1 files changed, 689 insertions, 0 deletions
diff --git a/vendor/github.com/emersion/go-imap/client/client.go b/vendor/github.com/emersion/go-imap/client/client.go
new file mode 100644
index 0000000..8b6fc84
--- /dev/null
+++ b/vendor/github.com/emersion/go-imap/client/client.go
@@ -0,0 +1,689 @@
+// Package client provides an IMAP client.
+//
+// It is not safe to use the same Client from multiple goroutines. In general,
+// the IMAP protocol doesn't make it possible to send multiple independent
+// IMAP commands on the same connection.
+package client
+
+import (
+	"crypto/tls"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/emersion/go-imap"
+	"github.com/emersion/go-imap/commands"
+	"github.com/emersion/go-imap/responses"
+)
+
+// errClosed is used when a connection is closed while waiting for a command
+// response.
+var errClosed = fmt.Errorf("imap: connection closed")
+
+// errUnregisterHandler is returned by a response handler to unregister itself.
+var errUnregisterHandler = fmt.Errorf("imap: unregister handler")
+
+// Update is an unilateral server update.
+type Update interface {
+	update()
+}
+
+// StatusUpdate is delivered when a status update is received.
+type StatusUpdate struct {
+	Status *imap.StatusResp
+}
+
+func (u *StatusUpdate) update() {}
+
+// MailboxUpdate is delivered when a mailbox status changes.
+type MailboxUpdate struct {
+	Mailbox *imap.MailboxStatus
+}
+
+func (u *MailboxUpdate) update() {}
+
+// ExpungeUpdate is delivered when a message is deleted.
+type ExpungeUpdate struct {
+	SeqNum uint32
+}
+
+func (u *ExpungeUpdate) update() {}
+
+// MessageUpdate is delivered when a message attribute changes.
+type MessageUpdate struct {
+	Message *imap.Message
+}
+
+func (u *MessageUpdate) update() {}
+
+// Client is an IMAP client.
+type Client struct {
+	conn       *imap.Conn
+	isTLS      bool
+	serverName string
+
+	loggedOut chan struct{}
+	continues chan<- bool
+	upgrading bool
+
+	handlers       []responses.Handler
+	handlersLocker sync.Mutex
+
+	// The current connection state.
+	state imap.ConnState
+	// The selected mailbox, if there is one.
+	mailbox *imap.MailboxStatus
+	// The cached server capabilities.
+	caps map[string]bool
+	// state, mailbox and caps may be accessed in different goroutines. Protect
+	// access.
+	locker sync.Mutex
+
+	// A channel to which unilateral updates from the server will be sent. An
+	// update can be one of: *StatusUpdate, *MailboxUpdate, *MessageUpdate,
+	// *ExpungeUpdate. Note that blocking this channel blocks the whole client,
+	// so it's recommended to use a separate goroutine and a buffered channel to
+	// prevent deadlocks.
+	Updates chan<- Update
+
+	// ErrorLog specifies an optional logger for errors accepting connections and
+	// unexpected behavior from handlers. By default, logging goes to os.Stderr
+	// via the log package's standard logger. The logger must be safe to use
+	// simultaneously from multiple goroutines.
+	ErrorLog imap.Logger
+
+	// Timeout specifies a maximum amount of time to wait on a command.
+	//
+	// A Timeout of zero means no timeout. This is the default.
+	Timeout time.Duration
+}
+
+func (c *Client) registerHandler(h responses.Handler) {
+	if h == nil {
+		return
+	}
+
+	c.handlersLocker.Lock()
+	c.handlers = append(c.handlers, h)
+	c.handlersLocker.Unlock()
+}
+
+func (c *Client) handle(resp imap.Resp) error {
+	c.handlersLocker.Lock()
+	for i := len(c.handlers) - 1; i >= 0; i-- {
+		if err := c.handlers[i].Handle(resp); err != responses.ErrUnhandled {
+			if err == errUnregisterHandler {
+				c.handlers = append(c.handlers[:i], c.handlers[i+1:]...)
+				err = nil
+			}
+			c.handlersLocker.Unlock()
+			return err
+		}
+	}
+	c.handlersLocker.Unlock()
+	return responses.ErrUnhandled
+}
+
+func (c *Client) reader() {
+	defer close(c.loggedOut)
+	// Loop while connected.
