WIP: Add a LineWrapper object

Only passing specs are focused. Everything is still broken. Editor uses
the line wrapper to render lines, but the line wrapper isn't updating
on buffer change events yet. Still moving vertically and clipping
positions based on unwrapped lines as well.

src/atom/editor.coffee

@@ -4,6 +4,7 @@ Point = require 'point'
 Cursor = require 'cursor'
 Selection = require 'selection'
 Highlighter = require 'highlighter'
+LineWrapper = require 'line-wrapper'
 UndoManager = require 'undo-manager'
 Range = require 'range'
 
@@ -20,12 +21,14 @@ class Editor extends View
   vScrollMargin: 2
   hScrollMargin: 10
   softWrap: false
-  cursor: null
-  buffer: null
-  undoManager: null
-  selection: null
   lineHeight: null
   charWidth: null
+  cursor: null
+  selection: null
+  buffer: null
+  highlighter: null
+  lineWrapper: null
+  undoManager: null
 
   initialize: () ->
     requireStylesheet 'editor.css'
@@ -111,26 +114,8 @@ class Editor extends View
     @on 'mousemove', moveHandler
     $(document).one 'mouseup', => @off 'mousemove', moveHandler
 
-
   buildLineElement: (row) ->
-    maxSegmentLength =
-      if @softWrap
-        Math.floor(@width() / @charWidth)
-      else
-        Infinity
-    currentSegmentLength = 0
-    currentSegment = []
-    segments = [currentSegment]
-
-    for token in @highlighter.tokensForRow(row)
-      if (currentSegmentLength + token.value.length) <= maxSegmentLength
-        currentSegmentLength += token.value.length
-        currentSegment.push(token)
-      else
-        currentSegment = [token]
-        currentSegmentLength = token.value.length
-        segments.push(currentSegment)
-
+    segments = @lineWrapper.segmentsForRow(row)
     $$ ->
       for segment in segments
         @pre class: 'line', =>
@@ -148,6 +133,7 @@ class Editor extends View
 
   setBuffer: (@buffer) ->
     @highlighter = new Highlighter(@buffer)
+    @lineWrapper = new LineWrapper(Infinity, @highlighter)
     @undoManager = new UndoManager(@buffer)
     @renderLines()
     @setCursorPosition(row: 0, column: 0)
@@ -186,6 +172,13 @@ class Editor extends View
     @lines.find("pre.line:eq(#{row})")
 
   setSoftWrap: (@softWrap) ->
+    maxLength =
+      if @softWrap
+        Math.floor(@width() / @charWidth)
+      else
+        infinity
+
+    @lineWrapper.setMaxLength(maxLength)
     @renderLines()
 
   clipPosition: ({row, column}) ->
@@ -199,7 +192,17 @@ class Editor extends View
     new Point(row, column)
 
   pixelPositionFromPoint: ({row, column}) ->
-    { top: row * @lineHeight, left: column * @charWidth }
+    segmentsAbove = 0
+    segmentsAbove += @lineWrapper.segmentsForRow(i).length for i in [0...row]
+
+    for segment in @lineWrapper.segmentsForRow(row)
+      if column > segment.lastIndex
+        segmentsAbove++
+        column -= segment.textLength
+      else
+        break
+
+    { top: segmentsAbove * @lineHeight, left: column * @charWidth }
 
   pointFromPixelPosition: ({top, left}) ->
     { row: Math.floor(top / @lineHeight), column: Math.floor(left / @charWidth) }

src/atom/line-wrapper.coffee

@@ -0,0 +1,52 @@
+getWordRegex = -> /\b[^\s]+/g
+
+module.exports =
+class LineWrapper
+  constructor: (@maxLength, @highlighter) ->
+    @buffer = @highlighter.buffer
+    @segmentBuffer()
+
+  setMaxLength: (@maxLength) ->
+    @segmentBuffer()
+
+  segmentBuffer: ->
+    @lines = @segmentRows(0, @buffer.lastRow())
+
+  segmentsForRow: (row) ->
+    @lines[row]
+
+  segmentRows: (start, end) ->
+    for row in [start..end]
+      @segmentRow(row)
+
+  segmentRow: (row) ->
+    wordRegex = getWordRegex()
+    line = @buffer.getLine(row)
+
+    breakIndices = []
+    lastBreakIndex = 0
+
+    while match = wordRegex.exec(line)
+      startIndex = match.index
+      endIndex = startIndex + match[0].length
+      if endIndex - lastBreakIndex > @maxLength
+        breakIndices.push(startIndex)
+        lastBreakIndex = startIndex
+
+    currentSegment = []
+    currentSegment.lastIndex = 0
+    segments = [currentSegment]
+    nextBreak = breakIndices.shift()
+    for token in @highlighter.tokensForRow(row)
+      if currentSegment.lastIndex >= nextBreak
+        nextBreak = breakIndices.shift()
+        newSegment = []
+        newSegment.lastIndex = currentSegment.lastIndex
+        newSegment.textLength = 0
+        segments.push(newSegment)
+        currentSegment = newSegment
+      currentSegment.push token
+      currentSegment.lastIndex += token.value.length
+      currentSegment.textLength += token.value.length
+
+    segments