From 7cd060a15f995215941641428a866bee8c109563 Mon Sep 17 00:00:00 2001
From: gorhill <rhill@raymondhill.net>
Date: Tue, 21 Apr 2015 16:22:29 -0400
Subject: [PATCH] refactoring, fixing script/frame blocking on FF, etc., more
 to do

---
 platform/firefox/vapi-background.js |  39 +--
 src/js/async.js                     |  30 +--
 src/js/background.js                |  10 +-
 src/js/cookies.js                   |  18 +-
 src/js/info.js                      |  38 +--
 src/js/messaging.js                 | 109 ++++----
 src/js/pagestats.js                 |  73 ++++--
 src/js/start.js                     |  12 +-
 src/js/tab.js                       | 387 ++++++++++++----------------
 src/js/traffic.js                   | 281 +++++++++-----------
 10 files changed, 471 insertions(+), 526 deletions(-)

diff --git a/platform/firefox/vapi-background.js b/platform/firefox/vapi-background.js
index ccc70a3..8ded8b3 100644
--- a/platform/firefox/vapi-background.js
+++ b/platform/firefox/vapi-background.js
@@ -1002,9 +1002,10 @@ var httpObserver = {
     ABORT: Components.results.NS_BINDING_ABORTED,
     ACCEPT: Components.results.NS_SUCCEEDED,
     // Request types: https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIContentPolicy#Constants
-    MAIN_FRAME: Ci.nsIContentPolicy.TYPE_DOCUMENT,
-    VALID_CSP_TARGETS: 1 << Ci.nsIContentPolicy.TYPE_DOCUMENT |
-                       1 << Ci.nsIContentPolicy.TYPE_SUBDOCUMENT,
+    frameTypeMap: {
+        6: 'main_frame',
+        7: 'sub_frame'
+    },
     typeMap: {
         1: 'other',
         2: 'script',
@@ -1128,13 +1129,15 @@ var httpObserver = {
                 return true;
             }
 
-            /*if ( result.redirectUrl ) {
-                channel.redirectionLimit = 1;
-                channel.redirectTo(
-                    Services.io.newURI(result.redirectUrl, null, null)
-                );
+            // For the time being, will block instead of redirecting
+            // TODO: figure a better way of blocking embedded frames.
+            // Maybe blocking network requests, then having a content script
+            // revisit the DOM to replace blocked frame with something more
+            // friendly. Will see.
+            if ( typeof result === 'object' && result.redirectUrl ) {
+                channel.cancel(this.ABORT);
                 return true;
-            }*/
+            }
         }
 
         var onBeforeSendHeaders = vAPI.net.onBeforeSendHeaders;
@@ -1158,7 +1161,7 @@ var httpObserver = {
         }
 
         var URI = channel.URI;
-        var channelData, result;
+        var channelData, type, result;
 
         if ( topic === 'http-on-examine-response' ) {
             if ( !(channel instanceof Ci.nsIWritablePropertyBag) ) {
@@ -1175,7 +1178,8 @@ var httpObserver = {
                 return;
             }
 
-            if ( (1 << channelData[4] & this.VALID_CSP_TARGETS) === 0 ) {
+            type = this.frameTypeMap[channelData[4]];
+            if ( !type ) {
                 return;
             }
 
@@ -1191,7 +1195,9 @@ var httpObserver = {
                 hostname: URI.asciiHost,
                 parentFrameId: channelData[1],
                 responseHeaders: result ? [{name: topic, value: result}] : [],
+                statusLine: channel.responseStatus.toString(),
                 tabId: channelData[3],
+                type: type,
                 url: URI.asciiSpec
             });
 
@@ -1469,7 +1475,7 @@ vAPI.toolbarButton.init = function() {
                 'font-size: 9px;',
                 'font-weight: bold;',
                 'color: #fff;',
-                'background: #666;',
+                'background: #000;',
                 'content: attr(badge);',
             '}'
         );
@@ -1503,7 +1509,7 @@ vAPI.toolbarButton.init = function() {
 
         this.CUIEvents.updateBadgeStyle = function() {
             var css = [
-                'background: #666',
+                'background: #000',
                 'color: #fff'
             ].join(';');
 
@@ -1592,18 +1598,19 @@ vAPI.toolbarButton.onBeforeCreated = function(doc) {
         if ( updateTimer ) {
             return;
         }
-
         updateTimer = setTimeout(resizePopup, 10);
     };
     var resizePopup = function() {
         updateTimer = null;
         var body = iframe.contentDocument.body;
         panel.parentNode.style.maxWidth = 'none';
+        // We set a limit for height
+        var height = Math.min(body.clientHeight, 600);
         // https://github.com/chrisaljoudi/uBlock/issues/730
         // Voodoo programming: this recipe works
-        panel.style.height = iframe.style.height = body.clientHeight.toString() + 'px';
+        panel.style.height = iframe.style.height = height.toString() + 'px';
         panel.style.width = iframe.style.width = body.clientWidth.toString() + 'px';
-        if ( iframe.clientHeight !== body.clientHeight || iframe.clientWidth !== body.clientWidth ) {
+        if ( iframe.clientHeight !== height || iframe.clientWidth !== body.clientWidth ) {
             delayedResize();
         }
     };
diff --git a/src/js/async.js b/src/js/async.js
index 5520cf3..a0ec58f 100644
--- a/src/js/async.js
+++ b/src/js/async.js
@@ -133,30 +133,12 @@ return asyncJobManager;
 // Update visual of extension icon.
 // A time out is used to coalesce adjacent requests to update badge.
 
-µMatrix.updateBadgeAsync = (function(){
-    var µm = µMatrix;
-
-    // Cache callback definition, it was a bad idea to define this one inside 
-    // updateBadgeAsync
-    var updateBadge = function(tabId) {
-        var µm = µMatrix;
-        var pageStore = µm.pageStatsFromTabId(tabId);
-        if ( pageStore ) {
-            pageStore.updateBadge(tabId);
-            return;
-        }
-        vAPI.setIcon(tabId, null, '?');
-    };
-
-    var updateBadgeAsync = function(tabId) {
-        if ( vAPI.isBehindTheSceneTabId(tabId) ) {
-            return;
-        }
-        µm.asyncJobs.add('updateBadge-' + tabId, tabId, updateBadge, 500);
-    };
-
-    return updateBadgeAsync;
-})();
+µMatrix.updateBadgeAsync = function(tabId) {
+    var pageStore = this.pageStoreFromTabId(tabId);
+    if ( pageStore ) {
+        pageStore.updateBadge();
+    }
+};
 
 /******************************************************************************/
 
diff --git a/src/js/background.js b/src/js/background.js
index 465142f..e091cd0 100644
--- a/src/js/background.js
+++ b/src/js/background.js
@@ -98,17 +98,13 @@ return {
 
     // urls stats are kept on the back burner while waiting to be reactivated
     // in a tab or another.
-    pageStats: {}, // TODO: rename
+    pageStores: {},
+    pageStoreCemetery: {},
 
     // A map of redirects, to allow reverse lookup of redirects from landing
     // page, so that redirection can be reported to the user.
     redirectRequests: {}, 
 
-    // tabs are used to redirect stats collection to a specific url stats
-    // structure.
-    pageUrlToTabId: {},
-    tabIdToPageUrl: {},
-
     // page url => permission scope
     tMatrix: null,
     pMatrix: null,
@@ -129,7 +125,7 @@ return {
 
     // record what chromium is doing behind the scene
     behindTheSceneURL: 'http://chromium-behind-the-scene/',
-    behindTheSceneTabId: 0x7FFFFFFF,
+    behindTheSceneTabId: vAPI.noTabId,
     behindTheSceneMaxReq: 250,
     behindTheSceneScope: 'chromium-behind-the-scene',
 
diff --git a/src/js/cookies.js b/src/js/cookies.js
index a55faaf..f9e3fcf 100644
--- a/src/js/cookies.js
+++ b/src/js/cookies.js
@@ -197,8 +197,7 @@ var recordPageCookiesAsync = function(pageStats) {
     if ( !pageStats ) {
         return;
     }
-    var pageURL = µm.pageUrlFromPageStats(pageStats);
-    recordPageCookiesQueue[pageURL] = pageStats;
+    recordPageCookiesQueue[pageStats.pageUrl] = pageStats;
     µm.asyncJobs.add(
         'cookieHunterPageRecord',
         null,
@@ -220,6 +219,10 @@ var cookieLogEntryBuilder = [
 ];
 
 var recordPageCookie = function(pageStore, cookieKey) {
+    if ( vAPI.isBehindTheSceneTabId(pageStore.tabId) ) {
+        return;
+    }
+
     var cookieEntry = cookieDict[cookieKey];
     var block = µm.mustBlock(pageStore.pageHostname, cookieEntry.hostname, 'cookie');
 
