Implement Mail service.

service/mail/message.go

Index: service/mail/message.go
diff --git a/service/mail/message.go b/service/mail/message.go
new file mode 100644
index 0000000000000000000000000000000000000000..95f844a1f396c453893cef6726740b19f48e69a8
--- /dev/null
+++ b/service/mail/message.go
@@ -0,0 +1,132 @@
+// 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.
+
+package mail
+
+import (
+	"fmt"
+	net_mail "net/mail"
+	"reflect"
+
+	"google.golang.org/appengine/mail"
+)
+
+// Attachment is a mimic of https://godoc.org/google.golang.org/appengine/mail#Attachment
+//
+// It's provided here for convenience, and is compile-time checked to be
+// identical.
+type Attachment struct {
+	// Name must be set to a valid file name.
+	Name      string
+	Data      []byte
+	ContentID string
+}
+
+var _ Attachment = (Attachment)(mail.Attachment{})
+
+// Message is a mimic of https://godoc.org/google.golang.org/appengine/mail#Message
+//
+// It's provided here for convenience, and is init-time checked to be identical
+// (not statically because []Attachement prevents static casting).
+type Message struct {
+	Sender      string
+	ReplyTo     string
+	To, Cc, Bcc []string
+	Subject     string
+	Body        string
+	HTMLBody    string
+	Attachments []Attachment
+	Headers     net_mail.Header
+}
+
+func init() {
+	mt := reflect.TypeOf(mail.Message{})
+	ot := reflect.TypeOf(Message{})
+	if mt.NumField() != ot.NumField() {
+		panic(fmt.Errorf("mismatched number of fields %s v %s", mt, ot))
+	}
+
+	for i := 0; i < mt.NumField(); i++ {
+		mf := mt.Field(i)
+		of := mt.Field(i)
+		if mf.Name != of.Name {
+			panic(fmt.Errorf("mismatched names %s v %s", mf.Name, of.Name))
+		}
+		if mf.Name == "Attachments" {
+			if !mf.Type.Elem().ConvertibleTo(of.Type.Elem()) {
+				panic(fmt.Errorf("mismatched element type for Attachments %s v %s",
+					mf.Type, of.Type))
+			}
+		} else {
+			if mf.Type != of.Type {
+				panic(fmt.Errorf("mismatched type for field %s: %s v %s", mf.Name, mf.Type, of.Type))
+			}
+		}
+	}
+}
+
+func dupStrs(strs []string) []string {
+	if len(strs) > 0 {
+		ret := make([]string, len(strs))
+		copy(ret, strs)
+		return ret
+	}
+	return nil
+}
+
+// ToSDKMessage returns a copy of this Message that's compatible with the native
+// SDK's Message type. It only needs to be used by implementations (like
+// "impl/prod") which need an SDK compatible object
+func (m *Message) ToSDKMessage() *mail.Message {
+	if m == nil {
+		return nil
+	}
+
+	m = m.Copy()
+
+	ret := &mail.Message{
+		Sender:   m.Sender,
+		ReplyTo:  m.ReplyTo,
+		Subject:  m.Subject,
+		Body:     m.Body,
+		HTMLBody: m.HTMLBody,
+		To:       m.To,
+		Cc:       m.Cc,
+		Bcc:      m.Bcc,
+		Headers:  m.Headers,
+	}
+
+	ret.Attachments = make([]mail.Attachment, len(m.Attachments))
+	for i := range m.Attachments {
+		ret.Attachments[i] = (mail.Attachment)(m.Attachments[i])
+	}
+	return ret
+}
+
+// Copy returns a duplicate Message
+func (m *Message) Copy() *Message {
+	if m == nil {
+		return nil
+	}
+
+	ret := *m
+
+	ret.To = dupStrs(m.To)
+	ret.Cc = dupStrs(m.Cc)
+	ret.Bcc = dupStrs(m.Bcc)
+
+	if len(m.Headers) > 0 {
+		ret.Headers = make(net_mail.Header, len(m.Headers))
+		for k, vals := range m.Headers {
+			ret.Headers[k] = dupStrs(vals)
+		}
+	}
+
+	if len(m.Attachments) > 0 {
+		ret.Attachments = make([]Attachment, len(m.Attachments))
+		copy(ret.Attachments, m.Attachments)
+	}
+
+	return &ret
+}