Support quoting scriptlet parameters with backticks

(In addition to in already supported single- and double-quote).

The parsing of (optionally) quoted arguments from an argument
list has been spinned off into a standalone helper in order to
be reused in other parts of the parser eventually.

src/js/static-filtering-parser.js

@@ -597,6 +597,106 @@ const exCharCodeAt = (s, i) => {
 
 /******************************************************************************/
 
+class argListParser {
+    constructor(separator = 0x2C /* , */, mustQuote = false) {
+        this.separatorCode = separator.charCodeAt(0);
+        this.mustQuote = mustQuote;
+        this.quoteBeg = 0;
+        this.argBeg = 0;
+        this.argEnd = 0;
+        this.quoteEnd = 0;
+        this.actualSeparatorCode = 0;
+        this.separatorBeg = 0;
+        this.separatorEnd = 0;
+        this.transform = false;
+        this.failed = false;
+        this.reWhitespaceStart = /^\s+/;
+        this.reWhitespaceEnd = /\s+$/;
+        this.reOddTrailingEscape = /(?:^|[^\\])(?:\\\\)*\\$/;
+        this.reUnescapeDoubleQuotes = /((?:^|[^\\])(?:\\\\)*)\\"/g;
+        this.reUnescapeSingleQuotes = /((?:^|[^\\])(?:\\\\)*)\\'/g;
+        this.reUnescapeBackticks = /((?:^|[^\\])(?:\\\\)*)\\`/g;
+        this.reUnescapeCommas = /((?:^|[^\\])(?:\\\\)*)\\,/g;
+    }
+    nextArg(pattern, beg = 0) {
+        const len = pattern.length;
+        this.quoteBeg = beg + this.leftWhitespaceCount(pattern.slice(beg));
+        this.failed = false;
+        const qc = pattern.charCodeAt(this.quoteBeg);
+        if ( qc === 0x22 /* " */ || qc === 0x27 /* ' */ || qc === 0x60 /* ` */ ) {
+            this.actualSeparatorCode = qc;
+            this.argBeg = this.argEnd = this.quoteBeg + 1;
+            this.transform = false;
+            this.indexOfNextScriptletArgSeparator(pattern);
+            if ( this.argEnd !== len ) {
+                this.quoteEnd = this.argEnd + 1;
+                this.separatorBeg = this.separatorEnd = this.quoteEnd;
+                this.separatorEnd += this.leftWhitespaceCount(pattern.slice(this.quoteEnd));
+                if ( this.separatorEnd === len ) { return this; }
+                if ( pattern.charCodeAt(this.separatorEnd) === this.separatorCode ) {
+                    this.separatorEnd += 1;
+                    return this;
+                }
+            }
+        }
+        this.actualSeparatorCode = this.separatorCode;
+        this.argBeg = this.argEnd = this.quoteBeg;
+        this.transform = false;
+        this.indexOfNextScriptletArgSeparator(pattern);
+        this.separatorBeg = this.separatorEnd = this.argEnd;
+        if ( this.separatorBeg < len ) {
+            this.separatorEnd += 1;
+        }
+        this.argEnd -= this.rightWhitespaceCount(pattern.slice(0, this.separatorBeg));
+        this.quoteEnd = this.argEnd;
+        if ( this.mustQuote ) {
+            this.failed = true;
+        }
+        return this;
+    }
+    normalizeArg(s) {
+        switch ( this.actualSeparatorCode ) {
+        case 0x22 /* " */:
+            if ( s.includes('"') === false ) { return; }
+            return s.replace(this.reUnescapeDoubleQuotes, '$1"');
+        case 0x27 /* ' */:
+            if ( s.includes("'") === false ) { return; }
+            return s.replace(this.reUnescapeSingleQuotes, "$1'");
+        case 0x60 /* ` */:
+            if ( s.includes('`') === false ) { return; }
+            return s.replace(this.reUnescapeBackticks, "$1`");
+        default:
+            break;
+        }
+        if ( s.includes(',') === false ) { return; }
+        return s.replace(this.reUnescapeCommas, '$1,');
+    }
+    leftWhitespaceCount(s) {
+        const match = this.reWhitespaceStart.exec(s);
+        return match === null ? 0 : match[0].length;
+    }
+    rightWhitespaceCount(s) {
+        const match = this.reWhitespaceEnd.exec(s);
+        return match === null ? 0 : match[0].length;
+    }
+    indexOfNextScriptletArgSeparator(pattern) {
+        const separatorChar = String.fromCharCode(this.actualSeparatorCode);
+        while ( this.argEnd < pattern.length ) {
+            const pos = pattern.indexOf(separatorChar, this.argEnd);
+            if ( pos === -1 ) {
+                return (this.argEnd = pattern.length);
+            }
+            if ( this.reOddTrailingEscape.test(pattern.slice(0, pos)) === false ) {
+                return (this.argEnd = pos);
+            }
+            this.transform = true;
+            this.argEnd = pos + 1;
+        }
+    }
+}
+
+/******************************************************************************/
+
 class AstWalker {
     constructor(parser, from = 0) {
         this.parser = parser;
@@ -797,11 +897,8 @@ export class AstFilterParser {
         this.rePatternScriptletJsonArgs = /^\{.*\}$/;
         this.reGoodRegexToken = /[^\x01%0-9A-Za-z][%0-9A-Za-z]{7,}|[^\x01%0-9A-Za-z][%0-9A-Za-z]{1,6}[^\x01%0-9A-Za-z]/;
         this.reBadCSP = /(?:=|;)\s*report-(?:to|uri)\b/;
-        this.reOddTrailingEscape = /(?:^|[^\\])(?:\\\\)*\\$/;
-        this.reUnescapeCommas = /((?:^|[^\\])(?:\\\\)*)\\,/g;
-        this.reUnescapeSingleQuotes = /((?:^|[^\\])(?:\\\\)*)\\'/g;
-        this.reUnescapeDoubleQuotes = /((?:^|[^\\])(?:\\\\)*)\\"/g;
         this.reNoopOption = /^_+$/;
+        this.scriptletArgListParser = new argListParser(',');
     }
 
