Remove `assets` dependency from redirect engine

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/1664

This change allows to add the redirect engine into the
nodejs package. The purpose of the redirect engine is to
resolve a redirect token into a path to a local resource,
to be used by the caller as wished.

src/js/redirect-engine.js

@@ -23,8 +23,6 @@
 
 /******************************************************************************/
 
-import io from './assets.js';
-
 import {
     LineIterator,
     orphanizeString,
@@ -204,6 +202,14 @@ const mimeFromName = function(name) {
     }
 };
 
+// vAPI.warSecret() is optional, it could be absent in some environments,
+// i.e. nodejs for example. Probably the best approach is to have the
+// "web_accessible_resources secret" added outside by the client of this
+// module, but for now I just want to remove an obstacle to modularization.
+const warSecret = typeof vAPI === 'object' && vAPI !== null
+    ? vAPI.warSecret
+    : ( ) => '';
+
 /******************************************************************************/
 /******************************************************************************/
 
@@ -230,14 +236,20 @@ const RedirectEntry = class {
             fctxt instanceof Object &&
             fctxt.type !== 'xmlhttprequest'
         ) {
-            let url = `${this.warURL}?secret=${vAPI.warSecret()}`;
+            const params = [];
+            const secret = warSecret();
+            if ( secret !== '' ) { params.push(`secret=${secret}`); }
             if ( this.params !== undefined ) {
                 for ( const name of this.params ) {
                     const value = fctxt[name];
                     if ( value === undefined ) { continue; }
-                    url += `&${name}=${encodeURIComponent(value)}`;
+                    params.push(`${name}=${encodeURIComponent(value)}`);
                 }
             }
+            let url = `${this.warURL}`;
+            if ( params.length !== 0 ) {
+                url += `?${params.join('&')}`;
+            }
             return url;
         }
         if ( this.data === undefined ) { return; }
@@ -439,18 +451,18 @@ const removeTopCommentBlock = function(text) {
 
 /******************************************************************************/
 
-RedirectEngine.prototype.loadBuiltinResources = function() {
+RedirectEngine.prototype.loadBuiltinResources = function(fetcher) {
     this.resources = new Map();
     this.aliases = new Map();
 
     const fetches = [
-        io.fetchText(
+        fetcher(
             '/assets/resources/scriptlets.js'
         ).then(result => {
             const content = result.content;
-            if ( typeof content === 'string' && content.length !== 0 ) {
+            if ( typeof content !== 'string' ) { return; }
+            if ( content.length === 0 ) { return; }
             this.resourcesFromString(content);
-            }
         }),
     ];
 
@@ -459,7 +471,7 @@ RedirectEngine.prototype.loadBuiltinResources = function() {
         const entry = RedirectEntry.fromSelfie({
             mime: mimeFromName(name),
             data,
-            warURL: vAPI.getURL(`/web_accessible_resources/${name}`),
+            warURL: `/web_accessible_resources/${name}`,
             params: details.params,
         });
         this.resources.set(name, entry);
@@ -506,10 +518,9 @@ RedirectEngine.prototype.loadBuiltinResources = function() {
             continue;
         }
         fetches.push(
-            io.fetch(
+            fetcher(`/web_accessible_resources/${name}`, {
-                `/web_accessible_resources/${name}?secret=${vAPI.warSecret()}`,
+                responseType: details.data
-                { responseType: details.data }
+            }).then(
-            ).then(
                 result => process(result)
             )
         );
@@ -545,21 +556,22 @@ RedirectEngine.prototype.getResourceDetails = function() {
 
 /******************************************************************************/
 
-const resourcesSelfieVersion = 5;
+const RESOURCES_SELFIE_VERSION = 6;
+const RESOURCES_SELFIE_NAME = 'compiled/redirectEngine/resources';
 
-RedirectEngine.prototype.selfieFromResources = function() {
+RedirectEngine.prototype.selfieFromResources = function(storage) {
-    io.put(
+    storage.put(
-        'compiled/redirectEngine/resources',
+        RESOURCES_SELFIE_NAME,
         JSON.stringify({
-            version: resourcesSelfieVersion,
+            version: RESOURCES_SELFIE_VERSION,
             aliases: Array.from(this.aliases),
             resources: Array.from(this.resources),
         })
     );
 };
 
