LibCore: Add Core::Stream::File::exists()

Author: https://github.com/arieldon
Commit: 244357472a
Pull-request: https://github.com/SerenityOS/serenity/pull/14027
Reviewed-by: https://github.com/kleinesfilmroellchen ✅

Userland/Libraries/LibCore/Stream.cpp

@@ -117,6 +117,11 @@ ErrorOr<NonnullOwnPtr<File>> File::adopt_fd(int fd, OpenMode mode)
     return file;
 }
 
+bool File::exists(StringView filename)
+{
+    return !Core::System::stat(filename).is_error();
+}
+
 int File::open_mode_to_options(OpenMode mode)
 {
     int flags = 0;

Userland/Libraries/LibCore/Stream.h

@@ -179,6 +179,7 @@ class File final : public SeekableStream {
 public:
     static ErrorOr<NonnullOwnPtr<File>> open(StringView filename, OpenMode, mode_t = 0644);
     static ErrorOr<NonnullOwnPtr<File>> adopt_fd(int fd, OpenMode);
+    static bool exists(StringView filename);
 
     File(File&& other) { operator=(move(other)); }