mox!

moxio/trace.go

@@ -0,0 +1,48 @@
+package moxio
+
+import (
+	"io"
+
+	"github.com/mjl-/mox/mlog"
+)
+
+type writer struct {
+	log    *mlog.Log
+	prefix string
+	w      io.Writer
+}
+
+// NewTraceWriter wraps "w" into a writer that logs all writes to "log" with
+// log level trace, prefixed with "prefix".
+func NewTraceWriter(log *mlog.Log, prefix string, w io.Writer) io.Writer {
+	return writer{log, prefix, w}
+}
+
+// Write logs a trace line for writing buf to the client, then writes to the
+// client.
+func (w writer) Write(buf []byte) (int, error) {
+	w.log.Trace(w.prefix + string(buf))
+	return w.w.Write(buf)
+}
+
+type reader struct {
+	log    *mlog.Log
+	prefix string
+	r      io.Reader
+}
+
+// NewTraceReader wraps reader "r" into a reader that logs all reads to "log"
+// with log level trace, prefixed with "prefix".
+func NewTraceReader(log *mlog.Log, prefix string, r io.Reader) io.Reader {
+	return reader{log, prefix, r}
+}
+
+// Read does a single Read on its underlying reader, logs data of successful
+// reads, and returns the data read.
+func (r reader) Read(buf []byte) (int, error) {
+	n, err := r.r.Read(buf)
+	if n > 0 {
+		r.log.Trace(r.prefix + string(buf[:n]))
+	}
+	return n, err
+}