1 files changed, 236 insertions, 0 deletions
diff --git a/packages/shared/src/filesystem.ts b/packages/shared/src/filesystem.ts
new file mode 100644
index 000000000..44346be8f
--- /dev/null
+++ b/packages/shared/src/filesystem.ts
@@ -0,0 +1,236 @@
+import { NodeFileSystem } from "@effect/platform-node"
+import { dirname, join, relative, resolve as pathResolve } from "path"
+import { realpathSync } from "fs"
+import * as NFS from "fs/promises"
+import { lookup } from "mime-types"
+import { Effect, FileSystem, Layer, Schema, Context } from "effect"
+import type { PlatformError } from "effect/PlatformError"
+import { Glob } from "./util/glob"
+
+export namespace AppFileSystem {
+  export class FileSystemError extends Schema.TaggedErrorClass<FileSystemError>()("FileSystemError", {
+    method: Schema.String,
+    cause: Schema.optional(Schema.Defect),
+  }) {}
+
+  export type Error = PlatformError | FileSystemError
+
+  export interface DirEntry {
+    readonly name: string
+    readonly type: "file" | "directory" | "symlink" | "other"
+  }
+
+  export interface Interface extends FileSystem.FileSystem {
+    readonly isDir: (path: string) => Effect.Effect<boolean>
+    readonly isFile: (path: string) => Effect.Effect<boolean>
+    readonly existsSafe: (path: string) => Effect.Effect<boolean>
+    readonly readJson: (path: string) => Effect.Effect<unknown, Error>
+    readonly writeJson: (path: string, data: unknown, mode?: number) => Effect.Effect<void, Error>
+    readonly ensureDir: (path: string) => Effect.Effect<void, Error>
+    readonly writeWithDirs: (path: string, content: string | Uint8Array, mode?: number) => Effect.Effect<void, Error>
+    readonly readDirectoryEntries: (path: string) => Effect.Effect<DirEntry[], Error>
+    readonly findUp: (target: string, start: string, stop?: string) => Effect.Effect<string[], Error>
+    readonly up: (options: { targets: string[]; start: string; stop?: string }) => Effect.Effect<string[], Error>
+    readonly globUp: (pattern: string, start: string, stop?: string) => Effect.Effect<string[], Error>
+    readonly glob: (pattern: string, options?: Glob.Options) => Effect.Effect<string[], Error>
+    readonly globMatch: (pattern: string, filepath: string) => boolean
+  }
+
+  export class Service extends Context.Service<Service, Interface>()("@opencode/FileSystem") {}
+
+  export const layer = Layer.effect(
+    Service,
+    Effect.gen(function* () {
+      const fs = yield* FileSystem.FileSystem
+
+      const existsSafe = Effect.fn("FileSystem.existsSafe")(function* (path: string) {
+        return yield* fs.exists(path).pipe(Effect.orElseSucceed(() => false))
+      })
+
+      const isDir = Effect.fn("FileSystem.isDir")(function* (path: string) {
+        const info = yield* fs.stat(path).pipe(Effect.catch(() => Effect.void))
+        return info?.type === "Directory"
+      })
+
+      const isFile = Effect.fn("FileSystem.isFile")(function* (path: string) {
+        const info = yield* fs.stat(path).pipe(Effect.catch(() => Effect.void))
+        return info?.type === "File"
+      })
+
+      const readDirectoryEntries = Effect.fn("FileSystem.readDirectoryEntries")(function* (dirPath: string) {
+        return yield* Effect.tryPromise({
+          try: async () => {
+            const entries = await NFS.readdir(dirPath, { withFileTypes: true })
+            return entries.map(
+              (e): DirEntry => ({
+                name: e.name,
+                type: e.isDirectory() ? "directory" : e.isSymbolicLink() ? "symlink" : e.isFile() ? "file" : "other",
+              }),
+            )
+          },
+          catch: (cause) => new FileSystemError({ method: "readDirectoryEntries", cause }),
+        })
+      })
+
+      const readJson = Effect.fn("FileSystem.readJson")(function* (path: string) {
+        const text = yield* fs.readFileString(path)
+        return JSON.parse(text)
+      })
+
+      const writeJson = Effect.fn("FileSystem.writeJson")(function* (path: string, data: unknown, mode?: number) {
+        const content = JSON.stringify(data, null, 2)
+        yield* fs.writeFileString(path, content)
+        if (mode) yield* fs.chmod(path, mode)
+      })
+
+      const ensureDir = Effect.fn("FileSystem.ensureDir")(function* (path: string) {
+        yield* fs.makeDirectory(path, { recursive: true })
+      })
+
+      const writeWithDirs = Effect.fn("FileSystem.writeWithDirs")(function* (
+        path: string,
+        content: string | Uint8Array,
+        mode?: number,
+      ) {
+        const write = typeof content === "string" ? fs.writeFileString(path, content) : fs.writeFile(path, content)
+
+        yield* write.pipe(
