refactor: migrate src/lsp/server.ts from Bun.file()/Bun.write() to Filesystem module (#14138)

packages/opencode/src/util/filesystem.ts

@@ -1,8 +1,10 @@
-import { mkdir, readFile, writeFile } from "fs/promises"
-import { existsSync, statSync } from "fs"
+import { chmod, mkdir, readFile, writeFile } from "fs/promises"
+import { createWriteStream, existsSync, statSync } from "fs"
 import { lookup } from "mime-types"
 import { realpathSync } from "fs"
 import { dirname, join, relative } from "path"
+import { Readable } from "stream"
+import { pipeline } from "stream/promises"
 
 export namespace Filesystem {
   // Fast sync version for metadata checks
@@ -68,6 +70,25 @@ export namespace Filesystem {
     return write(p, JSON.stringify(data, null, 2), mode)
   }
 
+  export async function writeStream(
+    p: string,
+    stream: ReadableStream<Uint8Array> | Readable,
+    mode?: number,
+  ): Promise<void> {
+    const dir = dirname(p)
+    if (!existsSync(dir)) {
+      await mkdir(dir, { recursive: true })
+    }
+
+    const nodeStream = stream instanceof ReadableStream ? Readable.fromWeb(stream as any) : stream
+    const writeStream = createWriteStream(p)
+    await pipeline(nodeStream, writeStream)
+
+    if (mode) {
+      await chmod(p, mode)
+    }
+  }
+
   export function mimeType(p: string): string {
     return lookup(p) || "application/octet-stream"
   }