-RedirectEngine.prototype.resourcesFromSelfie = async function() {
+RedirectEngine.prototype.resourcesFromSelfie = async function(storage) {
-    const result = await io.get('compiled/redirectEngine/resources');
+    const result = await storage.get(RESOURCES_SELFIE_NAME);
     let selfie;
     try {
         selfie = JSON.parse(result.content);
@@ -567,7 +579,7 @@ RedirectEngine.prototype.resourcesFromSelfie = async function() {
     }
     if (
         selfie instanceof Object === false ||
-        selfie.version !== resourcesSelfieVersion ||
+        selfie.version !== RESOURCES_SELFIE_VERSION ||
         Array.isArray(selfie.resources) === false
     ) {
         return false;
@@ -580,8 +592,8 @@ RedirectEngine.prototype.resourcesFromSelfie = async function() {
     return true;
 };
 
-RedirectEngine.prototype.invalidateResourcesSelfie = function() {
+RedirectEngine.prototype.invalidateResourcesSelfie = function(storage) {
-    io.remove('compiled/redirectEngine/resources');
+    storage.remove(RESOURCES_SELFIE_NAME);
 };
 
 /******************************************************************************/

src/js/start.js

@@ -140,7 +140,7 @@ const onVersionReady = function(lastVersion) {
 
     // Since built-in resources may have changed since last version, we
     // force a reload of all resources.
-    redirectEngine.invalidateResourcesSelfie();
+    redirectEngine.invalidateResourcesSelfie(io);
 
     // https://github.com/LiCybora/NanoDefenderFirefox/issues/196
     //   Toggle on the blocking of CSP reports by default for Firefox.

src/js/static-net-filtering.js

@@ -35,7 +35,6 @@ import {
     hostnameFromNetworkURL,
 } from './uri-utils.js';
 
-
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import#browser_compatibility
 //
 // This import would be best done dynamically, but since dynamic imports are
@@ -4287,22 +4286,20 @@ FilterContainer.prototype.redirectRequest = function(redirectEngine, fctxt) {
     const highest = directives.length - 1;
     // More than a single directive means more work.
     if ( highest !== 0 ) {
-        directives.sort(
+        directives.sort((a, b) => compareRedirectRequests(redirectEngine, a, b));
-            FilterContainer.compareRedirectRequests.bind(this, redirectEngine)
-        );
     }
     // Redirect to highest-ranked directive
     const directive = directives[highest];
     if ( (directive.bits & AllowAction) === 0 ) {
         const { token } =
-            FilterContainer.parseRedirectRequestValue(directive.modifier);
+            parseRedirectRequestValue(directive.modifier);
         fctxt.redirectURL = redirectEngine.tokenToURL(fctxt, token);
         if ( fctxt.redirectURL === undefined ) { return; }
     }
     return directives;
 };
 
-FilterContainer.parseRedirectRequestValue = function(modifier) {
+const parseRedirectRequestValue = function(modifier) {
     if ( modifier.cache === undefined ) {
         modifier.cache =
             StaticFilteringParser.parseRedirectValue(modifier.value);
@@ -4310,12 +4307,12 @@ FilterContainer.parseRedirectRequestValue = function(modifier) {
     return modifier.cache;
 };
 
-FilterContainer.compareRedirectRequests = function(redirectEngine, a, b) {
+const compareRedirectRequests = function(redirectEngine, a, b) {
     const { token: atok, priority: aint, bits: abits } =
-        FilterContainer.parseRedirectRequestValue(a.modifier);
+        parseRedirectRequestValue(a.modifier);
     if ( redirectEngine.hasToken(atok) === false ) { return -1; }
     const { token: btok, priority: bint, bits: bbits } =
-        FilterContainer.parseRedirectRequestValue(b.modifier);
+        parseRedirectRequestValue(b.modifier);
     if ( redirectEngine.hasToken(btok) === false ) { return 1; }
     if ( abits !== bbits ) {
         if ( (abits & Important) !== 0 ) { return 1; }

src/js/storage.js

@@ -1151,11 +1151,19 @@ self.addEventListener('hiddenSettingsChanged', ( ) => {
 
 µb.loadRedirectResources = async function() {
     try {
-        const success = await redirectEngine.resourcesFromSelfie();
+        const success = await redirectEngine.resourcesFromSelfie(io);
         if ( success === true ) { return true; }
 