@@ -263,8 +266,7 @@ var removePageCookiesAsync = function(pageStats) {
     if ( !pageStats ) {
         return;
     }
-    var pageURL = µm.pageUrlFromPageStats(pageStats);
-    removePageCookiesQueue[pageURL] = pageStats;
+    removePageCookiesQueue[pageStats.pageUrl] = pageStats;
     µm.asyncJobs.add(
         'cookieHunterPageRemove',
         null,
@@ -508,13 +510,13 @@ vAPI.cookies.onChanged = function(changeInfo) {
 
     // Go through all pages and update if needed, as one cookie can be used
     // by many web pages, so they need to be recorded for all these pages.
-    var pageStores = µm.pageStats;
+    var pageStores = µm.pageStores;
     var pageStore;
-    for ( var pageURL in pageStores ) {
-        if ( pageStores.hasOwnProperty(pageURL) === false ) {
+    for ( var tabId in pageStores ) {
+        if ( pageStores.hasOwnProperty(tabId) === false ) {
             continue;
         }
-        pageStore = pageStores[pageURL];
+        pageStore = pageStores[tabId];
         if ( !cookieMatchDomains(cookieKey, pageStore.allHostnamesString) ) {
             continue;
         }
diff --git a/src/js/info.js b/src/js/info.js
index dd64424..b6a5859 100644
--- a/src/js/info.js
+++ b/src/js/info.js
@@ -31,7 +31,7 @@
 
 var messager = vAPI.messaging.channel('info.js');
 
-var targetUrl = 'all';
+var targetTabId = null;
 var maxRequests = 500;
 var cachedUserSettings = {};
 
@@ -55,7 +55,7 @@ function updateRequestData(callback) {
     };
     var request = {
         what: 'getRequestLogs',
-        pageURL: targetUrl !== 'all' ? targetUrl : null
+        tabId: targetTabId
     };
     messager.send(request, onResponseReceived);
 }
@@ -65,7 +65,7 @@ function updateRequestData(callback) {
 function clearRequestData() {
     var request = {
         what: 'clearRequestLogs',
-        pageURL: targetUrl !== 'all' ? targetUrl : null
+        tabId: targetTabId
     };
     messager.send(request);
 }
@@ -108,7 +108,7 @@ var renderLocalized = function(id, map) {
 /******************************************************************************/
 
 function renderPageUrls() {
-    var onResponseReceived = function(r) {
+    var onResponseReceived = function(result) {
         var i, n;
         var select = uDom('#selectPageUrls');
 
@@ -118,25 +118,25 @@ function renderPageUrls() {
         n = builtinOptions.length;
         for ( i = 0; i < n; i++ ) {
             option = builtinOptions.at(i).clone();
-            if ( option.val() === targetUrl ) {
+            if ( option.val() === targetTabId ) {
                 option.attr('selected', true);
             }
             select.append(option);
         }
 
-        var pageURLs = r.pageURLs.sort();
-        var pageURL, option;
-        n = pageURLs.length;
+        var entries = result.pageURLs.sort();
+        var entry, pageURL, option;
+        n = entries.length;
         for ( i = 0; i < n; i++ ) {
-            pageURL = pageURLs[i];
+            entry = entries[i];
             // Behind-the-scene entry is always present, no need to recreate it
-            if ( pageURL === r.behindTheSceneURL ) {
+            if ( entry.pageURL === result.behindTheSceneURL ) {
                 continue;
             }
             option = uDom('<option>');
-            option.val(pageURL);
-            option.text(pageURL);
-            if ( pageURL === targetUrl ) {
+            option.val(entry.tabId);
+            option.text(entry.pageURL);
+            if ( entry.pageURL === targetTabId ) {
                 option.attr('selected', true);
             }
             select.append(option);
@@ -154,10 +154,10 @@ function renderPageUrls() {
 function renderStats() {
     var onResponseReceived = function(r) {
         if ( !r.pageNetStats ) {
-            targetUrl = 'all';
+            targetTabId = null;
         }
 
-        var requestStats = targetUrl === 'all' ? r.globalNetStats : r.pageNetStats;
+        var requestStats = targetTabId ? r.pageNetStats : r.globalNetStats;
         var blockedStats = requestStats.blocked;
         var allowedStats = requestStats.allowed;
 
@@ -197,7 +197,7 @@ function renderStats() {
 
     messager.send({
             what: 'getStats',
-            pageURL: targetUrl === 'all' ? null : targetUrl
+            tabId: targetTabId
         },
         onResponseReceived
     );
@@ -363,8 +363,8 @@ function renderTransientData(internal) {
 
 /******************************************************************************/
 
-function targetUrlChangeHandler() {
-    targetUrl = this[this.selectedIndex].value;
+function targetTabIdChangeHandler() {
+    targetTabId = this[this.selectedIndex].value;
     renderStats();
     updateRequests();
 }
@@ -381,7 +381,7 @@ var installEventHandlers = function() {
     uDom('#refreshRequests').on('click', updateRequests);
     uDom('#clearRequests').on('click', clearRequests);
     uDom('input[id^="show-"][type="checkbox"]').on('change', changeFilterHandler);
-    uDom('#selectPageUrls').on('change', targetUrlChangeHandler);
+    uDom('#selectPageUrls').on('change', targetTabIdChangeHandler);
     uDom('#max-logged-requests').on('change', function(){ changeValueHandler(uDom(this), 'maxLoggedRequests', 0, 999); });
 
     // https://github.com/gorhill/httpswitchboard/issues/197
diff --git a/src/js/messaging.js b/src/js/messaging.js
index dc21446..cbe268f 100644
--- a/src/js/messaging.js
+++ b/src/js/messaging.js
@@ -156,18 +156,18 @@ var matrixSnapshot = function(tabId, details) {
         }
     };
 
+    var tabContext = µm.tabContextManager.lookup(tabId);
+
     // Allow examination of behind-the-scene requests
-    // TODO: Not portable
-    if ( details.tabURL ) {
-        if ( details.tabURL.lastIndexOf(vAPI.getURL(''), 0) === 0 ) {
-            tabId = µm.behindTheSceneTabId;
-        } else if ( details.tabURL === µm.behindTheSceneURL ) {
-            tabId = µm.behindTheSceneTabId;
-        }
+    if (
+        tabContext.rawURL.lastIndexOf(vAPI.getURL(''), 0) === 0 ||
+        tabContext.rawURL === µm.behindTheSceneURL
+    ) {
+        tabId = µm.behindTheSceneTabId;
     }
 
-    var pageStore = µm.pageStatsFromTabId(tabId);
-    if ( !pageStore ) {
+    var pageStore = µm.pageStoreFromTabId(tabId);
+    if ( pageStore === null ) {
         return r;
     }
 
@@ -371,8 +371,8 @@ var contentScriptSummaryHandler = function(tabId, details) {
     if ( !details || !details.locationURL ) {
         return;
     }
-    var pageURL = µm.pageUrlFromTabId(tabId);
-    var pageStats = µm.pageStatsFromPageUrl(pageURL);
+    var pageStore = µm.pageStoreFromTabId(tabId);
+    var pageURL = pageStore.pageUrl;
     var µmuri = µm.URI.set(details.locationURL);
     var frameURL = µmuri.normalizedURI();
     var frameHostname = µmuri.hostname;
@@ -384,7 +384,7 @@ var contentScriptSummaryHandler = function(tabId, details) {
 
     // scripts
     // https://github.com/gorhill/httpswitchboard/issues/25
-    if ( pageStats && inlineScriptBlocked ) {
+    if ( pageStore && inlineScriptBlocked ) {
         urls = details.scriptSources;
         for ( url in urls ) {
             if ( !urls.hasOwnProperty(url) ) {
@@ -394,8 +394,9 @@ var contentScriptSummaryHandler = function(tabId, details) {
                 url = frameURL + '{inline_script}';
             }
             r = µm.filterRequest(pageURL, 'script', url);
-            pageStats.recordRequest('script', url, r !== false, r);
+            pageStore.recordRequest('script', url, r !== false, r);
         }
+        pageStore.updateBadgeAsync();
     }
 
     // TODO: as of 2014-05-26, not sure this is needed anymore, since µMatrix
@@ -403,28 +404,29 @@ var contentScriptSummaryHandler = function(tabId, details) {
     // this code was put in).
     // plugins
     // https://github.com/gorhill/httpswitchboard/issues/25
-    if ( pageStats ) {
+    if ( pageStore ) {
         urls = details.pluginSources;
         for ( url in urls ) {
             if ( !urls.hasOwnProperty(url) ) {
                 continue;
             }
             r = µm.filterRequest(pageURL, 'plugin', url);
-            pageStats.recordRequest('plugin', url, r !== false, r);
+            pageStore.recordRequest('plugin', url, r !== false, r);
         }
+        pageStore.updateBadgeAsync();
     }
 