+	for {
+		connected, err := c.readOnce()
+		if err != nil {
+			c.ErrorLog.Println("error reading response:", err)
+		}
+		if !connected {
+			return
+		}
+	}
+}
+
+func (c *Client) readOnce() (bool, error) {
+	if c.State() == imap.LogoutState {
+		return false, nil
+	}
+
+	resp, err := imap.ReadResp(c.conn.Reader)
+	if err == io.EOF || c.State() == imap.LogoutState {
+		return false, nil
+	} else if err != nil {
+		if imap.IsParseError(err) {
+			return true, err
+		} else {
+			return false, err
+		}
+	}
+
+	if err := c.handle(resp); err != nil && err != responses.ErrUnhandled {
+		c.ErrorLog.Println("cannot handle response ", resp, err)
+	}
+	return true, nil
+}
+
+func (c *Client) writeReply(reply []byte) error {
+	if _, err := c.conn.Writer.Write(reply); err != nil {
+		return err
+	}
+	// Flush reply
+	return c.conn.Writer.Flush()
+}
+
+type handleResult struct {
+	status *imap.StatusResp
+	err    error
+}
+
+func (c *Client) execute(cmdr imap.Commander, h responses.Handler) (*imap.StatusResp, error) {
+	cmd := cmdr.Command()
+	cmd.Tag = generateTag()
+
+	var replies <-chan []byte
+	if replier, ok := h.(responses.Replier); ok {
+		replies = replier.Replies()
+	}
+
+	if c.Timeout > 0 {
+		err := c.conn.SetDeadline(time.Now().Add(c.Timeout))
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		// It's possible the client had a timeout set from a previous command, but no
+		// longer does. Ensure we respect that. The zero time means no deadline.
+		if err := c.conn.SetDeadline(time.Time{}); err != nil {
+			return nil, err
+		}
+	}
+
+	// Check if we are upgrading.
+	upgrading := c.upgrading
+
+	// Add handler before sending command, to be sure to get the response in time
+	// (in tests, the response is sent right after our command is received, so
+	// sometimes the response was received before the setup of this handler)
+	doneHandle := make(chan handleResult, 1)
+	unregister := make(chan struct{})
+	c.registerHandler(responses.HandlerFunc(func(resp imap.Resp) error {
+		select {
+		case <-unregister:
+			// If an error occured while sending the command, abort
+			return errUnregisterHandler
+		default:
+		}
+
+		if s, ok := resp.(*imap.StatusResp); ok && s.Tag == cmd.Tag {
+			// This is the command's status response, we're done
+			doneHandle <- handleResult{s, nil}
+			// Special handling of connection upgrading.
+			if upgrading {
+				c.upgrading = false
+				// Wait for upgrade to finish.
+				c.conn.Wait()
+			}
+			// Cancel any pending literal write
+			select {
+			case c.continues <- false:
+			default:
+			}
+			return errUnregisterHandler
+		}
+
+		if h != nil {
+			// Pass the response to the response handler
+			if err := h.Handle(resp); err != nil && err != responses.ErrUnhandled {
+				// If the response handler returns an error, abort
+				doneHandle <- handleResult{nil, err}
+				return errUnregisterHandler
+			} else {
+				return err
+			}
+		}
+		return responses.ErrUnhandled
+	}))
+
+	// Send the command to the server
+	if err := cmd.WriteTo(c.conn.Writer); err != nil {
+		// Error while sending the command
+		close(unregister)
+
+		if err, ok := err.(imap.LiteralLengthErr); ok {
+			// Expected > Actual
+			//  The server is waiting for us to write
+			//  more bytes, we don't have them. Run.
+			// Expected < Actual
+			//  We are about to send a potentially truncated message, we don't
+			//  want this (ths terminating CRLF is not sent at this point).
+			c.conn.Close()
+			return nil, err
+		}
+
+		return nil, err
+	}
+	// Flush writer if we are upgrading
+	if upgrading {
+		if err := c.conn.Writer.Flush(); err != nil {
+			// Error while sending the command
+			close(unregister)
+			return nil, err
+		}
+	}
+
+	for {
+		select {
+		case reply := <-replies:
+			// Response handler needs to send a reply (Used for AUTHENTICATE)
+			if err := c.writeReply(reply); err != nil {
+				close(unregister)
+				return nil, err
+			}
+		case <-c.loggedOut:
+			// If the connection is closed (such as from an I/O error), ensure we
+			// realize this and don't block waiting on a response that will never
+			// come. loggedOut is a channel that closes when the reader goroutine
+			// ends.
