feat(db): deleteFileOwnedBy — owner-scoped file soft delete

src/lib/db/files.ts

@@ -168,3 +168,22 @@ export function deleteFile(id: string): boolean {
     .run(Math.floor(Date.now() / 1000), id);
   return result.changes > 0;
 }
+
+/**
+ * Owner-scoped soft delete: same effect as `deleteFile`, but only when the
+ * file belongs to `apiKeyId`. Used by the key-scoped completed-batch sweep so
+ * a batch that references another tenant's (or an unowned) file never nulls
+ * that file's content (GHSA-wvxc-jp3v-5mg5, SEC-C). Returns false when the
+ * row is not the caller's; throws on an empty owner so a caller cannot widen
+ * the delete by passing a blank id.
+ */
+export function deleteFileOwnedBy(id: string, apiKeyId: string): boolean {
+  if (typeof apiKeyId !== "string" || apiKeyId.trim() === "") {
+    throw new Error("deleteFileOwnedBy: apiKeyId is required");
+  }
+  const db = getDbInstance();
+  const result = db
+    .prepare("UPDATE files SET deleted_at = ?, content = NULL WHERE id = ? AND api_key_id = ?")
+    .run(Math.floor(Date.now() / 1000), id, apiKeyId);
+  return result.changes > 0;
+}

tests/unit/files-delete-owned-by.test.ts

@@ -0,0 +1,56 @@
+// tests/unit/files-delete-owned-by.test.ts
+import { describe, it, after } from "node:test";
+import assert from "node:assert";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "files-owned-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const { resetDbInstance } = await import("../../src/lib/db/core.ts");
+const { createFile, getFile, getFileContent, deleteFileOwnedBy } =
+  await import("../../src/lib/db/files.ts");
+
+const seed = (apiKeyId: string | null, label: string) =>
+  createFile({
+    bytes: label.length,
+    filename: `${label}.jsonl`,
+    purpose: "batch",
+    content: Buffer.from(label),
+    apiKeyId,
+  });
+
+describe("deleteFileOwnedBy — owner-scoped soft delete", () => {
+  after(() => {
+    resetDbInstance();
+    fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true, maxRetries: 5, retryDelay: 100 });
+  });
+
+  it("soft-deletes the owner's own file and nulls its content", () => {
+    const own = seed("key-A", "own");
+    assert.strictEqual(deleteFileOwnedBy(own.id, "key-A"), true);
+    assert.strictEqual(getFile(own.id), null, "metadata read hides a soft-deleted file");
+    assert.strictEqual(getFileContent(own.id), null);
+  });
+
+  it("returns false and leaves another key's file intact", () => {
+    const other = seed("key-B", "other");
+    assert.strictEqual(deleteFileOwnedBy(other.id, "key-A"), false);
+    assert.ok(getFile(other.id));
+    assert.strictEqual(getFileContent(other.id)?.toString(), "other");
+  });
+
+  it("returns false for an unowned file (api_key_id NULL) — only the instance sweep reaches those", () => {
+    const unowned = seed(null, "unowned");
+    assert.strictEqual(deleteFileOwnedBy(unowned.id, "key-A"), false);
+    assert.strictEqual(getFileContent(unowned.id)?.toString(), "unowned");
+  });
+
+  it("throws on an empty apiKeyId instead of widening", () => {
+    const own = seed("key-A", "guard");
+    assert.throws(() => deleteFileOwnedBy(own.id, ""), /apiKeyId/);
+    assert.throws(() => deleteFileOwnedBy(own.id, undefined as unknown as string), /apiKeyId/);
+    assert.strictEqual(getFileContent(own.id)?.toString(), "guard");
+  });
+});