LibCore: Make CFile::open() truncate when opening something "WriteOnly"

Unless we're also opening to append (and/or if the file is required to
be a new file), CFile::open(WriteOnly) will now truncate the file.

1 files changed, 3 insertions, 0 deletions

diff --git a/Libraries/LibCore/CFile.cpp b/Libraries/LibCore/CFile.cpp
index dfa5b2c073..91c0a09258 100644
--- a/Libraries/LibCore/CFile.cpp
+++ b/Libraries/LibCore/CFile.cpp
@@ -34,6 +34,9 @@ bool CFile::open(CIODevice::OpenMode mode)
         flags |= O_RDONLY;
     } else if (mode & CIODevice::WriteOnly) {
         flags |= O_WRONLY | O_CREAT;
+        bool should_truncate = !((mode & CIODevice::Append) || (mode & CIODevice::MustBeNew));
+        if (should_truncate)
+            flags |= O_TRUNC;
     }
     if (mode & CIODevice::Append)
         flags |= O_APPEND;