {
 139          // Only invalidate if this tag is valid to prevent infinite loops
 140          if (!$this->invalid)
 141          {
 142              $this->invalid = true;
 143              foreach ($this->cascade as $tag)
 144              {
 145                  $tag->invalidate();
 146              }
 147          }
 148      }
 149  
 150      /**
 151      * Pair this tag with given tag
 152      *
 153      * @param  Tag  $tag
 154      * @return void
 155      */
 156  	public function pairWith(Tag $tag)
 157      {
 158          if ($this->canBePaired($this, $tag))
 159          {
 160              $this->endTag  = $tag;
 161              $tag->startTag = $this;
 162  
 163              $this->cascadeInvalidationTo($tag);
 164          }
 165          elseif ($this->canBePaired($tag, $this))
 166          {
 167              $this->startTag = $tag;
 168              $tag->endTag    = $this;
 169          }
 170      }
 171  
 172      /**
 173      * Test whether two tags can be paired
 174      */
 175  	protected function canBePaired(Tag $startTag, Tag $endTag): bool
 176      {
 177          return $startTag->name === $endTag->name && $startTag->type === self::START_TAG && $endTag->type === self::END_TAG && $startTag->pos <= $endTag->pos;
 178      }
 179  
 180      /**
 181      * Remove a set of flags from this tag's
 182      *
 183      * @param  integer $flags
 184      * @return void
 185      */
 186  	public function removeFlags($flags)
 187      {
 188          $this->flags &= ~$flags;
 189      }
 190  
 191      /**
 192      * Set the bitfield of boolean rules that apply to this tag
 193      *
 194      * @param  integer $flags Bitfield of boolean rules that apply to this tag
 195      * @return void
 196      */
 197  	public function setFlags($flags)
 198      {
 199          $this->flags = $flags;
 200      }
 201  
 202      //==========================================================================
 203      // Getters
 204      //==========================================================================
 205  
 206      /**
 207      * Return this tag's attributes
 208      *
 209      * @return array
 210      */
 211  	public function getAttributes()
 212      {
 213          return $this->attributes;
 214      }
 215  
 216      /**
 217      * Return this tag's end tag
 218      *
 219      * @return Tag|null This tag's end tag, or NULL if none is set
 220      */
 221  	public function getEndTag()
 222      {
 223          return $this->endTag;
 224      }
 225  
 226      /**
 227      * Return the bitfield of boolean rules that apply to this tag
 228      *
 229      * @return integer
 230      */
 231  	public function getFlags()
 232      {
 233          return $this->flags;
 234      }
 235  
 236      /**
 237      * Return the length of text consumed by this tag
 238      *
 239      * @return integer
 240      */
 241  	public function getLen()
 242      {
 243          return $this->len;
 244      }
 245  
 246      /**
 247      * Return this tag's name
 248      *
 249      * @return string
 250      */
 251  	public function getName()
 252      {
 253          return $this->name;
 254      }
 255  
 256      /**
 257      * Return this tag's position
 258      *
 259      * @return integer
 260      */
 261  	public function getPos()
 262      {
 263          return $this->pos;
 264      }
 265  
 266      /**
 267      * Return this tag's tiebreaker
 268      *
 269      * @return integer
 270      */
 271  	public function getSortPriority()
 272      {
 273          return $this->sortPriority;
 274      }
 275  
 276      /**
 277      * Return this tag's start tag
 278      *
 279      * @return Tag|null This tag's start tag, or NULL if none is set
 280      */
 281  	public function getStartTag()
 282      {
 283          return $this->startTag;
 284      }
 285  
 286      /**
 287      * Return this tag's type
 288      *
 289      * @return integer
 290      */
 291  	public function getType()
 292      {
 293          return $this->type;
 294      }
 295  
 296      //==========================================================================
 297      // Tag's status
 298      //==========================================================================
 299  
 300      /**
 301      * Test whether this tag can close given start tag
 302      *
