[mv3] Inject specific cosmetic filters through scriptlet injection

This solves the following remaining issues regarding specific cosmetic
filtering:
- High rate of false positives in last build
- High number of generated content css files in the package

platform/mv3/extension/js/scripting-manager.js

@@ -109,9 +109,10 @@ const toRegisterable = (fname, entry) => {
         directive.excludeMatches = matchesFromHostnames(entry.excludeMatches);
     }
     if ( fname.at(-1) === CSS_TYPE ) {
-        directive.css = [
+        directive.js = [
-            `/rulesets/css/${fname.slice(0,1)}/${fname.slice(1,2)}/${fname.slice(2)}.css`
+            `/rulesets/css/${fname.slice(0,1)}/${fname.slice(1)}.js`,
         ];
+        directive.runAt = 'document_start';
     } else if ( fname.at(-1) === JS_TYPE ) {
         directive.js = [
             `/rulesets/js/${fname}.js`
@@ -123,17 +124,20 @@ const toRegisterable = (fname, entry) => {
     return directive;
 };
 
-const toMaybeUpdatable = (registered, candidate) => {
+/******************************************************************************/
+
+const shouldUpdate = (registered, candidate) => {
     const matches = candidate.matches &&
         matchesFromHostnames(candidate.matches);
     if ( arrayEq(registered.matches, matches) === false ) {
-        return toRegisterable(candidate);
+        return true;
     }
     const excludeMatches = candidate.excludeMatches &&
         matchesFromHostnames(candidate.excludeMatches);
     if ( arrayEq(registered.excludeMatches, excludeMatches) === false ) {
-        return toRegisterable(candidate);
+        return true;
     }
+    return false;
 };
 
 /******************************************************************************/
@@ -228,9 +232,8 @@ async function registerInjectable() {
             toAdd.push(toRegisterable(fname, entry));
             continue;
         }
-        const updated = toMaybeUpdatable(before.get(fname), entry);
+        if ( shouldUpdate(before.get(fname), entry) ) {
-        if ( updated !== undefined ) {
+            toUpdate.push(toRegisterable(fname, entry));
-            toUpdate.push(updated);
         }
     }
 

platform/mv3/make-rulesets.js

@@ -294,161 +294,8 @@ async function processNetworkFilters(assetDetails, network) {
 
