/[suikacvs]/markup/html/scripting-parser/parser.html

Diff of /markup/html/scripting-parser/parser.html

Parent Directory | Revision Log | View Patch Patch

-revision 1.4 by wakaba,
Sun Apr 20 12:19:13 2008 UTC
+revision 1.12 by wakaba,
Sun Apr 27 11:21:09 2008 UTC
 Line 1
  <!DOCTYPE HTML>
  <html lang=en>
  <head>
- <title>Demo of HTML5 Parsing Algorithm with Scripting Enabled</title>
+ <title>Live Scripting HTML Parser</title>
  <style>
+   h1, h2 {
+     margin: 0;
+     font-size: 100%;
+   }
+   p, pre {
+     margin: 0;
+   }
    textarea {
-      display: block;
+     width: 100%;
-      width: 80%;
+     -width: 99%;
-      margin-left: auto;
+     height: 10em;
-      margin-right: auto;
-      min-height: 20em;
    }
    output {
      display: block;
-Line 18
+Line 23
    }
  </style>
  <script>
+   var delayedUpdater = 0;
    function update () {
-     document.logElement.textContent = '';
+     if (delayedUpdater) {
-     var p = new Parser (new InputStream (document.sourceElement.value));
+       clearTimeout (delayedUpdater);
-     var doc = p.doc;
+       delayedUpdater = 0;
-     p.parse ();
+     }
-     log (dumpTree (doc, ''));
+     delayedUpdater = setTimeout (update2, 100);
    } // update
+   function update2 () {
+     var v = document.sourceElement.value;
+     if (v != document.previousSourceText) {
+       document.previousSourceText = v;
+       document.links['permalink'].href
+           = location.pathname + '?s=' + encodeURIComponent (v);
+       document.links['ldvlink'].href
+           = 'http://software.hixie.ch/utilities/js/live-dom-viewer/?'
+           + encodeURIComponent (v);
+       document.logElement.textContent = '';
+       var p = new Parser (new InputStream (v));
+       var doc = p.doc;
+       p.parse ();
+       log (dumpTree (doc, ''));
+       if (p.hasAsyncScript) {
+         log ('Some script codes are executed asynchronously; it means that the document might be rendered in different ways depending on the network condition and other factors');
+       }
+     }
+   } // update2
+   var logIndentLevel = 0;
    function log (s) {
+     for (var i = 0; i < logIndentLevel; i++) {
+       s = '  ' + s;
+     }
      document.logElement.appendChild (document.createTextNode (s + "\n"));
    } // log
-Line 42
+Line 76
      }
      this.doc = doc;
      this.openElements = [doc];
-     this.in = i;
+     this.input = i;
      this.scriptsExecutedAfterParsing = [];
+     this.scriptsExecutedSoon = [];
+     this.scriptsExecutedAsynchronously = [];
    } // Parser
    Parser.prototype.getNextToken = function () {
      var p = this;
-     var i = this.in;
+     var i = this.input;
      if (this.parseMode == 'script') {
        var token;
        if (p.insertionPoint <= 0) {
-Line 77
+Line 113
          return '';
        });
        if (token) return token;
+       var m;
+       if ((p.insertionPoint < '</script'.length) &&
+           (m = i.s.match (/^<\/([SCRIPTscript]+)/))) {
+         var v = m[1].substring (0, p.insertionPoint).toLowerCase ();
+         if (v == 'script'.substring (0, p.insertionPoint - '</'.length)) {
+           return {type: 'abort'};
+         }
+       }
        i.s = i.s.replace (/^</,
        function (s) {
          token = {type: 'char', value: s};
-Line 88
+Line 132
      }
      var token;
-     i.s = i.s.replace (/^<\/([^>]+)>/, function (s, e) {
+     i.s = i.s.replace (/^<\/([^>]+)(?:>|$)/, function (s, e) {
-       if (p.insertionPoint < s.length) {
+       if (p.insertionPoint < s.length ||
+           (p.insertionPoint <= s.length &&
+            s.substring (s.length - 1, 1) != '>')) {
          token = {type: 'abort'};
          return s;
        }
-Line 98
+Line 144
        return '';
      });
      if (token) return token;
-     i.s = i.s.replace (/^<([^>]+)>/, function (s, e) {
+     i.s = i.s.replace (/^<([^>]+)(?:>|$)/, function (s, e) {
-       if (p.insertionPoint < s.length) {
+       if (p.insertionPoint < s.length ||
+           (p.insertionPoint <= s.length &&
+            s.substring (s.length - 1, 1) != '>')) {
          token = {type: 'abort'};
          return s;
        }
-Line 109
+Line 157
          tagName = v.toLowerCase ();
          return '';
        });
-       e = e.replace (/^\s*(\S+)\s*(?:=\s*"([^"]*)"|'([^']*)'|([^"']+))?/,
