parser/html/nsHtml5Highlighter.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4 #ifndef nsHtml5Highlighter_h
   5 #define nsHtml5Highlighter_h
   6
   7 #include "nsCOMPtr.h"
   8 #include "nsHtml5TreeOperation.h"
   9 #include "nsHtml5UTF16Buffer.h"
  10 #include "nsHtml5TreeOperation.h"
  11 #include "nsAHtml5TreeOpSink.h"
  12
  13 #define NS_HTML5_HIGHLIGHTER_HANDLE_ARRAY_LENGTH 512
  14
  15 /**
  16  * A state machine for generating HTML for display in View Source based on
  17  * the transitions the tokenizer makes on the source being viewed.
  18  */
  19 class nsHtml5Highlighter {
  20  public:
  21   /**
  22    * The constructor.
  23    *
  24    * @param aOpSink the sink for the tree ops generated by this highlighter
  25    */
  26   explicit nsHtml5Highlighter(nsAHtml5TreeOpSink* aOpSink);
  27
  28   /**
  29    * The destructor.
  30    */
  31   ~nsHtml5Highlighter();
  32
  33   /**
  34    * Set the op sink (for speculation).
  35    */
  36   void SetOpSink(nsAHtml5TreeOpSink* aOpSink);
  37
  38   /**
  39    * Reset state to after generated head but before processing any of the input
  40    * stream.
  41    */
  42   void Rewind();
  43
  44   /**
  45    * Starts the generated document.
  46    */
  47   void Start(const nsAutoString& aTitle);
  48
  49   /**
  50    * Updates the charset source via the op queue.
  51    */
  52   void UpdateCharsetSource(nsCharsetSource aCharsetSource);
  53
  54   /**
  55    * Report a tokenizer state transition.
  56    *
  57    * @param aState the state being transitioned to
  58    * @param aReconsume whether this is a reconsuming transition
  59    * @param aPos the tokenizer's current position into the buffer
  60    */
  61   int32_t Transition(int32_t aState, bool aReconsume, int32_t aPos);
  62
  63   /**
  64    * Report end of file.
  65    *
  66    * Returns `true` normally and `false` on OOM.
  67    */
  68   [[nodiscard]] bool End();
  69
  70   /**
  71    * Set the current buffer being tokenized
  72    */
  73   void SetBuffer(nsHtml5UTF16Buffer* aBuffer);
  74
  75   /**
  76    * Let go of the buffer being tokenized but first, flush text from it.
  77    *
  78    * @param aPos the first UTF-16 code unit not to flush
  79    */
  80   void DropBuffer(int32_t aPos);
  81
  82   /**
  83    * Query whether there are some many ops in the queue
  84    * that they should be flushed now.
  85    *
  86    * @return true if FlushOps() should be called now
  87    */
  88   bool ShouldFlushOps();
  89
  90   /**
  91    * Flush the tree ops into the sink.
  92    *
  93    * @return Ok(true) if there were ops to flush, Ok(false)
  94    *         if there were no ops to flush and Err() on OOM.
  95    */
  96   mozilla::Result<bool, nsresult> FlushOps();
  97
  98   /**
  99    * Linkify the current attribute value if the attribute name is one of
 100    * known URL attributes. (When executing tree ops, javascript: URLs will
 101    * not be linkified, though.)
 102    *
 103    * @param aName the name of the attribute
 104    * @param aValue the value of the attribute
 105    */
 106   void MaybeLinkifyAttributeValue(nsHtml5AttributeName* aName,
 107                                   nsHtml5String aValue);
 108
 109   /**
 110    * Inform the highlighter that the tokenizer successfully completed a
 111    * named character reference.
 112    */
 113   void CompletedNamedCharacterReference();
 114
 115   /**
 116    * Adds an error annotation to the node that's currently on top of
 117    * mStack.
 118    *
 119    * @param aMsgId the id of the message in the property file
 120    */
 121   void AddErrorToCurrentNode(const char* aMsgId);
 122
 123   /**
 124    * Adds an error annotation to the node that corresponds to the most
 125    * recently opened markup declaration/tag span, character reference or
 126    * run of text.
 127    *
 128    * @param aMsgId the id of the message in the property file
 129    */
 130   void AddErrorToCurrentRun(const char* aMsgId);
 131
 132   /**
 133    * Adds an error annotation to the node that corresponds to the most
 134    * recently opened markup declaration/tag span, character reference or
 135    * run of text with one atom to use when formatting the message.
