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Diffstat (limited to '')
-rw-r--r-- | dependencies/pkg/mod/golang.org/x/xerrors@v0.0.0-20220907171357-04be3eba64a2/fmt.go | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/golang.org/x/xerrors@v0.0.0-20220907171357-04be3eba64a2/fmt.go b/dependencies/pkg/mod/golang.org/x/xerrors@v0.0.0-20220907171357-04be3eba64a2/fmt.go new file mode 100644 index 0000000..27a5d70 --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/xerrors@v0.0.0-20220907171357-04be3eba64a2/fmt.go @@ -0,0 +1,190 @@ +// 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 xerrors + +import ( + "fmt" + "strings" + "unicode" + "unicode/utf8" + + "golang.org/x/xerrors/internal" +) + +const percentBangString = "%!" + +// Errorf formats according to a format specifier and returns the string as a +// value that satisfies error. +// +// The returned error includes the file and line number of the caller when +// formatted with additional detail enabled. If the last argument is an error +// the returned error's Format method will return it if the format string ends +// with ": %s", ": %v", or ": %w". If the last argument is an error and the +// format string ends with ": %w", the returned error implements an Unwrap +// method returning it. +// +// If the format specifier includes a %w verb with an error operand in a +// position other than at the end, the returned error will still implement an +// Unwrap method returning the operand, but the error's Format method will not +// return the wrapped error. +// +// It is invalid to include more than one %w verb or to supply it with an +// operand that does not implement the error interface. The %w verb is otherwise +// a synonym for %v. +// +// Note that as of Go 1.13, the fmt.Errorf function will do error formatting, +// but it will not capture a stack backtrace. +func Errorf(format string, a ...interface{}) error { + format = formatPlusW(format) + // Support a ": %[wsv]" suffix, which works well with xerrors.Formatter. + wrap := strings.HasSuffix(format, ": %w") + idx, format2, ok := parsePercentW(format) + percentWElsewhere := !wrap && idx >= 0 + if !percentWElsewhere && (wrap || strings.HasSuffix(format, ": %s") || strings.HasSuffix(format, ": %v")) { + err := errorAt(a, len(a)-1) + if err == nil { + return &noWrapError{fmt.Sprintf(format, a...), nil, Caller(1)} + } + // TODO: this is not entirely correct. The error value could be + // printed elsewhere in format if it mixes numbered with unnumbered + // substitutions. With relatively small changes to doPrintf we can + // have it optionally ignore extra arguments and pass the argument + // list in its entirety. + msg := fmt.Sprintf(format[:len(format)-len(": %s")], a[:len(a)-1]...) + frame := Frame{} + if internal.EnableTrace { + frame = Caller(1) + } + if wrap { + return &wrapError{msg, err, frame} + } + return &noWrapError{msg, err, frame} + } + // Support %w anywhere. + // TODO: don't repeat the wrapped error's message when %w occurs in the middle. + msg := fmt.Sprintf(format2, a...) + if idx < 0 { + return &noWrapError{msg, nil, Caller(1)} + } + err := errorAt(a, idx) + if !ok || err == nil { + // Too many %ws or argument of %w is not an error. Approximate the Go + // 1.13 fmt.Errorf message. + return &noWrapError{fmt.Sprintf("%sw(%s)", percentBangString, msg), nil, Caller(1)} + } + frame := Frame{} + if internal.EnableTrace { + frame = Caller(1) + } + return &wrapError{msg, err, frame} +} + +func errorAt(args []interface{}, i int) error { + if i < 0 || i >= len(args) { + return nil + } + err, ok := args[i].(error) + if !ok { + return nil + } + return err +} + +// formatPlusW is used to avoid the vet check that will barf at %w. +func formatPlusW(s string) string { + return s +} + +// Return the index of the only %w in format, or -1 if none. +// Also return a rewritten format string with %w replaced by %v, and +// false if there is more than one %w. +// TODO: handle "%[N]w". +func parsePercentW(format string) (idx int, newFormat string, ok bool) { + // Loosely copied from golang.org/x/tools/go/analysis/passes/printf/printf.go. + idx = -1 + ok = true + n := 0 + sz := 0 + var isW bool + for i := 0; i < len(format); i += sz { + if format[i] != '%' { + sz = 1 + continue + } + // "%%" is not a format directive. + if i+1 < len(format) && format[i+1] == '%' { + sz = 2 + continue + } + sz, isW = parsePrintfVerb(format[i:]) + if isW { + if idx >= 0 { + ok = false + } else { + idx = n + } + // "Replace" the last character, the 'w', with a 'v'. + p := i + sz - 1 + format = format[:p] + "v" + format[p+1:] + } + n++ + } + return idx, format, ok +} + +// Parse the printf verb starting with a % at s[0]. +// Return how many bytes it occupies and whether the verb is 'w'. +func parsePrintfVerb(s string) (int, bool) { + // Assume only that the directive is a sequence of non-letters followed by a single letter. + sz := 0 + var r rune + for i := 1; i < len(s); i += sz { + r, sz = utf8.DecodeRuneInString(s[i:]) + if unicode.IsLetter(r) { + return i + sz, r == 'w' + } + } + return len(s), false +} + +type noWrapError struct { + msg string + err error + frame Frame +} + +func (e *noWrapError) Error() string { + return fmt.Sprint(e) +} + +func (e *noWrapError) Format(s fmt.State, v rune) { FormatError(e, s, v) } + +func (e *noWrapError) FormatError(p Printer) (next error) { + p.Print(e.msg) + e.frame.Format(p) + return e.err +} + +type wrapError struct { + msg string + err error + frame Frame +} + +func (e *wrapError) Error() string { + return fmt.Sprint(e) +} + +func (e *wrapError) Format(s fmt.State, v rune) { FormatError(e, s, v) } + +func (e *wrapError) FormatError(p Printer) (next error) { + p.Print(e.msg) + e.frame.Format(p) + return e.err +} + +func (e *wrapError) Unwrap() error { + return e.err +} |