Implement decoration management in minimap model

The biggest change so far is that changes are not stacked in the model
but emitted as events.

lib/minimap.coffee

@@ -1,10 +1,18 @@
-{CompositeDisposable} = require 'event-kit'
+{Emitter, CompositeDisposable} = require 'event-kit'
+DecorationManagement = require './mixins/decoration-management'
 
 module.exports =
 class Minimap
+  DecorationManagement.includeInto(this)
+
   constructor: ({@textEditor}) ->
+    @emitter = new Emitter
     @subscriptions = new CompositeDisposable
     @subscribeToConfig()
+    @initializeDecorations()
+
+  onDidChangeScreenLines: (callback) ->
+    @emitter.on 'did-change-screen-lines', callback
 
   getTextEditor: -> @textEditor
 
@@ -34,6 +42,13 @@ class Minimap
 
   canScroll: -> @getMinimapMaxScrollTop() > 0
 
+  getMarker: (id) -> @textEditor.getMarker(id)
+
+  markBufferRange: (range) -> @textEditor.markBufferRange(range)
+
+  stackChanges: (changes) ->
+    @emitter.emit('did-change-screen-lines', changes)
+
   subscribeToConfig: ->
     @subscriptions.add atom.config.observe 'minimap.charHeight', (@charHeight) =>
     @subscriptions.add atom.config.observe 'minimap.charWidth', (@charWidth) =>

spec/minimap-spec.coffee

@@ -92,4 +92,63 @@ describe 'Minimap', ->
         expect(minimap.getFirstVisibleScreenRow()).toEqual(largeLineCount - 10)
 
       it 'computes the last visible row in the minimap', ->
-        expect(minimap.getLastVisibleRow()).toEqual(largeLineCount)
+        expect(minimap.getLastVisibleScreenRow()).toEqual(largeLineCount)
+
+  #    ########  ########  ######   #######
+  #    ##     ## ##       ##    ## ##     ##
+  #    ##     ## ##       ##       ##     ##
+  #    ##     ## ######   ##       ##     ##
+  #    ##     ## ##       ##       ##     ##
+  #    ##     ## ##       ##    ## ##     ##
+  #    ########  ########  ######   #######
+
+  describe '::decorateMarker', ->
+    [marker, decoration, changeSpy] = []
+
+    beforeEach ->
+      changeSpy = jasmine.createSpy('didChangeScreenLines')
+      minimap.onDidChangeScreenLines(changeSpy)
+
+      marker = minimap.markBufferRange [[0,6], [0,11]]
+      decoration = minimap.decorateMarker marker, type: 'highlight', class: 'dummy'
+
+    it 'creates a decoration for the given marker', ->
+      expect(minimap.decorationsByMarkerId[marker.id]).toBeDefined()
+
+    it 'creates a change corresponding to the marker range', ->
+      expect(changeSpy).toHaveBeenCalled()
+      expect(changeSpy.calls[0].args[0].start).toEqual(0)
+      expect(changeSpy.calls[0].args[0].end).toEqual(0)
+
+    describe 'destroying the marker', ->
+      beforeEach ->
+        marker.destroy()
+
+      it 'removes the decoration from the render view', ->
+        expect(minimap.decorationsByMarkerId[marker.id]).toBeUndefined()
+
+      it 'creates a change corresponding to the marker range', ->
+        expect(changeSpy.calls[1].args[0].start).toEqual(0)
+        expect(changeSpy.calls[1].args[0].end).toEqual(0)
+
+    describe 'destroying the decoration', ->
+      beforeEach ->
+        decoration.destroy()
+
+      it 'removes the decoration from the render view', ->
+        expect(minimap.decorationsByMarkerId[marker.id]).toBeUndefined()
+
+      it 'creates a change corresponding to the marker range', ->
+        expect(changeSpy.calls[1].args[0].start).toEqual(0)
+        expect(changeSpy.calls[1].args[0].end).toEqual(0)
+
+    describe 'destroying all the decorations for the marker', ->
+      beforeEach ->
+        minimap.removeAllDecorationsForMarker(marker)
+
+      it 'removes the decoration from the render view', ->
+        expect(minimap.decorationsByMarkerId[marker.id]).toBeUndefined()
+
+      it 'creates a change corresponding to the marker range', ->
+        expect(changeSpy.calls[1].args[0].start).toEqual(0)
+        expect(changeSpy.calls[1].args[0].end).toEqual(0)