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Diffstat (limited to 'vendor/go.uber.org/multierr/error.go')
| -rw-r--r-- | vendor/go.uber.org/multierr/error.go | 652 |
1 files changed, 0 insertions, 652 deletions
diff --git a/vendor/go.uber.org/multierr/error.go b/vendor/go.uber.org/multierr/error.go deleted file mode 100644 index f45af149..00000000 --- a/vendor/go.uber.org/multierr/error.go +++ /dev/null @@ -1,652 +0,0 @@ -// Copyright (c) 2017-2021 Uber Technologies, Inc. -// -// Permission is hereby granted, free of charge, to any person obtaining a copy -// of this software and associated documentation files (the "Software"), to deal -// in the Software without restriction, including without limitation the rights -// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell -// copies of the Software, and to permit persons to whom the Software is -// furnished to do so, subject to the following conditions: -// -// The above copyright notice and this permission notice shall be included in -// all copies or substantial portions of the Software. -// -// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR -// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, -// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE -// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER -// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, -// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN -// THE SOFTWARE. - -// Package multierr allows combining one or more errors together. -// -// Overview -// -// Errors can be combined with the use of the Combine function. -// -// multierr.Combine( -// reader.Close(), -// writer.Close(), -// conn.Close(), -// ) -// -// If only two errors are being combined, the Append function may be used -// instead. -// -// err = multierr.Append(reader.Close(), writer.Close()) -// -// The underlying list of errors for a returned error object may be retrieved -// with the Errors function. -// -// errors := multierr.Errors(err) -// if len(errors) > 0 { -// fmt.Println("The following errors occurred:", errors) -// } -// -// Appending from a loop -// -// You sometimes need to append into an error from a loop. -// -// var err error -// for _, item := range items { -// err = multierr.Append(err, process(item)) -// } -// -// Cases like this may require knowledge of whether an individual instance -// failed. This usually requires introduction of a new variable. -// -// var err error -// for _, item := range items { -// if perr := process(item); perr != nil { -// log.Warn("skipping item", item) -// err = multierr.Append(err, perr) -// } -// } -// -// multierr includes AppendInto to simplify cases like this. -// -// var err error -// for _, item := range items { -// if multierr.AppendInto(&err, process(item)) { -// log.Warn("skipping item", item) -// } -// } -// -// This will append the error into the err variable, and return true if that -// individual error was non-nil. -// -// See AppendInto for more information. -// -// Deferred Functions -// -// Go makes it possible to modify the return value of a function in a defer -// block if the function was using named returns. This makes it possible to -// record resource cleanup failures from deferred blocks. -// -// func sendRequest(req Request) (err error) { -// conn, err := openConnection() -// if err != nil { -// return err -// } -// defer func() { -// err = multierr.Append(err, conn.Close()) -// }() -// // ... -// } -// -// multierr provides the Invoker type and AppendInvoke function to make cases -// like the above simpler and obviate the need for a closure. The following is -// roughly equivalent to the example above. -// -// func sendRequest(req Request) (err error) { -// conn, err := openConnection() -// if err != nil { -// return err -// } -// defer multierr.AppendInvoke(&err, multierr.Close(conn)) -// // ... -// } -// -// See AppendInvoke and Invoker for more information. -// -// Advanced Usage -// -// Errors returned by Combine and Append MAY implement the following -// interface. -// -// type errorGroup interface { -// // Returns a slice containing the underlying list of errors. -// // -// // This slice MUST NOT be modified by the caller. -// Errors() []error -// } -// -// Note that if you need access to list of errors behind a multierr error, you -// should prefer using the Errors function. That said, if you need cheap -// read-only access to the underlying errors slice, you can attempt to cast -// the error to this interface. You MUST handle the failure case gracefully -// because errors returned by Combine and Append are not guaranteed to -// implement this interface. -// -// var errors []error -// group, ok := err.