Delete unreturned clipboard cache files after a failed write (#24599)

Reuse existing provider-copy best-effort deletion for a newly created clipboard cache file whose write fails before its URI reaches the caller.

mobile/src/platform/native-media-device.ts

@@ -33,6 +33,14 @@ function stagedMediaFile(extension: string): FsFile {
   return new FsFile(Paths.cache, `orca-media-${Date.now()}-${Math.random()}.${extension}`)
 }
 
+function discardUnreturnedMediaFile(file: FsFile): void {
+  try {
+    file.delete()
+  } catch {
+    // Best effort; the cache is the OS's to reclaim.
+  }
+}
+
 /**
  * Copies what a uri names into this shell's cache and answers the copy's uri.
  *
@@ -57,11 +65,7 @@ export function copyPickedMediaIntoCache(uri: string): string {
     destination.write(new FsFile(uri).bytesSync())
   } catch (error) {
     // The empty file this just created is nobody's otherwise: the caller never learns its name.
-    try {
-      destination.delete()
-    } catch {
-      // Best effort; the cache is the OS's to reclaim.
-    }
+    discardUnreturnedMediaFile(destination)
     throw error
   }
   return destination.uri
@@ -94,7 +98,12 @@ export function nativeMediaDeviceDeps(registry: MediaHandleRegistry): NativeMedi
     stageBase64: (base64) => {
       const file = stagedMediaFile('png')
       file.create({ overwrite: true })
-      file.write(base64, { encoding: 'base64' })
+      try {
+        file.write(base64, { encoding: 'base64' })
+      } catch (error) {
+        discardUnreturnedMediaFile(file)
+        throw error
+      }
       return file.uri
     },
     openFile: (uri) => new FsFile(uri),

