Merge pull request #14695 from atom/jr-editors-live-in-workspace-center

Provide API for observing the active text editor

src/dock.js

@@ -4,6 +4,7 @@ const _ = require('underscore-plus')
 const {CompositeDisposable} = require('event-kit')
 const PaneContainer = require('./pane-container')
 const TextEditor = require('./text-editor')
+const Grim = require('grim')
 
 const MINIMUM_SIZE = 100
 const DEFAULT_INITIAL_SIZE = 300
@@ -384,21 +385,6 @@ module.exports = class Dock {
   Section: Event Subscription
   */
 
-  // Essential: Invoke the given callback with all current and future text
-  // editors in the dock.
-  //
-  // * `callback` {Function} to be called with current and future text editors.
-  //   * `editor` An {TextEditor} that is present in {::getTextEditors} at the time
-  //     of subscription or that is added at some later time.
-  //
-  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
-  observeTextEditors (callback) {
-    for (const textEditor of this.getTextEditors()) {
-      callback(textEditor)
-    }
-    return this.onDidAddTextEditor(({textEditor}) => callback(textEditor))
-  }
-
   // Essential: Invoke the given callback with all current and future panes items
   // in the dock.
   //
@@ -583,18 +569,13 @@ module.exports = class Dock {
     return this.paneContainer.getActivePaneItem()
   }
 
-  // Essential: Get all text editors in the dock.
+  // Deprecated: Get the active item if it is a {TextEditor}.
   //
-  // Returns an {Array} of {TextEditor}s.
-  getTextEditors () {
-    return this.paneContainer.getTextEditors()
-  }
-
-  // Essential: Get the active item if it is an {TextEditor}.
-  //
-  // Returns an {TextEditor} or `undefined` if the current active item is not an
+  // Returns a {TextEditor} or `undefined` if the current active item is not a
   // {TextEditor}.
   getActiveTextEditor () {
+    Grim.deprecate('Text editors are not allowed in docks. Use atom.workspace.getActiveTextEditor() instead.')
+
     const activeItem = this.getActivePaneItem()
     if (activeItem instanceof TextEditor) { return activeItem }
   }

src/text-editor.coffee

@@ -3628,6 +3628,9 @@ class TextEditor extends Model
       })
       @component.element
 
+  getAllowedLocations: ->
+    ['center']
+
   # Essential: Retrieves the greyed out placeholder of a mini editor.
   #
   # Returns a {String}.

src/workspace.js

@@ -216,6 +216,7 @@ module.exports = class Workspace extends Model {
       bottom: this.createDock('bottom')
     }
     this.activePaneContainer = this.paneContainers.center
+    this.hasActiveTextEditor = false
 
     this.panelContainers = {
       top: new PanelContainer({viewRegistry: this.viewRegistry, location: 'top'}),
@@ -296,6 +297,7 @@ module.exports = class Workspace extends Model {
       bottom: this.createDock('bottom')
     }
     this.activePaneContainer = this.paneContainers.center
+    this.hasActiveTextEditor = false
 
     this.panelContainers = {
       top: new PanelContainer({viewRegistry: this.viewRegistry, location: 'top'}),
@@ -371,6 +373,8 @@ module.exports = class Workspace extends Model {
       this.paneContainers.center.deserialize(state.paneContainer, deserializerManager)
     }
 
+    this.hasActiveTextEditor = this.getActiveTextEditor() != null
+
     this.updateWindowTitle()
   }
 
@@ -422,6 +426,16 @@ module.exports = class Workspace extends Model {
       this.didChangeActivePaneItem(item)
       this.emitter.emit('did-change-active-pane-item', item)
     }
+
+    if (paneContainer === this.getCenter()) {
+      const hadActiveTextEditor = this.hasActiveTextEditor
+      this.hasActiveTextEditor = item instanceof TextEditor
+
+      if (this.hasActiveTextEditor || hadActiveTextEditor) {
+        const itemValue = this.hasActiveTextEditor ? item : undefined
+        this.emitter.emit('did-change-active-text-editor', itemValue)
+      }
+    }
   }
 
   didChangeActivePaneItem (item) {
@@ -648,6 +662,18 @@ module.exports = class Workspace extends Model {
     return this.emitter.on('did-stop-changing-active-pane-item', callback)
   }
 
+  // Essential: Invoke the given callback when a text editor becomes the active
+  // text editor and when there is no longer an active text editor.
+  //
+  // * `callback` {Function} to be called when the active text editor changes.
+  //   * `editor` The active {TextEditor} or undefined if there is no longer an
+  //      active text editor.
+  //
+  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
+  onDidChangeActiveTextEditor (callback) {
+    return this.emitter.on('did-change-active-text-editor', callback)
+  }
+
   // Essential: Invoke the given callback with the current active pane item and
   // with all future active pane items in the workspace.
   //
@@ -660,6 +686,21 @@ module.exports = class Workspace extends Model {
     return this.onDidChangeActivePaneItem(callback)
   }
 
+  // Essential: Invoke the given callback with the current active text editor
+  // (if any), with all future active text editors, and when there is no longer
+  // an active text editor.
+  //
+  // * `callback` {Function} to be called when the active text editor changes.
+  //   * `editor` The active {TextEditor} or undefined if there is not an
+  //      active text editor.
+  //
+  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
+  observeActiveTextEditor (callback) {
+    callback(this.getActiveTextEditor())
+
+    return this.onDidChangeActiveTextEditor(callback)
+  }
+
   // Essential: Invoke the given callback whenever an item is opened. Unlike
   // {::onDidAddPaneItem}, observers will be notified for items that are already
   // present in the workspace when they are reopened.
@@ -1282,12 +1323,12 @@ module.exports = class Workspace extends Model {
     return this.getPaneItems().filter(item => item instanceof TextEditor)
   }
 
-  // Essential: Get the active item if it is an {TextEditor}.
+  // Essential: Get the workspace center's active item if it is a {TextEditor}.
   //
-  // Returns an {TextEditor} or `undefined` if the current active item is not an
-  // {TextEditor}.
+  // Returns a {TextEditor} or `undefined` if the workspace center's current
+  // active item is not a {TextEditor}.
   getActiveTextEditor () {
-    const activeItem = this.getActivePaneItem()
+    const activeItem = this.getCenter().getActivePaneItem()
     if (activeItem instanceof TextEditor) { return activeItem }
   }