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   /** Starts the body */
 177   void StartBodyContents();
 178
 179  private:
 180   /**
 181    * Starts a wrapper around a run of characters.
 182    */
 183   void StartCharacters();
 184
 185   /**
 186    * Starts a span with no class.
 187    */
 188   void StartSpan();
 189
 190   /**
 191    * Starts a <span> and sets the class attribute on it.
 192    *
 193    * @param aClass the class to set (MUST be a static string that does not
 194    *        need to be released!)
 195    */
 196   void StartSpan(const char16_t* aClass);
 197
 198   /**
 199    * End the current <span> or <a> in the highlighter output.
 200    */
 201   void EndSpanOrA();
 202
 203   /** Ends a wrapper around a run of characters. */
 204   void EndCharactersAndStartMarkupRun();
 205
 206   /**
 207    * Starts an <a>.
 208    */
 209   void StartA();
 210
 211   /**
 212    * Flushes characters up to but not including the current one.
 213    */
 214   void FlushChars();
 215
 216   /**
 217    * Flushes characters up to and including the current one.
 218    */
 219   void FlushCurrent();
 220
 221   /**
 222    * Finishes highlighting a tag in the input data by closing the open
 223    * <span> and <a> elements in the highlighter output and then starts
 224    * another <span> for potentially highlighting characters potentially
 225    * appearing next.
 226    */
 227   void FinishTag();
 228
 229   /**
 230    * Adds a class attribute to the current node.
 231    *
 232    * @param aClass the class to set (MUST be a static string that does not
 233    *        need to be released!)
 234    */
 235   void AddClass(const char16_t* aClass);
 236
 237   /**
 238    * Allocates a handle for an element.
 239    *
 240    * See the documentation for nsHtml5TreeBuilder::AllocateContentHandle()
 241    * in nsHtml5TreeBuilderHSupplement.h.
 242    *
 243    * @return the handle
 244    */
 245   nsIContent** AllocateContentHandle();
 246
 247   /**
 248    * Enqueues an element creation tree operation.
 249    *
 250    * @param aName the name of the element
 251    * @param aAttributes the attribute holder (ownership will be taken) or
 252    *        nullptr for no attributes
 253    * @param aIntendedParent the intended parent node for the created element
 254    * @param aCreator the content creator function
 255    * @return the handle for the element that will be created
 256    */
 257   nsIContent** CreateElement(nsAtom* aName, nsHtml5HtmlAttributes* aAttributes,
 258                              nsIContent** aIntendedParent,
 259                              mozilla::dom::HTMLContentCreatorFunction aCreator);
 260
 261   /**
 262    * Gets the handle for the current node. May be called only after the
 263    * root element has been set.
 264    *
 265    * @return the handle for the current node
 266    */
 267   nsIContent** CurrentNode();
 268
 269   /**
 270    * Create an element and push it (its handle) on the stack.
 271    *
 272    * @param aName the name of the element
 273    * @param aAttributes the attribute holder (ownership will be taken) or
 274    *        nullptr for no attributes
 275    * @param aCreator the content creator function
 276    */
 277   void Push(nsAtom* aName, nsHtml5HtmlAttributes* aAttributes,
 278             mozilla::dom::HTMLContentCreatorFunction aCreator);
 279
 280   /** Pushes a <span id="line<lineno>"> */
 281   void PushCurrentLineContainer();
 282
 283   /**
 284    * Pops all inlines from the stack, pushes a pre, and pushes all inlines back
 285    * with the same attributes.
 286    */
 287   void NewLine();
 288
 289   /**
 290    * Pops the current node off the stack.
 291    */
 292   void Pop();
 293
 294   /**
 295    * Appends text content to the current node.
 296    *
 297    * @param aBuffer the buffer to copy from
 298    * @param aStart the index of the first code unit to copy
 299    * @param aLength the number of code units to copy
 300    */
 301   void AppendCharacters(const char16_t* aBuffer, int32_t aStart,
 302                         int32_t aLength);
 303
 304   /**
 305    * Enqueues a tree op for adding an href attribute with the view-source:
 306    * URL scheme to the current node.
 307    *
 308    * @param aValue the (potentially relative) URL to link to
 309    */
 310   void AddViewSourceHref(nsHtml5String aValue);
 311
 312   /**
 313    * The state we are transitioning away from.
 314    */
 315   int32_t mState;
 316
 317   /**
 318    * The index of the first UTF-16 code unit in mBuffer that hasn't been
 319    * flushed yet.
 320    */
 321   int32_t mCStart;
 322
 323   /**
 324    * The position of the code unit in mBuffer that caused the current
 325    * transition.
 326    */
 327   int32_t mPos;
 328
 329   /**
 330    * The current line number.
 331    */
 332   int32_t mLineNumber;
 333
 334   /**
 335    * The number of inline elements open inside the <pre> excluding the
 336    * span potentially wrapping a run of characters.
 337    */
 338   int32_t mInlinesOpen;
 339
 340   /**
 341    * Whether there's a span wrapping a run of characters (excluding CDATA
 342    * section) open.
 343    */
 344   bool mInCharacters;
 345
 346   /**
 347    * The current buffer being tokenized.
 348    */
 349   nsHtml5UTF16Buffer* mBuffer;
 350
 351   /**
 352    * The outgoing tree op queue.
 353    */
 354   nsTArray<nsHtml5TreeOperation> mOpQueue;
 355
 356   /**
 357    * The tree op stage for the tree op executor or a speculation when looking
 358    * for meta charset.
 359    *
 360    * The op sink is owned by the nsHtml5TreeOpExecutor, which outlives this
 361    * object, because this object is owned by the nsHtml5Tokenizer instance that
 362    * is owned by the nsHtml5StreamParser, which keeps the executor alive via
 363    * nsHtml5Streamparser::mExecutorFlusher.
 364    */
 365   nsAHtml5TreeOpSink* mOpSink;
 366
 367   /**
 368    * The most recently opened markup declaration/tag or run of characters.
 369    */
 370   nsIContent** mCurrentRun;
 371
 372   /**
 373    * The most recent ampersand in a place where character references were
 374    * allowed.
 375    */
 376   nsIContent** mAmpersand;
 377
 378   /**
 379    * The most recent slash that might become a self-closing slash.
 380    */
 381   nsIContent** mSlash;
 382
 383   /**
 384    * Memory for element handles.
 385    */
 386   mozilla::UniquePtr<nsIContent*[]> mHandles;
 387
 388   /**
 389    * Number of handles used in mHandles
 390    */
 391   int32_t mHandlesUsed;
 392
 393   /**
 394    * A holder for old contents of mHandles
 395    */
 396   nsTArray<mozilla::UniquePtr<nsIContent*[]>> mOldHandles;
 397
 398   /**
 399    * The element stack.
 400    */
 401   nsTArray<nsIContent**> mStack;
 402
 403   /**
 404    * Whether base is already visited once.
 405    */
 406   bool mSeenBase;
 407 };
 408
 409 #endif  // nsHtml5Highlighter_h