 /******************************************************************************/
 
-function addScriptingAPIResources(id, entry, prop, fname) {
+// TODO: unify css/scriptlet processing code since now css styles are
-    if ( entry[prop] === undefined ) { return; }
+// injected using scriptlet injection.
-    for ( const hn of entry[prop] ) {
-        let details = scriptingDetails.get(id);
-        if ( details === undefined ) {
-            details = {
-                matches: new Map(),
-                excludeMatches: new Map(),
-            };
-            scriptingDetails.set(id, details);
-        }
-        let fnames = details[prop].get(hn);
-        if ( fnames === undefined ) {
-            fnames = new Set();
-            details[prop].set(hn, fnames);
-        }
-        fnames.add(fname);
-    }
-}
-
-/******************************************************************************/
-
-const globalCSSFileSet = new Set();
-
-// Using a at-rule layer declaration allows to raise uBOL's styles above
-// that of the page.
-const cssDeclaration =
-`@layer {
-$selector$ {
-  display:none!important;
- }
-}`;
-
-function processCosmeticFilters(assetDetails, mapin) {
-    if ( mapin === undefined ) { return 0; }
-
-    // Drop worryingly generic-looking selectors, they are too likely to
-    // cause false positives on unrelated sites. It's the price for a Lite
-    // version. Examples:
-    //   div[style*="z-index:"]
-    //   [style*="opacity:  0"]
-    for ( const s of mapin.keys() ) {
-        if ( /^[a-z]*\[style[^\]]*\](:|$)/.test(s) === false ) { continue; }
-        // `[style]` attributes with `/` characters are probably ok since they
-        // likely refer to specific `url()` property.
-        if ( s.indexOf('/') !== -1 ) { continue; }
-        // `[style]` attributes with dimension properties might be specific
-        // enough after all.
-        if ( /\b(height|width)\s*:\s*\d+px\b/.test(s) ) { continue; }
-        //console.log(`\tDropping ${s}`);
-        mapin.delete(s);
-    }
-
-    // This groups together selectors which are used by a the same hostname.
-    const optimizeExtendedFilters = filters => {
-        if ( filters === undefined ) { return []; }
-        const merge = new Map();
-        for ( const [ selector, details ] of filters ) {
-            const json = JSON.stringify(details);
-            let entries = merge.get(json);
-            if ( entries === undefined ) {
-                entries = new Set();
-                merge.set(json, entries);
-            }
-            entries.add(selector);
-        }
-        const out = [];
-        for ( const [ json, entries ] of merge ) {
-            const details = JSON.parse(json);
-            details.payload = Array.from(entries);
-            out.push(details);
-        }
-        return out;
-    };
-    const optimized = optimizeExtendedFilters(mapin);
-
-    // This creates a map of unique selectorset => all hostnames
-    // including/excluding the selectorset. This allows to avoid duplication
-    // of css content.
-    const cssContentMap = new Map();
-    for ( const entry of optimized ) {
-        const selectors = entry.payload.map(s => ` ${s}`).join(',\n');
-        // ends-with 0 = css resource
-        const fname = uid(selectors) + '0';
-        let contentDetails = cssContentMap.get(fname);
-        if ( contentDetails === undefined ) {
-            contentDetails = { selectors };
-            cssContentMap.set(fname, contentDetails);
-        }
-        if ( entry.matches !== undefined ) {
-            if ( contentDetails.matches === undefined ) {
-                contentDetails.matches = new Set();
-            }
-            for ( const hn of entry.matches ) {
-                contentDetails.matches.add(hn);
-            }
-        }
-        if ( entry.excludeMatches !== undefined ) {
-            if ( contentDetails.excludeMatches === undefined ) {
-                contentDetails.excludeMatches = new Set();
-            }
-            for ( const hn of entry.excludeMatches ) {
-                contentDetails.excludeMatches.add(hn);
-            }
-        }
-    }
-
-    // We do not want more than 128 CSS files per subscription, so we will
-    // group multiple unrelated selectors in the same file and hope this does
-    // not cause false positives.
-    const contentPerFile = Math.ceil(cssContentMap.size / 128);
-    const cssContentArray = Array.from(cssContentMap).map(entry => entry[1]);
-    let distinctResourceCount = 0;
-
-    for ( let i = 0; i < cssContentArray.length; i += contentPerFile ) {
-        const slice = cssContentArray.slice(i, i + contentPerFile);
-        const matches = slice.map(entry =>
-            Array.from(entry.matches || [])
-        ).flat();
-        const excludeMatches = slice.map(entry =>
-            Array.from(entry.excludeMatches || [])
-        ).flat();
-        const selectors = slice.map(entry =>
-            entry.selectors
-        ).join(',\n');
-        const fname = uid(selectors) + '0';
-        if ( globalCSSFileSet.has(fname) === false ) {
-            globalCSSFileSet.add(fname);
-            const fpath = `${fname.slice(0,1)}/${fname.slice(1,2)}/${fname.slice(2)}`;
-            writeFile(
-                `${cssDir}/${fpath}.css`,
-                cssDeclaration.replace('$selector$', selectors)
-            );
-            distinctResourceCount += 1;
-        }
-        addScriptingAPIResources(
-            assetDetails.id,
-            { matches },
-            'matches',
-            fname
-        );
-        addScriptingAPIResources(
-            assetDetails.id,
-            { excludeMatches },
-            'excludeMatches',
-            fname
-        );
-    }
-
-    log(`CSS entries: ${distinctResourceCount}`);
-
-    return distinctResourceCount;
-}
-
-/******************************************************************************/
 
 // Load all available scriptlets into a key-val map, where the key is the
 // scriptlet token, and val is the whole content of the file.
@@ -492,8 +339,173 @@ function loadAllSourceScriptlets() {
     return scriptletsMapPromise;
 }
 
+/******************************************************************************/
+
 const globalPatchedScriptletsSet = new Set();
 
