Merge pull request atom#15834 from atom/jr-decaf-gutter-container

Decaffeinate `GutterContainer`

spec/gutter-container-spec.js

@@ -0,0 +1,77 @@
+const Gutter = require('../src/gutter')
+const GutterContainer = require('../src/gutter-container')
+
+describe('GutterContainer', () => {
+  let gutterContainer = null
+  const fakeTextEditor = {
+    scheduleComponentUpdate () {}
+  }
+
+  beforeEach(() => {
+    gutterContainer = new GutterContainer(fakeTextEditor)
+  })
+
+  describe('when initialized', () =>
+    it('it has no gutters', () => {
+      expect(gutterContainer.getGutters().length).toBe(0)
+    })
+  )
+
+  describe('::addGutter', () => {
+    it('creates a new gutter', () => {
+      const newGutter = gutterContainer.addGutter({'test-gutter': 'test-gutter', priority: 1})
+      expect(gutterContainer.getGutters()).toEqual([newGutter])
+      expect(newGutter.priority).toBe(1)
+    })
+
+    it('throws an error if the provided gutter name is already in use', () => {
+      const name = 'test-gutter'
+      gutterContainer.addGutter({name})
+      expect(gutterContainer.addGutter.bind(null, {name})).toThrow()
+    })
+
+    it('keeps added gutters sorted by ascending priority', () => {
+      const gutter1 = gutterContainer.addGutter({name: 'first', priority: 1})
+      const gutter3 = gutterContainer.addGutter({name: 'third', priority: 3})
+      const gutter2 = gutterContainer.addGutter({name: 'second', priority: 2})
+      expect(gutterContainer.getGutters()).toEqual([gutter1, gutter2, gutter3])
+    })
+  })
+
+  describe('::removeGutter', () => {
+    let removedGutters
+
+    beforeEach(function () {
+      gutterContainer = new GutterContainer(fakeTextEditor)
+      removedGutters = []
+      gutterContainer.onDidRemoveGutter(gutterName => removedGutters.push(gutterName))
+    })
+
+    it('removes the gutter if it is contained by this GutterContainer', () => {
+      const gutter = gutterContainer.addGutter({'test-gutter': 'test-gutter'})
+      expect(gutterContainer.getGutters()).toEqual([gutter])
+      gutterContainer.removeGutter(gutter)
+      expect(gutterContainer.getGutters().length).toBe(0)
+      expect(removedGutters).toEqual([gutter.name])
+    })
+
+    it('throws an error if the gutter is not within this GutterContainer', () => {
+      const fakeOtherTextEditor = {}
+      const otherGutterContainer = new GutterContainer(fakeOtherTextEditor)
+      const gutter = new Gutter('gutter-name', otherGutterContainer)
+      expect(gutterContainer.removeGutter.bind(null, gutter)).toThrow()
+    })
+  })
+
+  describe('::destroy', () =>
+    it('clears its array of gutters and destroys custom gutters', () => {
+      const newGutter = gutterContainer.addGutter({'test-gutter': 'test-gutter', priority: 1})
+      const newGutterSpy = jasmine.createSpy()
+      newGutter.onDidDestroy(newGutterSpy)
+
+      gutterContainer.destroy()
+      expect(newGutterSpy).toHaveBeenCalled()
+      expect(gutterContainer.getGutters()).toEqual([])
+    })
+)
+})

src/gutter-container.js

@@ -0,0 +1,108 @@
+const {Emitter} = require('event-kit')
+const Gutter = require('./gutter')
+
+module.exports = class GutterContainer {
+  constructor (textEditor) {
+    this.gutters = []
+    this.textEditor = textEditor
+    this.emitter = new Emitter()
+  }
+
+  scheduleComponentUpdate () {
+    this.textEditor.scheduleComponentUpdate()
+  }
+
+  destroy () {
+    // Create a copy, because `Gutter::destroy` removes the gutter from
+    // GutterContainer's @gutters.
+    const guttersToDestroy = this.gutters.slice(0)
+    for (let gutter of guttersToDestroy) {
+      if (gutter.name !== 'line-number') { gutter.destroy() }
+    }
+    this.gutters = []
+    this.emitter.dispose()
+  }
+
+  addGutter (options) {
+    options = options || {}
+    const gutterName = options.name
+    if (gutterName === null) {
+      throw new Error('A name is required to create a gutter.')
+    }
+    if (this.gutterWithName(gutterName)) {
+      throw new Error('Tried to create a gutter with a name that is already in use.')
+    }
+    const newGutter = new Gutter(this, options)
+
+    let inserted = false
+    // Insert the gutter into the gutters array, sorted in ascending order by 'priority'.
+    // This could be optimized, but there are unlikely to be many gutters.
+    for (let i = 0; i < this.gutters.length; i++) {
+      if (this.gutters[i].priority >= newGutter.priority) {
+        this.gutters.splice(i, 0, newGutter)
+        inserted = true
+        break
+      }
+    }
+    if (!inserted) {
+      this.gutters.push(newGutter)
+    }
+    this.scheduleComponentUpdate()
+    this.emitter.emit('did-add-gutter', newGutter)
+    return newGutter
+  }
+
+  getGutters () {
+    return this.gutters.slice()
+  }
+
+  gutterWithName (name) {
+    for (let gutter of this.gutters) {
+      if (gutter.name === name) { return gutter }
+    }
+    return null
+  }
+
+  observeGutters (callback) {
+    for (let gutter of this.getGutters()) { callback(gutter) }
+    return this.onDidAddGutter(callback)
+  }
+
+  onDidAddGutter (callback) {
+    return this.emitter.on('did-add-gutter', callback)
+  }
+
+  onDidRemoveGutter (callback) {
+    return this.emitter.on('did-remove-gutter', callback)
+  }
+
+  /*
+  Section: Private Methods
+  */
+
+  // Processes the destruction of the gutter. Throws an error if this gutter is
+  // not within this gutterContainer.
+  removeGutter (gutter) {
+    const index = this.gutters.indexOf(gutter)
+    if (index > -1) {
+      this.gutters.splice(index, 1)
+      this.scheduleComponentUpdate()
+      this.emitter.emit('did-remove-gutter', gutter.name)
+    } else {
+      throw new Error('The given gutter cannot be removed because it is not ' +
+          'within this GutterContainer.'
+      )
+    }
+  }
+
+  // The public interface is Gutter::decorateMarker or TextEditor::decorateMarker.
+  addGutterDecoration (gutter, marker, options) {
+    if (gutter.name === 'line-number') {
+      options.type = 'line-number'
+    } else {
+      options.type = 'gutter'
+    }
+    options.gutterName = gutter.name
+    return this.textEditor.decorateMarker(marker, options)
+  }
+}