Drop all timeline seeks outside of the seekable range.

Source/core/html/shadow/MediaControlElements.cpp

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 19 matching lines @@
 #include "config.h"
 #include "core/html/shadow/MediaControlElements.h"
 
 #include "bindings/core/v8/ExceptionStatePlaceholder.h"
 #include "core/dom/DOMTokenList.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/events/MouseEvent.h"
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLVideoElement.h"
 #include "core/html/MediaController.h"
+#include "core/html/TimeRanges.h"
 #include "core/html/shadow/MediaControls.h"
 #include "core/html/track/TextTrack.h"
 #include "core/html/track/vtt/VTTRegionList.h"
 #include "core/page/EventHandler.h"
 #include "core/rendering/RenderMediaControlElements.h"
 #include "core/rendering/RenderSlider.h"
 #include "core/rendering/RenderTheme.h"
 #include "core/rendering/RenderVideo.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
 using namespace HTMLNames;
 
 static const AtomicString& getMediaControlCurrentTimeDisplayElementShadowPseudoId();
 static const AtomicString& getMediaControlTimeRemainingDisplayElementShadowPseudoId();
 
 // This is the duration from mediaControls.css
 static const double fadeOutDuration = 0.3;
 
+// Snap seeks to the nearest seekable() range if they're <= this percentage of the duration apart.
+// I.e., if the seekable() range is [4s, 5s] and the duration 10s, clicks on the timeline >= 3s or <= 6s
+// would snap to 4 and 5 respectively.  Clicks outside of those ranges would be dropped.
+//
+// This ensures accidental clicks don't cause annoying timeline jumps, or worse, restart the entire
+// playback process when only a seek to zero is available.
+static const double snapPercentageForSeeks = 10 / 100.0;

[philipj_slow, 2014/10/01 11:14:22]

This is 0.1 and not a percentage :)

+
 static bool isUserInteractionEvent(Event* event)
 {
     const AtomicString& type = event->type();
     return type == EventTypeNames::mousedown
         || type == EventTypeNames::mouseup
         || type == EventTypeNames::click
         || type == EventTypeNames::dblclick
         || event->isKeyboardEvent()
         || event->isTouchEvent();
 }
@@ skipping 341 matching lines @@
 
     MediaControlInputElement::defaultEventHandler(event);
 
     if (event->type() == EventTypeNames::mouseover || event->type() == EventTypeNames::mouseout || event->type() == EventTypeNames::mousemove)
         return;
 
     double time = value().toDouble();
     if (event->type() == EventTypeNames::input) {
         // FIXME: This will need to take the timeline offset into consideration
         // once that concept is supported, see https://crbug.com/312699
-        if (mediaElement().controller())
+        if (mediaElement().controller()) {
             mediaElement().controller()->setCurrentTime(time);

[philipj_slow, 2014/10/01 11:14:22]

Should the same rule not apply to a media element slaved to a controller?
MediaController::seekable() also returns TimeRanges, so it shouldn't be too
messy to deal with both.

[DaleCurtis, 2014/10/14 18:06:26]

Done.

[philipj_slow, 2014/10/16 18:52:51]

We appear to have miscommunicated :) I mean that the MediaController::seekable()
is also checked in the else branch. My rule of thumb is that a MediaController
with only a single HTMLMediaElement should behave like the HTMLMediaElement
itself, which can be done in this case.

[DaleCurtis, 2014/10/16 19:51:50]

Sorry I still don't understand. :| Are you saying I should check if a media
controller only represents a single element and call it directly in that case?
If so, how can I tell if the controller only represents one element?

The new code always uses the controller if it's present, otherwise it uses the
media element directly.

[philipj_slow, 2014/10/16 20:03:18]

Oops, sloppy reading on my part! You've already done what I asked for, I just
didn't notice because I was expecting the indentation level to change. Sorry.

-        else
-            mediaElement().setCurrentTime(time, IGNORE_EXCEPTION);
+        } else {
+            // Only pass through seeks that are within the seekable range or close enough that we're sure
+            // the user didn't make an accidental click.
+            RefPtrWillBeRawPtr<TimeRanges> seekableRanges = mediaElement().seekable();
+            if (seekableRanges->contain(time)) {
+                mediaElement().setCurrentTime(time, IGNORE_EXCEPTION);
+            } else {
+                const double duration = getFloatingPointAttribute(maxAttr);

[philipj_slow, 2014/10/01 11:14:22]

It took me a while to realize that the duration is in fact stored in the max
attribute, going directly to mediaElement().duration() would be more clear I
think.

+                const double nearestTime = seekableRanges->nearest(time, mediaElement().currentTime());
+                if (duration && std::abs(time - nearestTime) / duration <= snapPercentageForSeeks)
+                    mediaElement().setCurrentTime(time, IGNORE_EXCEPTION);
+            }
+        }
     }
 
     RenderSlider* slider = toRenderSlider(renderer());
     if (slider && slider->inDragMode())
         mediaControls().updateCurrentTimeDisplay();
 }
 
 bool MediaControlTimelineElement::willRespondToMouseClickEvents()
 {
     return inDocument() && document().isActive();
@@ skipping 335 matching lines @@
     float fontSize = smallestDimension * 0.05f;
     if (fontSize != m_fontSize) {
         m_fontSize = fontSize;
         setInlineStyleProperty(CSSPropertyFontSize, fontSize, CSSPrimitiveValue::CSS_PX);
     }
 }
 
 // ----------------------------
 
 } // namespace blink