     // https://github.com/gorhill/httpswitchboard/issues/181
-    µm.onPageLoadCompleted(pageURL);
+    µm.onPageLoadCompleted(tabId);
 };
 
 /******************************************************************************/
 
-var contentScriptLocalStorageHandler = function(pageURL) {
+var contentScriptLocalStorageHandler = function(tabId, pageURL) {
     var µmuri = µm.URI.set(pageURL);
     var response = µm.mustBlock(µm.scopeFromURL(pageURL), µmuri.hostname, 'cookie');
-    µm.recordFromPageUrl(
-        pageURL,
+    µm.recordFromTabId(
+        tabId,
         'cookie',
         µmuri.rootURL() + '/{localStorage}',
         response
@@ -452,13 +454,11 @@ var onMessage = function(request, sender, callback) {
 
     switch ( request.what ) {
     case 'contentScriptHasLocalStorage':
-        response = contentScriptLocalStorageHandler(request.url);
-        µm.updateBadgeAsync(tabId);
+        response = contentScriptLocalStorageHandler(tabId, request.url);
         break;
 
     case 'contentScriptSummary':
         contentScriptSummaryHandler(tabId, request);
-        µm.updateBadgeAsync(tabId);
         break;
 
     case 'checkScriptBlacklisted':
@@ -699,22 +699,46 @@ vAPI.messaging.listen('hosts-files.js', onMessage);
 
 (function() {
 
+var µm = µMatrix;
+
+/******************************************************************************/
+
+var getTabURLs = function() {
+    var pageURLs = [];
+    var pageStores = µm.pageStores;
+
+    for ( var tabId in pageStores ) {
+        if ( pageStores.hasOwnProperty(tabId) === false ) {
+            continue;
+        }
+        pageURLs.push({
+            tabId: tabId,
+            pageURL: pageStores[tabId].pageUrl
+        });
+    }
+
+    return {
+        pageURLs: pageURLs,
+        behindTheSceneURL: µm.behindTheSceneURL
+    };
+};
+
 /******************************************************************************/
 
 // map(pageURL) => array of request log entries
 
-var getRequestLog = function(pageURL) {
+var getRequestLog = function(tabId) {
     var requestLogs = {};
-    var pageStores = µMatrix.pageStats;
-    var pageURLs = pageURL ? [pageURL] : Object.keys(pageStores);
-    var pageStore, pageRequestLog, logEntries, j, logEntry;
+    var pageStores = µm.pageStores;
+    var tabIds = tabId ? [tabId] : Object.keys(pageStores);
+    var pageStore, pageURL, pageRequestLog, logEntries, j, logEntry;
 
-    for ( var i = 0; i < pageURLs.length; i++ ) {
-        pageURL = pageURLs[i];
-        pageStore = pageStores[pageURL];
+    for ( var i = 0; i < tabIds.length; i++ ) {
+        pageStore = pageStores[tabIds[i]];
         if ( !pageStore ) {
             continue;
         }
+        pageURL = pageStore.pageUrl;
         pageRequestLog = [];
         logEntries = pageStore.requests.getLoggedRequests();
         j = logEntries.length;
@@ -733,23 +757,23 @@ var getRequestLog = function(pageURL) {
 
 /******************************************************************************/
 
-var clearRequestLog = function(pageURL) {
-    var pageStores = µMatrix.pageStats;
-    var pageURLs = pageURL ? [pageURL] : Object.keys(pageStores);
+var clearRequestLog = function(tabId) {
+    var pageStores = µm.pageStores;
+    var tabIds = tabId ? [tabId] : Object.keys(pageStores);
     var pageStore;
 
-    for ( var i = 0; i < pageURLs.length; i++ ) {
-        if ( pageStore = pageStores[pageURLs[i]] ) {
-            pageStore.requests.clearLogBuffer();
+    for ( var i = 0; i < tabIds.length; i++ ) {
+        pageStore = pageStores[tabIds[i]];
+        if ( !pageStore ) {
+            continue;
         }
+        pageStore.requests.clearLogBuffer();
     }
 };
 
 /******************************************************************************/
 
 var onMessage = function(request, sender, callback) {
-    var µm = µMatrix;
-
     // Async
     switch ( request.what ) {
     default:
@@ -761,14 +785,11 @@ var onMessage = function(request, sender, callback) {
 
     switch ( request.what ) {
     case 'getPageURLs':
-        response = {
-            pageURLs: Object.keys(µm.pageUrlToTabId),
-            behindTheSceneURL: µm.behindTheSceneURL
-        };
+        response = getTabURLs();
         break;
 
     case 'getStats':
-        var pageStore = µm.pageStats[request.pageURL];
+        var pageStore = µm.pageStores[request.tabId];
         response = {
             globalNetStats: µm.requestStats,
             pageNetStats: pageStore ? pageStore.requestStats : null,
@@ -782,11 +803,11 @@ var onMessage = function(request, sender, callback) {
         break;
 
     case 'getRequestLogs':
-        response = getRequestLog(request.pageURL);
+        response = getRequestLog(request.tabId);
         break;
 
     case 'clearRequestLogs':
-        clearRequestLog(request.pageURL);
+        clearRequestLog(request.tabId);
         break;
 
     default:
diff --git a/src/js/pagestats.js b/src/js/pagestats.js
index 76d00da..49c6f1a 100644
--- a/src/js/pagestats.js
+++ b/src/js/pagestats.js
@@ -445,28 +445,30 @@ var pageStoreJunkyard = [];
 
 /******************************************************************************/
 
-var pageStoreFactory = function(pageUrl) {
+var pageStoreFactory = function(tabContext) {
     var entry = pageStoreJunkyard.pop();
     if ( entry ) {
-        return entry.init(pageUrl);
+        return entry.init(tabContext);
     }
-    return new PageStore(pageUrl);
+    return new PageStore(tabContext);
 };
 
 /******************************************************************************/
 
-function PageStore(pageUrl) {
+function PageStore(tabContext) {
     this.requestStats = new WebRequestStats();
     this.off = false;
-    this.init(pageUrl);
+    this.init(tabContext);
 }
 
 /******************************************************************************/
 
-PageStore.prototype.init = function(pageUrl) {
-    this.pageUrl = pageUrl;
-    this.pageHostname = µm.URI.hostnameFromURI(pageUrl);
-    this.pageDomain =  µm.URI.domainFromHostname(this.pageHostname) || this.pageHostname;
+PageStore.prototype.init = function(tabContext) {
+    this.tabId = tabContext.tabId;
+    this.rawUrl = tabContext.rawURL;
+    this.pageUrl = tabContext.normalURL;
+    this.pageHostname = tabContext.rootHostname;
+    this.pageDomain =  tabContext.rootDomain;
     this.pageScriptBlocked = false;
     this.thirdpartyScript = false;
     this.requests = µm.PageRequestStats.factory();
@@ -477,8 +479,8 @@ PageStore.prototype.init = function(pageUrl) {
     this.distinctRequestCount = 0;
     this.perLoadAllowedRequestCount = 0;
     this.perLoadBlockedRequestCount = 0;
-    this.boundCount = 0;
-    this.obsoleteAfter = 0;
+    this.incinerationTimer = null;
+    this.updateBadgeTimer = null;
     return this;
 };
 
@@ -486,12 +488,24 @@ PageStore.prototype.init = function(pageUrl) {
 
 PageStore.prototype.dispose = function() {
     this.requests.dispose();
+    this.rawUrl = '';
     this.pageUrl = '';
     this.pageHostname = '';
     this.pageDomain = '';
     this.domains = {};
     this.allHostnamesString = ' ';
     this.state = {};
+
+    if ( this.incinerationTimer !== null ) {
+        clearTimeout(this.incinerationTimer);
+        this.incinerationTimer = null;
+    }
+
+    if ( this.updateBadgeTimer !== null ) {
+        clearTimeout(this.updateBadgeTimer);
+        this.updateBadgeTimer = null;
+    }
+
     if ( pageStoreJunkyard.length < 8 ) {
         pageStoreJunkyard.push(this);
     }
@@ -550,24 +564,35 @@ PageStore.prototype.recordRequest = function(type, url, block) {
 
 /******************************************************************************/
 
-// Update badge, incrementally
+// Update badge
 
 // rhill 2013-11-09: well this sucks, I can't update icon/badge
 // incrementally, as chromium overwrite the icon at some point without
 // notifying me, and this causes internal cached state to be out of sync.
 
