diff options
Diffstat (limited to 'vendor/golang.org/x/exp/slog/text_handler.go')
-rw-r--r-- | vendor/golang.org/x/exp/slog/text_handler.go | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/vendor/golang.org/x/exp/slog/text_handler.go b/vendor/golang.org/x/exp/slog/text_handler.go new file mode 100644 index 000000000..75b66b716 --- /dev/null +++ b/vendor/golang.org/x/exp/slog/text_handler.go @@ -0,0 +1,161 @@ +// Copyright 2022 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 slog + +import ( + "context" + "encoding" + "fmt" + "io" + "reflect" + "strconv" + "unicode" + "unicode/utf8" +) + +// TextHandler is a Handler that writes Records to an io.Writer as a +// sequence of key=value pairs separated by spaces and followed by a newline. +type TextHandler struct { + *commonHandler +} + +// NewTextHandler creates a TextHandler that writes to w, +// using the given options. +// If opts is nil, the default options are used. +func NewTextHandler(w io.Writer, opts *HandlerOptions) *TextHandler { + if opts == nil { + opts = &HandlerOptions{} + } + return &TextHandler{ + &commonHandler{ + json: false, + w: w, + opts: *opts, + }, + } +} + +// Enabled reports whether the handler handles records at the given level. +// The handler ignores records whose level is lower. +func (h *TextHandler) Enabled(_ context.Context, level Level) bool { + return h.commonHandler.enabled(level) +} + +// WithAttrs returns a new TextHandler whose attributes consists +// of h's attributes followed by attrs. +func (h *TextHandler) WithAttrs(attrs []Attr) Handler { + return &TextHandler{commonHandler: h.commonHandler.withAttrs(attrs)} +} + +func (h *TextHandler) WithGroup(name string) Handler { + return &TextHandler{commonHandler: h.commonHandler.withGroup(name)} +} + +// Handle formats its argument Record as a single line of space-separated +// key=value items. +// +// If the Record's time is zero, the time is omitted. +// Otherwise, the key is "time" +// and the value is output in RFC3339 format with millisecond precision. +// +// If the Record's level is zero, the level is omitted. +// Otherwise, the key is "level" +// and the value of [Level.String] is output. +// +// If the AddSource option is set and source information is available, +// the key is "source" and the value is output as FILE:LINE. +// +// The message's key is "msg". +// +// To modify these or other attributes, or remove them from the output, use +// [HandlerOptions.ReplaceAttr]. +// +// If a value implements [encoding.TextMarshaler], the result of MarshalText is +// written. Otherwise, the result of fmt.Sprint is written. +// +// Keys and values are quoted with [strconv.Quote] if they contain Unicode space +// characters, non-printing characters, '"' or '='. +// +// Keys inside groups consist of components (keys or group names) separated by +// dots. No further escaping is performed. +// Thus there is no way to determine from the key "a.b.c" whether there +// are two groups "a" and "b" and a key "c", or a single group "a.b" and a key "c", +// or single group "a" and a key "b.c". +// If it is necessary to reconstruct the group structure of a key +// even in the presence of dots inside components, use +// [HandlerOptions.ReplaceAttr] to encode that information in the key. +// +// Each call to Handle results in a single serialized call to +// io.Writer.Write. +func (h *TextHandler) Handle(_ context.Context, r Record) error { + return h.commonHandler.handle(r) +} + +func appendTextValue(s *handleState, v Value) error { + switch v.Kind() { + case KindString: + s.appendString(v.str()) + case KindTime: + s.appendTime(v.time()) + case KindAny: + if tm, ok := v.any.(encoding.TextMarshaler); ok { + data, err := tm.MarshalText() + if err != nil { + return err + } + // TODO: avoid the conversion to string. + s.appendString(string(data)) + return nil + } + if bs, ok := byteSlice(v.any); ok { + // As of Go 1.19, this only allocates for strings longer than 32 bytes. + s.buf.WriteString(strconv.Quote(string(bs))) + return nil + } + s.appendString(fmt.Sprintf("%+v", v.Any())) + default: + *s.buf = v.append(*s.buf) + } + return nil +} + +// byteSlice returns its argument as a []byte if the argument's +// underlying type is []byte, along with a second return value of true. +// Otherwise it returns nil, false. +func byteSlice(a any) ([]byte, bool) { + if bs, ok := a.([]byte); ok { + return bs, true + } + // Like Printf's %s, we allow both the slice type and the byte element type to be named. + t := reflect.TypeOf(a) + if t != nil && t.Kind() == reflect.Slice && t.Elem().Kind() == reflect.Uint8 { + return reflect.ValueOf(a).Bytes(), true + } + return nil, false +} + +func needsQuoting(s string) bool { + if len(s) == 0 { + return true + } + for i := 0; i < len(s); { + b := s[i] + if b < utf8.RuneSelf { + // Quote anything except a backslash that would need quoting in a + // JSON string, as well as space and '=' + if b != '\\' && (b == ' ' || b == '=' || !safeSet[b]) { + return true + } + i++ + continue + } + r, size := utf8.DecodeRuneInString(s[i:]) + if r == utf8.RuneError || unicode.IsSpace(r) || !unicode.IsPrint(r) { + return true + } + i += size + } + return false +} |