extension/packages/hints.coffee

   1 utils                     = require 'utils'
   2 { getPref }               = require 'prefs'
   3 { Marker }                = require 'marker'
   4 { addHuffmanCodeWordsTo } = require 'huffman'
   5
   6 { interfaces: Ci } = Components
   7
   8 HTMLDocument = Ci.nsIDOMHTMLDocument
   9 XULDocument  = Ci.nsIDOMXULDocument
  10 XPathResult  = Ci.nsIDOMXPathResult
  11
  12 CONTAINER_ID = 'VimFxHintMarkerContainer'
  13
  14 # All the following elements qualify for their own marker in hints mode
  15 MARKABLE_ELEMENTS = [
  16   "a"
  17   "iframe"
  18   "area[@href]"
  19   "textarea"
  20   "button"
  21   "select"
  22   "input[not(@type='hidden' or @disabled or @readonly)]"
  23   "embed"
  24   "object"
  25 ]
  26
  27 # All elements that have one or more of the following properties
  28 # qualify for their own marker in hints mode
  29 MARKABLE_ELEMENT_PROPERTIES = [
  30   "@tabindex"
  31   "@onclick"
  32   "@onmousedown"
  33   "@onmouseup"
  34   "@oncommand"
  35   "@role='link'"
  36   "@role='button'"
  37   "contains(@class, 'button')"
  38   "contains(@class, 'js-new-tweets-bar')"
  39   "@contenteditable='' or translate(@contenteditable, 'TRUE', 'true')='true'"
  40 ]
  41
  42
  43 # Remove previously injected hints from the DOM
  44 removeHints = (document) ->
  45   if container = document.getElementById(CONTAINER_ID)
  46     document.documentElement.removeChild(container)
  47
  48   for frame in document.defaultView.frames
  49     removeHints(frame.document)
  50
  51
  52 # Like `injectMarkers`, but also sets hints for the markers
  53 injectHints = (document) ->
  54   markers = injectMarkers(document)
  55   hintChars = utils.getHintChars()
  56
  57   addHuffmanCodeWordsTo markers,
  58     alphabet: hintChars
  59     setCodeWord: (marker, hint, index) -> marker.setHint(hint)
  60
  61   return markers
  62
  63
  64 # Creates and injects markers into the DOM
  65 injectMarkers = (document) ->
  66   # First remove previous hints container
  67   removeHints(document)
  68
  69   # For now we aren't able to handle hint markers in XUL Documents :(
  70   if document instanceof HTMLDocument# or document instanceof XULDocument
  71     if document.documentElement
  72       # For performance use Document Fragment
  73       fragment = document.createDocumentFragment()
  74
  75       # Select all markable elements in the document, create markers
  76       # for each of them, and position them on the page.
  77       # Note that the markers are not given hints.
  78       set = getMarkableElements(document)
  79       markers = []
  80       for i in [0...set.snapshotLength] by 1
  81         element = set.snapshotItem(i)
  82         if rect = getElementRect(element)
  83           marker = new Marker(element)
  84
  85           marker.setPosition(rect)
  86           fragment.appendChild(marker.markerElement)
  87
  88           marker.weight = rect.area
  89
  90           markers.push(marker)
  91
  92       container = createHintsContainer(document)
  93       container.appendChild(fragment)
  94       document.documentElement.appendChild(container)
  95
  96       for frame in document.defaultView.frames
  97         markers = markers.concat(injectMarkers(frame.document))
  98
  99   return markers or []
 100
 101
 102 createHintsContainer = (document) ->
 103   container = document.createElement('div')
 104   container.id = CONTAINER_ID
 105   container.className = 'VimFxReset'
 106   return container
 107
 108
 109 # Returns elements that qualify for hint markers in hints mode.
 110 # Generates and memoizes an XPath query internally
 111 getMarkableElements = do ->
 112   # Some preparations done on startup
 113   elements = [
 114     MARKABLE_ELEMENTS...
 115     "*[#{ MARKABLE_ELEMENT_PROPERTIES.join(' or ') }]"
 116   ]
 117
 118   reduce = (m, rule) ->
 119       m.concat(["//#{ rule }", "//xhtml:#{ rule }"])
 120   xpath = elements
 121     .reduce(reduce, [])
 122     .join(' | ')
 123
 124   namespaceResolver = (namespace) ->
 125     if namespace == 'xhtml' then 'http://www.w3.org/1999/xhtml' else null
 126
 127   # The actual function that will return the desired elements
 128   return (document, resultType = XPathResult.ORDERED_NODE_SNAPSHOT_TYPE) ->
 129     return document.evaluate(xpath, document.documentElement, namespaceResolver, resultType, null)
 130
 131
 132 # Uses `element.getBoundingClientRect()`. If that does not return a visible rectange, then looks at
 133 # the children of the markable node.
 134 #
 135 # The logic has been copied over from Vimiun originally.
 136 getElementRect = (element) ->
 137   document = element.ownerDocument
 138   window   = document.defaultView
 139   docElem  = document.documentElement
 140   body     = document.body
 141
 142   clientTop  = docElem.clientTop  or body?.clientTop  or 0
 143   clientLeft = docElem.clientLeft or body?.clientLeft or 0
 144   scrollTop  = window.pageYOffset or docElem.scrollTop
 145   scrollLeft = window.pageXOffset or docElem.scrollLeft
 146
 147   clientRect = element.getBoundingClientRect()
 148
 149   if isRectOk(clientRect, window)
 150     return {
 151       top:    clientRect.top  + scrollTop  - clientTop
 152       left:   clientRect.left + scrollLeft - clientLeft
 153       width:  clientRect.width
 154       height: clientRect.height
 155       area:   clientRect.width * clientRect.height
 156     }
 157
 158   # If the rect has 0 dimensions, then check what's inside.
 159   # Floated or absolutely positioned elements are of particular interest.
 160   if clientRect.width is 0 or clientRect.height is 0
 161     for childElement in element.children
 162       if computedStyle = window.getComputedStyle(childElement, null)
 163         if computedStyle.getPropertyValue('float') != 'none' or \
 164            computedStyle.getPropertyValue('position') == 'absolute'
 165
 166           return getElementRect(childElement)
 167
 168   return
 169
 170
 171 # Checks if the given TextRectangle object qualifies
 172 # for its own Marker with respect to the `window` object
 173 isRectOk = (rect, window) ->
 174   minimum = 2
 175   rect.width >  minimum and rect.height >  minimum and \
 176   rect.top   > -minimum and rect.left   > -minimum and \
 177   rect.top   <  window.innerHeight - minimum and \
 178   rect.left  <  window.innerWidth  - minimum
 179
 180
 181 exports.injectHints = injectHints
 182 exports.removeHints = removeHints