this fixes https://github.com/gorhill/uMatrix/issues/144

platform/chromium/vapi-client.js

@@ -21,8 +21,6 @@
 
 // For non background pages
 
-/* global self */
-
 /******************************************************************************/
 
 (function(self) {
@@ -136,6 +134,9 @@ vAPI.messaging = {
             },
             close: function() {
                 delete vAPI.messaging.channels[this.channelName];
+                if ( Object.keys(vAPI.messaging.channels).length === 0 ) {
+                    vAPI.messaging.close();
+                }
             }
         };
 

src/js/contentscript-end.js

@@ -37,7 +37,8 @@ if ( document instanceof HTMLDocument === false ) {
     return false;
 }
 
-if ( !vAPI ) {
+// This can happen
+if ( !vAPI || !vAPI.messaging ) {
     //console.debug('contentscript-end.js > vAPI not found');
     return;
 }
@@ -57,10 +58,37 @@ if ( vAPI.contentscriptEndInjected ) {
 vAPI.contentscriptEndInjected = true;
 vAPI.styles = vAPI.styles || [];
 
+/******************************************************************************/
+/******************************************************************************/
+
+var shutdownJobs = (function() {
+    var jobs = [];
+
+    return {
+        add: function(job) {
+            jobs.push(job);
+        },
+        exec: function() {
+            //console.debug('Shutting down...');
+            var job;
+            while ( job = jobs.pop() ) {
+                job();
+            }
+        }
+    };
+})();
+
+/******************************************************************************/
 /******************************************************************************/
 
 var messager = vAPI.messaging.channel('contentscript-end.js');
 
+// https://github.com/gorhill/uMatrix/issues/144
+shutdownJobs.add(function() {
+    messager.close();
+});
+
+/******************************************************************************/
 /******************************************************************************/
 
 // https://github.com/chrisaljoudi/uBlock/issues/789
@@ -120,7 +148,14 @@ var uBlockCollapser = (function() {
         this.collapse = false;
     };
 
-    var onProcessed = function(requests) {
+    var onProcessed = function(response) {
+        // https://github.com/gorhill/uMatrix/issues/144
+        if ( response.shutdown ) {
+            shutdownJobs.exec();
+            return;
+        }
+
+        var requests = response.result;
         if ( requests === null || Array.isArray(requests) === false ) {
             return;
         }
@@ -257,6 +292,8 @@ var uBlockCollapser = (function() {
         return;
     }
 
+    //console.debug('Starts cosmetic filtering');
+
     //var timer = window.performance || Date;
     //var tStart = timer.now();
 
@@ -315,12 +352,13 @@ var uBlockCollapser = (function() {
         firstRetrieveHandler = null;
 
         // These are sent only once
-        if ( response ) {
+        var result = response && response.result;
-            if ( response.highGenerics ) {
+        if ( result ) {
-                highGenerics = response.highGenerics;
+            if ( result.highGenerics ) {
+                highGenerics = result.highGenerics;
             }
-            if ( response.donthide ) {
+            if ( result.donthide ) {
-                processLowGenerics(response.donthide, nullArray);
+                processLowGenerics(result.donthide, nullArray);
             }
         }
 
@@ -328,11 +366,19 @@ var uBlockCollapser = (function() {
     };
 
     var nextRetrieveHandler = function(response) {
+        // https://github.com/gorhill/uMatrix/issues/144
+        if ( response && response.shutdown ) {
+            shutdownJobs.exec();
+            return;
+        }
+
         //var tStart = timer.now();
         //console.debug('µBlock> contextNodes = %o', contextNodes);
+        var result = response && response.result;
         var hideSelectors = [];
-        if ( response && response.hide.length ) {
+
-            processLowGenerics(response.hide, hideSelectors);
+        if ( result && result.hide.length ) {
+            processLowGenerics(result.hide, hideSelectors);
         }
         if ( highGenerics ) {
             if ( highGenerics.hideLowCount ) {
@@ -684,12 +730,22 @@ var uBlockCollapser = (function() {
         }
     };
 