+       while (true) {
-       function (x, attrName, attrValue1, attrValue2, attrValue3) {
+         var m = false;
-         attrs[attrName] = attrValue1 || attrValue2 || attrValue3;
+         e = e.replace (/^\s*([^\s=]+)\s*(?:=\s*(?:"([^"]*)"|'([^']*)'|([^"'\s]*)))?/,
-         return '';
+         function (x, attrName, attrValue1, attrValue2, attrValue3) {
-       });
+           v = attrValue1 || attrValue2 || attrValue3;
+           v = v.replace (/&quot;/g, '"').replace (/&apos;/g, "'")
+               .replace (/&amp;/g, '&');
+           attrs[attrName.toLowerCase ()] = v;
+           m = true;
+           return '';
+         });
+         if (!m) break;
+       }
+       if (e.length) {
+         log ('Broken start tag: "' + e + '"');
+       }
        token = {type: 'start-tag', value: tagName, attrs: attrs};
        p.insertionPoint -= s.length;
        return '';
-Line 144
+Line 203
    } // getNextToken
    Parser.prototype.parse = function () {
-     log ('start parsing');
+     logIndentLevel++;
+     log ('parse: start');
      while (true) {
        var token = this.getNextToken ();
-Line 212
+Line 272
            this.openElements[this.openElements.length - 1].appendChild (el);
            // 11. Let the insertion point have the value of the old ...
+           oldInsertionPoint += this.insertionPoint;
            this.setInsertionPoint (oldInsertionPoint);
            // 12. If there is a script that will execute as soon as ...
+           while (this.scriptExecutedWhenParserResumes) {
+             // 12.1. If the tree construction stage is being called reentrantly
+             if (this.reentrant) {
+               log ('parse: abort (reentrance)');
+               logIndentLevel--;
+               return;
+             // 12.2. Otherwise
+             } else {
+               // 1.
+               var script = this.scriptExecutedWhenParserResumes;
+               this.scriptExecutedWhenParserResumes = null;
+               // 2. Pause until the script has completed loading.
+               //
+               // 3. Let the insertion point to just before the next input char.
+               this.setInsertionPoint (0);
+               // 4. Execute the script.
+               executeScript (this.doc, script);
+               // 5. Let the insertion point be undefined again.
+               this.setInsertionPoint (undefined);
+               // 6. If there is once again a script that will execute ...
+               //
+             }
+           }
          } else {
            var el = new JSElement (this.doc, token.value);
            this.openElements[this.openElements.length - 1].appendChild (el);
-Line 236
+Line 325
          break;
        } else if (token.type == 'abort') {
          log ('parse: abort');
+         logIndentLevel--;
          return;
        }
      }
-Line 246
+Line 336
      // "When a script completes loading" rules start applying.
-     // TODO: Handles "list of scripts that will execute as soon as possible"
+     while (this.scriptsExecutedSoon.length > 0 ||
-     // and "list of scripts that will execute asynchronously"
+            this.scriptsExecutedAsynchronously.length > 0) {
+       // Handle "list of scripts that will execute as soon as possible".
+       while (this.scriptsExecutedSoon.length > 0) {
+         var e = this.scriptsExecutedSoon.shift ();
+         // If it has completed loading
+         log ('Execute an external script not inserted by parser...');
+         executeScript (this.doc, e);
+         // NOTE: It MAY be executed before the end of the parsing, according
+         // to the spec.
+         this.hasAsyncScript = true;
+       }
+       // Handle "list of scripts that will execute asynchronously".
+       while (this.scriptsExecutedAsynchronously.length > 0) {
+         var e = this.scriptsExecutedAsynchronously.shift ();
+         // Step 1.
+         // We assume that all scripts have been loaded at this time.
+         // Step 2.
+         log ('Execute an asynchronous script...');
+         executeScript (this.doc, e);
+         // Step 3.
+         //
+         // Step 4.
+         //
+         this.hasAsyncScript = true;
+       }
+     }
      // Handle "list of scripts that will execute when the document has finished
      // parsing".
