diff options
Diffstat (limited to 'vendor/google.golang.org/protobuf/internal/encoding/text/decode_string.go')
-rw-r--r-- | vendor/google.golang.org/protobuf/internal/encoding/text/decode_string.go | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/vendor/google.golang.org/protobuf/internal/encoding/text/decode_string.go b/vendor/google.golang.org/protobuf/internal/encoding/text/decode_string.go new file mode 100644 index 000000000..d4d349023 --- /dev/null +++ b/vendor/google.golang.org/protobuf/internal/encoding/text/decode_string.go @@ -0,0 +1,161 @@ +// Copyright 2018 The Go 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 text + +import ( + "bytes" + "strconv" + "strings" + "unicode" + "unicode/utf16" + "unicode/utf8" + + "google.golang.org/protobuf/internal/strs" +) + +// parseStringValue parses string field token. +// This differs from parseString since the text format allows +// multiple back-to-back string literals where they are semantically treated +// as a single large string with all values concatenated. +// +// E.g., `"foo" "bar" "baz"` => "foobarbaz" +func (d *Decoder) parseStringValue() (Token, error) { + // Note that the ending quote is sufficient to unambiguously mark the end + // of a string. Thus, the text grammar does not require intervening + // whitespace or control characters in-between strings. + // Thus, the following is valid: + // `"foo"'bar'"baz"` => "foobarbaz" + in0 := d.in + var ss []string + for len(d.in) > 0 && (d.in[0] == '"' || d.in[0] == '\'') { + s, err := d.parseString() + if err != nil { + return Token{}, err + } + ss = append(ss, s) + } + // d.in already points to the end of the value at this point. + return Token{ + kind: Scalar, + attrs: stringValue, + pos: len(d.orig) - len(in0), + raw: in0[:len(in0)-len(d.in)], + str: strings.Join(ss, ""), + }, nil +} + +// parseString parses a string value enclosed in " or '. +func (d *Decoder) parseString() (string, error) { + in := d.in + if len(in) == 0 { + return "", ErrUnexpectedEOF + } + quote := in[0] + in = in[1:] + i := indexNeedEscapeInBytes(in) + in, out := in[i:], in[:i:i] // set cap to prevent mutations + for len(in) > 0 { + switch r, n := utf8.DecodeRune(in); { + case r == utf8.RuneError && n == 1: + return "", d.newSyntaxError("invalid UTF-8 detected") + case r == 0 || r == '\n': + return "", d.newSyntaxError("invalid character %q in string", r) + case r == rune(quote): + in = in[1:] + d.consume(len(d.in) - len(in)) + return string(out), nil + case r == '\\': + if len(in) < 2 { + return "", ErrUnexpectedEOF + } + switch r := in[1]; r { + case '"', '\'', '\\', '?': + in, out = in[2:], append(out, r) + case 'a': + in, out = in[2:], append(out, '\a') + case 'b': + in, out = in[2:], append(out, '\b') + case 'n': + in, out = in[2:], append(out, '\n') + case 'r': + in, out = in[2:], append(out, '\r') + case 't': + in, out = in[2:], append(out, '\t') + case 'v': + in, out = in[2:], append(out, '\v') + case 'f': + in, out = in[2:], append(out, '\f') + case '0', '1', '2', '3', '4', '5', '6', '7': + // One, two, or three octal characters. + n := len(in[1:]) - len(bytes.TrimLeft(in[1:], "01234567")) + if n > 3 { + n = 3 + } + v, err := strconv.ParseUint(string(in[1:1+n]), 8, 8) + if err != nil { + return "", d.newSyntaxError("invalid octal escape code %q in string", in[:1+n]) + } + in, out = in[1+n:], append(out, byte(v)) + case 'x': + // One or two hexadecimal characters. + n := len(in[2:]) - len(bytes.TrimLeft(in[2:], "0123456789abcdefABCDEF")) + if n > 2 { + n = 2 + } + v, err := strconv.ParseUint(string(in[2:2+n]), 16, 8) + if err != nil { + return "", d.newSyntaxError("invalid hex escape code %q in string", in[:2+n]) + } + in, out = in[2+n:], append(out, byte(v)) + case 'u', 'U': + // Four or eight hexadecimal characters + n := 6 + if r == 'U' { + n = 10 + } + if len(in) < n { + return "", ErrUnexpectedEOF + } + v, err := strconv.ParseUint(string(in[2:n]), 16, 32) + if utf8.MaxRune < v || err != nil { + return "", d.newSyntaxError("invalid Unicode escape code %q in string", in[:n]) + } + in = in[n:] + + r := rune(v) + if utf16.IsSurrogate(r) { + if len(in) < 6 { + return "", ErrUnexpectedEOF + } + v, err := strconv.ParseUint(string(in[2:6]), 16, 16) + r = utf16.DecodeRune(r, rune(v)) + if in[0] != '\\' || in[1] != 'u' || r == unicode.ReplacementChar || err != nil { + return "", d.newSyntaxError("invalid Unicode escape code %q in string", in[:6]) + } + in = in[6:] + } + out = append(out, string(r)...) + default: + return "", d.newSyntaxError("invalid escape code %q in string", in[:2]) + } + default: + i := indexNeedEscapeInBytes(in[n:]) + in, out = in[n+i:], append(out, in[:n+i]...) + } + } + return "", ErrUnexpectedEOF +} + +// indexNeedEscapeInString returns the index of the character that needs +// escaping. If no characters need escaping, this returns the input length. +func indexNeedEscapeInBytes(b []byte) int { return indexNeedEscapeInString(strs.UnsafeString(b)) } + +// UnmarshalString returns an unescaped string given a textproto string value. +// String value needs to contain single or double quotes. This is only used by +// internal/encoding/defval package for unmarshaling bytes. +func UnmarshalString(s string) (string, error) { + d := NewDecoder([]byte(s)) + return d.parseString() +} |