init: pristine aerc 0.20.0 source

2026-04-07 19:54:54 -04:00
commit 083402a548
502 changed files with 68722 additions and 0 deletions
@@ -0,0 +1,466 @@
+package rfc822
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"mime"
+	"regexp"
+	"strings"
+	"time"
+
+	"git.sr.ht/~rjarry/aerc/lib/log"
+	"git.sr.ht/~rjarry/aerc/lib/parse"
+	"git.sr.ht/~rjarry/aerc/models"
+	"github.com/emersion/go-message"
+	_ "github.com/emersion/go-message/charset"
+	"github.com/emersion/go-message/mail"
+)
+
+type MultipartError struct {
+	e error
+}
+
+func (u MultipartError) Unwrap() error { return u.e }
+
+func (u MultipartError) Error() string {
+	return "multipart error: " + u.e.Error()
+}
+
+// IsMultipartError returns a boolean indicating whether the error is known to
+// report that the multipart message is malformed and could not be parsed.
+func IsMultipartError(err error) bool {
+	return errors.As(err, new(MultipartError))
+}
+
+// RFC 1123Z regexp
+var dateRe = regexp.MustCompile(`(((Mon|Tue|Wed|Thu|Fri|Sat|Sun))[,]?\s[0-9]{1,2})\s` +
+	`(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s` +
+	`([0-9]{4})\s([0-9]{2}):([0-9]{2})(:([0-9]{2}))?\s([\+|\-][0-9]{4})`)
+
+func FetchEntityPartReader(e *message.Entity, index []int) (io.Reader, error) {
+	if len(index) == 0 {
+		// non multipart, simply return everything
+		return bufReader(e)
+	}
+	if mpr := e.MultipartReader(); mpr != nil {
+		idx := 0
+		for {
+			idx++
+			part, err := mpr.NextPart()
+			switch {
+			case message.IsUnknownCharset(err):
+				log.Warnf("FetchEntityPartReader: %v", err)
+			case message.IsUnknownEncoding(err):
+				log.Warnf("FetchEntityPartReader: %v", err)
+			case err != nil:
+				log.Warnf("FetchEntityPartReader: %v", err)
+				return bufReader(e)
+			}
+			if idx == index[0] {
+				rest := index[1:]
+				if len(rest) < 1 {
+					return bufReader(part)
+				}
+				return FetchEntityPartReader(part, index[1:])
+			}
+		}
+	}
+	return nil, fmt.Errorf("FetchEntityPartReader: unexpected code reached")
+}
+
+// TODO: the UI doesn't seem to like readers which aren't buffers
+func bufReader(e *message.Entity) (io.Reader, error) {
+	var buf bytes.Buffer
+	if _, err := io.Copy(&buf, e.Body); err != nil {
+		return nil, err
+	}
+	return &buf, nil
+}
+
+// split a MIME type into its major and minor parts
+func splitMIME(m string) (string, string) {
+	parts := strings.Split(m, "/")
+	if len(parts) != 2 {
+		return parts[0], ""
+	}
+	return parts[0], parts[1]
+}
+
+func fixContentType(h message.Header) (string, map[string]string) {
+	ct, rest := h.Get("Content-Type"), ""
+	if i := strings.Index(ct, ";"); i > 0 {
+		ct, rest = ct[:i], ct[i:]
+	}
+
+	// check if there are quotes around the content type
+	if strings.Contains(ct, "\"") {
+		header := strings.ReplaceAll(ct, "\"", "")
+		if rest != "" {
+			header += rest
+		}
+		h.Set("Content-Type", header)
+		if contenttype, params, err := h.ContentType(); err == nil {
+			return contenttype, params
+		}
+	}
+
+	// if all else fails, return text/plain
+	return "text/plain", nil
+}
+
+// ParseEntityStructure will parse the message and create a multipart structure
+// for multipart messages. Parsing is done on a best-efforts basis:
+//
+// If the content-type cannot be parsed, ParseEntityStructure will try to fix
+// it; otherwise, it returns a text/plain mime type as a fallback. No error will
+// be returned.
