From 303cf30b51b68d78d6d440aa10aa8cfc7afd115b Mon Sep 17 00:00:00 2001
From: hansonw <hansonw@fb.com>
Date: Wed, 1 Nov 2017 15:40:00 -0700
Subject: [PATCH] Allow directory providers to implement onDidChangeFiles for
 custom pathwatchers

---
 spec/project-spec.js | 28 ++++++++++++++++++++++++++++
 src/project.js       | 12 ++++++++++--
 2 files changed, 38 insertions(+), 2 deletions(-)

diff --git a/spec/project-spec.js b/spec/project-spec.js
index 63c065fa6..0f003b26b 100644
--- a/spec/project-spec.js
+++ b/spec/project-spec.js
@@ -335,9 +335,14 @@ describe('Project', () => {
       isRoot () { return true }
       existsSync () { return this.path.endsWith('does-exist') }
       contains (filePath) { return filePath.startsWith(this.path) }
+      onDidChangeFiles (callback) {
+        onDidChangeFilesCallback = callback
+        return {dispose: () => {}}
+      }
     }
 
     let serviceDisposable = null
+    let onDidChangeFilesCallback = null
 
     beforeEach(() => {
       serviceDisposable = atom.packages.serviceHub.provide('atom.directory-provider', '0.1.0', {
@@ -349,6 +354,7 @@ describe('Project', () => {
           }
         }
       })
+      onDidChangeFilesCallback = null
 
       waitsFor(() => atom.project.directoryProviders.length > 0)
     })
@@ -383,6 +389,28 @@ describe('Project', () => {
       atom.project.setPaths(['ssh://foreign-directory:8080/does-exist'])
       expect(atom.project.getDirectories().length).toBe(0)
     })
+
+    it('uses the custom onDidChangeFiles as the watcher if available', () => {
+      // Ensure that all preexisting watchers are stopped
+      waitsForPromise(() => stopAllWatchers())
+
+      const remotePath = 'ssh://another-directory:8080/does-exist'
+      runs(() => atom.project.setPaths([remotePath]))
+      waitsForPromise(() => atom.project.getWatcherPromise(remotePath))
+
+      runs(() => {
+        expect(onDidChangeFilesCallback).not.toBeNull()
+
+        const changeSpy = jasmine.createSpy('atom.project.onDidChangeFiles')
+        const disposable = atom.project.onDidChangeFiles(changeSpy)
+
+        const events = [{action: 'created', path: remotePath + '/test.txt'}]
+        onDidChangeFilesCallback(events)
+
+        expect(changeSpy).toHaveBeenCalledWith(events)
+        disposable.dispose()
+      })
+    })
   })
 
   describe('.open(path)', () => {
diff --git a/src/project.js b/src/project.js
index 48541c395..92a11ec7a 100644
--- a/src/project.js
+++ b/src/project.js
@@ -338,13 +338,21 @@ class Project extends Model {
     }
 
     this.rootDirectories.push(directory)
-    this.watcherPromisesByPath[directory.getPath()] = watchPath(directory.getPath(), {}, events => {
+
+    const didChangeCallback = events => {
       // Stop event delivery immediately on removal of a rootDirectory, even if its watcher
       // promise has yet to resolve at the time of removal
       if (this.rootDirectories.includes(directory)) {
         this.emitter.emit('did-change-files', events)
       }
-    })
+    }
+    // We'll use the directory's custom onDidChangeFiles callback, if available.
+    // CustomDirectory::onDidChangeFiles should match the signature of
+    // Project::onDidChangeFiles below (although it may resolve asynchronously)
+    this.watcherPromisesByPath[directory.getPath()] =
+      directory.onDidChangeFiles != null
+        ? Promise.resolve(directory.onDidChangeFiles(didChangeCallback))
+        : watchPath(directory.getPath(), {}, didChangeCallback)
 
     for (let watchedPath in this.watcherPromisesByPath) {
       if (!this.rootDirectories.find(dir => dir.getPath() === watchedPath)) {