From 4caf28b13990b95122eec5ac17177deb47f23144 Mon Sep 17 00:00:00 2001
From: Vadim Dalecky <streamich@gmail.com>
Date: Mon, 19 Jun 2023 00:12:52 +0200
Subject: [PATCH] =?UTF-8?q?feat:=20=F0=9F=8E=B8=20add=20truncateSync()=20a?=
 =?UTF-8?q?nd=20ftruncateSync()=20methods?=
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---
 demo/fsa/main.ts                            |  5 +++++
 src/fsa-to-node/FsaNodeFs.ts                | 13 +++++++++++--
 src/fsa-to-node/types.ts                    |  1 +
 src/fsa-to-node/worker/FsaNodeSyncWorker.ts |  3 +++
 4 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/demo/fsa/main.ts b/demo/fsa/main.ts
index 1a016b76e..dceeee119 100644
--- a/demo/fsa/main.ts
+++ b/demo/fsa/main.ts
@@ -66,6 +66,11 @@ const demo = async (dir: fsa.IFileSystemDirectoryHandle) => {
   await fs.promises.mkdir('/tmp');
   const tmpDirName = fs.mkdtempSync('/tmp/temporary-');
   strictEqual(fs.statSync(tmpDirName).isDirectory(), true);
+
+  console.log('truncateSync() - can truncate a file');
+  await fs.promises.writeFile('/truncated.txt', 'truncate here: abcdefghijklmnopqrstuvwxyz');
+  fs.truncateSync('/truncated.txt', 14);
+  strictEqual(fs.readFileSync('/truncated.txt', 'utf8'), 'truncate here:');
 };
 
 const main = async () => {
diff --git a/src/fsa-to-node/FsaNodeFs.ts b/src/fsa-to-node/FsaNodeFs.ts
index c1ea2a130..96f03428e 100644
--- a/src/fsa-to-node/FsaNodeFs.ts
+++ b/src/fsa-to-node/FsaNodeFs.ts
@@ -891,12 +891,21 @@ export class FsaNodeFs extends FsaNodeCore implements FsCallbackApi, FsSynchrono
     return bufferToEncoding(buffer, opts.encoding);
   };
 
-  public readonly ftruncateSync: FsSynchronousApi['ftruncateSync'] = notSupported;
+  public readonly truncateSync: FsSynchronousApi['truncateSync'] = (id: misc.TFileId, len?: number): void => {
+    if (isFd(id)) return this.ftruncateSync(id as number, len);
+    const filename = pathToFilename(id as misc.PathLike);
+    this.getSyncAdapter().call('trunc', [filename, Number(len) || 0]);
+  };
+
+  public readonly ftruncateSync: FsSynchronousApi['ftruncateSync'] = (fd: number, len?: number): void => {
+    const filename = this.getFileName(fd);
+    this.truncateSync(filename, len);
+  };
+
   public readonly openSync: FsSynchronousApi['openSync'] = notSupported;
   public readonly readdirSync: FsSynchronousApi['readdirSync'] = notSupported;
   public readonly readSync: FsSynchronousApi['readSync'] = notSupported;
   public readonly realpathSync: FsSynchronousApi['realpathSync'] = notSupported;
-  public readonly truncateSync: FsSynchronousApi['truncateSync'] = notSupported;
   public readonly unlinkSync: FsSynchronousApi['unlinkSync'] = notSupported;
   public readonly writeSync: FsSynchronousApi['writeSync'] = notSupported;
 
diff --git a/src/fsa-to-node/types.ts b/src/fsa-to-node/types.ts
index 24db7d05e..50de9e687 100644
--- a/src/fsa-to-node/types.ts
+++ b/src/fsa-to-node/types.ts
@@ -18,6 +18,7 @@ export interface FsaNodeSyncAdapterApi {
   rm(req: [filename: string, opts?: opts.IRmOptions]): void;
   mkdir(req: [filename: string, opts?: misc.TMode | opts.IMkdirOptions]): string | undefined;
   mkdtemp(req: [filename: string, opts?: misc.TMode | opts.IOptions]): string;
+  trunc(req: [filename: string, len: number]): void;
 }
 
 export interface FsaNodeSyncAdapter {
diff --git a/src/fsa-to-node/worker/FsaNodeSyncWorker.ts b/src/fsa-to-node/worker/FsaNodeSyncWorker.ts
index 70f2f8f39..69ef8f9b4 100644
--- a/src/fsa-to-node/worker/FsaNodeSyncWorker.ts
+++ b/src/fsa-to-node/worker/FsaNodeSyncWorker.ts
@@ -153,5 +153,8 @@ export class FsaNodeSyncWorker {
     mkdtemp: async ([filename]): Promise<string> => {
       return await this.fs.promises.mkdtemp(filename, {encoding: 'utf8'}) as string;
     },
+    trunc: async ([filename, len]): Promise<void> => {
+      await this.fs.promises.truncate(filename, len);
+    },
   };
 }