-Line 270
+Line 393
      // "delays tha load event" things has completed:
      // readyState = 'complete'
      log ('load event fired');
+     logIndentLevel--;
    } // parse
    Parser.prototype.setInsertionPoint = function (ip) {
      if (ip == undefined || ip == null || isNaN (ip)) {
        log ('insertion point: set to undefined');
        this.insertionPoint = undefined;
-     } else if (ip == this.in.s.length) {
+     } else if (ip == this.input.s.length) {
        log ('insertion point: end of file');
        this.insertionPoint = ip;
      } else {
        log ('insertion point: set to ' + ip +
-            ' (before "' + this.in.s.substring (0, 10) + '")');
+            ' (before "' + this.input.s.substring (0, 10) + '")');
        this.insertionPoint = ip;
      }
    }; // setInsertionPoint
-Line 303
+Line 428
      e.parentNode = this;
      if (e.localName == 'script') {
+       logIndentLevel++;
        log ('Running a script: start');
        var doc = this.ownerDocument || this;
-Line 321
+Line 447
        if (e.manakaiAlreadyExecuted) {
          // 2.5. Abort these steps at this point.
          log ('Running a script: aborted');
+         logIndentLevel--;
          return e;
        }
-Line 338
+Line 465
          p.scriptsExecutedAfterParsing.push (e);
          log ('Running a script: aborted (defer)');
        } else if (e.async && e.src != null) {
-         // TODO
+         p.scriptsExecutedAsynchronously.push (e);
-       } else if (e.async && e.src == null
+         log ('Running a script: aborted (async src)');
-                  /* && list of scripts that will execute asynchronously is not empty */) {
+       } else if (e.async && e.src == null &&
-         // TODO
+                  p.scriptsExecutedAsynchronously.length > 0) {
+         p.scriptsExecutedAsynchronously.push (e);
+         log ('Running a script: aborted (async)');
+         // ISSUE: What is the difference with the case above?
        } else if (e.src != null && e.manakaiParserInserted) {
-         // TODO
+         if (p.scriptExecutedWhenParserResumes) {
+           log ('Error: There is a script that will execute as soon as the parser resumes.');
+         }
+         p.scriptExecutedWhenParserResumes = e;
+         log ('Running a script: aborted (src parser-inserted)');
        } else if (e.src != null) {
-         // TODO
+         p.scriptsExecutedSoon.push (e);
+         log ('Running a script: aborted (src)');
        } else {
          executeScript (doc, e); // even if other scripts are already executing.
        }
        log ('Running a script: end');
+       logIndentLevel--;
      }
      return e;
-Line 359
+Line 495
    function executeScript (doc, e) {
      log ('executing a script block: start');
-     // If the load resulted in an error, then ... firing an error event ...
+     var s;
+     if (e.src != null) {
+       s = getExternalScript (e.src);
+       // If the load resulted in an error, then ... firing an error event ...
+       if (s == null) {
+         log ('error event fired at the script element');
+         return;
+       }
+       log ('External script loaded: "' + s + '"');
+     } else {
+       s = e.text;
+     }
      // If the load was successful
      log ('load event fired at the script element');
-Line 368
+Line 517
      // Scripting is enabled, Document.designMode is disabled,
      // Document is the active document in its browsing context
-       var s;
-       if (e.src != null) {
-         // TODO: from external file
-       } else {
-         s = e.text;
-       }
        parseAndRunScript (doc, s);
      }
      log ('executing a script block: end');
    } // executeScript
+   function getExternalScript (uri) {
+     if (uri.match (/^javascript:/i)) {
+       var m;
+       if (m = uri.match (/^javascript:\s*(?:'([^']*)'|"([^"]+)")\s*$/i)) {
+         if (m[1]) {
+           return unescapeJSLiteral (m[1]);
+         } else if (m[2]) {
+           return unescapeJSLiteral (m[2]);
+         } else {
+           return null;
+         }
+       } else {
+         log ('Complex javascript: URI is not supported: <' + uri + '>');
+         return null;
+       }
+     } else {
+       log ('URI scheme not supported: <' + uri + '>');
+       return null;
+     }
+   } // getExternalScript
    function parseAndRunScript (doc, s) {
      while (true) {
        var matched = false;
-Line 388
+Line 551
          matched = true;
          var args = [];
          t.replace (/('[^']*'|"[^"]*")/g, function (s, v) {
-           args.push (v.substring (1, v.length - 1));
+           args.push (unescapeJSLiteral (v.substring (1, v.length - 1)));
            return '';
          });
          doc.write.apply (doc, args);
          return '';
        });
+       s = s.replace (/^\s*var\s+s\s*=\s*document\.createElement\s*\(\s*['"]script['"]\s*\)\s*;\s*s\.src\s*=\s*(?:'(javascript:[^']*)'|"(javascript:[^"]*)")\s*;\s*document\.documentElement\.appendChild\s*\(\s*s\s*\)\s*;\s*/,
+       function (s, t, u) {
+         matched = true;
+         var args = [unescapeJSLiteral (t ? t : u)];
+         doc._insertExternalScript.apply (doc, args);
+         return '';
+       });
        if (s == '') break;
        if (!matched) {
          log ('Script parse error: "' + s + '"');
-Line 402
+Line 572
      }
    } // parseAndRunScript
+   function unescapeJSLiteral (s) {
+     return s.replace (/\\u([0-9A-Fa-f]{4})/g, function (t, v) {
+       return String.fromCharCode (parseInt ('0x' + v));
+     });
+   } // unescapeJSLiteral
    function JSText (data) {
      this.data = data;
    } // JSText
-Line 429
+Line 605
      // Step 3.