(errorGroup) -// if ok { -// errors = group.Errors() -// } else { -// errors = []error{err} -// } -package multierr // import "go.uber.org/multierr" - -import ( - "bytes" - "errors" - "fmt" - "io" - "strings" - "sync" - - "go.uber.org/atomic" -) - -var ( - // Separator for single-line error messages. - _singlelineSeparator = []byte("; ") - - // Prefix for multi-line messages - _multilinePrefix = []byte("the following errors occurred:") - - // Prefix for the first and following lines of an item in a list of - // multi-line error messages. - // - // For example, if a single item is: - // - // foo - // bar - // - // It will become, - // - // - foo - // bar - _multilineSeparator = []byte("\n - ") - _multilineIndent = []byte(" ") -) - -// _bufferPool is a pool of bytes.Buffers. -var _bufferPool = sync.Pool{ - New: func() interface{} { - return &bytes.Buffer{} - }, -} - -type errorGroup interface { - Errors() []error -} - -// Errors returns a slice containing zero or more errors that the supplied -// error is composed of. If the error is nil, a nil slice is returned. -// -// err := multierr.Append(r.Close(), w.Close()) -// errors := multierr.Errors(err) -// -// If the error is not composed of other errors, the returned slice contains -// just the error that was passed in. -// -// Callers of this function are free to modify the returned slice. -func Errors(err error) []error { - if err == nil { - return nil - } - - // Note that we're casting to multiError, not errorGroup. Our contract is - // that returned errors MAY implement errorGroup. Errors, however, only - // has special behavior for multierr-specific error objects. - // - // This behavior can be expanded in the future but I think it's prudent to - // start with as little as possible in terms of contract and possibility - // of misuse. - eg, ok := err.(*multiError) - if !ok { - return []error{err} - } - - errors := eg.Errors() - result := make([]error, len(errors)) - copy(result, errors) - return result -} - -// multiError is an error that holds one or more errors. -// -// An instance of this is guaranteed to be non-empty and flattened. That is, -// none of the errors inside multiError are other multiErrors. -// -// multiError formats to a semi-colon delimited list of error messages with -// %v and with a more readable multi-line format with %+v. -type multiError struct { - copyNeeded atomic.Bool - errors []error -} - -var _ errorGroup = (*multiError)(nil) - -// Errors returns the list of underlying errors. -// -// This slice MUST NOT be modified. -func (merr *multiError) Errors() []error { - if merr == nil { - return nil - } - return merr.errors -} - -// As attempts to find the first error in the error list that matches the type -// of the value that target points to. -// -// This function allows errors.As to traverse the values stored on the -// multierr error. -func (merr *multiError) As(target interface{}) bool { - for _, err := range merr.Errors() { - if errors.As(err, target) { - return true - } - } - return false -} - -// Is attempts to match the provided error against errors in the error list. -// -// This function allows errors.Is to traverse the values stored on the -// multierr error. -func (merr *multiError) Is(target error) bool { - for _, err := range merr.Errors() { - if errors.Is(err, target) { - return true - } - } - return false -} - -func (merr *multiError) Error() string { - if merr == nil { - return "" - } - - buff := _bufferPool.Get().(*bytes.Buffer) - buff.Reset() - - merr.writeSingleline(buff) - - result := buff.String() - _bufferPool.Put(buff) - return result -} - -func (merr *multiError) Format(f fmt.State, c rune) { - if c == 'v' && f.Flag('+') { - merr.writeMultiline(f) - } else { - merr.writeSingleline(f) - } -} - -func (merr *multiError) writeSingleline(w io.Writer) { - first := true - for _, item := range merr.errors { - if first { - first = false - } else { - w.Write(_singlelineSeparator) - } - io.WriteString(w, item.Error()) - } -} - -func (merr *multiError) writeMultiline(w io.Writer) { - w.Write(_multilinePrefix) - for _, item := range merr.errors { - w.Write(_multilineSeparator) - writePrefixLine(w, _multilineIndent, fmt.Sprintf("%+v", item)) - } -} - -// Writes s to the writer with the given prefix added before each line after -// the first. -func writePrefixLine(w io.Writer, prefix []byte, s string) { - first := true - for len(s) > 0 { - if first { - first = false - } else { - w.Write(prefix) - } - - idx := strings.IndexByte(s, '\n') - if idx < 0 { - idx = len(s) - 