     parse(raw) {
@@ -2224,7 +2321,9 @@ export class AstFilterParser {
         const s = this.getNodeString(parent);
         const argsEnd = s.length;
         // token
-        const details = this.parseExtPatternScriptletArg(s, 0);
+        this.scriptletArgListParser.mustQuote = 
+            this.getFlags(AST_FLAG_EXT_SCRIPTLET_ADG) !== 0;
+        const details = this.scriptletArgListParser.nextArg(s, 0);
         if ( details.argBeg > 0 ) {
             next = this.allocTypedNode(
                 NODE_TYPE_EXT_DECORATION,
@@ -2283,7 +2382,7 @@ export class AstFilterParser {
         let decorationBeg = 0;
         let i = 0;
         for (;;) {
-            const details = this.parseExtPatternScriptletArg(s, i);
+            const details = this.scriptletArgListParser.nextArg(s, i);
             if ( decorationBeg < details.argBeg ) {
                 next = this.allocTypedNode(
                     NODE_TYPE_EXT_DECORATION,
@@ -2299,10 +2398,10 @@ export class AstFilterParser {
                 parentBeg + details.argEnd
             );
             if ( details.transform ) {
-                this.setNodeTransform(next, this.normalizeScriptletArg(
+                const arg = s.slice(details.argBeg, details.argEnd);
-                    s.slice(details.argBeg, details.argEnd),
+                this.setNodeTransform(next,
-                    details.separatorCode
+                    this.scriptletArgListParser.normalizeArg(arg)
-                ));
+                );
             }
             prev = this.linkRight(prev, next);
             if ( details.failed ) {
@@ -2315,79 +2414,6 @@ export class AstFilterParser {
         return this.throwHeadNode(head);
     }
 
-    parseExtPatternScriptletArg(pattern, beg = 0) {
-        if ( this.parseExtPatternScriptletArg.details === undefined ) {
-            this.parseExtPatternScriptletArg.details = {
-                quoteBeg: 0, argBeg: 0, argEnd: 0, quoteEnd: 0,
-                separatorCode: 0, separatorBeg: 0, separatorEnd: 0,
-                transform: false, failed: false,
-            };
-        }
-        const details = this.parseExtPatternScriptletArg.details;
-        const len = pattern.length;
-        details.quoteBeg = beg + this.leftWhitespaceCount(pattern.slice(beg));
-        details.failed = false;
-        const qc = pattern.charCodeAt(details.quoteBeg);
-        if ( qc === 0x22 /* " */ || qc === 0x27 /* ' */ ) {
-            details.separatorCode = qc;
-            details.argBeg = details.argEnd = details.quoteBeg + 1;
-            details.transform = false;
-            this.indexOfNextScriptletArgSeparator(pattern, details);
-            if ( details.argEnd !== len ) {
-                details.quoteEnd = details.argEnd + 1;
-                details.separatorBeg = details.separatorEnd = details.quoteEnd;
-                details.separatorEnd += this.leftWhitespaceCount(pattern.slice(details.quoteEnd));
-                if ( details.separatorEnd === len ) { return details; }
-                if ( pattern.charCodeAt(details.separatorEnd) === 0x2C ) {
-                    details.separatorEnd += 1;
-                    return details;
-                }
-            }
-        }
-        details.separatorCode = 0x2C /* , */;
-        details.argBeg = details.argEnd = details.quoteBeg;
-        details.transform = false;
-        this.indexOfNextScriptletArgSeparator(pattern, details);
-        details.separatorBeg = details.separatorEnd = details.argEnd;
-        if ( details.separatorBeg < len ) {
-            details.separatorEnd += 1;
-        }
-        details.argEnd -= this.rightWhitespaceCount(pattern.slice(0, details.separatorBeg));
-        details.quoteEnd = details.argEnd;
-        if ( this.getFlags(AST_FLAG_EXT_SCRIPTLET_ADG) ) {
-            details.failed = true;
-        }
-        return details;
-    }
-
-    indexOfNextScriptletArgSeparator(pattern, details) {
-        const separatorChar = String.fromCharCode(details.separatorCode);
-        while ( details.argEnd < pattern.length ) {
-            const pos = pattern.indexOf(separatorChar, details.argEnd);
-            if ( pos === -1 ) {
-                return (details.argEnd = pattern.length);
-            }
-            if ( this.reOddTrailingEscape.test(pattern.slice(0, pos)) === false ) {
-                return (details.argEnd = pos);
-            }
-            details.transform = true;
-            details.argEnd = pos + 1;
-        }
-    }
-
-    normalizeScriptletArg(arg, separatorCode) {
-        if ( separatorCode === 0x22 /* " */ ) {
-            if ( arg.includes('"') === false ) { return; }
-            return arg.replace(this.reUnescapeDoubleQuotes, '$1"');
-        }
-        if ( separatorCode === 0x27 /* ' */ ) {
-            if ( arg.includes("'") === false ) { return; }
-            return arg.replace(this.reUnescapeSingleQuotes, "$1'");
-        }
-        if ( arg.includes(',') === false ) { return; }
-        return arg.replace(this.reUnescapeCommas, '$1,');
-    }
-
     getScriptletArgs() {
         const args = [];
         if ( this.isScriptletFilter() === false ) { return args; }