+function addScriptingAPIResources(id, entry, prop, fname) {
+    if ( entry[prop] === undefined ) { return; }
+    for ( const hn of entry[prop] ) {
+        let details = scriptingDetails.get(id);
+        if ( details === undefined ) {
+            details = {
+                matches: new Map(),
+                excludeMatches: new Map(),
+            };
+            scriptingDetails.set(id, details);
+        }
+        let fnames = details[prop].get(hn);
+        if ( fnames === undefined ) {
+            fnames = new Set();
+            details[prop].set(hn, fnames);
+        }
+        fnames.add(fname);
+    }
+}
+
+/******************************************************************************/
+
+async function processCosmeticFilters(assetDetails, mapin) {
+    if ( mapin === undefined ) { return 0; }
+
+    // This groups together selectors which are used by the same hostname.
+    const optimized = (filters => {
+        if ( filters === undefined ) { return []; }
+        const merge = new Map();
+        for ( const [ selector, details ] of filters ) {
+            const json = JSON.stringify(details);
+            let entries = merge.get(json);
+            if ( entries === undefined ) {
+                entries = new Set();
+                merge.set(json, entries);
+            }
+            entries.add(selector);
+        }
+        const out = [];
+        for ( const [ json, entries ] of merge ) {
+            const details = JSON.parse(json);
+            details.selector = Array.from(entries).join(',');
+            out.push(details);
+        }
+        return out;
+    })(mapin);
+
+    // This creates a map of unique selectorset => all hostnames
+    // including/excluding the selectorset. This allows to avoid duplication
+    // of css content.
+    const cssContentMap = new Map();
+    for ( const entry of optimized ) {
+        // ends-with 0 = css resource
+        const id = parseInt(uid(entry.selector), 16);
+        let details = cssContentMap.get(id);
+        if ( details === undefined ) {
+            details = { a: entry.selector };
+            cssContentMap.set(id, details);
+        }
+        if ( entry.matches !== undefined ) {
+            if ( details.y === undefined ) {
+                details.y = new Set();
+            }
+            for ( const hn of entry.matches ) {
+                details.y.add(hn);
+            }
+        }
+        if ( entry.excludeMatches !== undefined ) {
+            if ( details.n === undefined ) {
+                details.n = new Set();
+            }
+            for ( const hn of entry.excludeMatches ) {
+                details.n.add(hn);
+            }
+        }
+    }
+
+    // We do not want more than 16 CSS files per subscription, so we will
+    // group multiple unrelated selectors in the same file, and distinct
+    // css declarations will be injected programmatically according to the
+    // hostname of the current document.
+    //
+    // The cosmetic filters will be injected programmatically as content
+    // script and the decisions to activate the cosmetic filters will be
+    // done at injection time according to the document's hostname.
+    const originalScriptletMap = await loadAllSourceScriptlets();
+    const contentPerFile = Math.ceil(cssContentMap.size / 16);
+    const cssContentArray = Array.from(cssContentMap);
+
+    const jsonReplacer = (k, v) => {
+        if ( k === 'n' ) {
+            if ( v === undefined || v.size === 0 ) { return; }
+            return Array.from(v);
+        }
+        if ( v instanceof Set || v instanceof Map ) {
+            if ( v.size === 0 ) { return; }
+            return Array.from(v);
+        }
+        return v;
+    };
+
+    const toHostnamesMap = (hostnames, id, out) => {
+        for ( const hn of hostnames ) {
+            const existing = out.get(hn);
+            if ( existing === undefined ) {
+                out.set(hn, id);
+            } else if ( Array.isArray(existing) ) {
+                existing.push(id);
+            } else {
+                out.set(hn, [ existing, id ]);
+            }
+        }
+    };
+
+    let distinctResourceCount = 0;
+
+    for ( let i = 0; i < cssContentArray.length; i += contentPerFile ) {
+        const slice = cssContentArray.slice(i, i + contentPerFile);
+        const argsMap = slice.map(entry => [
+            entry[0], { a: entry[1].a, n: entry[1].n }
+        ]);
+        const hostnamesMap = new Map();
+        for ( const [ id, details ] of slice ) {
+            if ( details.y === undefined ) { continue; }
+            toHostnamesMap(details.y, id, hostnamesMap);
+        }
+        const patchedScriptlet = originalScriptletMap.get('css-specific')
+            .replace(
+                /\bself\.\$argsMap\$/m,
+                `${JSON.stringify(argsMap, jsonReplacer)}`
+            ).replace(
+                /\bself\.\$hostnamesMap\$/m,
+                `${JSON.stringify(hostnamesMap, jsonReplacer)}`
+            );
+        // ends-with 0 = css resource
+        const fname = uid(patchedScriptlet) + '0';
+        if ( globalPatchedScriptletsSet.has(fname) === false ) {
+            globalPatchedScriptletsSet.add(fname);
+            writeFile(`${cssDir}/${fname.slice(0,1)}/${fname.slice(1)}.js`, patchedScriptlet, {});
+            distinctResourceCount += 1;
+        }
+        for ( const entry of slice ) {
+            addScriptingAPIResources(
+                assetDetails.id,
+                { matches: entry[1].y },
+                'matches',
+                fname
+            );
+            addScriptingAPIResources(
+                assetDetails.id,
+                { excludeMatches: entry[1].n },
+                'excludeMatches',
+                fname
+            );
+        }
+    }
+    log(`CSS entries: ${distinctResourceCount}`);
+
+    return distinctResourceCount;
+}
+
+/******************************************************************************/
+
 async function processScriptletFilters(assetDetails, mapin) {
     if ( mapin === undefined ) { return 0; }
 
