refactor(core): rename app node modules (#34238)

packages/core/src/effect/layer-node.ts

@@ -0,0 +1,273 @@
+import { Brand, Context, Layer } from "effect"
+
+type AnyNode = Node<unknown, unknown, any>
+type RuntimeLayer = Layer.Layer<never, unknown, unknown>
+type NodeList<Item extends AnyNode = AnyNode> = readonly [] | readonly [Item, ...Item[]]
+export type Output<Item> = [Item] extends [never] ? never : Item extends Node<infer A, unknown, any> ? A : never
+export type Error<Item> = [Item] extends [never] ? never : Item extends Node<unknown, infer E, any> ? E : never
+type NodeTag<Item> = [Item] extends [never] ? undefined : Item extends Node<unknown, unknown, infer T> ? T : never
+type Missing<Required, Dependencies extends NodeList> = Exclude<Required, Output<Dependencies[number]>>
+type CheckDependencies<Implementation extends Layer.Any, Dependencies extends NodeList> = [
+  Missing<Layer.Services<Implementation>, Dependencies>,
+] extends [never]
+  ? unknown
+  : { readonly "Missing dependencies": Missing<Layer.Services<Implementation>, Dependencies> }
+declare const $OutputType: unique symbol
+declare const $ErrorType: unique symbol
+
+export type Tag<Name extends string = string> = Name & Brand.Brand<"LayerNode.Tag">
+
+const makeTag = Brand.nominal<Tag>()
+
+export interface Node<A, E = never, T extends Tag | undefined = undefined> {
+  readonly kind: "layer" | "unbound" | "group"
+  readonly name: string
+  readonly service?: Context.Service.Any
+  readonly implementation?: Layer.Any
+  readonly dependencies: readonly AnyNode[]
+  readonly tag?: T
+  readonly [$OutputType]?: () => A
+  readonly [$ErrorType]?: () => E
+}
+
+type NodeIdentity =
+  | { readonly service: Context.Service.Any; readonly name?: never }
+  | { readonly name: string; readonly service?: never }
+type DistributiveOmit<A, K extends PropertyKey> = A extends unknown ? Omit<A, K> : never
+
+export type TagConfig = Readonly<Record<string, readonly string[]>>
+type TagNames<Config extends TagConfig> = keyof Config & string
+type NodeInTags<Names extends string> = Node<unknown, unknown, Tag<Names> | undefined>
+type CheckTags<Items extends NodeList, Names extends string> = [Exclude<Items[number], NodeInTags<Names>>] extends [
+  never,
+]
+  ? unknown
+  : { readonly "Invalid tag dependencies": Exclude<Items[number], NodeInTags<Names>> }
+
+export interface Tags<Config extends TagConfig> {
+  readonly values: { readonly [Name in TagNames<Config>]: Tag<Name> }
+  readonly make: <Name extends TagNames<Config>>(
+    name: Name,
+  ) => <const Implementation extends Layer.Any, const Items extends NodeList>(
+    input: DistributiveOmit<MakeInput<Implementation, Items, Tag<Name>>, "tag"> &
+      CheckTags<Items, Name | Extract<Config[Name][number], string>>,
+  ) => Node<Layer.Success<Implementation>, Layer.Error<Implementation> | Error<Items[number]>, Tag<Name>>
+}
+
+export function tags<const Config extends { readonly [Name in keyof Config]: readonly (keyof Config & string)[] }>(
+  config: Config,
+): Tags<Config> {
+  const names = Object.keys(config) as TagNames<Config>[]
+  const values = Object.fromEntries(names.map((name) => [name, makeTag(name)])) as Tags<Config>["values"]
+  return {
+    values,
+    make: ((name: TagNames<Config>) => (input: DistributiveOmit<MakeInput<Layer.Any, NodeList, Tag>, "tag">) =>
+      make({ ...input, tag: values[name] })) as Tags<Config>["make"],
+  }
+}
+
+// Nodes ---------------------------------------------------------------------
+
+type MakeInput<
+  Implementation extends Layer.Any,
+  Items extends NodeList,
+  T extends Tag | undefined = undefined,
+> = NodeIdentity & {
+  readonly layer: Implementation
+  readonly deps: Items & CheckDependencies<Implementation, NoInfer<Items>>
+  readonly tag?: T
+}
+
+export function make<
+  const Implementation extends Layer.Any,
+  const Items extends NodeList,
+  const T extends Tag | undefined = undefined,
+>(
+  input: MakeInput<Implementation, Items, T>,
+): Node<Layer.Success<Implementation>, Layer.Error<Implementation> | Error<Items[number]>, T> {
+  return {
+    kind: "layer",
+    name: input.service !== undefined ? input.service.key : input.name,
+    service: input.service,
+    implementation: input.layer,
+    dependencies: input.deps,
+    tag: input.tag,
+  }
+}
+
+export function unbound<R, Shape, const T extends Tag>(service: Context.Key<R, Shape>, tag: T): Node<R, never, T> {
+  return {
+    kind: "unbound",
+    name: service.key,
+    service,
+    dependencies: [],
+    tag,
+  }
+}
+
+export function group<const Items extends readonly AnyNode[]>(
+  dependencies: Items,
+): Node<Output<Items[number]>, Error<Items[number]>, NodeTag<Items[number]>> {
+  return { kind: "group", name: "group", dependencies }
+}
+
+export type Replacement = {
+  readonly source: Layer.Any
+  readonly replacement: Layer.Any
+}
+
+type CheckReplacementErrors<SourceError, ReplacementError> = [Exclude<ReplacementError, SourceError>] extends [never]
+  ? unknown
+  : { readonly "New replacement errors": Exclude<ReplacementError, SourceError> }
+
+export function replace<A, E, R, E2>(
+  source: Layer.Layer<A, E, R>,
+  replacement: Layer.Layer<NoInfer<A>, E2, never> & CheckReplacementErrors<E, NoInfer<E2>>,
+): Replacement {
+  return { source, replacement }
+}
+
+// Tree -----------------------------------------------------------------------
+
+type Visit<Result> = (node: AnyNode, context: VisitContext<Result>) => Result
+
+type VisitContext<Result> = {
+  readonly cache: Map<AnyNode, Result>
+  readonly visit: (node: AnyNode) => Result
+}
+
+function walk<Result>(
+  root: AnyNode,
+  visit: Visit<Result>,
+  options: {
+    readonly cache?: Map<AnyNode, Result>
+    readonly resolve?: (node: AnyNode) => AnyNode
+    readonly detectCycles?: boolean
+  } = {},
+) {
+  const cache = options.cache ?? new Map<AnyNode, Result>()
+  const visiting = new Set<AnyNode>()
+  const stack: AnyNode[] = []
+
+  const recur = (node: AnyNode): Result => {
+    const target = options.resolve?.(node) ?? node
+    const cached = cache.get(target)
+    if (cached !== undefined || cache.has(target)) return cached!
