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Use onWillStop() instead of onDidStop()

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This will prevent new Watchers from attaching to NativeWatchers that are
in the process of stopping.
This commit is contained in:
Ash Wilson
2017-06-22 12:44:07 -04:00
parent b34a9d6972
commit f75aa1ae03
4 changed files with 110 additions and 54 deletions
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92
spec/filesystem-manager-spec.js
View File

@@ -93,14 +93,17 @@ describe('FileSystemManager', function () {
const sub1 = watcher.onDidChange(() => {})
await watcher.getStartPromise()
expect(watcher.native).not.toBe(null)
expect(watcher.native.isRunning()).toBe(true)
const native = watcher.native
expect(native).not.toBe(null)
expect(native.isRunning()).toBe(true)
sub0.dispose()
expect(watcher.native.isRunning()).toBe(true)
expect(watcher.native).toBe(native)
expect(native.isRunning()).toBe(true)
sub1.dispose()
expect(watcher.native.isRunning()).toBe(false)
expect(watcher.native).toBeNull()
expect(native.isRunning()).toBe(false)
})
it('reuses an existing native watcher and resolves getStartPromise immediately if attached to a running watcher', async function () {
@@ -117,48 +120,73 @@ describe('FileSystemManager', function () {
expect(watcher0.native).toBe(watcher1.native)
})
it('reuses an existing native watcher on a parent directory and filters events', async function () {
const rootDir = await temp.mkdir('atom-fsmanager-').then(fs.realpath)
it("reuses existing native watchers even while they're still starting", async function () {
const rootDir = await temp.mkdir('atom-fsmanager-')
const watcher0 = manager.getWatcher(rootDir)
watcher0.onDidChange(() => {})
await watcher0.getAttachedPromise()
expect(watcher0.native.isRunning()).toBe(false)
const watcher1 = manager.getWatcher(rootDir)
watcher1.onDidChange(() => {})
await watcher1.getAttachedPromise()
expect(watcher0.native).toBe(watcher1.native)
await Promise.all([watcher0.getStartPromise(), watcher1.getStartPromise()])
})
it("doesn't attach new watchers to a native watcher that's stopping", async function () {
const rootDir = await temp.mkdir('atom-fsmanager-')
const watcher0 = manager.getWatcher(rootDir)
const sub = watcher0.onDidChange(() => {})
await watcher0.getStartPromise()
const native0 = watcher0.native
sub.dispose()
const watcher1 = manager.getWatcher(rootDir)
watcher1.onDidChange(() => {})
expect(watcher1.native).not.toBe(native0)
})
it('reuses an existing native watcher on a parent directory and filters events', async function () {
const rootDir = await temp.mkdir('atom-fsmanager-0-').then(fs.realpath)
const rootFile = path.join(rootDir, 'rootfile.txt')
const subDir = path.join(rootDir, 'subdir')
const subFile = path.join(subDir, 'subfile.txt')
await Promise.all([
fs.mkdir(subDir).then(
fs.writeFile(subFile, 'subfile\n', {encoding: 'utf8'})
),
fs.writeFile(rootFile, 'rootfile\n', {encoding: 'utf8'})
])
await fs.mkdir(subDir)
// Keep the watchers alive with an undisposed subscription
const rootWatcher = manager.getWatcher(rootDir)
rootWatcher.onDidChange(() => {})
const childWatcher = manager.getWatcher(subDir)
expect(rootWatcher.native).toBe(childWatcher.native)
const firstRootChange = waitForChanges(rootWatcher, subFile)
const firstChildChange = waitForChanges(childWatcher, subFile)
childWatcher.onDidChange(() => {})
await Promise.all([
rootWatcher.getStartPromise(),
childWatcher.getStartPromise()
])
await fs.appendFile(subFile, 'changes\n', {encoding: 'utf8'})
expect(rootWatcher.native).toBe(childWatcher.native)
expect(rootWatcher.native.isRunning()).toBe(true)
const firstPayloads = await Promise.all([firstRootChange, firstChildChange])
const firstChanges = Promise.all([
waitForChanges(rootWatcher, subFile),
waitForChanges(childWatcher, subFile)
])
for (const events of firstPayloads) {
expect(events.length).toBe(1)
expect(events[0].oldPath).toBe(subFile)
}
await fs.writeFile(subFile, 'subfile\n', {encoding: 'utf8'})
await firstChanges
const nextRootEvent = waitForChanges(rootWatcher, rootFile)
await fs.appendFile(rootFile, 'changes\n', {encoding: 'utf8'})
await fs.writeFile(rootFile, 'rootfile\n', {encoding: 'utf8'})
const nextPayload = await nextRootEvent
expect(nextPayload.length).toBe(1)
expect(nextPayload[0].oldPath).toBe(rootFile)
await nextRootEvent
})
it('adopts existing child watchers and filters events appropriately to them', async function () {
@@ -181,17 +209,17 @@ describe('FileSystemManager', function () {
)
])
// Begin the child watchers
// Begin the child watchers and keep them alive
const subWatcher0 = manager.getWatcher(subDir0)
subWatcher0.onDidChange(() => {})
const subWatcherChanges0 = waitForChanges(subWatcher0, subFile0)
const subWatcher1 = manager.getWatcher(subDir1)
subWatcher1.onDidChange(() => {})
const subWatcherChanges1 = waitForChanges(subWatcher1, subFile1)
await Promise.all(
[subWatcher0, subWatcher1].map(watcher => {
return watcher.getStartPromise()
})
[subWatcher0, subWatcher1].map(watcher => watcher.getStartPromise())
)
expect(subWatcher0.native).not.toBe(subWatcher1.native)