@@ -605,12 +617,10 @@ async function processScriptletFilters(assetDetails, mapin) {
     };
 
     for ( const [ token, argsDetails ] of scriptletDetails ) {
-        const argsMap = Array.from(argsDetails).map(entry => {
+        const argsMap = Array.from(argsDetails).map(entry => [
-            return [ 
             parseInt(uid(entry[0]),16),
             { a: entry[1].a, n: entry[1].n }
-            ];
+        ]);
-        });
         const hostnamesMap = new Map();
         for ( const [ argsHash, details ] of argsDetails ) {
             toHostnamesMap(details.y, parseInt(uid(argsHash),16), hostnamesMap);

platform/mv3/scriptlets/abort-current-script.js

@@ -146,6 +146,7 @@ const scriptlet = (
 /******************************************************************************/
 
 const argsMap = new Map(self.$argsMap$);
+
 const hostnamesMap = new Map(self.$hostnamesMap$);
 
 let hn;

platform/mv3/scriptlets/css-specific.js

@@ -0,0 +1,79 @@
+/*******************************************************************************
+
+    uBlock Origin - a browser extension to block requests.
+    Copyright (C) 2019-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+
+    The scriptlets below are meant to be injected only into a
+    web page context.
+*/
+
+/* jshint esversion:11 */
+
+'use strict';
+
+/******************************************************************************/
+
+/// name css-specific
+
+/******************************************************************************/
+
+// Important!
+// Isolate from global scope
+(function() {
+
+/******************************************************************************/
+
+const argsMap = new Map(self.$argsMap$);
+
+const hostnamesMap = new Map(self.$hostnamesMap$);
+
+let hn;
+try { hn = document.location.hostname; } catch(ex) { }
+const styles = [];
+while ( hn ) {
+    if ( hostnamesMap.has(hn) ) {
+        let argsHashes = hostnamesMap.get(hn);
+        if ( typeof argsHashes === 'number' ) { argsHashes = [ argsHashes ]; }
+        for ( const argsHash of argsHashes ) {
+            const details = argsMap.get(argsHash);
+            if ( details.n && details.n.includes(hn) ) { continue; }
+            styles.push(details.a);
+        }
+    }
+    const pos = hn.indexOf('.');
+    if ( pos === -1 ) { break; }
+    hn = hn.slice(pos + 1);
+}
+
+if ( styles.length === 0 ) { return; }
+
+try {
+    const sheet = new CSSStyleSheet();
+    sheet.replace(`@layer{${styles.join(',')}{display:none!important;}}`);
+    document.adoptedStyleSheets = [
+        ...document.adoptedStyleSheets,
+        sheet
+    ];
+} catch(ex) {
+}
+
+/******************************************************************************/
+
+})();
+
+/******************************************************************************/

platform/mv3/scriptlets/json-prune.js

@@ -122,6 +122,7 @@ const scriptlet = (
 /******************************************************************************/
 
 const argsMap = new Map(self.$argsMap$);
+
 const hostnamesMap = new Map(self.$hostnamesMap$);
 
 let hn;

platform/mv3/scriptlets/set-constant.js

@@ -164,6 +164,7 @@ const scriptlet = (
 /******************************************************************************/
 
 const argsMap = new Map(self.$argsMap$);
+
 const hostnamesMap = new Map(self.$hostnamesMap$);
 
 let hn;

src/js/static-dnr-filtering.js

@@ -93,15 +93,12 @@ function addExtendedToDNR(context, parser) {
     // https://github.com/chrisaljoudi/uBlock/issues/151
     //   Negated hostname means the filter applies to all non-negated hostnames
     //   of same filter OR globally if there is no non-negated hostnames.
-    // Drop selectors which can potentially lead to the hiding of
-    // html/body elements.
     for ( const { hn, not, bad } of parser.extOptions() ) {
         if ( bad ) { continue; }
         if ( hn.endsWith('.*') ) { continue; }
         const { compiled, exception } = parser.result;
         if ( compiled.startsWith('{') ) { continue; }
         if ( exception ) { continue; }
-        if ( /(^|[^\w#.\-\[])(html|body)(,|$)/i.test(compiled) ) { continue; }
         let details = context.cosmeticFilters.get(compiled);
         if ( details === undefined ) {
             details = {};