simplify caching of last hovered/expanded file

src/General/css/style.css

@@ -813,10 +813,10 @@ span.hide-announcement {
 .expanded-image > .post > .file > .fileThumb > img[data-md5] {
   display: none;
 }
-.full-image:not(#ihover) {
+.full-image {
   display: none;
 }
-.expanded-image > .post > .file > .fileThumb > .full-image:not(#ihover) {
+.expanded-image > .post > .file > .fileThumb > .full-image {
   display: inline;
 }
 .expanded-image {
@@ -825,13 +825,13 @@ span.hide-announcement {
 .expanding {
   opacity: .5;
 }
-:root.fit-height .full-image:not(#ihover) {
+:root.fit-height .full-image {
   max-height: 100vh;
 }
-:root.fit-width .full-image:not(#ihover) {
+:root.fit-width .full-image {
   max-width: 100%;
 }
-:root.gecko.fit-width .full-image:not(#ihover) {
+:root.gecko.fit-width .full-image {
   width: 100%;
 }
 .fileThumb > .warning {

src/Images/ImageExpand.coffee

@@ -134,12 +134,15 @@ ImageExpand =
       window.scrollBy 0, d.body.clientHeight - oldHeight
 
     if el = file.fullImage
+      delete file.fullImage
       $.off el, 'error', ImageExpand.error
       if file.isVideo
         el.pause()
         for eventName, cb of ImageExpand.videoCB
           $.off el, eventName, cb
-      TrashQueue.add el, post
+      $.rm el
+      $.rmClass el, 'full-image'
+      ImageCommon.cache = el
 
   expand: (post, src) ->
     # Do not expand images of hidden/filtered replies, or already expanded pictures.
@@ -150,18 +153,23 @@ ImageExpand =
     $.addClass thumb, 'expanding'
     file.isExpanding = true
 
-    el = file.fullImage or $.el (if isVideo then 'video' else 'img'), className: 'full-image'
-    $.on el, 'error', ImageExpand.error
     if file.fullImage
-      # Expand already-loaded/ing picture.
-      TrashQueue.remove el
+      el = file.fullImage
+    else if ImageCommon.cache?.dataset.fullID is post.fullID
+      el = file.fullImage = ImageCommon.cache
+      delete ImageCommon.cache
       unless file.isHovered
         $.queueTask(-> el.src = el.src) if /\.gif$/.test el.src
         el.currentTime = 0 if isVideo and el.readyState >= el.HAVE_METADATA
+      $.on el, 'error', ImageExpand.error
     else
+      el = file.fullImage = $.el (if isVideo then 'video' else 'img')
+      el.dataset.fullID = post.fullID
+      $.on el, 'error', ImageExpand.error
       el.src = src or file.URL
-      $.after thumb, el
-      file.fullImage = el
+
+    el.className = 'full-image'
+    $.after thumb, el
 
     if isVideo
       # add contract link to file info

src/Images/ImageHover.coffee

@@ -15,24 +15,24 @@ ImageHover =
     {isVideo} = file
     return if file.isExpanding or file.isExpanded
     file.isHovered = true
-    if el = file.fullImage
-      el.id = 'ihover'
-      TrashQueue.remove el
+    if ImageCommon.cache?.dataset.fullID is post.fullID
+      el = ImageCommon.cache
+      delete ImageCommon.cache
       $.queueTask(-> el.src = el.src) if /\.gif$/.test el.src
       el.currentTime = 0 if isVideo and el.readyState >= el.HAVE_METADATA
     else
-      file.fullImage = el = $.el (if isVideo then 'video' else 'img'),
-        className: 'full-image'
-        id: 'ihover'
+      el = $.el (if isVideo then 'video' else 'img')
+      el.dataset.fullID = post.fullID
       $.on el, 'error', ImageHover.error
       el.src = file.URL
-      $.after file.thumb, el
+    el.id = 'ihover'
+    $.after Header.hover, el
     if isVideo
       el.loop     = true
       el.controls = false
       el.play() if Conf['Autoplay']
     [width, height] = file.dimensions.split('x').map (x) -> +x
-    {left, right} = file.thumb.getBoundingClientRect()
+    {left, right} = @getBoundingClientRect()
     padding = 16
     maxWidth = Math.max left, doc.clientWidth - right
     maxHeight = doc.clientHeight - padding
@@ -50,9 +50,10 @@ ImageHover =
       cb: ->
         if isVideo
           el.pause()
-        TrashQueue.add el, post
+        $.rm el
         el.removeAttribute 'id'
         el.removeAttribute 'style'
+        ImageCommon.cache = el
         $.queueTask -> delete file.isHovered
   error: ->
     post = Get.postFromNode @
@@ -64,7 +65,5 @@ ImageHover =
           @src = URL + if @src is URL then '?' + Date.now() else ''
         else
           $.rm @
-          delete post.file.fullImage
     else
       $.rm @
-      delete post.file.fullImage

src/Images/TrashQueue.coffee

@@ -1,14 +0,0 @@
-TrashQueue =
-  init: -> return
-
-  add: (video, post) ->
-    if @killNext and video isnt @killNext
-      delete @killNextPost?.file?.fullImage
-      $.rm @killNext
-    @killNext = video
-    @killNextPost = post
-
-  remove: (video) ->
-    if video is @killNext
-      delete @killNext
-