 303      * @param  Tag  $startTag A start tag
 304      * @return bool
 305      */
 306  	public function canClose(Tag $startTag)
 307      {
 308          if ($this->invalid
 309           || !$this->canBePaired($startTag, $this)
 310           || ($this->startTag && $this->startTag !== $startTag)
 311           || ($startTag->endTag && $startTag->endTag !== $this))
 312          {
 313              return false;
 314          }
 315  
 316          return true;
 317      }
 318  
 319      /**
 320      * Test whether this tag is a br tag
 321      *
 322      * @return bool
 323      */
 324  	public function isBrTag()
 325      {
 326          return ($this->name === 'br');
 327      }
 328  
 329      /**
 330      * Test whether this tag is an end tag (self-closing tags inclusive)
 331      *
 332      * @return bool
 333      */
 334  	public function isEndTag()
 335      {
 336          return (bool) ($this->type & self::END_TAG);
 337      }
 338  
 339      /**
 340      * Test whether this tag is an ignore tag
 341      *
 342      * @return bool
 343      */
 344  	public function isIgnoreTag()
 345      {
 346          return ($this->name === 'i');
 347      }
 348  
 349      /**
 350      * Test whether this tag is invalid
 351      *
 352      * @return bool
 353      */
 354  	public function isInvalid()
 355      {
 356          return $this->invalid;
 357      }
 358  
 359      /**
 360      * Test whether this tag represents a paragraph break
 361      *
 362      * @return bool
 363      */
 364  	public function isParagraphBreak()
 365      {
 366          return ($this->name === 'pb');
 367      }
 368  
 369      /**
 370      * Test whether this tag is a self-closing tag
 371      *
 372      * @return bool
 373      */
 374  	public function isSelfClosingTag()
 375      {
 376          return ($this->type === self::SELF_CLOSING_TAG);
 377      }
 378  
 379      /**
 380      * Test whether this tag is a special tag: "br", "i", "pb" or "v"
 381      *
 382      * @return bool
 383      */
 384  	public function isSystemTag()
 385      {
 386          return (strpos('br i pb v', $this->name) !== false);
 387      }
 388  
 389      /**
 390      * Test whether this tag is a start tag (self-closing tags inclusive)
 391      *
 392      * @return bool
 393      */
 394  	public function isStartTag()
 395      {
 396          return (bool) ($this->type & self::START_TAG);
 397      }
 398  
 399      /**
 400      * Test whether this tag represents verbatim text
 401      *
 402      * @return bool
 403      */
 404  	public function isVerbatim()
 405      {
 406          return ($this->name === 'v');
 407      }
 408  
 409      //==========================================================================
 410      // Attributes handling
 411      //==========================================================================
 412  
 413      /**
 414      * Return the value of given attribute
 415      *
 416      * @param  string $attrName
 417      * @return mixed
 418      */
 419  	public function getAttribute($attrName)
 420      {
 421          return $this->attributes[$attrName];
 422      }
 423  
 424      /**
 425      * Return whether given attribute is set
 426      *
 427      * @param  string $attrName
 428      * @return bool
 429      */
 430  	public function hasAttribute($attrName)
 431      {
 432          return isset($this->attributes[$attrName]);
 433      }
 434  
 435      /**
 436      * Remove given attribute
 437      *
 438      * @param  string $attrName
 439      * @return void
 440      */
 441  	public function removeAttribute($attrName)
 442      {
 443          unset($this->attributes[$attrName]);
 444      }
 445  
 446      /**
 447      * Set the value of an attribute
 448      *
 449      * @param  string $attrName  Attribute's name
 450      * @param  string $attrValue Attribute's value
 451      * @return void
 452      */
 453  	public function setAttribute($attrName, $attrValue)
 454      {
 455          $this->attributes[$attrName] = $attrValue;
 456      }
 457  
 458      /**
 459      * Set all of this tag's attributes at once
 460      *
 461      * @param  array $attributes
 462      * @return void
 463      */
 464  	public function setAttributes(array $attributes)
 465      {
 466          $this->attributes = $attributes;
 467      }
 468  }