+//
+// If a charset or encoding error is encountered for a message part of a
+// multipart message, the error is logged and ignored. In those cases, we still
+// get a valid message body but the content is just not decoded or converted. No
+// error will be returned.
+//
+// If reading a multipart message fails, ParseEntityStructure will return a
+// multipart error. This error indicates that this message is malformed and
+// there is nothing more we can do. The caller is then advised to use a single
+// text/plain body structure using CreateTextPlainPart().
+func ParseEntityStructure(e *message.Entity) (*models.BodyStructure, error) {
+	var body models.BodyStructure
+	contentType, ctParams, err := e.Header.ContentType()
+	if err != nil {
+		// try to fix the error; if all measures fail, then return a
+		// text/plain content type to display at least plaintext
+		contentType, ctParams = fixContentType(e.Header)
+	}
+
+	mimeType, mimeSubType := splitMIME(contentType)
+	body.MIMEType = mimeType
+	body.MIMESubType = mimeSubType
+	body.Params = ctParams
+	body.Description = e.Header.Get("content-description")
+	body.Encoding = e.Header.Get("content-transfer-encoding")
+	if cd := e.Header.Get("content-disposition"); cd != "" {
+		contentDisposition, cdParams, err := e.Header.ContentDisposition()
+		if err != nil {
+			return nil, fmt.Errorf("could not parse content disposition: %w", err)
+		}
+		body.Disposition = contentDisposition
+		body.DispositionParams = cdParams
+	}
+	body.Parts = []*models.BodyStructure{}
+	if mpr := e.MultipartReader(); mpr != nil {
+		for {
+			part, err := mpr.NextPart()
+			switch {
+			case errors.Is(err, io.EOF):
+				return &body, nil
+			case message.IsUnknownCharset(err):
+				log.Warnf("ParseEntityStructure: %v", err)
+			case message.IsUnknownEncoding(err):
+				log.Warnf("ParseEntityStructure: %v", err)
+			case err != nil:
+				return nil, MultipartError{err}
+			}
+			ps, err := ParseEntityStructure(part)
+			if err != nil {
+				return nil, fmt.Errorf("could not parse child entity structure: %w", err)
+			}
+			body.Parts = append(body.Parts, ps)
+		}
+	}
+	return &body, nil
+}
+
+// CreateTextPlainBody creates a plain-vanilla text/plain body structure.
+func CreateTextPlainBody() *models.BodyStructure {
+	body := &models.BodyStructure{}
+	body.MIMEType = "text"
+	body.MIMESubType = "plain"
+	body.Params = map[string]string{"charset": "utf-8"}
+	body.Parts = []*models.BodyStructure{}
+	return body
+}
+
+func parseEnvelope(h *mail.Header) *models.Envelope {
+	subj, err := h.Subject()
+	if err != nil {
+		log.Errorf("could not decode subject: %v", err)
+		subj = h.Get("Subject")
+	}
+	msgID, err := h.MessageID()
+	if err != nil {
+		log.Errorf("invalid Message-ID header: %v", err)
+		// proper parsing failed, so fall back to whatever is there
+		msgID = strings.Trim(h.Get("message-id"), "<>")
+	}
+	var irt string
+	irtList := parse.MsgIDList(h, "in-reply-to")
+	if len(irtList) > 0 {
+		irt = irtList[0]
+	}
+	date, err := parseDate(h)
+	if err != nil {
+		// if only the date parsing failed we still get the rest of the
+		// envelop structure in a valid state.
