Add support for special exception filter `#@#+js()`

The purpose is to wholly disable scriptlet injection
for a given site without having to create exceptions
for all matching scriptlet injection filters.

The following exception filter will cause scriptlet
injection to be wholly disable for `example.com`:

    `example.com#@#+js()`

Or to disable scriptlet injection everywhere:

    `#@#+js()`

The following form is meaningless and will be
ignored:

    `example.com##+js()`

src/js/cosmetic-filtering.js

@@ -1127,41 +1127,39 @@ FilterContainer.prototype.getFilterCount = function() {
 
 /******************************************************************************/
 
-FilterContainer.prototype.benchmark = function() {
+FilterContainer.prototype.benchmark = async function() {
-    µb.loadBenchmarkDataset().then(requests => {
+    const requests = await µb.loadBenchmarkDataset();
-        if ( Array.isArray(requests) === false || requests.length === 0 ) {
+    if ( Array.isArray(requests) === false || requests.length === 0 ) {
-            console.info('No requests found to benchmark');
+        console.info('No requests found to benchmark');
-            return;
+        return;
-        }
+    }
-        console.info(`Benchmarking cosmeticFilteringEngine.matchString()...`);
+    console.info('Benchmarking cosmeticFilteringEngine.retrieveSpecificSelectors()...');
-        const details = {
+    const details = {
-            tabId: undefined,
+        tabId: undefined,
-            frameId: undefined,
+        frameId: undefined,
-            hostname: '',
+        hostname: '',
-            domain: '',
+        domain: '',
-            entity: '',
+        entity: '',
-        };
+    };
-        const options = {
+    const options = {
-            noCosmeticFiltering: false,
+        noCosmeticFiltering: false,
-            noGenericCosmeticFiltering: false,
+        noGenericCosmeticFiltering: false,
-        };
+    };
-        let count = 0;
+    let count = 0;
-        const t0 = self.performance.now();
+    const t0 = self.performance.now();
-        for ( let i = 0; i < requests.length; i++ ) {
+    for ( let i = 0; i < requests.length; i++ ) {
-            const request = requests[i];
+        const request = requests[i];
-            if ( request.cpt !== 'document' ) { continue; }
+        if ( request.cpt !== 'document' ) { continue; }
-            count += 1;
+        count += 1;
-            details.hostname = µb.URI.hostnameFromURI(request.url);
+        details.hostname = µb.URI.hostnameFromURI(request.url);
-            details.domain = µb.URI.domainFromHostname(details.hostname);
+        details.domain = µb.URI.domainFromHostname(details.hostname);
-            details.entity = µb.URI.entityFromDomain(details.domain);
+        details.entity = µb.URI.entityFromDomain(details.domain);
-            void this.retrieveSpecificSelectors(details, options);
+        void this.retrieveSpecificSelectors(details, options);
-        }
+    }
-        const t1 = self.performance.now();
+    const t1 = self.performance.now();
-        const dur = t1 - t0;
+    const dur = t1 - t0;
-        console.info(`Evaluated ${count} requests in ${dur.toFixed(0)} ms`);
+    console.info(`Evaluated ${count} requests in ${dur.toFixed(0)} ms`);
-        console.info(`\tAverage: ${(dur / count).toFixed(3)} ms per request`);
+    console.info(`\tAverage: ${(dur / count).toFixed(3)} ms per request`);
-    });
-    return 'ok';
 };
 
 /******************************************************************************/

src/js/scriptlet-filtering.js

@@ -27,8 +27,6 @@
     const µb = µBlock,
         duplicates = new Set(),
         scriptletCache = new µb.MRUCache(32),
-        scriptletsRegister = new Map(),
-        exceptionsRegister = new Set(),
         reEscapeScriptArg = /[\\'"]/g;
 
     let acceptedCount = 0,
@@ -289,6 +287,11 @@
         // Only exception filters are allowed to be global.
         const normalized = normalizeRawFilter(parsed.suffix);
 
+        // Tokenless is meaningful only for exception filters.
+        if ( normalized === '+js()' && parsed.exception === false ) {
+            return;
+        }
+
         if ( parsed.hostnames.length === 0 ) {
             if ( parsed.exception ) {
                 writer.push([ 32, '', 1, normalized ]);
@@ -358,7 +361,7 @@
         }
 
         const scriptlets = new Set();
-        const exceptions = exceptionsRegister;
+        const exceptions = new Set();
 
         scriptletDB.retrieve(
             hostname,
@@ -370,17 +373,27 @@
                 [ scriptlets, exceptions ]
             );
         }
+        if ( scriptlets.size === 0 ) { return; }
 
-        for ( const rawToken of scriptlets ) {
+        const loggerEnabled = µb.logger.enabled;
-            lookupScriptlet(rawToken, reng, scriptletsRegister);
+
+        // Wholly disable scriptlet injection?
+        if ( exceptions.has('') ) {
+            if ( loggerEnabled ) {
+                logOne(true, '', request);
+            }
+            return;
         }
 
-        if ( scriptletsRegister.size === 0 ) { return; }
+        const scriptletToCodeMap = new Map();
+        for ( const rawToken of scriptlets ) {
+            lookupScriptlet(rawToken, reng, scriptletToCodeMap);
+        }
+        if ( scriptletToCodeMap.size === 0 ) { return; }
 
         // Return an array of scriptlets, and log results if needed.
         const out = [];
-        const loggerEnabled = µb.logger.enabled;
+        for ( const [ rawToken, code ] of scriptletToCodeMap ) {
-        for ( const [ rawToken, code ] of scriptletsRegister ) {
             const isException = exceptions.has(rawToken);
             if ( isException === false ) {
                 out.push(code);
@@ -390,9 +403,6 @@
             }
         }
 
-        scriptletsRegister.clear();
-        exceptionsRegister.clear();
-
         if ( out.length === 0 ) { return; }
 
         if ( µb.hiddenSettings.debugScriptlets ) {
@@ -454,6 +464,38 @@
         scriptletDB = new µb.staticExtFilteringEngine.HostnameBasedDB(1, selfie);
     };
 
+    api.benchmark = async function() {
+        const requests = await µb.loadBenchmarkDataset();
+        if ( Array.isArray(requests) === false || requests.length === 0 ) {
+            console.info('No requests found to benchmark');
+            return;
+        }
+        console.info('Benchmarking scriptletFilteringEngine.retrieve()...');
+        const details = {
+            domain: '',
+            entity: '',
+            hostname: '',
+            tabId: 0,
+            url: '',
+        };
+        let count = 0;
+        const t0 = self.performance.now();
+        for ( let i = 0; i < requests.length; i++ ) {
+            const request = requests[i];
+            if ( request.cpt !== 'document' ) { continue; }
+            count += 1;
+            details.url = request.url;
+            details.hostname = µb.URI.hostnameFromURI(request.url);
+            details.domain = µb.URI.domainFromHostname(details.hostname);
+            details.entity = µb.URI.entityFromDomain(details.domain);
+            void this.retrieve(details);
+        }
+        const t1 = self.performance.now();
+        const dur = t1 - t0;
+        console.info(`Evaluated ${count} requests in ${dur.toFixed(0)} ms`);
+        console.info(`\tAverage: ${(dur / count).toFixed(3)} ms per request`);
+    };
+
     return api;
 })();