Implement Mail service.

service/mail/message.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.
+
+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
+}