-PageStore.prototype.updateBadge = function(tabId) {
-    var iconId = null;
-    var badgeStr = '';
-    var total = this.perLoadAllowedRequestCount + this.perLoadBlockedRequestCount;
-    if ( total ) {
-        var squareSize = 19;
-        var greenSize = squareSize * Math.sqrt(this.perLoadAllowedRequestCount / total);
-        iconId = greenSize < squareSize/2 ? Math.ceil(greenSize) : Math.floor(greenSize);
-        badgeStr = µm.formatCount(this.distinctRequestCount);
-    }
-    vAPI.setIcon(tabId, iconId, badgeStr);
-};
+PageStore.prototype.updateBadgeAsync = (function() {
+    var updateBadge = function() {
+        this.updateBadgeTimer = null;
+
+        var iconId = null;
+        var badgeStr = '';
+        var total = this.perLoadAllowedRequestCount + this.perLoadBlockedRequestCount;
+        if ( total ) {
+            var squareSize = 19;
+            var greenSize = squareSize * Math.sqrt(this.perLoadAllowedRequestCount / total);
+            iconId = greenSize < squareSize/2 ? Math.ceil(greenSize) : Math.floor(greenSize);
+            badgeStr = µm.formatCount(this.distinctRequestCount);
+        }
+
+        vAPI.setIcon(this.tabId, iconId, badgeStr);
+    };
+
+    return function() {
+        if ( this.updateBadgeTimer === null ) {
+            this.updateBadgeTimer = setTimeout(updateBadge.bind(this), 500);
+        }
+    };
+})();
 
 /******************************************************************************/
 
diff --git a/src/js/start.js b/src/js/start.js
index 23c85fb..864cc94 100644
--- a/src/js/start.js
+++ b/src/js/start.js
@@ -31,10 +31,8 @@
 
 (function() {
     var µm = µMatrix;
-    var pageStore = µm.createPageStore(µm.behindTheSceneURL);
-    µm.pageUrlToTabId[µm.behindTheSceneURL] = µm.behindTheSceneTabId;
-    µm.tabIdToPageUrl[µm.behindTheSceneTabId] = µm.behindTheSceneURL;
-    pageStore.boundCount += 1;
+    var tabContext = µm.tabContextManager.mustLookup(vAPI.noTabId);
+    µm.pageStores[vAPI.noTabId] = µm.PageStore.factory(tabContext);
 })();
 
 /******************************************************************************/
@@ -95,11 +93,13 @@
 
     // This needs to be done when the PSL is loaded
     var bindTabs = function(tabs) {
+        var tab;
         var i = tabs.length;
         // console.debug('start.js > binding %d tabs', i);
         while ( i-- ) {
-            µm.tabContextManager.commit(tabs[i].id, tabs[i].url);
-            µm.bindTabToPageStats(tabs[i].id, tabs[i].url);
+            tab = tabs[i];
+            µm.tabContextManager.commit(tab.id, tab.url);
+            µm.bindTabToPageStats(tab.id);
         }
         µm.webRequest.start();
     };
diff --git a/src/js/tab.js b/src/js/tab.js
index ff80fd0..f1d8f8c 100644
--- a/src/js/tab.js
+++ b/src/js/tab.js
@@ -55,13 +55,13 @@ var µm = µMatrix;
         return uri.normalizedURI();
     }
 
-    var url = 'http://' + scheme + '-scheme/';
+    var url = scheme + '-scheme';
 
     if ( uri.hostname !== '' ) {
-        url += uri.hostname + '/';
+        url = uri.hostname + '.' + url;
     }
 
-    return url;
+    return 'http://' + url + '/';
 };
 
 /******************************************************************************/
@@ -198,7 +198,7 @@ housekeep itself.
             this.rawURL = this.stack[this.stack.length - 1];
             this.normalURL = µm.normalizePageURL(this.tabId, this.rawURL);
             this.rootHostname = µm.URI.hostnameFromURI(this.normalURL);
-            this.rootDomain = µm.URI.domainFromHostname(this.rootHostname);
+            this.rootDomain = µm.URI.domainFromHostname(this.rootHostname) || this.rootHostname;
         }
     };
 
@@ -264,7 +264,7 @@ housekeep itself.
 
     // Find a tab context for a specific tab. If none is found, attempt to
     // fix this. When all fail, the behind-the-scene context is returned.
-    var lookup = function(tabId, url) {
+    var mustLookup = function(tabId, url) {
         var entry;
         if ( url !== undefined ) {
             entry = push(tabId, url);
@@ -315,8 +315,8 @@ housekeep itself.
         }
     };
 
-    var exists = function(tabId) {
-        return tabContexts[tabId] !== undefined;
+    var lookup = function(tabId) {
+        return tabContexts[tabId] || null;
     };
 
     // Behind-the-scene tab context
@@ -350,7 +350,7 @@ housekeep itself.
         unpush: unpush,
         commit: commit,
         lookup: lookup,
-        exists: exists,
+        mustLookup: mustLookup,
         createContext: createContext
     };
 })();
@@ -365,9 +365,15 @@ vAPI.tabs.onNavigation = function(details) {
     if ( details.frameId !== 0 ) {
         return;
     }
-    var tabContext = µm.tabContextManager.commit(details.tabId, details.url);
-    var pageStore = µm.bindTabToPageStats(details.tabId, 'afterNavigate');
 
+    // This actually can happen
+    var tabId = details.tabId;
+    if ( vAPI.isBehindTheSceneTabId(tabId) ) {
+        return;
+    }
+
+    µm.tabContextManager.commit(tabId, details.url);
+    µm.bindTabToPageStats(tabId, 'commit');
 };
 
 /******************************************************************************/
@@ -381,9 +387,14 @@ vAPI.tabs.onUpdated = function(tabId, changeInfo, tab) {
         return;
     }
 
+    // This actually can happen
+    if ( vAPI.isBehindTheSceneTabId(tabId) ) {
+        return;
+    }
+
     if ( changeInfo.url ) {
         µm.tabContextManager.commit(tabId, changeInfo.url);
-        µm.bindTabToPageStats(tabId, 'tabUpdated');
+        µm.bindTabToPageStats(tabId, 'updated');
     }
 
     // rhill 2013-12-23: Compute state after whole page is loaded. This is
@@ -396,7 +407,7 @@ vAPI.tabs.onUpdated = function(tabId, changeInfo, tab) {
     // unblocked when user un-blacklist the hostname.
     // https://github.com/gorhill/httpswitchboard/issues/198
     if ( changeInfo.status === 'complete' ) {
-        var pageStats = µm.pageStatsFromTabId(tabId);
+        var pageStats = µm.pageStoreFromTabId(tabId);
         if ( pageStats ) {
             pageStats.state = µm.computeTabState(tabId);
         }
@@ -406,10 +417,10 @@ vAPI.tabs.onUpdated = function(tabId, changeInfo, tab) {
 /******************************************************************************/
 
 vAPI.tabs.onClosed = function(tabId) {
-    if ( vAPI.isBehindTheSceneTabId(tabId) ) {
-        return;
-    }
-    µm.unbindTabFromPageStats(tabId);
+    // I could incinerate all the page stores in the crypt associated with the
+    // tab id, but this will be done anyway once all incineration timers
+    // elapse. Let's keep it simple: they can all just rot a bit more before
+    // incineration.
 };
 
 /******************************************************************************/
@@ -419,173 +430,201 @@ vAPI.tabs.registerListeners();
 /******************************************************************************/
 /******************************************************************************/
 
-// Create a new page url stats store (if not already present)
-
-µm.createPageStore = function(pageURL) {
-    // https://github.com/gorhill/httpswitchboard/issues/303
-    // At this point, the URL has been page-URL-normalized
-
-    // do not create stats store for urls which are of no interest
-    if ( pageURL.search(/^https?/) !== 0 ) {
-        return;
-    }
-    var pageStore = null;
-    if ( this.pageStats.hasOwnProperty(pageURL) ) {
-        pageStore = this.pageStats[pageURL];
-    }
-    if ( pageStore === null ) {
-        pageStore = this.PageStore.factory(pageURL);
-        // These counters are used so that icon presents an overview of how
-        // much allowed/blocked.
-        pageStore.perLoadAllowedRequestCount =
-        pageStore.perLoadBlockedRequestCount = 0;
-        this.pageStats[pageURL] = pageStore;
-    }
-
-    // TODO: revisit code, need to account for those web pages for which the
-    // URL changes with the content only updated
-    if ( pageStore.pageUrl !== pageURL ) {
-        pageStore.init(pageURL);
-    }
-
-    return pageStore;
-};
-
-/******************************************************************************/
-
 // Create an entry for the tab if it doesn't exist
 
