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, {alphabet: hintChars}, (marker, hint) -> marker.setHint(hint))
  58
  59   return markers
  60
  61
  62 # Creates and injects markers into the DOM
  63 injectMarkers = (document) ->
  64   # First remove previous hints container
  65   removeHints(document)
  66
  67   # For now we aren't able to handle hint markers in XUL Documents :(
  68   if document instanceof HTMLDocument# or document instanceof XULDocument
  69     if document.documentElement
  70       # For performance use Document Fragment
  71       fragment = document.createDocumentFragment()
  72
  73       # Select all markable elements in the document, create markers
  74       # for each of them, and position them on the page.
  75       # Note that the markers are not given hints.
  76       set = getMarkableElements(document)
  77       markers = []
  78       for i in [0...set.snapshotLength] by 1
  79         element = set.snapshotItem(i)
  80         if rect = getElementRect(element)
  81           marker = new Marker(element)
  82
  83           marker.setPosition(rect)
  84           fragment.appendChild(marker.markerElement)
  85
  86           marker.weight = rect.area * marker.calcBloomRating()
  87
  88           markers.push(marker)
  89
  90       container = createHintsContainer(document)
  91       container.appendChild(fragment)
  92       document.documentElement.appendChild(container)
  93
  94       for frame in document.defaultView.frames
  95         markers = markers.concat(injectMarkers(frame.document))
  96
  97   return markers or []
  98
  99
 100 createHintsContainer = (document) ->
 101   container = document.createElement('div')
 102   container.id = CONTAINER_ID
 103   container.className = 'VimFxReset'
 104   return container
 105
 106
 107 # Returns elements that qualify for hint markers in hints mode.
 108 # Generates and memoizes an XPath query internally
 109 getMarkableElements = do ->
 110   # Some preparations done on startup
 111   elements = [
 112     MARKABLE_ELEMENTS...
 113     "*[#{ MARKABLE_ELEMENT_PROPERTIES.join(' or ') }]"
 114   ]
 115
 116   reduce = (m, rule) -> m.concat(["//#{ rule }", "//xhtml:#{ rule }"])
 117   xpath = elements.reduce(reduce, []).join(' | ')
 118
 119   namespaceResolver = (namespace) ->
 120     if namespace == 'xhtml' then 'http://www.w3.org/1999/xhtml' else null
 121
 122   # The actual function that will return the desired elements
 123   return (document, resultType = XPathResult.ORDERED_NODE_SNAPSHOT_TYPE) ->
 124     return document.evaluate(xpath, document.documentElement, namespaceResolver, resultType, null)
 125
 126
 127 # Uses `element.getBoundingClientRect()`. If that does not return a visible rectange, then looks at
 128 # the children of the markable node.
 129 #
 130 # The logic has been copied over from Vimiun originally.
 131 getElementRect = (element) ->
 132   document = element.ownerDocument
 133   window   = document.defaultView
 134   docElem  = document.documentElement
 135   body     = document.body
 136
 137   # Prune elements that aren't visible on the page
 138   computedStyle = window.getComputedStyle(element, null)
 139   if computedStyle
 140     if computedStyle.getPropertyValue('visibility') != 'visible' or \
 141        computedStyle.getPropertyValue('display') == 'none' or \
 142        computedStyle.getPropertyValue('opacity') == '0'
 143       return
 144
 145   clientTop  = docElem.clientTop  or body?.clientTop  or 0
 146   clientLeft = docElem.clientLeft or body?.clientLeft or 0
 147   scrollTop  = window.pageYOffset or docElem.scrollTop
 148   scrollLeft = window.pageXOffset or docElem.scrollLeft
 149
 150   clientRect = element.getBoundingClientRect()
 151
 152   if isRectOk(clientRect, window)
 153     return {
 154       top:    clientRect.top  + scrollTop  - clientTop
 155       left:   clientRect.left + scrollLeft - clientLeft
 156       width:  clientRect.width
 157       height: clientRect.height
 158       area:   clientRect.width * clientRect.height
 159     }
 160
 161   # If the rect has 0 dimensions, then check what's inside.
 162   # Floated or absolutely positioned elements are of particular interest.
 163   if clientRect.width is 0 or clientRect.height is 0
 164     for childElement in element.children
 165       if computedStyle = window.getComputedStyle(childElement, null)
 166         if computedStyle.getPropertyValue('float') != 'none' or \
 167            computedStyle.getPropertyValue('position') == 'absolute'
 168
 169           return getElementRect(childElement)
 170
 171   return
 172
 173
 174 # Checks if the given TextRectangle object qualifies
 175 # for its own Marker with respect to the `window` object
 176 isRectOk = (rect, window) ->
 177   minimum = 2
 178   rect.width >  minimum and rect.height >  minimum and \
 179   rect.top   > -minimum and rect.left   > -minimum and \
 180   rect.top   <  window.innerHeight - minimum and \
 181   rect.left  <  window.innerWidth  - minimum
 182
 183
 184 exports.injectHints = injectHints
 185 exports.removeHints = removeHints