 136    *
 137    * @param aMsgId the id of the message in the property file
 138    * @param aName the atom
 139    */
 140   void AddErrorToCurrentRun(const char* aMsgId, nsAtom* aName);
 141
 142   /**
 143    * Adds an error annotation to the node that corresponds to the most
 144    * recently opened markup declaration/tag span, character reference or
 145    * run of text with two atoms to use when formatting the message.
 146    *
 147    * @param aMsgId the id of the message in the property file
 148    * @param aName the first atom
 149    * @param aOther the second atom
 150    */
 151   void AddErrorToCurrentRun(const char* aMsgId, nsAtom* aName, nsAtom* aOther);
 152
 153   /**
 154    * Adds an error annotation to the node that corresponds to the most
 155    * recent potentially character reference-starting ampersand.
 156    *
 157    * @param aMsgId the id of the message in the property file
 158    */
 159   void AddErrorToCurrentAmpersand(const char* aMsgId);
 160
 161   /**
 162    * Adds an error annotation to the node that corresponds to the most
 163    * recent potentially self-closing slash.
 164    *
 165    * @param aMsgId the id of the message in the property file
 166    */
 167   void AddErrorToCurrentSlash(const char* aMsgId);
 168
 169   /**
 170    * Enqueues a tree op for adding base to the urls with the view-source:
 171    *
 172    * @param aValue the base URL to add
 173    */
 174   void AddBase(nsHtml5String aValue);
 175
 176   /**
 177    * Starts a wrapper around a run of characters.
 178    */
 179   void StartCharacters();
 180
 181  private:
 182   /**
 183    * Starts a span with no class.
 184    */
 185   void StartSpan();
 186
 187   /**
 188    * Starts a <span> and sets the class attribute on it.
 189    *
 190    * @param aClass the class to set (MUST be a static string that does not
 191    *        need to be released!)
 192    */
 193   void StartSpan(const char16_t* aClass);
 194
 195   /**
 196    * End the current <span> or <a> in the highlighter output.
 197    */
 198   void EndSpanOrA();
 199
 200   /**
 201    * Ends a wrapper around a run of characters.
 202    */
 203   void EndCharactersAndStartMarkupRun();
 204
 205   /**
 206    * Starts an <a>.
 207    */
 208   void StartA();
 209
 210   /**
 211    * Flushes characters up to but not including the current one.
 212    */
 213   void FlushChars();
 214
 215   /**
 216    * Flushes characters up to and including the current one.
 217    */
 218   void FlushCurrent();
 219
 220   /**
 221    * Finishes highlighting a tag in the input data by closing the open
 222    * <span> and <a> elements in the highlighter output and then starts
 223    * another <span> for potentially highlighting characters potentially
 224    * appearing next.
 225    */
 226   void FinishTag();
 227
 228   /**
 229    * Adds a class attribute to the current node.
 230    *
 231    * @param aClass the class to set (MUST be a static string that does not
 232    *        need to be released!)
 233    */
 234   void AddClass(const char16_t* aClass);
 235
 236   /**
 237    * Allocates a handle for an element.
 238    *
 239    * See the documentation for nsHtml5TreeBuilder::AllocateContentHandle()
 240    * in nsHtml5TreeBuilderHSupplement.h.
 241    *
 242    * @return the handle
 243    */
 244   nsIContent** AllocateContentHandle();
 245
 246   /**
 247    * Enqueues an element creation tree operation.
 248    *
 249    * @param aName the name of the element
 250    * @param aAttributes the attribute holder (ownership will be taken) or
 251    *        nullptr for no attributes
 252    * @param aIntendedParent the intended parent node for the created element
 253    * @param aCreator the content creator function
 254    * @return the handle for the element that will be created
 255    */
 256   nsIContent** CreateElement(nsAtom* aName, nsHtml5HtmlAttributes* aAttributes,
 257                              nsIContent** aIntendedParent,
 258                              mozilla::dom::HTMLContentCreatorFunction aCreator);
 259
 260   /**
 261    * Gets the handle for the current node. May be called only after the
 262    * root element has been set.
 263    *
 264    * @return the handle for the current node
 265    */
 266   nsIContent** CurrentNode();
 267
 268   /**
 269    * Create an element and push it (its handle) on the stack.
 270    *
 271    * @param aName the name of the element
 272    * @param aAttributes the attribute holder (ownership will be taken) or
 273    *        nullptr for no attributes
 274    * @param aCreator the content creator function
 275    */
 276   void Push(nsAtom* aName, nsHtml5HtmlAttributes* aAttributes,
 277             mozilla::dom::HTMLContentCreatorFunction aCreator);
 278
 279   /**
 280    * Pops the current node off the stack.