      if (this._parser &&
          !this._parser.scriptCreated &&
-         this._parser.in.insertionPoint != undefined) {
+         this._parser.input.insertionPoint != undefined) {
        log ('document.open () in parsing mode is ignored');
        return this;
      }
-Line 463
+Line 639
      }
      // Step 11.
-     this._parser.setInsertionPoint (this._parser.in.s.length);
+     this._parser.setInsertionPoint (this._parser.input.s.length);
      // Step 12.
      return this;
    }; // document.open
    JSDocument.prototype.write = function () {
+     logIndentLevel++;
      var p = this._parser;
      // 1. If the insertion point is undefined, the open() method must be ...
-Line 481
+Line 659
      // 2. ... inserted into the input stream just before the insertion point.
      var s = Array.join (arguments, '');
      log ('document.write: insert "' + s + '"' +
-          ' before "' + p.in.s.substring (p.insertionPoint, p.insertionPoint + 10) + '"');
+          ' before "' +
-     p.in.s = p.in.s.substring (0, p.insertionPoint) + s
+          p.input.s.substring (p.insertionPoint, p.insertionPoint + 10) + '"');
-         + p.in.s.substring (p.insertionPoint, p.in.s.length);
+     p.input.s = p.input.s.substring (0, p.insertionPoint) + s
+         + p.input.s.substring (p.insertionPoint, p.input.s.length);
      p.insertionPoint += s.length;
      // 3. If there is a script that will execute as soon as the parser resumes
-     // TODO
+     if (p.scriptExecutedAfterParserResumes) {
+       log ('document.write: processed later (there is an unprocessed <script src>)');
+       logIndentLevel--;
+       return;
+     }
      // 4. Process the characters that were inserted, ...
+     var originalReentrant = p.reentrant;
+     p.reentrant = true;
      p.parse ();
+     p.reentrant = originalReentrant;
+     // TODO: "Abort the processing of any nested invokations of the tokeniser,
+     // yielding control back to the caller." (<script> parsing).  Do we need
+     // to do something here?
      // 5. Return
      log ('document.write: return');
+     logIndentLevel--;
      return;
    }; // document.write
+   JSDocument.prototype._insertExternalScript = function (uri) {
+     var s = new JSElement (this, 'script');
+     s.src = uri;
+     this.documentElement.appendChild (s);
+   }; // _insertExternalScript
+   JSDocument.prototype.__defineGetter__ ('documentElement', function () {
+     var cn = this.childNodes;
+     for (var i = 0; i < cn.length; i++) {
+       if (cn[i] instanceof JSElement) {
+         return cn[i]
+       }
+     }
+     return null;
+   });
    JSElement.prototype.__defineGetter__ ('text', function () {
      var r = '';
      for (var i = 0; i < this.childNodes.length; i++) {
-Line 515
+Line 722
          r += '| ' + indent + node.localName + '\n';
          if (node.async) r += '| ' + indent + '  async=""\n';
          if (node.defer) r += '| ' + indent + '  defer=""\n';
-         if (node.src) r += '| ' + indent + '  src="' + node.src + '"\n';
+         if (node.src != null) {
+           r += '| ' + indent + '  src="' + node.src + '"\n';
+         }
          r += dumpTree (node, indent + '  ');
        } else if (node instanceof JSText) {
          r += '| ' + indent + '"' + node.data + '"\n';
-Line 529
+Line 738
  </head>
  <body onload="
    document.sourceElement = document.getElementsByTagName ('textarea')[0];
+   var q = location.search;
+   if (q != null) {
+     q = q.substring (1).split (/;/);
+     for (var i = 0; i < q.length; i++) {
+       var v = q[i].split (/=/, 2);
+       v[0] = decodeURIComponent (v[0]);
+       v[1] = decodeURIComponent (v[1] || '');
+       if (v[0] == 's') {
+         document.sourceElement.value = v[1];
+       }
+     }
+   }
    document.logElement = document.getElementsByTagName ('output')[0];
