Move timeutils functions to the only places where they are used.

- Move time json marshaling to the jsonlog package: this is a docker
  internal hack that we should not promote as a library.
- Move Timestamp encoding/decoding functions to the API types: This is
  only used there. It could be a standalone library but I don't this
it's worth having a separated repo for this. It could introduce more
complexity than it solves.

Signed-off-by: David Calavera <david.calavera@gmail.com>

jsonlog/jsonlog_marshalling.go

@@ -13,8 +13,6 @@
 //        "bytes"
 //-
 //        "unicode/utf8"
-//+
-//+       "github.com/docker/docker/pkg/timeutils"
 // )
 //
 // func (mj *JSONLog) MarshalJSON() ([]byte, error) {
@@ -43,7 +41,7 @@
 //        }
 //        buf.WriteString(`"time":`)
 //-       obj, err = mj.Created.MarshalJSON()
-//+       timestamp, err = timeutils.FastMarshalJSON(mj.Created)
+//+       timestamp, err = FastTimeMarshalJSON(mj.Created)
 //        if err != nil {
 //                return err
 //        }
@@ -69,8 +67,6 @@ package jsonlog
 import (
 	"bytes"
 	"unicode/utf8"
-
-	"github.com/docker/docker/pkg/timeutils"
 )
 
 // MarshalJSON marshals the JSONLog.
@@ -111,7 +107,7 @@ func (mj *JSONLog) MarshalJSONBuf(buf *bytes.Buffer) error {
 		buf.WriteString(`,`)
 	}
 	buf.WriteString(`"time":`)
-	timestamp, err = timeutils.FastMarshalJSON(mj.Created)
+	timestamp, err = FastTimeMarshalJSON(mj.Created)
 	if err != nil {
 		return err
 	}

jsonlog/time_marshalling.go

@@ -0,0 +1,27 @@
+// Package jsonlog provides helper functions to parse and print time (time.Time) as JSON.
+package jsonlog
+
+import (
+	"errors"
+	"time"
+)
+
+const (
+	// RFC3339NanoFixed is our own version of RFC339Nano because we want one
+	// that pads the nano seconds part with zeros to ensure
+	// the timestamps are aligned in the logs.
+	RFC3339NanoFixed = "2006-01-02T15:04:05.000000000Z07:00"
+	// JSONFormat is the format used by FastMarshalJSON
+	JSONFormat = `"` + time.RFC3339Nano + `"`
+)
+
+// FastTimeMarshalJSON avoids one of the extra allocations that
+// time.MarshalJSON is making.
+func FastTimeMarshalJSON(t time.Time) (string, error) {
+	if y := t.Year(); y < 0 || y >= 10000 {
+		// RFC 3339 is clear that years are 4 digits exactly.
+		// See golang.org/issue/4556#c15 for more discussion.
+		return "", errors.New("time.MarshalJSON: year outside of range [0,9999]")
+	}
+	return t.Format(JSONFormat), nil
+}

jsonlog/time_marshalling_test.go

@@ -0,0 +1,47 @@
+package jsonlog
+
+import (
+	"testing"
+	"time"
+)
+
+// Testing to ensure 'year' fields is between 0 and 9999
+func TestFastTimeMarshalJSONWithInvalidDate(t *testing.T) {
+	aTime := time.Date(-1, 1, 1, 0, 0, 0, 0, time.Local)
+	json, err := FastTimeMarshalJSON(aTime)
+	if err == nil {
+		t.Fatalf("FastTimeMarshalJSON should throw an error, but was '%v'", json)
+	}
+	anotherTime := time.Date(10000, 1, 1, 0, 0, 0, 0, time.Local)
+	json, err = FastTimeMarshalJSON(anotherTime)
+	if err == nil {
+		t.Fatalf("FastTimeMarshalJSON should throw an error, but was '%v'", json)
+	}
+
+}
+
+func TestFastTimeMarshalJSON(t *testing.T) {
+	aTime := time.Date(2015, 5, 29, 11, 1, 2, 3, time.UTC)
+	json, err := FastTimeMarshalJSON(aTime)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := "\"2015-05-29T11:01:02.000000003Z\""
+	if json != expected {
+		t.Fatalf("Expected %v, got %v", expected, json)
+	}
+
+	location, err := time.LoadLocation("Europe/Paris")
+	if err != nil {
+		t.Fatal(err)
+	}
+	aTime = time.Date(2015, 5, 29, 11, 1, 2, 3, location)
+	json, err = FastTimeMarshalJSON(aTime)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected = "\"2015-05-29T11:01:02.000000003+02:00\""
+	if json != expected {
+		t.Fatalf("Expected %v, got %v", expected, json)
+	}
+}