+		// Date parsing errors are fairly common and it's better to be
+		// slightly off than to not be able to read the mails at all
+		// hence we continue here
+		log.Errorf("invalid Date header: %v", err)
+	}
+	return &models.Envelope{
+		Date:      date,
+		Subject:   subj,
+		MessageId: msgID,
+		From:      parseAddressList(h, "from"),
+		ReplyTo:   parseAddressList(h, "reply-to"),
+		Sender:    parseAddressList(h, "sender"),
+		To:        parseAddressList(h, "to"),
+		Cc:        parseAddressList(h, "cc"),
+		Bcc:       parseAddressList(h, "bcc"),
+		InReplyTo: irt,
+	}
+}
+
+// If the date is formatted like ...... -0500 (EST), parser takes the EST part
+// and ignores the numeric offset. Then it might easily fail to guess what EST
+// means unless the proper locale is loaded. This function checks that, so such
+// time values can be safely ignored
+// https://stackoverflow.com/questions/49084316/why-doesnt-gos-time-parse-parse-the-timezone-identifier
+func isDateOK(t time.Time) bool {
+	name, offset := t.Zone()
+
+	// non-zero offsets are fine
+	if offset != 0 {
+		return true
+	}
+
+	// zero offset is ok if that's UTC or GMT
+	if name == "UTC" || name == "GMT" || name == "" {
+		return true
+	}
+
+	// otherwise this date should not be trusted
+	return false
+}
+
+// parseDate tries to parse the date from the Date header with non std formats
+// if this fails it tries to parse the received header as well
+func parseDate(h *mail.Header) (time.Time, error) {
+	// here we store the best parsed time we have so far
+	// if we find no "correct" time, we'll use that
+	bestDate := time.Time{}
+
+	// trying the easy way
+	t, err := h.Date()
+	if err == nil {
+		if isDateOK(t) {
+			return t, nil
+		}
+		bestDate = t
+	}
+	text := h.Get("date")
+
+	// sometimes, no error occurs but the date is empty.
+	// In this case, guess time from received header field
+	if text == "" {
+		t, err := parseReceivedHeader(h)
+		if err == nil {
+			return t, nil
+		}
+	}
+	layouts := []string{
+		// X-Mailer: EarthLink Zoo Mail 1.0
+		"Mon, _2 Jan 2006 15:04:05 -0700 (GMT-07:00)",
+	}
+	for _, layout := range layouts {
+		if t, err := time.Parse(layout, text); err == nil {
+			if isDateOK(t) {
+				return t, nil
+			}
+			bestDate = t
+		}
+	}
+
+	// still no success, try the received header
+	t, err = parseReceivedHeader(h)
+	if err == nil {
+		if isDateOK(t) {
+			return t, nil
+		}
+		bestDate = t
+	}
+
+	// do we have at least something?
+	if !bestDate.IsZero() {
+		return bestDate, nil
+	}
+
+	// sad...
+	return time.Time{}, fmt.Errorf("unrecognized date format: %s", text)
+}
+
+func parseReceivedHeader(h *mail.Header) (time.Time, error) {
+	guess, err := h.Text("received")
+	if err != nil {
+		return time.Time{}, fmt.Errorf("received header not parseable: %w",
+			err)
+	}
+	return time.Parse(time.RFC1123Z, dateRe.FindString(guess))
+}
+
+func parseAddressList(h *mail.Header, key string) []*mail.Address {
+	addrs, err := h.AddressList(key)
+	if len(addrs) == 0 {
+		// Only consider the error if the returned address list is empty
+		// Sometimes, we get a list of addresses and unknown charset
+		// errors which are not fatal.
+		if val := h.Get(key); val != "" {
+			if err != nil {
+				log.Errorf("%s: %s: %v", key, val, err)
+			}
+			// Header value is not empty but parsing completely
+			// failed. Return something so that the message can at
+			// least be displayed.
+			return []*mail.Address{{Name: val}}
+		}
+		return nil
+	}
+	for _, addr := range addrs {
+		// Handle invalid headers with quoted *AND* encoded names
+		if strings.HasPrefix(addr.Name, "=?") && strings.HasSuffix(addr.Name, "?=") {
+			d := mime.WordDecoder{CharsetReader: message.CharsetReader}
+			addr.Name, _ = d.DecodeHeader(addr.Name)
+		}
+	}
+	// If we got at least one address, ignore any returned error.
+	return addrs
+}
+
+// RawMessage is an interface that describes a raw message
+type RawMessage interface {
+	NewReader() (io.ReadCloser, error)
+	ModelFlags() (models.Flags, error)
+	Labels() ([]string, error)
+	UID() models.UID
+}
+
+// MessageInfo populates a models.MessageInfo struct for the message.
