From 35b844ba4c8aa940444ed7b013462520e57b0f05 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 6 Sep 2020 16:09:26 +0200
Subject: [PATCH] LibCore: Add Core::IODevice::truncate()

This is just a wrapper around ftruncate(). Today I also learned that
ftruncate() does not reset the file descriptor offset. :^)
---
 Libraries/LibCore/IODevice.cpp | 10 ++++++++++
 Libraries/LibCore/IODevice.h   |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/Libraries/LibCore/IODevice.cpp b/Libraries/LibCore/IODevice.cpp
index df69d3b182f..22d4eb994bf 100644
--- a/Libraries/LibCore/IODevice.cpp
+++ b/Libraries/LibCore/IODevice.cpp
@@ -266,6 +266,16 @@ bool IODevice::seek(i64 offset, SeekMode mode, off_t* pos)
     return true;
 }
 
+bool IODevice::truncate(off_t size)
+{
+    int rc = ftruncate(m_fd, size);
+    if (rc < 0) {
+        set_error(errno);
+        return false;
+    }
+    return true;
+}
+
 bool IODevice::write(const u8* data, int size)
 {
     int rc = ::write(m_fd, data, size);
diff --git a/Libraries/LibCore/IODevice.h b/Libraries/LibCore/IODevice.h
index 8c8ee6beb6d..2fe1e93e65f 100644
--- a/Libraries/LibCore/IODevice.h
+++ b/Libraries/LibCore/IODevice.h
@@ -65,6 +65,8 @@ public:
     bool write(const u8*, int size);
     bool write(const StringView&);
 
+    bool truncate(off_t);
+
     bool can_read_line() const;
 
     bool can_read() const;