 µm.bindTabToPageStats = function(tabId, context) {
-    if ( vAPI.isBehindTheSceneTabId(tabId) === false ) {
-        this.updateBadgeAsync(tabId);
-    }
-
     // Do not create a page store for URLs which are of no interests
-    if ( µm.tabContextManager.exists(tabId) === false ) {
-        this.unbindTabFromPageStats(tabId);
-        return null;
+    // Example: dev console
+    var tabContext = this.tabContextManager.lookup(tabId);
+    if ( tabContext === null ) {
+        throw new Error('Unmanaged tab id: ' + tabId);
     }
 
-    var tabContext = µm.tabContextManager.lookup(tabId);
-    var rawURL = tabContext.rawURL;
+    // rhill 2013-11-24: Never ever rebind chromium-behind-the-scene
+    // virtual tab.
+    // https://github.com/gorhill/httpswitchboard/issues/67
+    if ( vAPI.isBehindTheSceneTabId(tabId) ) {
+        return this.pageStores[tabId];
+    }
 
     // https://github.com/gorhill/httpswitchboard/issues/303
     // Don't rebind pages blocked by µMatrix.
     var blockedRootFramePrefix = this.webRequest.blockedRootFramePrefix;
-    if ( rawURL.lastIndexOf(blockedRootFramePrefix, 0) === 0 ) {
+    if ( tabContext.rawURL.lastIndexOf(blockedRootFramePrefix, 0) === 0 ) {
         return null;
     }
 
-    var pageStore;
-    var pageURL = tabContext.normalURL;
+    var normalURL = tabContext.normalURL;
+    var pageStore = this.pageStores[tabId] || null;
 
     // The previous page URL, if any, associated with the tab
-    if ( this.tabIdToPageUrl.hasOwnProperty(tabId) ) {
-        var previousPageURL = this.tabIdToPageUrl[tabId];
-
+    if ( pageStore !== null ) {
         // No change, do not rebind
-        if ( previousPageURL === pageURL ) {
-            return this.pageStats[pageURL];
+        if ( pageStore.pageUrl === normalURL ) {
+            return pageStore;
+        }
+
+        // Do not change anything if it's weak binding -- typically when
+        // binding from network request handler.
+        if ( context === 'weak' ) {
+            return pageStore;
         }
 
         // https://github.com/gorhill/uMatrix/issues/37
-        // Just rebind whenever possible: the URL changed, but the document maybe is the same.
+        // Just rebind whenever possible: the URL changed, but the document
+        // maybe is the same.
         // Example: Google Maps, Github
-
         // https://github.com/gorhill/uMatrix/issues/72
         // Need to double-check that the new scope is same as old scope
-        if ( context === 'pageUpdated' ) {
-            pageStore = this.pageStats[previousPageURL];
-            if ( pageStore.pageHostname === this.hostnameFromURL(pageURL) ) {
-                pageStore.pageUrl = pageURL;
-                delete this.pageStats[previousPageURL];
-                this.pageStats[pageURL] = pageStore;
-                delete this.pageUrlToTabId[previousPageURL];
-                this.pageUrlToTabId[pageURL] = tabId;
-                this.tabIdToPageUrl[tabId] = pageURL;
-                return pageStore;
-            }
+        if ( context === 'updated' && pageStore.pageHostname === tabContext.rootHostname ) {
+            pageStore.rawURL = tabContext.rawURL;
+            pageStore.normalURL = normalURL;
+            return pageStore;
         }
+
+        // We won't be reusing this page store.
+        this.unbindTabFromPageStats(tabId);
     }
 
-    pageStore = this.createPageStore(pageURL, context);
+    // Try to resurrect first.
+    pageStore = this.resurrectPageStore(tabId, normalURL);
+    if ( pageStore === null ) {
+        pageStore = this.PageStore.factory(tabContext);
+    }
+    this.pageStores[tabId] = pageStore;
 
     // console.debug('tab.js > bindTabToPageStats(): dispatching traffic in tab id %d to page store "%s"', tabId, pageUrl);
 
-    // rhill 2013-11-24: Never ever rebind chromium-behind-the-scene
-    // virtual tab.
-    // https://github.com/gorhill/httpswitchboard/issues/67
-    if ( tabId === this.behindTheSceneTabId ) {
-        return pageStore;
+    // https://github.com/gorhill/uMatrix/issues/37
+    pageStore.updateBadgeAsync();
+
+    return pageStore;
+};
+
+/******************************************************************************/
+
+µm.unbindTabFromPageStats = function(tabId) {
+    // Never unbind behind-the-scene page store.
+    if ( vAPI.isBehindTheSceneTabId(tabId) ) {
+        return;
     }
 
-    // https://github.com/gorhill/uMatrix/issues/37
-    this.updateBadgeAsync(tabId);
+    var pageStore = this.pageStores[tabId] || null;
+    if ( pageStore === null ) {
+        return;
+    }
+    delete this.pageStores[tabId];
 
-    this.unbindTabFromPageStats(tabId);
+    if ( pageStore.incinerationTimer ) {
+        clearTimeout(pageStore.incinerationTimer);
+        pageStore.incinerationTimer = null;
+    }
 
-    // rhill 2014-02-08: Do not create an entry if no page store
-    // exists (like when visiting about:blank)
-    // https://github.com/gorhill/httpswitchboard/issues/186
-    if ( !pageStore ) {
+    if ( this.pageStoreCemetery.hasOwnProperty(tabId) === false ) {
+        this.pageStoreCemetery[tabId] = {};
+    }
+    var pageStoreCrypt = this.pageStoreCemetery[tabId];
+
+    var pageURL = pageStore.pageUrl;
+    pageStoreCrypt[pageURL] = pageStore;
+
+    pageStore.incinerationTimer = setTimeout(
+        this.incineratePageStore.bind(this, tabId, pageURL),
+        4 * 60 * 1000
+    );
+};
+
+/******************************************************************************/
+
+µm.resurrectPageStore = function(tabId, pageURL) {
+    if ( this.pageStoreCemetery.hasOwnProperty(tabId) === false ) {
         return null;
     }
+    var pageStoreCrypt = this.pageStoreCemetery[tabId];
+
+    if ( pageStoreCrypt.hasOwnProperty(pageURL) === false ) {
+        return null;
+    }
+
+    var pageStore = pageStoreCrypt[pageURL];
+
+    if ( pageStore.incinerationTimer !== null ) {
+        clearTimeout(pageStore.incinerationTimer);
+        pageStore.incinerationTimer = null;
+    }
 
-    this.pageUrlToTabId[pageURL] = tabId;
-    this.tabIdToPageUrl[tabId] = pageURL;
-    pageStore.boundCount += 1;
+    delete pageStoreCrypt[pageURL];
+    if ( Object.keys(pageStoreCrypt).length === 0 ) {
+        delete this.pageStoreCemetery[tabId];
+    }
 
     return pageStore;
 };
 
 /******************************************************************************/
 
-µm.unbindTabFromPageStats = function(tabId) {
-    if ( this.tabIdToPageUrl.hasOwnProperty(tabId) === false ) {
+µm.incineratePageStore = function(tabId, pageURL) {
+    if ( this.pageStoreCemetery.hasOwnProperty(tabId) === false ) {
         return;
     }
-    var pageURL = this.tabIdToPageUrl[tabId];
-    if ( this.pageStats.hasOwnProperty(pageURL) ) {
-        var pageStore = this.pageStats[pageURL];
-        pageStore.boundCount -= 1;
-        if ( pageStore.boundCount === 0 ) {
-            pageStore.obsoleteAfter = Date.now() + (5 * 60 * 1000);
-        }
+    var pageStoreCrypt = this.pageStoreCemetery[tabId];
+
+    if ( pageStoreCrypt.hasOwnProperty(pageURL) === false ) {
+        return;
+    }
+
+    var pageStore = pageStoreCrypt[pageURL];
+    if ( pageStore.incinerationTimer !== null ) {
+        clearTimeout(pageStore.incinerationTimer);
+        pageStore.incinerationTimer = null;
+    }
+
+    delete pageStoreCrypt[pageURL];
+    if ( Object.keys(pageStoreCrypt).length === 0 ) {
+        delete this.pageStoreCemetery[tabId];
     }
-    delete this.tabIdToPageUrl[tabId];
-    delete this.pageUrlToTabId[pageURL];
+
+    pageStore.dispose();
 };
 
 /******************************************************************************/
 
-// Log a request
+µm.pageStoreFromTabId = function(tabId) {
+    return this.pageStores[tabId] || null;
+};
 