+    //console.debug('Starts cosmetic filtering\'s mutations observer');
+
     // https://github.com/gorhill/httpswitchboard/issues/176
     var treeObserver = new MutationObserver(treeMutationObservedHandlerAsync);
     treeObserver.observe(document.body, {
         childList: true,
         subtree: true
     });
+
+    // https://github.com/gorhill/uMatrix/issues/144
+    shutdownJobs.add(function() {
+        treeObserver.disconnect();
+        if ( addedNodeListsTimer !== null ) {
+            clearTimeout(addedNodeListsTimer);
+        }
+    });
 })();
 
 /******************************************************************************/
@@ -702,6 +758,7 @@ var uBlockCollapser = (function() {
 // - Elements dynamically added to the page
 // - Elements which resource URL changes
 
+(function() {
     var onResourceFailed = function(ev) {
         //console.debug('onResourceFailed(%o)', ev);
         uBlockCollapser.add(ev.target);
@@ -709,6 +766,12 @@ var onResourceFailed = function(ev) {
     };
     document.addEventListener('error', onResourceFailed, true);
 
+    // https://github.com/gorhill/uMatrix/issues/144
+    shutdownJobs.add(function() {
+        document.removeEventListener('error', onResourceFailed, true);
+    });
+})();
+
 /******************************************************************************/
 /******************************************************************************/
 
@@ -766,6 +829,11 @@ document.addEventListener('error', onResourceFailed, true);
     };
 
     window.addEventListener('contextmenu', onContextMenu, true);
+
+    // https://github.com/gorhill/uMatrix/issues/144
+    shutdownJobs.add(function() {
+        document.removeEventListener('contextmenu', onContextMenu, true);
+    });
 })();
 
 /******************************************************************************/

src/js/contentscript-start.js

@@ -40,8 +40,8 @@ if ( document instanceof HTMLDocument === false ) {
     return false;
 }
 
-// Because in case
+// This can happen
-if ( !vAPI ) {
+if ( !vAPI || !vAPI.messaging ) {
     //console.debug('contentscript-start.js > vAPI not found');
     return;
 }

src/js/cosmetic-count.js

@@ -35,9 +35,9 @@ if ( document instanceof HTMLDocument === false ) {
     return;
 }
 
-// Because in case
+// This can happen
-if ( !vAPI ) {
+if ( !vAPI || !vAPI.messaging ) {
-    //console.debug('cosmetic-on.js > vAPI not found');
+    //console.debug('cosmetic-count.js > no vAPI');
     return;
 }
 

src/js/cosmetic-off.js

@@ -35,9 +35,9 @@ if ( document instanceof HTMLDocument === false ) {
     return;
 }
 
-// Because in case
+// This can happen
-if ( !vAPI ) {
+if ( !vAPI || !vAPI.messaging ) {
-    //console.debug('cosmetic-off.js > vAPI not found');
+    //console.debug('cosmetic-off.js > no vAPI');
     return;
 }
 

src/js/cosmetic-on.js

@@ -35,9 +35,9 @@ if ( document instanceof HTMLDocument === false ) {
     return;
 }
 
-// Because in case
+// This can happen
-if ( !vAPI ) {
+if ( !vAPI || !vAPI.messaging ) {
-    //console.debug('cosmetic-on.js > vAPI not found');
+    //console.debug('cosmetic-on.js > no vAPI');
     return;
 }
 

src/js/messaging.js

@@ -516,8 +516,12 @@ var onMessage = function(details, sender, callback) {
 
     switch ( details.what ) {
         case 'retrieveGenericCosmeticSelectors':
-            if ( pageStore && pageStore.getGenericCosmeticFilteringSwitch() ) {
+            response = {
-                response = µb.cosmeticFilteringEngine.retrieveGenericSelectors(details);
+                shutdown: !pageStore || pageStore.getGenericCosmeticFilteringSwitch() === false,
+                result: null
+            };
+            if ( response.shutdown === false ) {
+                response.result = µb.cosmeticFilteringEngine.retrieveGenericSelectors(details);
             }
             break;
 
@@ -527,7 +531,13 @@ var onMessage = function(details, sender, callback) {
 
         // Evaluate many requests
         case 'filterRequests':
-            response = filterRequests(pageStore, details);
+            response = {
+                shutdown: !pageStore || pageStore.getGenericCosmeticFilteringSwitch() === false,
+                result: null
+            };
+            if ( response.shutdown === false ) {
+                response.result = filterRequests(pageStore, details);
+            }
             break;
 
         default: