Avoid forcing computation of all screen lines when opening a file

package.json

@@ -58,7 +58,7 @@
     "sinon": "1.17.4",
     "source-map-support": "^0.3.2",
     "temp": "0.8.1",
-    "text-buffer": "9.3.0",
+    "text-buffer": "9.3.1-1",
     "typescript-simple": "1.0.0",
     "underscore-plus": "^1.6.6",
     "winreg": "^1.2.1",

src/lines-yardstick.coffee

@@ -13,19 +13,20 @@ class LinesYardstick
   measuredRowForPixelPosition: (pixelPosition) ->
     targetTop = pixelPosition.top
     row = Math.floor(targetTop / @model.getLineHeightInPixels())
-    row if 0 <= row <= @model.getLastScreenRow()
+    row if 0 <= row
 
   screenPositionForPixelPosition: (pixelPosition) ->
     targetTop = pixelPosition.top
-    targetLeft = pixelPosition.left
-    row = @lineTopIndex.rowForPixelPosition(targetTop)
-    targetLeft = 0 if targetTop < 0 or targetLeft < 0
-    targetLeft = Infinity if row > @model.getLastScreenRow()
-    row = Math.min(row, @model.getLastScreenRow())
-    row = Math.max(0, row)
-
+    row = Math.max(0, @lineTopIndex.rowForPixelPosition(targetTop))
     lineNode = @lineNodesProvider.lineNodeForScreenRow(row)
-    return Point(row, 0) unless lineNode
+    unless lineNode
+      if row > @model.getLastScreenRow()
+        return Point(@model.getLastScreenRow(), Infinity)
+      else
+        return Point(row, 0)
+
+    targetLeft = pixelPosition.left
+    targetLeft = 0 if targetTop < 0 or targetLeft < 0
 
     textNodes = @lineNodesProvider.textNodesForScreenRow(row)
     lineOffset = lineNode.getBoundingClientRect().left

src/text-editor-presenter.coffee

@@ -137,6 +137,11 @@ class TextEditorPresenter
     @shouldUpdateDecorations = true
 
   observeModel: ->
+    @disposables.add @model.displayLayer.onDidReset =>
+      @spliceBlockDecorationsInRange(0, Infinity, Infinity)
+      @shouldUpdateDecorations = true
+      @emitDidUpdateState()
+
     @disposables.add @model.displayLayer.onDidChangeSync (changes) =>
       for change in changes
         startRow = change.start.row
@@ -291,24 +296,21 @@ class TextEditorPresenter
   tileForRow: (row) ->
     row - (row % @tileSize)
 
-  constrainRow: (row) ->
-    Math.max(0, Math.min(row, @model.getScreenLineCount()))
-
   getStartTileRow: ->
-    @constrainRow(@tileForRow(@startRow ? 0))
+    @tileForRow(@startRow ? 0)
 
   getEndTileRow: ->
-    @constrainRow(@tileForRow(@endRow ? 0))
+    @tileForRow(@endRow ? 0)
 
   isValidScreenRow: (screenRow) ->
-    screenRow >= 0 and screenRow < @model.getScreenLineCount()
+    screenRow >= 0 and screenRow < @model.getApproximateScreenLineCount()
 
   getScreenRowsToRender: ->
     startRow = @getStartTileRow()
-    endRow = @constrainRow(@getEndTileRow() + @tileSize)
+    endRow = @getEndTileRow() + @tileSize
 
     screenRows = [startRow...endRow]
-    longestScreenRow = @model.getLongestScreenRow()
+    longestScreenRow = @model.getApproximateLongestScreenRow()
     if longestScreenRow?
       screenRows.push(longestScreenRow)
     if @screenRowsToMeasure?
@@ -354,7 +356,7 @@ class TextEditorPresenter
     zIndex = 0
 
     for tileStartRow in [@tileForRow(endRow)..@tileForRow(startRow)] by -@tileSize
-      tileEndRow = @constrainRow(tileStartRow + @tileSize)
+      tileEndRow = tileStartRow + @tileSize
       rowsWithinTile = []
 
       while screenRowIndex >= 0
@@ -389,7 +391,7 @@ class TextEditorPresenter
       visibleTiles[tileStartRow] = true
       zIndex++
 
-    if @mouseWheelScreenRow? and 0 <= @mouseWheelScreenRow < @model.getScreenLineCount()
+    if @mouseWheelScreenRow? and 0 <= @mouseWheelScreenRow < @model.getApproximateScreenLineCount()
       mouseWheelTile = @tileForRow(@mouseWheelScreenRow)
 
       unless visibleTiles[mouseWheelTile]?
@@ -408,8 +410,7 @@ class TextEditorPresenter
     visibleLineIds = {}
     for screenRow in screenRows
       line = @linesByScreenRow.get(screenRow)
-      unless line?
-        throw new Error("No line exists for row #{screenRow}. Last screen row: #{@model.getLastScreenRow()}")
+      continue unless line?
 
       visibleLineIds[line.id] = true
       precedingBlockDecorations = @precedingBlockDecorationsByScreenRow[screenRow] ? []
@@ -597,7 +598,9 @@ class TextEditorPresenter
     visibleLineNumberIds = {}
 
     for screenRow in screenRows when @isRowRendered(screenRow)
-      lineId = @linesByScreenRow.get(screenRow).id
+      line = @linesByScreenRow.get(screenRow)
+      continue unless line?
+      lineId = line.id
       {bufferRow, softWrappedAtStart: softWrapped} = @displayLayer.softWrapDescriptorForScreenRow(screenRow)
       foldable = not softWrapped and @model.isFoldableAtBufferRow(bufferRow)
       decorationClasses = @lineNumberDecorationClassesForRow(screenRow)
@@ -624,7 +627,7 @@ class TextEditorPresenter
     return unless @scrollTop? and @lineHeight? and @height?
 
     @endRow = Math.min(
-      @model.getScreenLineCount(),
+      @model.getApproximateScreenLineCount(),
       @lineTopIndex.rowForPixelPosition(@scrollTop + @height + @lineHeight - 1) + 1
     )
 
@@ -658,7 +661,7 @@ class TextEditorPresenter
   updateVerticalDimensions: ->
     if @lineHeight?
       oldContentHeight = @contentHeight
-      @contentHeight = Math.round(@lineTopIndex.pixelPositionAfterBlocksForRow(@model.getScreenLineCount()))
+      @contentHeight = Math.round(@lineTopIndex.pixelPositionAfterBlocksForRow(@model.getApproximateScreenLineCount()))
 
     if @contentHeight isnt oldContentHeight
       @updateHeight()
@@ -668,7 +671,7 @@ class TextEditorPresenter
   updateHorizontalDimensions: ->
     if @baseCharacterWidth?
       oldContentWidth = @contentWidth
-      rightmostPosition = @model.getRightmostScreenPosition()
+      rightmostPosition = @model.getApproximateRightmostScreenPosition()
       @contentWidth = @pixelPositionForScreenPosition(rightmostPosition).left
       @contentWidth += @scrollLeft
       @contentWidth += 1 unless @model.isSoftWrapped() # account for cursor width
@@ -1529,7 +1532,7 @@ class TextEditorPresenter
     [@startRow, @endRow]
 
   isRowRendered: (row) ->
-    @getStartTileRow() <= row < @constrainRow(@getEndTileRow() + @tileSize)
+    @getStartTileRow() <= row < @getEndTileRow() + @tileSize
 
   isOpenTagCode: (tagCode) ->
     @displayLayer.isOpenTagCode(tagCode)

src/text-editor.coffee

@@ -391,6 +391,9 @@ class TextEditor extends Model
     @disposables.add @displayLayer.onDidChangeSync (e) =>
       @mergeIntersectingSelections()
       @emitter.emit 'did-change', e
+    @disposables.add @displayLayer.onDidReset =>
+      @mergeIntersectingSelections()
+      @emitter.emit 'did-change', {}
 
   destroyed: ->
     @disposables.dispose()
@@ -907,6 +910,8 @@ class TextEditor extends Model
   # editor. This accounts for folds.
   getScreenLineCount: -> @displayLayer.getScreenLineCount()
 
+  getApproximateScreenLineCount: -> @displayLayer.getApproximateScreenLineCount()
+
   # Essential: Returns a {Number} representing the last zero-indexed buffer row
   # number of the editor.
   getLastBufferRow: -> @buffer.getLastRow()
@@ -953,8 +958,8 @@ class TextEditor extends Model
     tokens
 
   screenLineForScreenRow: (screenRow) ->
-    return if screenRow < 0 or screenRow > @getLastScreenRow()
-    @displayLayer.getScreenLines(screenRow, screenRow + 1)[0]
+    result = @displayLayer.getScreenLines(screenRow, screenRow + 1)
+    result[0] if result
 
   bufferRowForScreenRow: (screenRow) ->
     @displayLayer.translateScreenPosition(Point(screenRow, 0)).row
@@ -971,10 +976,14 @@ class TextEditor extends Model
 
   getRightmostScreenPosition: -> @displayLayer.getRightmostScreenPosition()
 
+  getApproximateRightmostScreenPosition: -> @displayLayer.getApproximateRightmostScreenPosition()
+
   getMaxScreenLineLength: -> @getRightmostScreenPosition().column
 
   getLongestScreenRow: -> @getRightmostScreenPosition().row
 
+  getApproximateLongestScreenRow: -> @getApproximateRightmostScreenPosition().row
+
   lineLengthForScreenRow: (screenRow) -> @displayLayer.lineLengthForScreenRow(screenRow)
 
   # Returns the range for the given buffer row.