internal/debug: APIs for profiling and tracing

The debug package provides an RPC wrapper for glog settings and the
debugging facilities of the Go runtime. They can be triggered through
both command line flags and the IPC listener.

internal/debug/trace_fallback.go

@@ -0,0 +1,31 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+//+build !go1.5
+
+// no-op implementation of tracing methods for Go < 1.5.
+
+package debug
+
+import "errors"
+
+func (*HandlerT) StartTrace(string) error {
+	return errors.New("tracing is not supported on Go < 1.5")
+}
+
+func (*HandlerT) StopTrace() error {
+	return errors.New("tracing is not supported on Go < 1.5")
+}