+        const fetcher = (path, options = undefined) => {
+            if ( path.startsWith('/web_accessible_resources/') ) {
+                path += `?secret=${vAPI.warSecret()}`;
+                return io.fetch(path, options);
+            }
+            return io.fetchText(path);
+        };
+
         const fetchPromises = [
-            redirectEngine.loadBuiltinResources()
+            redirectEngine.loadBuiltinResources(fetcher)
         ];
 
         const userResourcesLocation = this.hiddenSettings.userResourcesLocation;
@@ -1182,7 +1190,7 @@ self.addEventListener('hiddenSettingsChanged', ( ) => {
         }
 
         redirectEngine.resourcesFromString(content);
-        redirectEngine.selfieFromResources();
+        redirectEngine.selfieFromResources(io);
     } catch(ex) {
         ubolog(ex);
         return false;
@@ -1617,7 +1625,7 @@ self.addEventListener('hiddenSettingsChanged', ( ) => {
                 this.hiddenSettings.userResourcesLocation !== 'unset' ||
                 vAPI.webextFlavor.soup.has('devbuild')
             ) {
-                redirectEngine.invalidateResourcesSelfie();
+                redirectEngine.invalidateResourcesSelfie(io);
             }
             this.loadFilterLists();
         }

src/js/traffic.js

@@ -61,6 +61,12 @@ const supportsFloc = document.interestCohort instanceof Function;
 
 /******************************************************************************/
 
+const patchLocalRedirectURL = url => url.charCodeAt(0) === 0x2F /* '/' */
+    ? vAPI.getURL(url)
+    : url;
+
+/******************************************************************************/
+
 // Intercept and filter web requests.
 
 const onBeforeRequest = function(details) {
@@ -102,7 +108,7 @@ const onBeforeRequest = function(details) {
     // Redirected
 
     if ( fctxt.redirectURL !== undefined ) {
-        return { redirectUrl: fctxt.redirectURL };
+        return { redirectUrl: patchLocalRedirectURL(fctxt.redirectURL) };
     }
 
     // Not redirected
@@ -208,7 +214,7 @@ const onBeforeRootFrameRequest = function(fctxt) {
     // Redirected
 
     if ( fctxt.redirectURL !== undefined ) {
-        return { redirectUrl: fctxt.redirectURL };
+        return { redirectUrl: patchLocalRedirectURL(fctxt.redirectURL) };
     }
 
     // Not blocked
@@ -414,7 +420,7 @@ const onBeforeBehindTheSceneRequest = function(fctxt) {
     // Redirected
 
     if ( fctxt.redirectURL !== undefined ) {
-        return { redirectUrl: fctxt.redirectURL };
+        return { redirectUrl: patchLocalRedirectURL(fctxt.redirectURL) };
     }
 
     // Blocked?

src/js/ublock.js

@@ -25,6 +25,7 @@
 
 import contextMenu from './contextmenu.js';
 import cosmeticFilteringEngine from './cosmetic-filtering.js';
+import io from './assets.js';
 import µb from './background.js';
 import { hostnameFromURI } from './uri-utils.js';
 import { redirectEngine } from './redirect-engine.js';
@@ -423,7 +424,7 @@ const matchBucket = function(url, hostname, bucket, start) {
     this.hiddenSettings = hs;
     this.saveHiddenSettings();
     if ( mustReloadResources ) {
-        redirectEngine.invalidateResourcesSelfie();
+        redirectEngine.invalidateResourcesSelfie(io);
         this.loadRedirectResources();
     }
     this.fireDOMEvent('hiddenSettingsChanged');