LogDog: Update protobufs, add support library.

common/logdog/protocol/protoutil/utils.go

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+

[tandrii(chromium), 2015/08/11 17:41:37]

// package protoutil is a library to operate on protobuf structures.

[dnj, 2015/08/11 18:20:37]

Done.

+package protoutil
+
+import (
+        "time"
+
+        "github.com/luci/luci-go/common/logdog/protocol"
+        "github.com/luci/luci-go/common/logdog/types"
+)
+
+// DescriptorPath returns the StreamPath for a descriptor.
+func DescriptorPath(d *protocol.LogStreamDescriptor) types.StreamPath {
+        if d == nil {
+                return types.StreamPath("")
+        }
+        return types.StreamName(d.GetPrefix()).Join(types.StreamName(d.GetName()))
+}
+
+// NewTimestamp creates a new Butler protocol Timestamp from a time.Time type.
+func NewTimestamp(t time.Time) *protocol.Timestamp {
+        value := uint64(t.UTC().UnixNano()) / uint64(time.Microsecond)
+        return &protocol.Timestamp{
+                UsFromEpoch: &value,
+        }
+}
+
+// TimeOffset returns the equivalent time offset in microseconds for a Duration.
+// This is suitable for use in offset-since-microseconds protobuf fields.
+func TimeOffset(d time.Duration) uint64 {
+        offset := d.Nanoseconds()

[tandrii(chromium), 2015/08/11 17:41:37]

bummer, i didn't expect time.Duration to miss .Microseconds() method.

[dnj, 2015/08/11 18:20:37]

Acknowledged.

+        if offset < 0 {
+                offset = 0
+        }
+        value := uint64(offset / int64(time.Microsecond))
+        return value
+}