 281    */
 282   void Pop();
 283
 284   /**
 285    * Appends text content to the current node.
 286    *
 287    * @param aBuffer the buffer to copy from
 288    * @param aStart the index of the first code unit to copy
 289    * @param aLength the number of code units to copy
 290    */
 291   void AppendCharacters(const char16_t* aBuffer, int32_t aStart,
 292                         int32_t aLength);
 293
 294   /**
 295    * Enqueues a tree op for adding an href attribute with the view-source:
 296    * URL scheme to the current node.
 297    *
 298    * @param aValue the (potentially relative) URL to link to
 299    */
 300   void AddViewSourceHref(nsHtml5String aValue);
 301
 302   /**
 303    * The state we are transitioning away from.
 304    */
 305   int32_t mState;
 306
 307   /**
 308    * The index of the first UTF-16 code unit in mBuffer that hasn't been
 309    * flushed yet.
 310    */
 311   int32_t mCStart;
 312
 313   /**
 314    * The position of the code unit in mBuffer that caused the current
 315    * transition.
 316    */
 317   int32_t mPos;
 318
 319   /**
 320    * The current line number.
 321    */
 322   int32_t mLineNumber;
 323
 324   /**
 325    * The number of inline elements open inside the <pre> excluding the
 326    * span potentially wrapping a run of characters.
 327    */
 328   int32_t mInlinesOpen;
 329
 330   /**
 331    * Whether there's a span wrapping a run of characters (excluding CDATA
 332    * section) open.
 333    */
 334   bool mInCharacters;
 335
 336   /**
 337    * The current buffer being tokenized.
 338    */
 339   nsHtml5UTF16Buffer* mBuffer;
 340
 341   /**
 342    * The outgoing tree op queue.
 343    */
 344   nsTArray<nsHtml5TreeOperation> mOpQueue;
 345
 346   /**
 347    * The tree op stage for the tree op executor or a speculation when looking
 348    * for meta charset.
 349    *
 350    * The op sink is owned by the nsHtml5TreeOpExecutor, which outlives this
 351    * object, because this object is owned by the nsHtml5Tokenizer instance that
 352    * is owned by the nsHtml5StreamParser, which keeps the executor alive via
 353    * nsHtml5Streamparser::mExecutorFlusher.
 354    */
 355   nsAHtml5TreeOpSink* mOpSink;
 356
 357   /**
 358    * The most recently opened markup declaration/tag or run of characters.
 359    */
 360   nsIContent** mCurrentRun;
 361
 362   /**
 363    * The most recent ampersand in a place where character references were
 364    * allowed.
 365    */
 366   nsIContent** mAmpersand;
 367
 368   /**
 369    * The most recent slash that might become a self-closing slash.
 370    */
 371   nsIContent** mSlash;
 372
 373   /**
 374    * Memory for element handles.
 375    */
 376   mozilla::UniquePtr<nsIContent*[]> mHandles;
 377
 378   /**
 379    * Number of handles used in mHandles
 380    */
 381   int32_t mHandlesUsed;
 382
 383   /**
 384    * A holder for old contents of mHandles
 385    */
 386   nsTArray<mozilla::UniquePtr<nsIContent*[]>> mOldHandles;
 387
 388   /**
 389    * The element stack.
 390    */
 391   nsTArray<nsIContent**> mStack;
 392
 393   /**
 394    * The string "comment"
 395    */
 396   static char16_t sComment[];
 397
 398   /**
 399    * The string "cdata"
 400    */
 401   static char16_t sCdata[];
 402
 403   /**
 404    * The string "start-tag"
 405    */
 406   static char16_t sStartTag[];
 407
 408   /**
 409    * The string "attribute-name"
 410    */
 411   static char16_t sAttributeName[];
 412
 413   /**
 414    * The string "attribute-value"
 415    */
 416   static char16_t sAttributeValue[];
 417
 418   /**
 419    * The string "end-tag"
 420    */
 421   static char16_t sEndTag[];
 422
 423   /**
 424    * The string "doctype"
 425    */
 426   static char16_t sDoctype[];
 427
 428   /**
 429    * The string "entity"
 430    */
 431   static char16_t sEntity[];
 432
 433   /**
 434    * The string "pi"
 435    */
 436   static char16_t sPi[];
 437
 438   /**
 439    * Whether base is already visited once.
 440    */
 441   bool mSeenBase;
 442 };
 443
 444 #endif  // nsHtml5Highlighter_h