-µm.recordFromTabId = function(tabId, type, url, blocked) {
-    var pageStats = this.pageStatsFromTabId(tabId);
-    if ( pageStats ) {
-        pageStats.recordRequest(type, url, blocked);
-        this.updateBadgeAsync(tabId);
-    }
+// Never return null
+µm.mustPageStoreFromTabId = function(tabId) {
+    return this.pageStores[tabId] || this.pageStores[vAPI.noTabId];
 };
 
-µm.recordFromPageUrl = function(pageUrl, type, url, blocked, reason) {
-    var pageStats = this.pageStatsFromPageUrl(pageUrl);
-    if ( pageStats ) {
-        pageStats.recordRequest(type, url, blocked, reason);
+/******************************************************************************/
+
+// Log a request
+
+µm.recordFromTabId = function(tabId, type, url, blocked) {
+    var pageStore = this.pageStoreFromTabId(tabId);
+    if ( pageStore ) {
+        pageStore.recordRequest(type, url, blocked);
+        pageStore.updateBadgeAsync();
     }
 };
 
 /******************************************************************************/
 
-µm.onPageLoadCompleted = function(pageURL) {
-    var pageStats = this.pageStatsFromPageUrl(pageURL);
-    if ( !pageStats ) {
+µm.onPageLoadCompleted = function(tabId) {
+    var pageStore = this.pageStoreFromTabId(tabId);
+    if ( !pageStore ) {
         return;
     }
 
     // https://github.com/gorhill/httpswitchboard/issues/181
-    if ( pageStats.thirdpartyScript ) {
-        pageStats.recordRequest('script', pageURL + '{3rd-party_scripts}', pageStats.pageScriptBlocked);
+    if ( pageStore.thirdpartyScript ) {
+        pageStore.recordRequest(
+            'script',
+            pageStore.pageURL + '{3rd-party_scripts}',
+            pageStore.pageScriptBlocked
+        );
     }
 };
 
@@ -609,7 +648,7 @@ vAPI.tabs.registerListeners();
         var i = chromeTabs.length;
         while ( i-- ) {
             tabId = chromeTabs[i].id;
-            if ( µm.tabExists(tabId) ) {
+            if ( µm.pageStores.hasOwnProperty(tabId) ) {
                 µm.smartReloadTab(tabId);
             }
         }
@@ -627,7 +666,7 @@ vAPI.tabs.registerListeners();
 // Reload content of a tab
 
 µm.smartReloadTab = function(tabId) {
-    var pageStats = this.pageStatsFromTabId(tabId);
+    var pageStats = this.pageStoreFromTabId(tabId);
     if ( !pageStats ) {
         //console.error('HTTP Switchboard> µMatrix.smartReloadTab(): page stats for tab id %d not found', tabId);
         return;
@@ -691,20 +730,8 @@ vAPI.tabs.registerListeners();
 
 /******************************************************************************/
 
-// Required since not all tabs are of interests to HTTP Switchboard.
-// Examples:
-//      `chrome://extensions/`
-//      `chrome-devtools://devtools/devtools.html`
-//      etc.
-
-µm.tabExists = function(tabId) {
-    return !!this.pageUrlFromTabId(tabId);
-};
-
-/******************************************************************************/
-
 µm.computeTabState = function(tabId) {
-    var pageStats = this.pageStatsFromTabId(tabId);
+    var pageStats = this.pageStoreFromTabId(tabId);
     if ( !pageStats ) {
         //console.error('tab.js > µMatrix.computeTabState(): page stats for tab id %d not found', tabId);
         return {};
@@ -738,36 +765,8 @@ vAPI.tabs.registerListeners();
 
 /******************************************************************************/
 
-µm.pageUrlFromTabId = function(tabId) {
-    return this.tabIdToPageUrl[tabId];
-};
-
-µm.pageUrlFromPageStats = function(pageStats) {
-    if ( pageStats ) {
-        return pageStats.pageUrl;
-    }
-    return undefined;
-};
-
-µm.pageStatsFromTabId = function(tabId) {
-    var pageUrl = this.tabIdToPageUrl[tabId];
-    if ( pageUrl ) {
-        return this.pageStats[pageUrl];
-    }
-    return undefined;
-};
-
-µm.pageStatsFromPageUrl = function(pageURL) {
-    if ( pageURL ) {
-        return this.pageStats[this.normalizePageURL(pageURL)];
-    }
-    return null;
-};
-
-/******************************************************************************/
-
 µm.resizeLogBuffers = function(size) {
-    var pageStores = this.pageStats;
+    var pageStores = this.pageStores;
     for ( var pageURL in pageStores ) {
         if ( pageStores.hasOwnProperty(pageURL) ) {
             pageStores[pageURL].requests.resizeLogBuffer(size);
@@ -783,58 +782,4 @@ vAPI.tabs.registerListeners();
 
