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69 lines
2.5 KiB
CoffeeScript
69 lines
2.5 KiB
CoffeeScript
# Create an op which converts oldval -> newval.
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#
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# This function should be called every time the text element is changed. Because changes are
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# always localised, the diffing is quite easy.
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#
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# This algorithm is O(N), but I suspect you could speed it up somehow using regular expressions.
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applyChange = (doc, oldval, newval) ->
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return if oldval == newval
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commonStart = 0
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commonStart++ while oldval.charAt(commonStart) == newval.charAt(commonStart)
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commonEnd = 0
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commonEnd++ while oldval.charAt(oldval.length - 1 - commonEnd) == newval.charAt(newval.length - 1 - commonEnd) and
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commonEnd + commonStart < oldval.length and commonEnd + commonStart < newval.length
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doc.del commonStart, oldval.length - commonStart - commonEnd unless oldval.length == commonStart + commonEnd
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doc.insert commonStart, newval[commonStart ... newval.length - commonEnd] unless newval.length == commonStart + commonEnd
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window.sharejs.extendDoc 'attach_textarea', (elem) ->
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doc = this
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elem.value = @getText()
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prevvalue = elem.value
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replaceText = (newText, transformCursor) ->
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newSelection = [
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transformCursor elem.selectionStart
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transformCursor elem.selectionEnd
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]
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scrollTop = elem.scrollTop
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elem.value = newText
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elem.scrollTop = scrollTop if elem.scrollTop != scrollTop
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[elem.selectionStart, elem.selectionEnd] = newSelection
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@on 'insert', (pos, text) ->
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transformCursor = (cursor) ->
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if pos < cursor
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cursor + text.length
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else
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cursor
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#for IE8 and Opera that replace \n with \r\n.
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prevvalue = elem.value.replace /\r\n/g, '\n'
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replaceText prevvalue[...pos] + text + prevvalue[pos..], transformCursor
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@on 'delete', (pos, text) ->
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transformCursor = (cursor) ->
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if pos < cursor
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cursor - Math.min(text.length, cursor - pos)
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else
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cursor
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#for IE8 and Opera that replace \n with \r\n.
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prevvalue = elem.value.replace /\r\n/g, '\n'
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replaceText prevvalue[...pos] + prevvalue[pos + text.length..], transformCursor
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genOp = (event) ->
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onNextTick = (fn) -> setTimeout fn, 0
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onNextTick ->
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if elem.value != prevvalue
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# IE constantly replaces unix newlines with \r\n. ShareJS docs
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# should only have unix newlines.
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prevvalue = elem.value
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applyChange doc, doc.getText(), elem.value.replace /\r\n/g, '\n'
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for event in ['textInput', 'keydown', 'keyup', 'select', 'cut', 'paste']
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if elem.addEventListener
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elem.addEventListener event, genOp, false
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else
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elem.attachEvent 'on'+event, genOp
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