From ae68a912725e5a3a0482bc5945687663f2ddafe3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Daniel=20Mart=C3=AD?= Date: Wed, 3 Jul 2019 00:37:05 +0200 Subject: [PATCH] encoding/json: remove unnecessary isValidNumber call MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The decoder called this function to check numbers being decoded into a json.Number. However, these can't be quoted as strings, so the tokenizer has already verified they are valid JSON numbers. Verified this by adding a test with such an input. As expected, it produces a syntax error, not the fmt.Errorf - that line could never execute. Since the only remaining non-test caller of isvalidnumber is in encode.go, move the function there. This change should slightly reduce the amount of work when decoding into json.Number, though that isn't very common nor part of any current benchmarks. Change-Id: I67a1723deb3d18d5b542d6dd35f3ae56a43f23eb Reviewed-on: https://go-review.googlesource.com/c/go/+/184817 Run-TryBot: Daniel Martí Reviewed-by: Brad Fitzpatrick TryBot-Result: Gobot Gobot --- src/encoding/json/decode.go | 65 +------------------------------- src/encoding/json/decode_test.go | 1 + src/encoding/json/encode.go | 60 +++++++++++++++++++++++++++++ 3 files changed, 63 insertions(+), 63 deletions(-) diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go index cbd71acfc6c38..df1c085917832 100644 --- a/src/encoding/json/decode.go +++ b/src/encoding/json/decode.go @@ -199,66 +199,6 @@ func (n Number) Int64() (int64, error) { return strconv.ParseInt(string(n), 10, 64) } -// isValidNumber reports whether s is a valid JSON number literal. -func isValidNumber(s string) bool { - // This function implements the JSON numbers grammar. - // See https://tools.ietf.org/html/rfc7159#section-6 - // and https://json.org/number.gif - - if s == "" { - return false - } - - // Optional - - if s[0] == '-' { - s = s[1:] - if s == "" { - return false - } - } - - // Digits - switch { - default: - return false - - case s[0] == '0': - s = s[1:] - - case '1' <= s[0] && s[0] <= '9': - s = s[1:] - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - } - } - - // . followed by 1 or more digits. - if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' { - s = s[2:] - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - } - } - - // e or E followed by an optional - or + and - // 1 or more digits. - if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') { - s = s[1:] - if s[0] == '+' || s[0] == '-' { - s = s[1:] - if s == "" { - return false - } - } - for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { - s = s[1:] - } - } - - // Make sure we are at the end. - return s == "" -} - // decodeState represents the state while decoding a JSON value. type decodeState struct { data []byte @@ -1027,10 +967,9 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool switch v.Kind() { default: if v.Kind() == reflect.String && v.Type() == numberType { + // s must be a valid number, because it's + // already been tokenized. v.SetString(s) - if !isValidNumber(s) { - return fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item) - } break } if fromQuoted { diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go index d66be44d4e134..8dcb08cbd2776 100644 --- a/src/encoding/json/decode_test.go +++ b/src/encoding/json/decode_test.go @@ -448,6 +448,7 @@ var unmarshalTests = []unmarshalTest{ {in: `[1, 2, 3+]`, err: &SyntaxError{"invalid character '+' after array element", 9}}, {in: `{"X":12x}`, err: &SyntaxError{"invalid character 'x' after object key:value pair", 8}, useNumber: true}, {in: `[2, 3`, err: &SyntaxError{msg: "unexpected end of JSON input", Offset: 5}}, + {in: `{"F3": -}`, ptr: new(V), out: V{F3: Number("-")}, err: &SyntaxError{msg: "invalid character '}' in numeric literal", Offset: 9}}, // raw value errors {in: "\x01 42", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}}, diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go index 67412763d6400..07d3098f1c1ed 100644 --- a/src/encoding/json/encode.go +++ b/src/encoding/json/encode.go @@ -611,6 +611,66 @@ func stringEncoder(e *encodeState, v reflect.Value, opts encOpts) { } } +// isValidNumber reports whether s is a valid JSON number literal. +func isValidNumber(s string) bool { + // This function implements the JSON numbers grammar. + // See https://tools.ietf.org/html/rfc7159#section-6 + // and https://json.org/number.gif + + if s == "" { + return false + } + + // Optional - + if s[0] == '-' { + s = s[1:] + if s == "" { + return false + } + } + + // Digits + switch { + default: + return false + + case s[0] == '0': + s = s[1:] + + case '1' <= s[0] && s[0] <= '9': + s = s[1:] + for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { + s = s[1:] + } + } + + // . followed by 1 or more digits. + if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' { + s = s[2:] + for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { + s = s[1:] + } + } + + // e or E followed by an optional - or + and + // 1 or more digits. + if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') { + s = s[1:] + if s[0] == '+' || s[0] == '-' { + s = s[1:] + if s == "" { + return false + } + } + for len(s) > 0 && '0' <= s[0] && s[0] <= '9' { + s = s[1:] + } + } + + // Make sure we are at the end. + return s == "" +} + func interfaceEncoder(e *encodeState, v reflect.Value, opts encOpts) { if v.IsNil() { e.WriteString("null")