 /******************************************************************************/
 
-// Garbage collect stale url stats entries
-(function() {
-    var gcPageStats = function() {
-        var pageStore;
-        var now = Date.now();
-        for ( var pageURL in µm.pageStats ) {
-            if ( µm.pageStats.hasOwnProperty(pageURL) === false ) {
-                continue;
-            }
-            pageStore = µm.pageStats[pageURL];
-            if ( pageStore.boundCount !== 0 ) {
-                continue;
-            }
-            if ( pageStore.obsoleteAfter > now ) {
-                continue;
-            }
-            µm.cookieHunter.removePageCookies(pageStore);
-            pageStore.dispose();
-            delete µm.pageStats[pageURL];
-        }
-
-        // Prune content of chromium-behind-the-scene virtual tab
-        // When `suggest-as-you-type` is on in Chromium, this can lead to a
-        // LOT of uninteresting behind the scene requests.
-        pageStore = µm.pageStats[µm.behindTheSceneURL];
-        if ( !pageStore ) {
-            return;
-        }
-        var reqKeys = pageStore.requests.getRequestKeys();
-        if ( reqKeys.length <= µm.behindTheSceneMaxReq ) {
-            return;
-        }
-        reqKeys = reqKeys.sort(function(a,b){
-            return pageStore.requests[b] - pageStore.requests[a];
-        }).slice(µm.behindTheSceneMaxReq);
-        var iReqKey = reqKeys.length;
-        while ( iReqKey-- ) {
-            pageStore.requests.disposeOne(reqKeys[iReqKey]);
-        }
-    };
-
-    // Time somewhat arbitrary: If a web page has not been in a tab
-    // for some time minutes, flush its stats.
-    µm.asyncJobs.add(
-        'gcPageStats',
-        null,
-        gcPageStats,
-        (2.5 * 60 * 1000) | 0,
-        true
-    );
-})();
-
-/******************************************************************************/
-
 })();
diff --git a/src/js/traffic.js b/src/js/traffic.js
index c7371b4..489d23d 100644
--- a/src/js/traffic.js
+++ b/src/js/traffic.js
@@ -39,57 +39,55 @@ var rootFrameReplacement = [
     '<meta charset="utf-8" />',
     '<style>',
     '@font-face {',
-    'font-family:httpsb;',
-    'font-style:normal;',
-    'font-weight:400;',
-    'src: local("httpsb"),url("',
-    µMatrix.fontCSSURL,
-    '") format("truetype");',
+        'font-family:httpsb;',
+        'font-style:normal;',
+        'font-weight:400;',
+        'src: local("httpsb"),url("', µMatrix.fontCSSURL, '") format("truetype");',
     '}',
     'body {',
-    'margin:0;',
-    'border:0;',
-    'padding:0;',
-    'font:15px httpsb,sans-serif;',
-    'width:100%;',
-    'height:100%;',
-    'background-color:transparent;',
-    'background-size:10px 10px;',
-    'background-image:',
-    'repeating-linear-gradient(',
-    '-45deg,',
-    'rgba(204,0,0,0.5),rgba(204,0,0,0.5) 24%,',
-    'transparent 26%,transparent 49%,',
-    'rgba(204,0,0,0.5) 51%,rgba(204,0,0,0.5) 74%,',
-    'transparent 76%,transparent',
-    ');',
-    'text-align: center;',
+        'margin:0;',
+        'border:0;',
+        'padding:0;',
+        'font:15px httpsb,sans-serif;',
+        'width:100%;',
+        'height:100%;',
+        'background-color:transparent;',
+        'background-size:10px 10px;',
+        'background-image:',
+        'repeating-linear-gradient(',
+            '-45deg,',
+            'rgba(204,0,0,0.5),rgba(204,0,0,0.5) 24%,',
+            'transparent 26%,transparent 49%,',
+            'rgba(204,0,0,0.5) 51%,rgba(204,0,0,0.5) 74%,',
+            'transparent 76%,transparent',
+        ');',
+        'text-align: center;',
     '}',
     '#p {',
-    'margin:8px;',
-    'padding:4px;',
-    'display:inline-block;',
-    'background-color:white;',
+        'margin:8px;',
+        'padding:4px;',
+        'display:inline-block;',
+        'background-color:white;',
     '}',
     '#t {',
-    'margin:2px;',
-    'border:0;',
-    'padding:0 2px;',
-    'display:inline-block;',
+        'margin:2px;',
+        'border:0;',
+        'padding:0 2px;',
+        'display:inline-block;',
     '}',
     '#t b {',
-    'padding:0 4px;',
-    'background-color:#eee;',
-    'font-weight:normal;',
+        'padding:0 4px;',
+        'background-color:#eee;',
+        'font-weight:normal;',
     '}',
     '</style>',
     '<link href="{{cssURL}}?url={{originalURL}}&hostname={{hostname}}&t={{now}}" rel="stylesheet" type="text/css">',
     '<title>Blocked by &mu;Matrix</title>',
     '</head>',
     '<body>',
-    '<div id="p">',
-    '<div id="t"><b>{{hostname}}</b> blocked by &mu;Matrix</div>',
-    '</div>',
+        '<div id="p">',
+        '<div id="t"><b>{{hostname}}</b> blocked by &mu;Matrix</div>',
+        '</div>',
     '</body>',
     '</html>'
 ].join('');
@@ -100,56 +98,54 @@ var subFrameReplacement = [
     '<head>',
     '<meta charset="utf-8" />',
     '<style>',
-    '@font-face{',
-    'font-family:httpsb;',
-    'font-style:normal;',
-    'font-weight:400;',
-    'src:local("httpsb"),url("',
-    µMatrix.fontCSSURL,
-    '") format("truetype");',
+        '@font-face{',
+        'font-family:httpsb;',
+        'font-style:normal;',
+        'font-weight:400;',
+        'src:local("httpsb"),url("', µMatrix.fontCSSURL, '") format("truetype");',
     '}',
     'body{',
-    'margin:0;',
-    'border:0;',
-    'padding:0;',
-    'font:13px httpsb,sans-serif;',
+        'margin:0;',
+        'border:0;',
+        'padding:0;',
+        'font:13px httpsb,sans-serif;',
     '}',
     '#bg{',
-    'border:1px dotted {{subframeColor}};',
-    'position:absolute;',
-    'top:0;',
-    'right:0;',
-    'bottom:0;',
-    'left:0;',
-    'background-color:transparent;',
-    'background-size:10px 10px;',
-    'background-image:',
-    'repeating-linear-gradient(',
-    '-45deg,',
-    '{{subframeColor}},{{subframeColor}} 24%,',
-    'transparent 25%,transparent 49%,',
-    '{{subframeColor}} 50%,{{subframeColor}} 74%,',
-    'transparent 75%,transparent',
-    ');',
-    'opacity:{{subframeOpacity}};',
-    'text-align:center;',
+        'border:1px dotted {{subframeColor}};',
+        'position:absolute;',
+        'top:0;',
+        'right:0;',
+        'bottom:0;',
+        'left:0;',
+        'background-color:transparent;',
+        'background-size:10px 10px;',
+        'background-image:',
+        'repeating-linear-gradient(',
+            '-45deg,',
+            '{{subframeColor}},{{subframeColor}} 24%,',
+            'transparent 25%,transparent 49%,',
+            '{{subframeColor}} 50%,{{subframeColor}} 74%,',
+            'transparent 75%,transparent',
+        ');',
+        'opacity:{{subframeOpacity}};',
+        'text-align:center;',
     '}',
     '#bg > div{',
-    'display:inline-block;',
-    'background-color:rgba(255,255,255,1);',
+        'display:inline-block;',
+        'background-color:rgba(255,255,255,1);',
     '}',
     '#bg > div > a {',
-    'padding:0 2px;',
-    'display:inline-block;',
-    'color:white;',
-    'background-color:{{subframeColor}};',
-    'text-decoration:none;',
+        'padding:0 2px;',
+        'display:inline-block;',
+        'color:white;',
+        'background-color:{{subframeColor}};',
+        'text-decoration:none;',
     '}',
     '</style>',
     '<title>Blocked by &mu;Matrix</title>',
     '</head>',
     '<body title="&ldquo;{{hostname}}&rdquo; frame\nblocked by &mu;Matrix">',
-    '<div id="bg"><div><a href="{{frameSrc}}" target="_blank">{{hostname}}</a></div></div>',
+        '<div id="bg"><div><a href="{{frameSrc}}" target="_blank">{{hostname}}</a></div></div>',
     '</body>',
     '</html>'
 ].join('');
@@ -202,44 +198,31 @@ var onBeforeRootFrameRequestHandler = function(details) {
 
     µm.tabContextManager.push(tabId, requestURL);
 
-    if ( vAPI.isBehindTheSceneTabId(tabId) ) {
-        tabId = µm.behindTheSceneTabId;
-    } else {
-        µm.bindTabToPageStats(tabId);
-    }
-
-    var uri = µm.URI.set(details.url);
-    if ( uri.scheme.indexOf('http') === -1 ) {
-        return;
-    }
-
-    var requestHostname = uri.hostname;
-    var pageStore = µm.pageStatsFromTabId(tabId);
+    var tabContext = µm.tabContextManager.mustLookup(tabId);
+    var pageStore = µm.bindTabToPageStats(tabId, 'weak');
 
     // Disallow request as per matrix?
-    var block = µm.mustBlock(pageStore.pageHostname, requestHostname, 'doc');
+    var block = µm.mustBlock(tabContext.rootHostname, details.hostname, 'doc');
 
     // console.debug('onBeforeRequestHandler()> block=%s "%s": %o', block, details.url, details);
 
-    // whitelisted?
+
+    // Not blocked
     if ( !block ) {
         // rhill 2013-11-07: Senseless to do this for behind-the-scene requests.
         // rhill 2013-12-03: Do this here only for root frames.
-        if ( tabId !== µm.behindTheSceneTabId ) {
-            µm.cookieHunter.recordPageCookies(pageStore);
-        }
+        µm.cookieHunter.recordPageCookies(pageStore);
         return;
     }
 
-    // blacklisted
+    // Blocked
 
     // rhill 2014-01-15: Delay logging of non-blocked top `main_frame`
     // requests, in order to ensure any potential redirects is reported
     // in proper chronological order.
     // https://github.com/gorhill/httpswitchboard/issues/112
     pageStore.recordRequest('doc', requestURL, block);
-
-    µm.updateBadgeAsync(tabId);
+    pageStore.updateBadgeAsync();
 
     // If it's a blacklisted frame, redirect to frame.html
     // rhill 2013-11-05: The root frame contains a link to noop.css, this
@@ -308,11 +291,8 @@ var onBeforeRequestHandler = function(details) {
     // to scope on unknown scheme? Etc.
     // https://github.com/gorhill/httpswitchboard/issues/191
     // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
-    var tabId = details.tabId;
-    var pageStore = µm.pageStatsFromTabId(tabId);
-    if ( !pageStore ) {
-        pageStore = µm.pageStatsFromTabId(µm.behindTheSceneTabId);
-    }
+    var pageStore = µm.mustPageStoreFromTabId(details.tabId);
+    var tabId = pageStore.tabId;
 
     // Disallow request as per temporary matrix?
     var block = µm.mustBlock(pageStore.pageHostname, requestHostname, requestType);
@@ -324,8 +304,7 @@ var onBeforeRequestHandler = function(details) {
     // been constructed for logging purpose. Use this synthetic URL if
     // it is available.
     pageStore.recordRequest(requestType, requestURL, block);
-
-    µm.updateBadgeAsync(tabId);
+    pageStore.updateBadgeAsync();
 
     // whitelisted?
     if ( !block ) {
@@ -357,7 +336,6 @@ var onBeforeRequestHandler = function(details) {
 // Sanitize outgoing headers as per user settings.
 
 var onBeforeSendHeadersHandler = function(details) {
-
     var µm = µMatrix;
 
     // console.debug('onBeforeSendHeadersHandler()> "%s": %o', details.url, details);
@@ -369,12 +347,8 @@ var onBeforeSendHeadersHandler = function(details) {
     // to scope on unknown scheme? Etc.
     // https://github.com/gorhill/httpswitchboard/issues/191
     // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
-    var tabId = details.tabId;
-    var pageStore = µm.pageStatsFromTabId(tabId);
-    if ( !pageStore ) {
-        tabId = µm.behindTheSceneTabId;
-        pageStore = µm.pageStatsFromTabId(tabId);
-    }
+    var pageStore = µm.mustPageStoreFromTabId(details.tabId);
+    var tabId = pageStore.tabId;
 