6
spec/native-watcher-registry-spec.js
View File

@@ -41,8 +41,8 @@ class MockNative {
this.attached = []
}
onDidStop (callback) {
return this.emitter.on('did-stop', callback)
onWillStop (callback) {
return this.emitter.on('will-stop', callback)
}
dispose () {
@@ -51,7 +51,7 @@ class MockNative {
stop () {
this.stopped = true
this.emitter.emit('did-stop')
this.emitter.emit('will-stop')
}
}

62
src/filesystem-manager.js
View File

@@ -16,6 +16,14 @@ const ACTION_MAP = new Map([
[nsfw.actions.RENAMED, 'renamed']
])
// Private: Possible states of a {NativeWatcher}.
export const WATCHER_STATE = {
STOPPED: Symbol('stopped'),
STARTING: Symbol('starting'),
RUNNING: Symbol('running'),
STOPPING: Symbol('stopping')
}
// Private: Interface with and normalize events from a native OS filesystem watcher.
class NativeWatcher {
@@ -27,16 +35,17 @@ class NativeWatcher {
this.emitter = new Emitter()
this.watcher = null
this.running = false
this.state = WATCHER_STATE.STOPPED
}
// Private: Begin watching for filesystem events.
//
// Has no effect if the watcher has already been started.
async start () {
if (this.running) {
if (this.state !== WATCHER_STATE.STOPPED) {
return
}
this.state = WATCHER_STATE.STARTING
this.watcher = await nsfw(
this.normalizedPath,
@@ -49,13 +58,14 @@ class NativeWatcher {
await this.watcher.start()
this.running = true
this.state = WATCHER_STATE.RUNNING
this.emitter.emit('did-start')
}
// Private: Return true if the underlying watcher has been started.
// Private: Return true if the underlying watcher is actively listening for filesystem events.
isRunning () {
return this.running
return this.state === WATCHER_STATE.RUNNING
}
// Private: Register a callback to be invoked when the filesystem watcher has been initialized.
@@ -71,9 +81,7 @@ class NativeWatcher {
//
// Returns: A {Disposable} to revoke the subscription.
onDidChange (callback) {
if (!this.isRunning()) {
this.start()
}
this.start()
const sub = this.emitter.on('did-change', callback)
return new Disposable(() => {
@@ -91,7 +99,14 @@ class NativeWatcher {
return this.emitter.on('should-detach', callback)
}
// Private: Register a callback to be invoked when the filesystem watcher has been initialized.
// Private: Register a callback to be invoked when a {NativeWatcher} is about to be stopped.
//
// Returns: A {Disposable} to revoke the subscription.
onWillStop (callback) {
return this.emitter.on('will-stop', callback)
}
// Private: Register a callback to be invoked when the filesystem watcher has been stopped.
//
// Returns: A {Disposable} to revoke the subscription.
onDidStop (callback) {
@@ -108,12 +123,15 @@ class NativeWatcher {
//
// Has no effect if the watcher is not running.
async stop () {
if (!this.running) {
if (this.state !== WATCHER_STATE.RUNNING) {
return
}
this.running = false
this.state = WATCHER_STATE.STOPPING
this.emitter.emit('will-stop')
await this.watcher.stop()
this.state = WATCHER_STATE.STOPPED
this.emitter.emit('did-stop')
}
@@ -171,6 +189,9 @@ class Watcher {
})
})
this.attachedPromise = new Promise(resolve => {
this.resolveAttachedPromise = resolve
})
this.startPromise = new Promise(resolve => {
this.resolveStartPromise = resolve
})
@@ -183,6 +204,10 @@ class Watcher {
return this.normalizedPathPromise
}
getAttachedPromise () {
return this.attachedPromise
}
getStartPromise () {
return this.startPromise
}
@@ -194,7 +219,7 @@ class Watcher {
this.native.start()
} else {
// Attach and retry
// Attach to a new native listener and retry
this.nativeWatcherRegistry.attach(this).then(() => {
this.onDidChange(callback)
})
@@ -226,15 +251,18 @@ class Watcher {
formerSub.dispose()
}
if (this.changeCallbacks.size > 0) {
native.start()
}
this.subs.add(native.onShouldDetach(replacement => {
if (replacement !== native) {
this.attachToNative(replacement)
}
}))
this.subs.add(native.onWillStop(() => {
this.subs.dispose()
this.native = null
}))
this.resolveAttachedPromise()
}
onNativeEvents (events, callback) {
@@ -265,7 +293,7 @@ export default class FileSystemManager {
const nativeWatcher = new NativeWatcher(normalizedPath)
this.liveWatchers.add(nativeWatcher)
const sub = nativeWatcher.onDidStop(() => {
const sub = nativeWatcher.onWillStop(() => {
this.liveWatchers.delete(nativeWatcher)
sub.dispose()
})

4
src/native-watcher-registry.js
View File

@@ -248,8 +248,8 @@ export default class NativeWatcherRegistry {
const leaf = new RegistryWatcherNode(native)
this.tree = this.tree.insert(pathSegments, leaf)
const sub = native.onDidStop(() => {
this.tree = this.tree.remove(pathSegments)
const sub = native.onWillStop(() => {
this.tree = this.tree.remove(pathSegments) || new RegistryNode()
sub.dispose()
})