    update ();
  ">
+ <h1>Live Scripting <abbr title="Hypertext Markup Language">HTML</abbr>
+ Parser</h1>
- <textarea onchange=" update () ">&lt;html>
+ <h2>Markup to test
+ (<a href=data:, id=permalink rel=bookmark>permalink</a>,
+ <a href="http://software.hixie.ch/utilities/js/live-dom-viewer/"
+     id=ldvlink>Live <abbr title="Document Object Model">DOM</abbr>
+     Viewer</a>)</h2>
+ <p>
+ <textarea onkeydown=" update () " onchange=" update () " oninput=" update () ">&lt;html>
  &lt;head>&lt;/head>&lt;body>
  &lt;p>
  &lt;script>
-Line 542 
 document.write ('aaaaaaa&lt;/p>&lt;scrip
+Line 773 
 document.write ('aaaaaaa&lt;/p>&lt;scrip
  &lt;p>
  </textarea>
- <output></output>
+ <h2 id=log>Log</h2>
+ <p><output></output>
+ <h2 id=notes>Notes</h2>
+ <p>This is a <em>simplified</em> implementation of
+ <a href="http://www.whatwg.org/specs/web-apps/current-work/#parsing">HTML5
+ Parsing Algorithm</a>.  It only implements script-related part of the
+ algorithm.  Especially, this parser:
+ <ul>
+ <li>Does not support <code>DOCTYPE</code> and comment tokens.
+ <li>Does not support entities except for <code>&amp;quot;</code>,
+ <code>&amp;apos;</code>, and <code>&amp;amp;</code> in <code>script</code>
+ <code>src</code> attribute value.
+ <li>Does not support omissions of start or end tags, the <abbr>AAA</abbr>
+ algorithm, and so on.
+ <li>Does not raise parse errors for invalid attribute specifications in start
+ or end tags.
+ <li>Does not support CDATA/PCDATA element other than <code>script</code>.
+ <li>Does not support <code>&lt;!--</code>..<code>--></code> parsing rule
+ in <code>script</code> element.
+ <li>Does not support foreign (SVG or MathML) elements.
+ <li>Only supports <code>script</code> <code>type</code>
+ <code>text/javascript</code>.  <code>type</code> and <code>language</code>
+ attributes are ignored.
+ <li>Only supports limited statements.  It must consist of zero or more
+ of statements looking similar to the following statements, possibly
+ introduced, followed, or separated by white space characters:
+   <ul>
+   <li><code>document.write ("<var>string</var>", ["<var>string</var>", ...]);</code>.
+   <li><code>var s = document.createElement ("script");
+             s.src = "<var>string</var>";
+             document.documentElement.appendChild (s);</code>
+   </ul>
+ Note that strings may be delimited by <code>'</code>s instead of
+ <code>"</code>s.
+ <li>Only supports <code>javascript:</code>
+ <abbr title="Uniform Resourace Identifiers">URI</abbr> scheme in the
+ <code>src</code> attribute of the <code>script</code> element.  In addition,
+ the <abbr title="Uniform Resource Identifiers">URI</abbr> must be conform to
+ the regular expression <code>^javascript:\s*(?:"[^"]*"|'[^']*')\s*$</code>.
+ <li>Only supports <code>\u<var>HHHH</var></code> escapes in JavaScript
+ string literals.
+ <li>Does not handle <i>stop parsing</i> phase correctly if the document is
+ replaced by <code>document.open ()</code> call.  In other word, delayed
+ (deferred or asynchronous) script executions and event firings might be
+ treated in a wrong way if a <code>document.open ()</code> invocation
+ is implicitly done by <code>document.write ()</code> in a delayed script.
+ </ul>
+ <p>For some reason, this parser does not work in browsers that do
+ not support JavaScript 1.5.
+ <!-- TODO: |src| attribute value should refer the value at the time
+ when it is inserted into the document, not the value when the script is
+ executed.  Currently it does not matter, since we don't allow dynamic
+ modification to the |src| content/DOM attribute value yet. -->
+ <!-- TODO: license -->
  </body>
  </html>

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+Added in v.1.12

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