1 files changed, 71 insertions, 0 deletions
diff --git a/vendor/github.com/emersion/go-imap/date.go b/vendor/github.com/emersion/go-imap/date.go
new file mode 100644
index 0000000..bf99647
--- /dev/null
+++ b/vendor/github.com/emersion/go-imap/date.go
@@ -0,0 +1,71 @@
+package imap
+
+import (
+	"fmt"
+	"regexp"
+	"time"
+)
+
+// Date and time layouts.
+// Dovecot adds a leading zero to dates:
+//   https://github.com/dovecot/core/blob/4fbd5c5e113078e72f29465ccc96d44955ceadc2/src/lib-imap/imap-date.c#L166
+// Cyrus adds a leading space to dates:
+//   https://github.com/cyrusimap/cyrus-imapd/blob/1cb805a3bffbdf829df0964f3b802cdc917e76db/lib/times.c#L543
+// GMail doesn't support leading spaces in dates used in SEARCH commands.
+const (
+	// Defined in RFC 3501 as date-text on page 83.
+	DateLayout = "_2-Jan-2006"
+	// Defined in RFC 3501 as date-time on page 83.
+	DateTimeLayout = "_2-Jan-2006 15:04:05 -0700"
+	// Defined in RFC 5322 section 3.3, mentioned as env-date in RFC 3501 page 84.
+	envelopeDateTimeLayout = "Mon, 02 Jan 2006 15:04:05 -0700"
+	// Use as an example in RFC 3501 page 54.
+	searchDateLayout = "2-Jan-2006"
+)
+
+// time.Time with a specific layout.
+type (
+	Date             time.Time
+	DateTime         time.Time
+	envelopeDateTime time.Time
+	searchDate       time.Time
+)
+
+// Permutations of the layouts defined in RFC 5322, section 3.3.
+var envelopeDateTimeLayouts = [...]string{
+	envelopeDateTimeLayout, // popular, try it first
+	"_2 Jan 2006 15:04:05 -0700",
+	"_2 Jan 2006 15:04:05 MST",
+	"_2 Jan 2006 15:04 -0700",
+	"_2 Jan 2006 15:04 MST",
+	"_2 Jan 06 15:04:05 -0700",
+	"_2 Jan 06 15:04:05 MST",
+	"_2 Jan 06 15:04 -0700",
+	"_2 Jan 06 15:04 MST",
+	"Mon, _2 Jan 2006 15:04:05 -0700",
+	"Mon, _2 Jan 2006 15:04:05 MST",
+	"Mon, _2 Jan 2006 15:04 -0700",
+	"Mon, _2 Jan 2006 15:04 MST",
+	"Mon, _2 Jan 06 15:04:05 -0700",
+	"Mon, _2 Jan 06 15:04:05 MST",
+	"Mon, _2 Jan 06 15:04 -0700",
+	"Mon, _2 Jan 06 15:04 MST",
+}
+
+// TODO: this is a blunt way to strip any trailing CFWS (comment). A sharper
+// one would strip multiple CFWS, and only if really valid according to
+// RFC5322.
+var commentRE = regexp.MustCompile(`[ \t]+\(.*\)$`)
+
+// Try parsing the date based on the layouts defined in RFC 5322, section 3.3.
+// Inspired by https://github.com/golang/go/blob/master/src/net/mail/message.go
+func parseMessageDateTime(maybeDate string) (time.Time, error) {
+	maybeDate = commentRE.ReplaceAllString(maybeDate, "")
+	for _, layout := range envelopeDateTimeLayouts {
+		parsed, err := time.Parse(layout, maybeDate)
+		if err == nil {
+			return parsed, nil
+		}
+	}
+	return time.Time{}, fmt.Errorf("date %s could not be parsed", maybeDate)
+}