+			close(unregister)
+			return nil, errClosed
+		case result := <-doneHandle:
+			return result.status, result.err
+		}
+	}
+}
+
+// State returns the current connection state.
+func (c *Client) State() imap.ConnState {
+	c.locker.Lock()
+	state := c.state
+	c.locker.Unlock()
+	return state
+}
+
+// Mailbox returns the selected mailbox. It returns nil if there isn't one.
+func (c *Client) Mailbox() *imap.MailboxStatus {
+	// c.Mailbox fields are not supposed to change, so we can return the pointer.
+	c.locker.Lock()
+	mbox := c.mailbox
+	c.locker.Unlock()
+	return mbox
+}
+
+// SetState sets this connection's internal state.
+//
+// This function should not be called directly, it must only be used by
+// libraries implementing extensions of the IMAP protocol.
+func (c *Client) SetState(state imap.ConnState, mailbox *imap.MailboxStatus) {
+	c.locker.Lock()
+	c.state = state
+	c.mailbox = mailbox
+	c.locker.Unlock()
+}
+
+// Execute executes a generic command. cmdr is a value that can be converted to
+// a raw command and h is a response handler. The function returns when the
+// command has completed or failed, in this case err is nil. A non-nil err value
+// indicates a network error.
+//
+// This function should not be called directly, it must only be used by
+// libraries implementing extensions of the IMAP protocol.
+func (c *Client) Execute(cmdr imap.Commander, h responses.Handler) (*imap.StatusResp, error) {
+	return c.execute(cmdr, h)
+}
+
+func (c *Client) handleContinuationReqs() {
+	c.registerHandler(responses.HandlerFunc(func(resp imap.Resp) error {
+		if _, ok := resp.(*imap.ContinuationReq); ok {
+			go func() {
+				c.continues <- true
+			}()
+			return nil
+		}
+		return responses.ErrUnhandled
+	}))
+}
+
+func (c *Client) gotStatusCaps(args []interface{}) {
+	c.locker.Lock()
+
+	c.caps = make(map[string]bool)
+	for _, cap := range args {
+		if cap, ok := cap.(string); ok {
+			c.caps[cap] = true
+		}
+	}
+
+	c.locker.Unlock()
+}
+
+// The server can send unilateral data. This function handles it.
+func (c *Client) handleUnilateral() {
+	c.registerHandler(responses.HandlerFunc(func(resp imap.Resp) error {
+		switch resp := resp.(type) {
+		case *imap.StatusResp:
+			if resp.Tag != "*" {
+				return responses.ErrUnhandled
+			}
+
+			switch resp.Type {
+			case imap.StatusRespOk, imap.StatusRespNo, imap.StatusRespBad:
+				if c.Updates != nil {
+					c.Updates <- &StatusUpdate{resp}
+				}
+			case imap.StatusRespBye:
+				c.locker.Lock()
+				c.state = imap.LogoutState
+				c.mailbox = nil
+				c.locker.Unlock()
+
+				c.conn.Close()
+
+				if c.Updates != nil {
+					c.Updates <- &StatusUpdate{resp}
+				}
+			default:
+				return responses.ErrUnhandled
+			}
+		case *imap.DataResp:
+			name, fields, ok := imap.ParseNamedResp(resp)
+			if !ok {
+				return responses.ErrUnhandled
+			}
+
+			switch name {
+			case "CAPABILITY":
+				c.gotStatusCaps(fields)
+			case "EXISTS":
+				if c.Mailbox() == nil {
+					break
+				}
+
+				if messages, err := imap.ParseNumber(fields[0]); err == nil {
+					c.locker.Lock()
+					c.mailbox.Messages = messages
+					c.locker.Unlock()
+
+					c.mailbox.ItemsLocker.Lock()
+					c.mailbox.Items[imap.StatusMessages] = nil
+					c.mailbox.ItemsLocker.Unlock()
+				}
+
+				if c.Updates != nil {
+					c.Updates <- &MailboxUpdate{c.Mailbox()}
+				}
+			case "RECENT":
+				if c.Mailbox() == nil {
+					break
+				}
+
+				if recent, err := imap.ParseNumber(fields[0]); err == nil {
