From 1552854f3b3e55c9ea243cedb37f13dfe8882a2f Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Mon, 3 Apr 2017 16:54:22 -0700
Subject: [PATCH] Allow workspace item objects to be passed to Workspace.open

---
 spec/workspace-spec.js | 48 ++++++++++++++++++++++++++++++++++++++++--
 src/workspace.js       | 20 ++++++++++++------
 2 files changed, 59 insertions(+), 9 deletions(-)

diff --git a/spec/workspace-spec.js b/spec/workspace-spec.js
index 5c02b8852..4ab183886 100644
--- a/spec/workspace-spec.js
+++ b/spec/workspace-spec.js
@@ -1,4 +1,4 @@
-'use strict'
+/** @babel */
 
 /* global advanceClock, HTMLElement, waits */
 
@@ -12,6 +12,7 @@ const _ = require('underscore-plus')
 const fstream = require('fstream')
 const fs = require('fs-plus')
 const AtomEnvironment = require('../src/atom-environment')
+const {it, fit, ffit, fffit, beforeEach, afterEach} = require('./async-spec-helpers')
 
 describe('Workspace', () => {
   let workspace
@@ -187,7 +188,7 @@ describe('Workspace', () => {
     })
 
     describe("when the 'searchAllPanes' option is false (default)", () => {
-      describe('when called without a uri', () => {
+      describe('when called without a uri or item', () => {
         it('adds and activates an empty editor on the active pane', () => {
           let editor1
           let editor2
@@ -406,6 +407,49 @@ describe('Workspace', () => {
       })
     })
 
+    describe('when called with an item rather than a URI', () => {
+      it('adds the item itself to the workspace', async () => {
+        const item = document.createElement('div')
+        await atom.workspace.open(item)
+        expect(atom.workspace.getActivePaneItem()).toBe(item)
+      })
+
+      describe('when the active pane already contains the item', () => {
+        it('activates the item', async () => {
+          const item = document.createElement('div')
+
+          await atom.workspace.open(item)
+          await atom.workspace.open()
+          expect(atom.workspace.getActivePaneItem()).not.toBe(item)
+          expect(atom.workspace.getActivePane().getItems().length).toBe(2)
+
+          await atom.workspace.open(item)
+          expect(atom.workspace.getActivePaneItem()).toBe(item)
+          expect(atom.workspace.getActivePane().getItems().length).toBe(2)
+        })
+      })
+
+      describe('when the item already exists in another pane', () => {
+        it('rejects the promise', async () => {
+          const item = document.createElement('div')
+
+          await atom.workspace.open(item)
+          await atom.workspace.open(null, {split: 'right'})
+          expect(atom.workspace.getActivePaneItem()).not.toBe(item)
+          expect(atom.workspace.getActivePane().getItems().length).toBe(1)
+
+          let rejection
+          try {
+            await atom.workspace.open(item)
+          } catch (error) {
+            rejection = error
+          }
+
+          expect(rejection.message).toMatch(/The workspace can only contain one instance of item/)
+        })
+      })
+    })
+
     describe("when the 'split' option is set", () => {
       describe("when the 'split' option is 'left'", () => {
         it('opens the editor in the leftmost pane of the current pane axis', () => {
diff --git a/src/workspace.js b/src/workspace.js
index 894d67b62..7bc7b3244 100644
--- a/src/workspace.js
+++ b/src/workspace.js
@@ -628,8 +628,14 @@ module.exports = class Workspace extends Model {
   //     should almost always be omitted to honor user preference.
   //
   // Returns a {Promise} that resolves to the {TextEditor} for the file URI.
-  async open (uri_, options = {}) {
-    const uri = this.project.resolvePath(uri_)
+  async open (itemOrURI, options = {}) {
+    let uri, item
+    if (typeof itemOrURI === 'string') {
+      uri = this.project.resolvePath(itemOrURI)
+    } else if (itemOrURI) {
+      item = itemOrURI
+      if (typeof item.getURI === 'function') uri = item.getURI()
+    }
 
     if (!atom.config.get('core.allowPendingPaneItems')) {
       options.pending = false
@@ -641,14 +647,14 @@ module.exports = class Workspace extends Model {
       this.applicationDelegate.addRecentDocument(uri)
     }
 
-    let container, pane, item
+    let container, pane
 
-    // Try to find an existing item with the given URI.
-    if (uri) {
+    // Try to find an existing item in the workspace.
+    if (item || uri) {
       if (options.pane) {
         pane = options.pane
       } else if (options.searchAllPanes) {
-        pane = this.paneForURI(uri)
+        pane = item ? this.paneForItem(item) : this.paneForURI(uri)
       } else {
         // The `split` option affects where we search for the item.
         pane = this.getActivePane()
@@ -668,7 +674,7 @@ module.exports = class Workspace extends Model {
         }
       }
 
-      if (pane) item = pane.itemForURI(uri)
+      if (pane && !item) item = pane.itemForURI(uri)
     }
 
     // If an item is already present, yield the event loop to ensure this method