v/vlib/io/multi_writer.v

34 lines
1.1 KiB
V

module io
// new_multi_writer returns a Writer that writes to all writers. The write
// function of the returned Writer writes to all writers of the MultiWriter,
// returns the length of bytes written, and if any writer fails to write the
// full length an error is returned and writing to other writers stops, and if
// any writer returns an error the error is returned immediately and writing to
// other writers stops.
pub fn new_multi_writer(writers ...Writer) Writer {
return &MultiWriter{
writers: writers
}
}
// MultiWriter writes to all its writers.
pub struct MultiWriter {
pub:
writers []Writer
}
// write writes to all writers of the MultiWriter. Returns the length of bytes
// written. If any writer fails to write the full length an error is returned
// and writing to other writers stops. If any writer returns an error the error
// is returned immediately and writing to other writers stops.
pub fn (m MultiWriter) write(buf []byte) ?int {
for w in m.writers {
n := w.write(buf) ?
if n != buf.len {
return error('io: incomplete write to writer of MultiWriter')
}
}
return buf.len
}