1 - } - - io.WriteString(w, s[:idx+1]) - s = s[idx+1:] - } -} - -type inspectResult struct { - // Number of top-level non-nil errors - Count int - - // Total number of errors including multiErrors - Capacity int - - // Index of the first non-nil error in the list. Value is meaningless if - // Count is zero. - FirstErrorIdx int - - // Whether the list contains at least one multiError - ContainsMultiError bool -} - -// Inspects the given slice of errors so that we can efficiently allocate -// space for it. -func inspect(errors []error) (res inspectResult) { - first := true - for i, err := range errors { - if err == nil { - continue - } - - res.Count++ - if first { - first = false - res.FirstErrorIdx = i - } - - if merr, ok := err.(*multiError); ok { - res.Capacity += len(merr.errors) - res.ContainsMultiError = true - } else { - res.Capacity++ - } - } - return -} - -// fromSlice converts the given list of errors into a single error. -func fromSlice(errors []error) error { - // Don't pay to inspect small slices. - switch len(errors) { - case 0: - return nil - case 1: - return errors[0] - } - - res := inspect(errors) - switch res.Count { - case 0: - return nil - case 1: - // only one non-nil entry - return errors[res.FirstErrorIdx] - case len(errors): - if !res.ContainsMultiError { - // Error list is flat. Make a copy of it - // Otherwise "errors" escapes to the heap - // unconditionally for all other cases. - // This lets us optimize for the "no errors" case. - out := make([]error, len(errors)) - copy(out, errors) - return &multiError{errors: out} - } - } - - nonNilErrs := make([]error, 0, res.Capacity) - for _, err := range errors[res.FirstErrorIdx:] { - if err == nil { - continue - } - - if nested, ok := err.(*multiError); ok { - nonNilErrs = append(nonNilErrs, nested.errors...) - } else { - nonNilErrs = append(nonNilErrs, err) - } - } - - return &multiError{errors: nonNilErrs} -} - -// Combine combines the passed errors into a single error. -// -// If zero arguments were passed or if all items are nil, a nil error is -// returned. -// -// Combine(nil, nil) // == nil -// -// If only a single error was passed, it is returned as-is. -// -// Combine(err) // == err -// -// Combine skips over nil arguments so this function may be used to combine -// together errors from operations that fail independently of each other. -// -// multierr.Combine( -// reader.Close(), -// writer.Close(), -// pipe.Close(), -// ) -// -// If any of the passed errors is a multierr error, it will be flattened along -// with the other errors. -// -// multierr.Combine(multierr.Combine(err1, err2), err3) -// // is the same as -// multierr.Combine(err1, err2, err3) -// -// The returned error formats into a readable multi-line error message if -// formatted with %+v. -// -// fmt.Sprintf("%+v", multierr.Combine(err1, err2)) -func Combine(errors ...error) error { - return fromSlice(errors) -} - -// Append appends the given errors together. Either value may be nil. -// -// This function is a specialization of Combine for the common case where -// there are only two errors. -// -// err = multierr.Append(reader.Close(), writer.Close()) -// -// The following pattern may also be used to record failure of deferred -// operations without losing information about the original error. -// -// func doSomething(..) (err error) { -// f := acquireResource() -// defer func() { -// err = multierr.Append(err, f.Close()) -// }() -func Append(left error, right error) error { - switch { - case left == nil: - return right - case right == nil: - return left - } - - if _, ok := right.(*multiError); !ok { - if l, ok := left.(*multiError); ok && !l.copyNeeded.Swap(true) { - // Common case where the error on the left is constantly being - // appended to. - errs := append(l.errors, right) - return &multiError{errors: errs} - } else if !ok { - // Both errors are single errors. - return &multiError{errors: []error{left, right}} - } - } - - // Either right or both, left and right, are multiErrors. Rely on usual - // expensive logic. - errors := [2]error{left, right} - return fromSlice(errors[0:]) -} - -// AppendInto appends an error into the destination of an error pointer and -// returns whether the error being appended was non-nil. -// -// var err error -// multierr.AppendInto(&err, r.Close()) -// multierr.AppendInto(&err, w.Close()) -// -// The above is equivalent to, -// -// err := multierr.Append(r.Close(), w.Close()) -// -// As AppendInto reports whether the provided error was non-nil, it may be -// used to build a multierr error in a loop more ergonomically. For example: -// -// var