+					c.locker.Lock()
+					c.mailbox.Recent = recent
+					c.locker.Unlock()
+
+					c.mailbox.ItemsLocker.Lock()
+					c.mailbox.Items[imap.StatusRecent] = nil
+					c.mailbox.ItemsLocker.Unlock()
+				}
+
+				if c.Updates != nil {
+					c.Updates <- &MailboxUpdate{c.Mailbox()}
+				}
+			case "EXPUNGE":
+				seqNum, _ := imap.ParseNumber(fields[0])
+
+				if c.Updates != nil {
+					c.Updates <- &ExpungeUpdate{seqNum}
+				}
+			case "FETCH":
+				seqNum, _ := imap.ParseNumber(fields[0])
+				fields, _ := fields[1].([]interface{})
+
+				msg := &imap.Message{SeqNum: seqNum}
+				if err := msg.Parse(fields); err != nil {
+					break
+				}
+
+				if c.Updates != nil {
+					c.Updates <- &MessageUpdate{msg}
+				}
+			default:
+				return responses.ErrUnhandled
+			}
+		default:
+			return responses.ErrUnhandled
+		}
+		return nil
+	}))
+}
+
+func (c *Client) handleGreetAndStartReading() error {
+	var greetErr error
+	gotGreet := false
+
+	c.registerHandler(responses.HandlerFunc(func(resp imap.Resp) error {
+		status, ok := resp.(*imap.StatusResp)
+		if !ok {
+			greetErr = fmt.Errorf("invalid greeting received from server: not a status response")
+			return errUnregisterHandler
+		}
+
+		c.locker.Lock()
+		switch status.Type {
+		case imap.StatusRespPreauth:
+			c.state = imap.AuthenticatedState
+		case imap.StatusRespBye:
+			c.state = imap.LogoutState
+		case imap.StatusRespOk:
+			c.state = imap.NotAuthenticatedState
+		default:
+			c.state = imap.LogoutState
+			c.locker.Unlock()
+			greetErr = fmt.Errorf("invalid greeting received from server: %v", status.Type)
+			return errUnregisterHandler
+		}
+		c.locker.Unlock()
+
+		if status.Code == imap.CodeCapability {
+			c.gotStatusCaps(status.Arguments)
+		}
+
+		gotGreet = true
+		return errUnregisterHandler
+	}))
+
+	// call `readOnce` until we get the greeting or an error
+	for !gotGreet {
+		connected, err := c.readOnce()
+		// Check for read errors
+		if err != nil {
+			// return read errors
+			return err
+		}
+		// Check for invalid greet
+		if greetErr != nil {
+			// return read errors
+			return greetErr
+		}
+		// Check if connection was closed.
+		if !connected {
+			// connection closed.
+			return io.EOF
+		}
+	}
+
+	// We got the greeting, now start the reader goroutine.
+	go c.reader()
+
+	return nil
+}
+
+// Upgrade a connection, e.g. wrap an unencrypted connection with an encrypted
+// tunnel.
+//
+// This function should not be called directly, it must only be used by
+// libraries implementing extensions of the IMAP protocol.
+func (c *Client) Upgrade(upgrader imap.ConnUpgrader) error {
+	return c.conn.Upgrade(upgrader)
+}
+
+// Writer returns the imap.Writer for this client's connection.
+//
+// This function should not be called directly, it must only be used by
+// libraries implementing extensions of the IMAP protocol.
+func (c *Client) Writer() *imap.Writer {
+	return c.conn.Writer
+}
+
+// IsTLS checks if this client's connection has TLS enabled.
+func (c *Client) IsTLS() bool {
+	return c.isTLS
+}
+
+// LoggedOut returns a channel which is closed when the connection to the server
+// is closed.
+func (c *Client) LoggedOut() <-chan struct{} {
+	return c.loggedOut
+}
+
+// SetDebug defines an io.Writer to which all network activity will be logged.
+// If nil is provided, network activity will not be logged.
+func (c *Client) SetDebug(w io.Writer) {
+	// Need to send a command to unblock the reader goroutine.