+// based on the reader returned by NewReader
+func MessageInfo(raw RawMessage) (*models.MessageInfo, error) {
+	var parseErr error
+	r, err := raw.NewReader()
+	if err != nil {
+		return nil, err
+	}
+	defer r.Close()
+	msg, err := ReadMessage(r)
+	if err != nil {
+		return nil, fmt.Errorf("could not read message: %w", err)
+	}
+	bs, err := ParseEntityStructure(msg)
+	if IsMultipartError(err) {
+		log.Warnf("multipart error: %v", err)
+		bs = CreateTextPlainBody()
+	} else if err != nil {
+		return nil, fmt.Errorf("could not get structure: %w", err)
+	}
+	h := &mail.Header{Header: msg.Header}
+	env := parseEnvelope(h)
+	recDate, _ := parseReceivedHeader(h)
+	if recDate.IsZero() {
+		// better than nothing, if incorrect
+		recDate = env.Date
+	}
+	flags, err := raw.ModelFlags()
+	if err != nil {
+		return nil, err
+	}
+	labels, err := raw.Labels()
+	if err != nil {
+		return nil, err
+	}
+	return &models.MessageInfo{
+		BodyStructure: bs,
+		Envelope:      env,
+		Flags:         flags,
+		Labels:        labels,
+		InternalDate:  recDate,
+		RFC822Headers: h,
+		Size:          0,
+		Uid:           raw.UID(),
+		Error:         parseErr,
+	}, nil
+}
+
+// MessageHeaders populates a models.MessageInfo struct for the message.
+// based on the reader returned by NewReader. Minimal information is included.
+// There is no body structure or RFC822Headers set
+func MessageHeaders(raw RawMessage) (*models.MessageInfo, error) {
+	var parseErr error
+	r, err := raw.NewReader()
+	if err != nil {
+		return nil, err
+	}
+	defer r.Close()
+	msg, err := ReadMessage(r)
+	if err != nil {
+		return nil, fmt.Errorf("could not read message: %w", err)
+	}
+	h := &mail.Header{Header: msg.Header}
+	env := parseEnvelope(h)
+	recDate, _ := parseReceivedHeader(h)
+	if recDate.IsZero() {
+		// better than nothing, if incorrect
+		recDate = env.Date
+	}
+	flags, err := raw.ModelFlags()
+	if err != nil {
+		return nil, err
+	}
+	labels, err := raw.Labels()
+	if err != nil {
+		return nil, err
+	}
+	return &models.MessageInfo{
+		Envelope:     env,
+		Flags:        flags,
+		Labels:       labels,
+		InternalDate: recDate,
+		Refs:         parse.MsgIDList(h, "references"),
+		Size:         0,
+		Uid:          raw.UID(),
+		Error:        parseErr,
+	}, nil
+}
+
+// NewCRLFReader returns a reader with CRLF line endings
+func NewCRLFReader(r io.Reader) io.Reader {
+	var buf bytes.Buffer
+	scanner := bufio.NewScanner(r)
+	for scanner.Scan() {
+		buf.WriteString(scanner.Text() + "\r\n")
+	}
+	return &buf
+}
+
+// ReadMessage is a wrapper for the message.Read function to read a message
+// from r. The message's encoding and charset are automatically decoded to
+// UTF-8. If an unknown charset or unknown encoding is encountered, the error is
+// logged but a nil error is returned since the entity object can still be read.
+func ReadMessage(r io.Reader) (*message.Entity, error) {
+	entity, err := message.Read(r)
+	switch {
+	case message.IsUnknownCharset(err):
+		// message body is valid, just not converted, so continue
+		log.Warnf("ReadMessage: %v", err)
+	case message.IsUnknownEncoding(err):
+		// message body is valid, just not decoded, so continue
+		log.Warnf("ReadMessage: %v", err)
+	case err != nil:
+		return nil, fmt.Errorf("could not read message: %w", err)
+	}
+	return entity, nil
+}