     // https://github.com/gorhill/httpswitchboard/issues/342
     // Is this hyperlink auditing?
@@ -404,7 +378,7 @@ var onBeforeSendHeadersHandler = function(details) {
         if ( linkAuditor !== '' ) {
             var block = µm.userSettings.processHyperlinkAuditing;
             pageStore.recordRequest('other', requestURL + '{Ping-To:' + linkAuditor + '}', block);
-            µm.updateBadgeAsync(tabId);
+            pageStore.updateBadgeAsync();
             if ( block ) {
                 µm.hyperlinkAuditingFoiledCounter += 1;
                 return { 'cancel': true };
@@ -464,11 +438,10 @@ var foilRefererHeaders = function(µm, toHostname, details) {
 // https://github.com/gorhill/httpswitchboard/issues/35
 
 var onHeadersReceived = function(details) {
-
     // console.debug('onHeadersReceived()> "%s": %o', details.url, details);
 
     // Ignore schemes other than 'http...'
-    if ( details.url.slice(0, 4) !== 'http' ) {
+    if ( details.url.lastIndexOf('http', 0) !== 0 ) {
         return;
     }
 
@@ -484,30 +457,24 @@ var onHeadersReceived = function(details) {
 /******************************************************************************/
 
 var onMainDocHeadersReceived = function(details) {
+    // https://github.com/gorhill/uMatrix/issues/145
+    // Check if the main_frame is a download
+    if ( headerValue(details.responseHeaders, 'content-disposition').lastIndexOf('attachment', 0) === 0 ) {
+        µb.tabContextManager.unpush(details.tabId, details.url);
+    }
 
     // console.debug('onMainDocHeadersReceived()> "%s": %o', details.url, details);
 
     var µm = µMatrix;
 
-    // Do not ignore traffic outside tabs.
-    // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
-    var tabId = details.tabId;
-    if ( tabId < 0 ) {
-        tabId = µm.behindTheSceneTabId;
-    }
-
-    var µmuri = µm.URI.set(details.url);
-    var requestURL = µmuri.normalizedURI();
-    var requestScheme = µmuri.scheme;
-    var requestHostname = µmuri.hostname;
-
     // rhill 2013-12-07:
     // Apparently in Opera, onBeforeRequest() is triggered while the
     // URL is not yet bound to a tab (-1), which caused the code here
-    // to not be able to lookup the pageStats. So let the code here bind
+    // to not be able to lookup the page store. So let the code here bind
     // the page to a tab if not done yet.
     // https://github.com/gorhill/httpswitchboard/issues/75
-    µm.bindTabToPageStats(tabId, requestURL);
+
+    // TODO: check this works fine on Opera
 
     // Re-classify orphan HTTP requests as behind-the-scene requests. There is
     // not much else which can be done, because there are URLs
@@ -516,12 +483,12 @@ var onMainDocHeadersReceived = function(details) {
     // to scope on unknown scheme? Etc.
     // https://github.com/gorhill/httpswitchboard/issues/191
     // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
-    var pageStats = µm.pageStatsFromTabId(tabId);
-    if ( !pageStats ) {
-        tabId = µm.behindTheSceneTabId;
-        pageStats = µm.pageStatsFromTabId(tabId);
-    }
-
+    var pageStore = µm.mustPageStoreFromTabId(details.tabId);
+    var tabId = pageStore.tabId;
+    var µmuri = µm.URI.set(details.url);
+    var requestURL = µmuri.normalizedURI();
+    var requestScheme = µmuri.scheme;
+    var requestHostname = µmuri.hostname;
     var headers = details.responseHeaders;
 
     // Simplify code paths by splitting func in two different handlers, one
@@ -530,7 +497,7 @@ var onMainDocHeadersReceived = function(details) {
     // https://github.com/gorhill/httpswitchboard/issues/112
     // rhill 2014-02-10: Handle all redirects.
     // https://github.com/gorhill/httpswitchboard/issues/188
-    if ( /\s+30[12378]\s+/.test(details.statusLine) ) {
+    if ( /\b30[12378]\b/.test(details.statusLine) ) {
         var i = headerIndexFromName('location', headers);
         if ( i >= 0 ) {
             // rhill 2014-01-20: Be ready to handle relative URLs.
@@ -557,22 +524,22 @@ var onMainDocHeadersReceived = function(details) {
         }
 
         while ( destinationURL = mainFrameStack.pop() ) {
-            pageStats.recordRequest('doc', destinationURL, false);
+            pageStore.recordRequest('doc', destinationURL, false);
         }
-        µm.updateBadgeAsync(tabId);
+        pageStore.updateBadgeAsync();
     }
 
     // Maybe modify inbound headers
     var csp = '';
 
     // Enforce strict HTTPS?
-    if ( requestScheme === 'https' && µm.tMatrix.evaluateSwitchZ('https-strict', pageStats.pageHostname) ) {
+    if ( requestScheme === 'https' && µm.tMatrix.evaluateSwitchZ('https-strict', pageStore.pageHostname) ) {
         csp += "default-src chrome-search: data: https: wss: 'unsafe-eval' 'unsafe-inline';";
     }
 
     // https://github.com/gorhill/httpswitchboard/issues/181
-    pageStats.pageScriptBlocked = µm.mustBlock(pageStats.pageHostname, requestHostname, 'script');
-    if ( pageStats.pageScriptBlocked ) {
+    pageStore.pageScriptBlocked = µm.mustBlock(pageStore.pageHostname, requestHostname, 'script');
+    if ( pageStore.pageScriptBlocked ) {
         // If javascript not allowed, say so through a `Content-Security-Policy` directive.
         // console.debug('onMainDocHeadersReceived()> PAGE CSP "%s": %o', details.url, details);
         csp += " script-src 'none'";
@@ -599,25 +566,13 @@ var onSubDocHeadersReceived = function(details) {
     // Do not ignore traffic outside tabs.
     // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
     var tabId = details.tabId;
-    if ( tabId < 0 ) {
-        tabId = µm.behindTheSceneTabId;
-    }
-
-    // Re-classify orphan HTTP requests as behind-the-scene requests. There is
-    // not much else which can be done, because there are URLs
-    // which cannot be handled by HTTP Switchboard, i.e. `opera://startpage`,
-    // as this would lead to complications with no obvious solution, like how
-    // to scope on unknown scheme? Etc.
-    // https://github.com/gorhill/httpswitchboard/issues/191
-    // https://github.com/gorhill/httpswitchboard/issues/91#issuecomment-37180275
-    var pageStats = µm.pageStatsFromTabId(tabId);
-    if ( !pageStats ) {
-        tabId = µm.behindTheSceneTabId;
-        pageStats = µm.pageStatsFromTabId(tabId);
+    var tabContext = µm.tabContextManager.lookup(tabId);
+    if ( tabContext === null ) {
+        return;
     }
 
     // Evaluate
-    if ( µm.mustAllow(pageStats.pageHostname, µm.hostnameFromURL(details.url), 'script') ) {
+    if ( µm.mustAllow(tabContext.rootHostname, µm.hostnameFromURL(details.url), 'script') ) {
         return;
     }
 
@@ -644,7 +599,7 @@ var onSubDocHeadersReceived = function(details) {
 
     details.responseHeaders.push({
         'name': 'Content-Security-Policy',
-        'value': 'sandbox allow-forms allow-same-origin allow-popups allow-top-navigation'
+        'value': "script-src 'none'"
     });
 
     return { responseHeaders: details.responseHeaders };
@@ -652,6 +607,18 @@ var onSubDocHeadersReceived = function(details) {
 
 /******************************************************************************/
 
+var headerValue = function(headers, name) {
+    var i = headers.length;
+    while ( i-- ) {
+        if ( headers[i].name.toLowerCase() === name ) {
+            return headers[i].value.trim();
+        }
+    }
+    return '';
+};
+
+/******************************************************************************/
+
 var onErrorOccurredHandler = function(details) {
     // console.debug('onErrorOccurred()> "%s": %o', details.url, details);
     var requestType = requestTypeNormalizer[details.type] || 'other';
@@ -662,7 +629,7 @@ var onErrorOccurredHandler = function(details) {
     }
 
     var µm = µMatrix;
-    var pageStats = µm.pageStatsFromPageUrl(details.url);
+    var pageStats = µm.pageStoreFromTabId(details.tabId);
     if ( !pageStats ) {
         return;
     }
@@ -684,7 +651,7 @@ var onErrorOccurredHandler = function(details) {
     while ( destinationURL = mainFrameStack.pop() ) {
         pageStats.recordRequest('doc', destinationURL, false);
     }
-    µm.updateBadgeAsync(details.tabId);
+    pageStats.updateBadgeAsync();
 };
 
 /******************************************************************************/