+
+    if (options.detectCycles !== false && visiting.has(target)) {
+      const start = stack.indexOf(target)
+      throw new Error(
+        `Cycle detected in layer tree: ${[...stack.slice(start), target].map((item) => item.name).join(" -> ")}`,
+      )
+    }
+
+    visiting.add(target)
+    stack.push(target)
+    try {
+      const result = visit(target, { cache, visit: recur })
+      if (!cache.has(target)) cache.set(target, result)
+      return result
+    } finally {
+      stack.pop()
+      visiting.delete(target)
+    }
+  }
+
+  return recur(root)
+}
+
+export function hoist<A, E, T extends Tag>(
+  root: Node<A, E, any>,
+  tag: T,
+): {
+  readonly node: Node<A, E>
+  readonly hoisted: Node<unknown, E>
+} {
+  const hoisted = new Map<string, AnyNode>()
+
+  const node = walk<AnyNode>(root, (node, context) => {
+    if (node.kind === "group") {
+      return { ...node, dependencies: node.dependencies.map(context.visit) }
+    }
+    if (node.tag === tag) {
+      const existing = hoisted.get(node.name)
+      if (existing && existing !== node) {
+        throw new Error(`Tag ${tag} has conflicting implementations for ${node.name}`)
+      }
+      hoisted.set(node.name, node)
+      return group([])
+    }
+    if (node.kind === "unbound") {
+      return node
+    }
+    return { ...node, dependencies: node.dependencies.map(context.visit) }
+  })
+
+  return {
+    node: node as Node<A, E>,
+    hoisted: group(Array.from(hoisted.values())) as Node<unknown, E>,
+  }
+}
+
+export function compile<A, E>(
+  root: Node<A, E, any>,
+  replacements?: ReadonlyMap<Layer.Any, Layer.Any>,
+): Layer.Layer<A, E> {
+  const cache = new Map<AnyNode, RuntimeLayer>()
+  const compileNode = (node: AnyNode) =>
+    walk<RuntimeLayer>(
+      node,
+      (node, context) => {
+        if (node.kind === "unbound") throw new Error(`Unbound layer node: ${node.name}`)
+        const dependencies = node.dependencies.flatMap(flatten).map(context.visit)
+        const implementation = (replacements?.get(node.implementation!) ?? node.implementation!) as RuntimeLayer
+        return dependencies.length === 0
+          ? implementation
+          : implementation.pipe(Layer.provide(dependencies as [RuntimeLayer, ...RuntimeLayer[]]))
+      },
+      { cache },
+    )
+  const layers = flatten(root).map((node) => compileNode(node))
+  const layer = layers.reduce<RuntimeLayer>((result, layer) => layer.pipe(Layer.provideMerge(result)), Layer.empty)
+  return layer as Layer.Layer<A, E>
+}
+
+export function hasUnbound(root: Node<unknown, unknown, any>, source: AnyNode): boolean {
+  if (source.kind !== "unbound") throw new Error(`Cannot check non-unbound layer node: ${source.name}`)
+  return walk<boolean>(root, (node, context) => {
+    if (node === source) return true
+    return node.dependencies.some(context.visit)
+  })
+}
+
+export function bind<A, E, T extends Tag | undefined>(
+  root: Node<A, E, T>,
+  source: AnyNode,
+  replacement: AnyNode,
+): Node<A, E, T> {
+  if (source.kind !== "unbound") throw new Error(`Cannot bind non-unbound layer node: ${source.name}`)
+  if (source.name !== replacement.name) {
+    throw new Error(`Cannot bind ${source.name} to ${replacement.name}`)
+  }
+  if (source.tag !== replacement.tag) {
+    throw new Error(`Cannot bind ${source.name} across tags`)
+  }
+  return walk<AnyNode>(
+    root,
+    (target, context) => {
+      if (target.kind === "unbound") return target
+      const dependencies: AnyNode[] = []
+      const clone = { ...target, dependencies }
+      context.cache.set(target, clone)
+      dependencies.push(...target.dependencies.map(context.visit))
+      return clone
+    },
+    { detectCycles: false, resolve: (node) => (node === source ? replacement : node) },
+  ) as Node<A, E, T>
+}
+
+function flatten(node: AnyNode): readonly AnyNode[] {
+  return node.kind === "group" ? node.dependencies.flatMap(flatten) : [node]
+}
+
+export * as LayerNode from "./layer-node"