+	cmd := new(commands.Noop)
+	err := c.Upgrade(func(conn net.Conn) (net.Conn, error) {
+		// Flag connection as in upgrading
+		c.upgrading = true
+		if status, err := c.execute(cmd, nil); err != nil {
+			return nil, err
+		} else if err := status.Err(); err != nil {
+			return nil, err
+		}
+
+		// Wait for reader to block.
+		c.conn.WaitReady()
+
+		c.conn.SetDebug(w)
+		return conn, nil
+	})
+	if err != nil {
+		log.Println("SetDebug:", err)
+	}
+
+}
+
+// New creates a new client from an existing connection.
+func New(conn net.Conn) (*Client, error) {
+	continues := make(chan bool)
+	w := imap.NewClientWriter(nil, continues)
+	r := imap.NewReader(nil)
+
+	c := &Client{
+		conn:      imap.NewConn(conn, r, w),
+		loggedOut: make(chan struct{}),
+		continues: continues,
+		state:     imap.ConnectingState,
+		ErrorLog:  log.New(os.Stderr, "imap/client: ", log.LstdFlags),
+	}
+
+	c.handleContinuationReqs()
+	c.handleUnilateral()
+	if err := c.handleGreetAndStartReading(); err != nil {
+		return c, err
+	}
+
+	plusOk, _ := c.Support("LITERAL+")
+	minusOk, _ := c.Support("LITERAL-")
+	// We don't use non-sync literal if it is bigger than 4096 bytes, so
+	// LITERAL- is fine too.
+	c.conn.AllowAsyncLiterals = plusOk || minusOk
+
+	return c, nil
+}
+
+// Dial connects to an IMAP server using an unencrypted connection.
+func Dial(addr string) (*Client, error) {
+	return DialWithDialer(new(net.Dialer), addr)
+}
+
+type Dialer interface {
+	// Dial connects to the given address.
+	Dial(network, addr string) (net.Conn, error)
+}
+
+// DialWithDialer connects to an IMAP server using an unencrypted connection
+// using dialer.Dial.
+//
+// Among other uses, this allows to apply a dial timeout.
+func DialWithDialer(dialer Dialer, addr string) (*Client, error) {
+	conn, err := dialer.Dial("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	// We don't return to the caller until we try to receive a greeting. As such,
+	// there is no way to set the client's Timeout for that action. As a
+	// workaround, if the dialer has a timeout set, use that for the connection's
+	// deadline.
+	if netDialer, ok := dialer.(*net.Dialer); ok && netDialer.Timeout > 0 {
+		err := conn.SetDeadline(time.Now().Add(netDialer.Timeout))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	c, err := New(conn)
+	if err != nil {
+		return nil, err
+	}
+
+	c.serverName, _, _ = net.SplitHostPort(addr)
+	return c, nil
+}
+
+// DialTLS connects to an IMAP server using an encrypted connection.
+func DialTLS(addr string, tlsConfig *tls.Config) (*Client, error) {
+	return DialWithDialerTLS(new(net.Dialer), addr, tlsConfig)
+}
+
+// DialWithDialerTLS connects to an IMAP server using an encrypted connection
+// using dialer.Dial.
+//
+// Among other uses, this allows to apply a dial timeout.
+func DialWithDialerTLS(dialer Dialer, addr string, tlsConfig *tls.Config) (*Client, error) {
+	conn, err := dialer.Dial("tcp", addr)
+	if err != nil {
+		return nil, err
+	}
+
+	serverName, _, _ := net.SplitHostPort(addr)
+	if tlsConfig == nil {
+		tlsConfig = &tls.Config{}
+	}
+	if tlsConfig.ServerName == "" {
+		tlsConfig = tlsConfig.Clone()
+		tlsConfig.ServerName = serverName
+	}
+	tlsConn := tls.Client(conn, tlsConfig)
+
+	// We don't return to the caller until we try to receive a greeting. As such,
+	// there is no way to set the client's Timeout for that action. As a
+	// workaround, if the dialer has a timeout set, use that for the connection's
+	// deadline.
+	if netDialer, ok := dialer.(*net.Dialer); ok && netDialer.Timeout > 0 {
+		err := tlsConn.SetDeadline(time.Now().Add(netDialer.Timeout))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	c, err := New(tlsConn)
+	if err != nil {
+		return nil, err
+	}
+
+	c.isTLS = true
+	c.serverName = serverName
+	return c, nil
+}