Fix #117: Implement email alerts

vendor/gopkg.in/alexcesaro/quotedprintable.v3/reader.go

@@ -0,0 +1,121 @@
+// Package quotedprintable implements quoted-printable encoding as specified by
+// RFC 2045.
+package quotedprintable
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+)
+
+// Reader is a quoted-printable decoder.
+type Reader struct {
+	br   *bufio.Reader
+	rerr error  // last read error
+	line []byte // to be consumed before more of br
+}
+
+// NewReader returns a quoted-printable reader, decoding from r.
+func NewReader(r io.Reader) *Reader {
+	return &Reader{
+		br: bufio.NewReader(r),
+	}
+}
+
+func fromHex(b byte) (byte, error) {
+	switch {
+	case b >= '0' && b <= '9':
+		return b - '0', nil
+	case b >= 'A' && b <= 'F':
+		return b - 'A' + 10, nil
+	// Accept badly encoded bytes.
+	case b >= 'a' && b <= 'f':
+		return b - 'a' + 10, nil
+	}
+	return 0, fmt.Errorf("quotedprintable: invalid hex byte 0x%02x", b)
+}
+
+func readHexByte(a, b byte) (byte, error) {
+	var hb, lb byte
+	var err error
+	if hb, err = fromHex(a); err != nil {
+		return 0, err
+	}
+	if lb, err = fromHex(b); err != nil {
+		return 0, err
+	}
+	return hb<<4 | lb, nil
+}
+
+func isQPDiscardWhitespace(r rune) bool {
+	switch r {
+	case '\n', '\r', ' ', '\t':
+		return true
+	}
+	return false
+}
+
+var (
+	crlf       = []byte("\r\n")
+	lf         = []byte("\n")
+	softSuffix = []byte("=")
+)
+
+// Read reads and decodes quoted-printable data from the underlying reader.
+func (r *Reader) Read(p []byte) (n int, err error) {
+	// Deviations from RFC 2045:
+	// 1. in addition to "=\r\n", "=\n" is also treated as soft line break.
+	// 2. it will pass through a '\r' or '\n' not preceded by '=', consistent
+	//    with other broken QP encoders & decoders.
+	for len(p) > 0 {
+		if len(r.line) == 0 {
+			if r.rerr != nil {
+				return n, r.rerr
+			}
+			r.line, r.rerr = r.br.ReadSlice('\n')
+
+			// Does the line end in CRLF instead of just LF?
+			hasLF := bytes.HasSuffix(r.line, lf)
+			hasCR := bytes.HasSuffix(r.line, crlf)
+			wholeLine := r.line
+			r.line = bytes.TrimRightFunc(wholeLine, isQPDiscardWhitespace)
+			if bytes.HasSuffix(r.line, softSuffix) {
+				rightStripped := wholeLine[len(r.line):]
+				r.line = r.line[:len(r.line)-1]
+				if !bytes.HasPrefix(rightStripped, lf) && !bytes.HasPrefix(rightStripped, crlf) {
+					r.rerr = fmt.Errorf("quotedprintable: invalid bytes after =: %q", rightStripped)
+				}
+			} else if hasLF {
+				if hasCR {
+					r.line = append(r.line, '\r', '\n')
+				} else {
+					r.line = append(r.line, '\n')
+				}
+			}
+			continue
+		}
+		b := r.line[0]
+
+		switch {
+		case b == '=':
+			if len(r.line[1:]) < 2 {
+				return n, io.ErrUnexpectedEOF
+			}
+			b, err = readHexByte(r.line[1], r.line[2])
+			if err != nil {
+				return n, err
+			}
+			r.line = r.line[2:] // 2 of the 3; other 1 is done below
+		case b == '\t' || b == '\r' || b == '\n':
+			break
+		case b < ' ' || b > '~':
+			return n, fmt.Errorf("quotedprintable: invalid unescaped byte 0x%02x in body", b)
+		}
+		p[0] = b
+		p = p[1:]
+		r.line = r.line[1:]
+		n++
+	}
+	return n, nil
+}