err error -// for line := range lines { -// var item Item -// if multierr.AppendInto(&err, parse(line, &item)) { -// continue -// } -// items = append(items, item) -// } -// -// Compare this with a version that relies solely on Append: -// -// var err error -// for line := range lines { -// var item Item -// if parseErr := parse(line, &item); parseErr != nil { -// err = multierr.Append(err, parseErr) -// continue -// } -// items = append(items, item) -// } -func AppendInto(into *error, err error) (errored bool) { - if into == nil { - // We panic if 'into' is nil. This is not documented above - // because suggesting that the pointer must be non-nil may - // confuse users into thinking that the error that it points - // to must be non-nil. - panic("misuse of multierr.AppendInto: into pointer must not be nil") - } - - if err == nil { - return false - } - *into = Append(*into, err) - return true -} - -// Invoker is an operation that may fail with an error. Use it with -// AppendInvoke to append the result of calling the function into an error. -// This allows you to conveniently defer capture of failing operations. -// -// See also, Close and Invoke. -type Invoker interface { - Invoke() error -} - -// Invoke wraps a function which may fail with an error to match the Invoker -// interface. Use it to supply functions matching this signature to -// AppendInvoke. -// -// For example, -// -// func processReader(r io.Reader) (err error) { -// scanner := bufio.NewScanner(r) -// defer multierr.AppendInvoke(&err, multierr.Invoke(scanner.Err)) -// for scanner.Scan() { -// // ... -// } -// // ... -// } -// -// In this example, the following line will construct the Invoker right away, -// but defer the invocation of scanner.Err() until the function returns. -// -// defer multierr.AppendInvoke(&err, multierr.Invoke(scanner.Err)) -type Invoke func() error - -// Invoke calls the supplied function and returns its result. -func (i Invoke) Invoke() error { return i() } - -// Close builds an Invoker that closes the provided io.Closer. Use it with -// AppendInvoke to close io.Closers and append their results into an error. -// -// For example, -// -// func processFile(path string) (err error) { -// f, err := os.Open(path) -// if err != nil { -// return err -// } -// defer multierr.AppendInvoke(&err, multierr.Close(f)) -// return processReader(f) -// } -// -// In this example, multierr.Close will construct the Invoker right away, but -// defer the invocation of f.Close until the function returns. -// -// defer multierr.AppendInvoke(&err, multierr.Close(f)) -func Close(closer io.Closer) Invoker { - return Invoke(closer.Close) -} - -// AppendInvoke appends the result of calling the given Invoker into the -// provided error pointer. Use it with named returns to safely defer -// invocation of fallible operations until a function returns, and capture the -// resulting errors. -// -// func doSomething(...) (err error) { -// // ... -// f, err := openFile(..) -// if err != nil { -// return err -// } -// -// // multierr will call f.Close() when this function returns and -// // if the operation fails, its append its error into the -// // returned error. -// defer multierr.AppendInvoke(&err, multierr.Close(f)) -// -// scanner := bufio.NewScanner(f) -// // Similarly, this scheduled scanner.Err to be called and -// // inspected when the function returns and append its error -// // into the returned error. -// defer multierr.AppendInvoke(&err, multierr.Invoke(scanner.Err)) -// -// // ... -// } -// -// Without defer, AppendInvoke behaves exactly like AppendInto. -// -// err := // ... -// multierr.AppendInvoke(&err, mutltierr.Invoke(foo)) -// -// // ...is roughly equivalent to... -// -// err := // ... -// multierr.AppendInto(&err, foo()) -// -// The advantage of the indirection introduced by Invoker is to make it easy -// to defer the invocation of a function. Without this indirection, the -// invoked function will be evaluated at the time of the defer block rather -// than when the function returns. -// -// // BAD: This is likely not what the caller intended. This will evaluate -// // foo() right away and append its result into the error when the -// // function returns. -// defer multierr.AppendInto(&err, foo()) -// -// // GOOD: This will defer invocation of foo unutil the function returns. -// defer multierr.AppendInvoke(&err, multierr.Invoke(foo)) -// -// multierr provides a few Invoker implementations out of the box for -// convenience. See Invoker for more information. -func AppendInvoke(into *error, invoker Invoker) { - AppendInto(into, invoker.Invoke()) -} |