add placeholder support to memfs implementation

[ghstack-poisoned]

.changeset/lemon-boxes-dream.md

@@ -0,0 +1,7 @@
+---
+"@lix-js/client": minor
+"@lix-js/server": minor
+"@lix-js/fs": minor
+---
+
+release for lazy checkout

lix/source-code/client/src/helpers.ts

@@ -8,8 +8,13 @@ type Args = {
 	nodeishFs: NodeishFilesystem
 	verbose?: boolean
 	description?: string
-	intercept?: (args: { prop: keyof NodeishFilesystem; execute: () => any }) => any
+	intercept?: (args: {
+		prop: keyof NodeishFilesystem
+		execute: () => any
+		argumentsList: any[]
+	}) => any
 }
+
 export const withLazyFetching = ({
 	nodeishFs,
 	verbose = false,
@@ -31,6 +36,7 @@ export const withLazyFetching = ({
 							? intercept({ prop, argumentsList, execute } as {
 									prop: keyof typeof nodeishFs
 									execute: () => any
+									argumentsList: any[]
 							  })
 							: execute()
 					},

lix/source-code/fs/src/implementations.test.ts

@@ -267,6 +267,41 @@ const runFsTestSuite = async (
 		])
 	})
 
+  test.skipIf(isNodeFs)("placeholders", async () => {
+		const placeholderPath = `/placeholders/subdir`
+
+		await fs.mkdir(placeholderPath, { recursive: true })
+
+		await fs.writeFile(`${placeholderPath}/file`, "")
+
+		fs._createPlaceholder(placeholderPath + "/test")
+
+		expect(fs._isPlaceholder(placeholderPath + "/test")).toBe(true)
+		expect(fs._isPlaceholder(placeholderPath + "/noexists")).toBe(false)
+		expect(fs._isPlaceholder(placeholderPath + "/file")).toBe(false)
+
+		const dirents = await fs.readdir(`/placeholders/subdir`)
+
+		expect(dirents).toStrictEqual(["file", "test"])
+
+		await expect(async () => await fs.readFile(`${placeholderPath}/test`)).rejects.toThrow(
+			/EPLACEHOLDER/
+		)
+
+		await fs.rm("/placeholders", { recursive: true })
+
+		const finalDirents = await fs.readdir(`/`)
+
+		expect(finalDirents).toStrictEqual([
+			"home",
+			"file2",
+			"file3",
+			"file1.link",
+			"file3.link",
+			"user1.link",
+		])
+	})
+
 	test("unlink", async () => {
 		await fs.unlink(`${tempDir}/user1.link`)
 		await fs.unlink(`${tempDir}/file1.link`)

lix/source-code/fs/src/memoryFs.ts

@@ -2,11 +2,11 @@ import type { NodeishFilesystem, NodeishStats, FileChangeInfo } from "./NodeishF
 import { FilesystemError } from "./errors/FilesystemError.js"
 import { normalPath, getBasename, getDirname } from "./utilities/helpers.js"
 
-type Inode = Uint8Array | Set<string>
+type Inode = Uint8Array | Set<string> | { placeholder: true }
 
 export type Snapshot = {
 	fsMap: {
-		[key: string]: string[] | string
+		[key: string]: string[] | string | { placeholder: true }
 	}
 	fsStats: {
 		[key: string]: {
@@ -148,6 +148,31 @@ export function createNodeishMemoryFs(): NodeishFilesystem {
 
 	return {
 		_state: state,
+
+		_createPlaceholder: function (
+			path: Parameters<NodeishFilesystem["writeFile"]>[0],
+			options?: Parameters<NodeishFilesystem["writeFile"]>[2]
+		) {
+			path = normalPath(path)
+			const dirName = getDirname(path)
+			const baseName = getBasename(path)
+			const parentDir: Inode | undefined = state.fsMap.get(dirName)
+			if (!(parentDir instanceof Set)) throw new FilesystemError("ENOENT", path, "writeFile")
+			parentDir.add(baseName)
+			newStatEntry(path, state.fsStats, 0, options?.mode ?? 0o644)
+			state.fsMap.set(path, { placeholder: true })
+		},
+
+		_isPlaceholder: function (path: Parameters<NodeishFilesystem["writeFile"]>[0]) {
+			path = normalPath(path)
+			const entry = state.fsMap.get(path)
+
+			if (entry && "placeholder" in entry) {
+				return true
+			}
+			return false
+		},
+
 		writeFile: async function (
 			path: Parameters<NodeishFilesystem["writeFile"]>[0],
 			data: Parameters<NodeishFilesystem["writeFile"]>[1],
@@ -194,6 +219,7 @@ export function createNodeishMemoryFs(): NodeishFilesystem {
 
 			if (file instanceof Set) throw new FilesystemError("EISDIR", path, "readFile")
 			if (file === undefined) throw new FilesystemError("ENOENT", path, "readFile")
+			if ("placeholder" in file) throw new FilesystemError("EPLACEHOLDER", path, "readFile")
 			if (!(options?.encoding || typeof options === "string")) return file
 
 			return decoder.decode(file)
@@ -257,8 +283,9 @@ export function createNodeishMemoryFs(): NodeishFilesystem {
 				throw new FilesystemError("ENOENT", path, "rm")
 
 			if (parentDir instanceof Uint8Array) throw new FilesystemError("ENOTDIR", path, "rm")
+			if ("placeholder" in parentDir) throw new FilesystemError("EPLACEHOLDER", path, "readFile")
 
-			if (target instanceof Uint8Array) {
+			if (target instanceof Uint8Array || "placeholder" in target) {
 				parentDir.delete(baseName)
 				state.fsStats.delete(path)
 				state.fsMap.delete(path)
@@ -392,6 +419,10 @@ export function createNodeishMemoryFs(): NodeishFilesystem {
 			if (parentDir instanceof Uint8Array || target instanceof Uint8Array)
 				throw new FilesystemError("ENOTDIR", path, "rmdir")
 
+			if ("placeholder" in parentDir || "placeholder" in target) {
+				throw new FilesystemError("EPLACEHOLDER", path, "readFile")
+			}
+
 			if (target.size) throw new FilesystemError("ENOTEMPTY", path, "rmdir")
 
 			parentDir.delete(baseName)
@@ -427,6 +458,9 @@ export function createNodeishMemoryFs(): NodeishFilesystem {
 			if (targetInode !== undefined) {
 				state.fsMap.set(path, targetInode)
 			}
+			if ("placeholder" in parentDir) {
+				throw new FilesystemError("EPLACEHOLDER", path, "readFile")
+			}
 
 			parentDir.add(getBasename(path))
 			newStatEntry(path, state.fsStats, 2, 0o777, target)
@@ -449,6 +483,10 @@ export function createNodeishMemoryFs(): NodeishFilesystem {
 				throw new FilesystemError("EISDIR", path, "unlink")
 			}
 
+			if ("placeholder" in parentDir || "placeholder" in target) {
+				throw new FilesystemError("EPLACEHOLDER", path, "readFile")
+			}
+
 			parentDir.delete(getBasename(path))
 			state.fsStats.delete(path)
 			state.fsMap.delete(path)

lix/source-code/server/package.json

@@ -1,6 +1,7 @@
 {
 	"name": "@lix-js/server",
 	"type": "module",
+	"version": "0.0.1",
 	"private": true,
 	"exports": {
 		".": "./dist/index.js"
@@ -39,6 +40,5 @@
 		"typescript": "5.2.2",
 		"vitest": "0.34.3"
 	},
-	"license": "Apache-2.0",
-	"version": null
+	"license": "Apache-2.0"
 }