mobile/src/platform/native-media-stage-cleanup.test.ts

@@ -0,0 +1,204 @@
+import { beforeEach, afterEach, expect, it, vi } from 'vitest'
+
+type FileEvent = {
+  operation: 'create' | 'write' | 'delete'
+  uri: string
+  content?: string | Uint8Array
+  options?: { overwrite?: boolean; encoding?: string }
+}
+
+type StorageState = {
+  files: Map<string, Uint8Array>
+  events: FileEvent[]
+  writeFailure: unknown
+  deleteFailure: unknown
+  createFailure: unknown
+  readFailure: unknown
+  partialBytes: number
+}
+
+const storage = vi.hoisted<StorageState>(() => ({
+  files: new Map(),
+  events: [],
+  writeFailure: null,
+  deleteFailure: null,
+  createFailure: null,
+  readFailure: null,
+  partialBytes: 0
+}))
+
+vi.mock('expo-clipboard', () => ({
+  getImageAsync: () => Promise.resolve({ data: 'data:image/png;base64,AQID' })
+}))
+vi.mock('expo-document-picker', () => ({}))
+vi.mock('expo-image-picker', () => ({}))
+vi.mock('expo-file-system', () => ({
+  File: class {
+    readonly uri: string
+
+    constructor(...parts: string[]) {
+      this.uri = parts.join('/')
+    }
+
+    get size(): number {
+      return storage.files.get(this.uri)?.byteLength ?? 0
+    }
+
+    create(options: { overwrite?: boolean }): void {
+      storage.events.push({ operation: 'create', uri: this.uri, options })
+      storage.files.set(this.uri, new Uint8Array())
+      if (storage.createFailure !== null) {
+        throw storage.createFailure
+      }
+    }
+
+    write(content: string | Uint8Array, options?: { encoding?: string }): void {
+      storage.events.push({ operation: 'write', uri: this.uri, content, options })
+      if (storage.writeFailure !== null) {
+        storage.files.set(this.uri, new Uint8Array(storage.partialBytes))
+        throw storage.writeFailure
+      }
+      storage.files.set(
+        this.uri,
+        typeof content === 'string' ? Uint8Array.from(Buffer.from(content, 'base64')) : content
+      )
+    }
+
+    bytesSync(): Uint8Array {
+      if (storage.readFailure !== null) {
+        throw storage.readFailure
+      }
+      return Uint8Array.from([9, 8])
+    }
+
+    delete(): void {
+      storage.events.push({ operation: 'delete', uri: this.uri })
+      if (storage.deleteFailure !== null) {
+        throw storage.deleteFailure
+      }
+      storage.files.delete(this.uri)
+    }
+  },
+  Paths: { cache: 'file:///cache' }
+}))
+
+import { MediaHandleRegistry } from '../mobile-web-shell/media-handle-registry'
+import { createNativeMediaVerbServer } from './native-media'
+import { copyPickedMediaIntoCache, nativeMediaDeviceDeps } from './native-media-device'
+
+beforeEach(() => {
+  storage.files.clear()
+  storage.events.length = 0
+  storage.writeFailure = null
+  storage.deleteFailure = null
+  storage.createFailure = null
+  storage.readFailure = null
+  storage.partialBytes = 0
+  vi.spyOn(Date, 'now').mockReturnValue(1234)
+  vi.spyOn(Math, 'random').mockReturnValue(0.25)
+})
+
+afterEach(() => vi.restoreAllMocks())
+
+function device() {
+  return nativeMediaDeviceDeps(new MediaHandleRegistry({ now: () => 0, discard: vi.fn() }))
+}
+
+function thrownBy(operation: () => unknown): unknown {
+  try {
+    operation()
+  } catch (error) {
+    return error
+  }
+  throw new Error('Expected staging to throw')
+}
+
+function heldBytes(): number {
+  return [...storage.files.values()].reduce((total, bytes) => total + bytes.byteLength, 0)
+}
+
+it('preserves the successful staged URI, base64 options and bytes without deleting it', () => {
+  const uri = device().stageBase64('AQID')
+  expect(uri).toBe('file:///cache/orca-media-1234-0.25.png')
+  expect(storage.events).toEqual([
+    { operation: 'create', uri, options: { overwrite: true } },
+    { operation: 'write', uri, content: 'AQID', options: { encoding: 'base64' } }
+  ])
+  expect(storage.files.get(uri)).toEqual(Uint8Array.from([1, 2, 3]))
+})
+
+it.each([0, 4096])('releases an unreturned file after a write fails with %i bytes', (bytes) => {
+  const original = new Error('partial native write')
+  storage.writeFailure = original
+  storage.partialBytes = bytes
+  expect(thrownBy(() => device().stageBase64('AQID'))).toBe(original)
+  expect(heldBytes()).toBe(0)
+  expect(storage.files.size).toBe(0)
+  expect(storage.events.at(-1)).toEqual({
+    operation: 'delete',
+    uri: 'file:///cache/orca-media-1234-0.25.png'
+  })
+})
+
+it('preserves the write failure when best-effort deletion also fails', () => {
+  const original = new Error('native write failed')
+  storage.writeFailure = original
+  storage.deleteFailure = new Error('cache cannot be deleted')
+  storage.partialBytes = 4096
+  expect(thrownBy(() => device().stageBase64('AQID'))).toBe(original)
+  expect(storage.events.map((event) => event.operation)).toEqual(['create', 'write', 'delete'])
+  expect(heldBytes()).toBe(4096)
+})
+
+it('preserves creation failure and its original operation order', () => {
+  const original = new Error('native create failed')
+  storage.createFailure = original
+  expect(thrownBy(() => device().stageBase64('AQID'))).toBe(original)
+  expect(storage.events.map((event) => event.operation)).toEqual(['create'])
+})
+
+it('deletes only the failed file while a prior successful file remains readable', () => {
+  vi.spyOn(Math, 'random').mockReturnValueOnce(0.1).mockReturnValueOnce(0.2)
+  const successfulUri = device().stageBase64('AQID')
+  const original = new Error('next write failed')
+  storage.writeFailure = original
+  storage.partialBytes = 4096
+  expect(thrownBy(() => device().stageBase64('BAUG'))).toBe(original)
+  expect(storage.events.filter((event) => event.operation === 'delete')).toEqual([
+    { operation: 'delete', uri: 'file:///cache/orca-media-1234-0.2.png' }
+  ])
+  expect([...storage.files.keys()]).toEqual([successfulUri])
+  expect(storage.files.get(successfulUri)).toEqual(Uint8Array.from([1, 2, 3]))
+  expect(heldBytes()).toBe(3)
+})
+
+it('keeps the clipboard verb rejection while leaving no unregistered cache bytes', async () => {
+  const original = new Error('clipboard write failed')
+  storage.writeFailure = original
+  storage.partialBytes = 4096
+  const registryDiscard = vi.fn()
+  const registry = new MediaHandleRegistry({ now: () => 0, discard: registryDiscard })
+  const serve = createNativeMediaVerbServer(nativeMediaDeviceDeps(registry))
+  await expect(serve('native.media.pick', { source: 'clipboard', multiple: false })).rejects.toBe(
+    original
+  )
+  expect(registry.liveCount()).toBe(0)
+  expect(registryDiscard).not.toHaveBeenCalled()
+  expect(heldBytes()).toBe(0)
+  expect(storage.files.size).toBe(0)
+})
+
+it('retains the provider-copy cleanup and original read error when deletion fails', () => {
+  const original = new Error('provider read failed')
+  storage.readFailure = original
+  storage.deleteFailure = new Error('cache delete failed')
+  expect(thrownBy(() => copyPickedMediaIntoCache('content://media/1'))).toBe(original)
+  expect(storage.events).toEqual([
+    {
+      operation: 'create',
+      uri: 'file:///cache/orca-media-1234-0.25.bin',
+      options: { overwrite: true }
+    },
+    { operation: 'delete', uri: 'file:///cache/orca-media-1234-0.25.bin' }
+  ])
+})