+          Effect.catchIf(
+            (e) => e.reason._tag === "NotFound",
+            () =>
+              Effect.gen(function* () {
+                yield* fs.makeDirectory(dirname(path), { recursive: true })
+                yield* write
+              }),
+          ),
+        )
+        if (mode) yield* fs.chmod(path, mode)
+      })
+
+      const glob = Effect.fn("FileSystem.glob")(function* (pattern: string, options?: Glob.Options) {
+        return yield* Effect.tryPromise({
+          try: () => Glob.scan(pattern, options),
+          catch: (cause) => new FileSystemError({ method: "glob", cause }),
+        })
+      })
+
+      const findUp = Effect.fn("FileSystem.findUp")(function* (target: string, start: string, stop?: string) {
+        const result: string[] = []
+        let current = start
+        while (true) {
+          const search = join(current, target)
+          if (yield* fs.exists(search)) result.push(search)
+          if (stop === current) break
+          const parent = dirname(current)
+          if (parent === current) break
+          current = parent
+        }
+        return result
+      })
+
+      const up = Effect.fn("FileSystem.up")(function* (options: { targets: string[]; start: string; stop?: string }) {
+        const result: string[] = []
+        let current = options.start
+        while (true) {
+          for (const target of options.targets) {
+            const search = join(current, target)
+            if (yield* fs.exists(search)) result.push(search)
+          }
+          if (options.stop === current) break
+          const parent = dirname(current)
+          if (parent === current) break
+          current = parent
+        }
+        return result
+      })
+
+      const globUp = Effect.fn("FileSystem.globUp")(function* (pattern: string, start: string, stop?: string) {
+        const result: string[] = []
+        let current = start
+        while (true) {
+          const matches = yield* glob(pattern, { cwd: current, absolute: true, include: "file", dot: true }).pipe(
+            Effect.catch(() => Effect.succeed([] as string[])),
+          )
+          result.push(...matches)
+          if (stop === current) break
+          const parent = dirname(current)
+          if (parent === current) break
+          current = parent
+        }
+        return result
+      })
+
+      return Service.of({
+        ...fs,
+        existsSafe,
+        isDir,
+        isFile,
+        readDirectoryEntries,
+        readJson,
+        writeJson,
+        ensureDir,
+        writeWithDirs,
+        findUp,
+        up,
+        globUp,
+        glob,
+        globMatch: Glob.match,
+      })
+    }),
+  )
+
+  export const defaultLayer = layer.pipe(Layer.provide(NodeFileSystem.layer))
+
+  // Pure helpers that don't need Effect (path manipulation, sync operations)
+  export function mimeType(p: string): string {
+    return lookup(p) || "application/octet-stream"
+  }
+
+  export function normalizePath(p: string): string {
+    if (process.platform !== "win32") return p
+    const resolved = pathResolve(windowsPath(p))
+    try {
+      return realpathSync.native(resolved)
+    } catch {
+      return resolved
+    }
+  }
+
+  export function normalizePathPattern(p: string): string {
+    if (process.platform !== "win32") return p
+    if (p === "*") return p
+    const match = p.match(/^(.*)[\\/]\*$/)
+    if (!match) return normalizePath(p)
+    const dir = /^[A-Za-z]:$/.test(match[1]) ? match[1] + "\\" : match[1]
+    return join(normalizePath(dir), "*")
+  }
+
+  export function resolve(p: string): string {
+    const resolved = pathResolve(windowsPath(p))
+    try {
+      return normalizePath(realpathSync(resolved))
+    } catch (e: any) {
+      if (e?.code === "ENOENT") return normalizePath(resolved)
+      throw e
+    }
+  }
+
+  export function windowsPath(p: string): string {
+    if (process.platform !== "win32") return p
+    return p
+      .replace(/^\/([a-zA-Z]):(?:[\\/]|$)/, (_, drive) => `${drive.toUpperCase()}:/`)
+      .replace(/^\/([a-zA-Z])(?:\/|$)/, (_, drive) => `${drive.toUpperCase()}:/`)
+      .replace(/^\/cygdrive\/([a-zA-Z])(?:\/|$)/, (_, drive) => `${drive.toUpperCase()}:/`)
+      .replace(/^\/mnt\/([a-zA-Z])(?:\/|$)/, (_, drive) => `${drive.toUpperCase()}:/`)
+  }
+
+  export function overlaps(a: string, b: string) {
+    const relA = relative(a, b)
+    const relB = relative(b, a)
+    return !relA || !relA.startsWith("..") || !relB || !relB.startsWith("..")
+  }
+
+  export function contains(parent: string, child: string) {
+    return !relative(parent, child).startsWith("..")
+  }
+}