Browser videos start without waiting for a second tap, and video streams skip the ad lists

The blocker also logs what it cost each page, to tell whether it slows anything down.

gearslip/src/main/java/app/seb3thehacker/gearslip/browser/adblock/AdBlockManager.kt

@@ -71,6 +71,11 @@ object AdBlockManager {
     private val refreshRunning = AtomicBoolean(false)
     private val autoUpdateAttempted = AtomicBoolean(false)
     private val blockedCount = AtomicLong(0)
+    // Time spent deciding requests since the last page load, for the log line that tells whether
+    // the blocker is what makes a page or a video slow to start.
+    private val checkedCount = AtomicLong(0)
+    private val checkedNanos = AtomicLong(0)
+    private val blockedSincePage = AtomicLong(0)
 
     val isEngineReady: Boolean get() = engine != null
     val blockedRequestCount: Long get() = blockedCount.get()
@@ -275,6 +280,27 @@ object AdBlockManager {
      */
     fun response(request: WebResourceRequest, pageUrl: String?): WebResourceResponse? {
         if (!enabled) return null
+        // A ranged request is a video or audio stream fetching its next piece: ads never come
+        // that way, and a stream makes hundreds of them, so they skip the lists entirely.
+        if (request.requestHeaders?.keys?.any { it.equals("Range", ignoreCase = true) } == true) return null
+        val started = System.nanoTime()
+        try {
+            return decide(request, pageUrl)
+        } finally {
+            checkedCount.incrementAndGet()
+            checkedNanos.addAndGet(System.nanoTime() - started)
+        }
+    }
+
+    /** Logs what the blocker cost the page that just finished loading, and starts counting afresh. */
+    fun logPageCost(url: String?) {
+        val count = checkedCount.getAndSet(0)
+        val ms = checkedNanos.getAndSet(0) / 1_000_000
+        val blocked = blockedSincePage.getAndSet(0)
+        if (count > 0) GearslipLog.i("adblock: $count requests checked in ${ms}ms, $blocked blocked, for ${url?.substringBefore('?')}")
+    }
+
+    private fun decide(request: WebResourceRequest, pageUrl: String?): WebResourceResponse? {
         val current = engine ?: return null
 
         // Never interfere with top-level navigation: a mistake there costs the whole page.
@@ -296,6 +322,7 @@ object AdBlockManager {
         }.getOrNull() ?: return null
 
         blockedCount.incrementAndGet()
+        blockedSincePage.incrementAndGet()
         return blockedResponse(request, match.redirectResource)
     }
 

gearslip/src/main/java/app/seb3thehacker/gearslip/car/WebApp.kt

@@ -192,6 +192,11 @@ fun WebApp(content: String) {
                     settings.domStorageEnabled = true
                     settings.loadWithOverviewMode = true
                     settings.useWideViewPort = true
+                    // A video starts when the page asks, as in a normal browser. Left at Android's
+                    // default, YouTube's player waits for a second tap before it will play.
+                    settings.mediaPlaybackRequiresUserGesture = false
+                    // Draws the page before it's on screen, so the first frame is ready sooner.
+                    settings.offscreenPreRaster = true
                     webViewClient = LoggingClient(ring, documentUrl, onStarted = { pageUrl = it }) { view ->
                         canGoForward = view.canGoForward()
                         pageUrl = view.url
@@ -339,6 +344,7 @@ private class LoggingClient(
     override fun onPageFinished(view: WebView?, url: String?) {
         documentUrl.set(url)
         GearslipLog.i("car web page loaded: $url")
+        AdBlockManager.logPageCost(url)
         view?.let(onLoaded)
         view?.evaluateJavascript(FOCUS_TRACKING_JS, null)
         view?.evaluateJavascript(focusRingJs(ring), null)