internal.go

package errorlogger

import (
	"fmt"
	"io"
	"sync"

	"github.com/pkg/errors"
	"github.com/sirupsen/logrus"
)

// test_info provides samples and test cases for the tests
// and benchmarks in this package.

// EOF is the error returned by Read when no more input is available.
// (Read must return EOF itself, not an error wrapping EOF,
// because callers will test for EOF using ==.)
// Functions should return EOF only to signal a graceful end of input.
// If the EOF occurs unexpectedly in a structured data stream,
// the appropriate error is either ErrUnexpectedEOF or some other error
// giving more detail.
var EOF = errors.New("EOF")

var (
	testLogrusLogger *Logger = &logrus.Logger{
		Out:       Discard,
		Formatter: new(logrus.TextFormatter),
		Hooks:     make(logrus.LevelHooks),
		Level:     logrus.DebugLevel,
	}
	testDefaultLogger ErrorLogger = NewWithOptions(true, "", nil, nil, testLogrusLogger)
	errFake           error       = errors.New("fake")
	fakeSysCallError  error       = NewSyscallError("fake syscall error", fmt.Errorf("fake syscall error"))
	blankSysCallError error       = new(SyscallError)
	blankPathError    error       = new(PathError)
)

func newTestStruct(enabled bool, msg string, wrap error, _ func(args ...interface{}), logger *Logger) *errorLogger {
	if logger == nil {
		logger = defaultlogger
	}

	e := errorLogger{
		msg:    msg,
		Logger: logger,
	}

	if enabled {
		e.Enable()
	} else {
		e.Disable()
	}

	// e.Logger = logger
	e.logFunc = e.Error

	if wrap == nil {
		// the defaultErrWrap is actually nil ... so this is not needed.
		// However, if the default is later changed to a package-wide
		// wrapper, this will be a valid check
		wrap = defaultErrWrap
	}
	e.wrap = wrap
	return &e
}

//////////////////////////////////// copied from io to avoid dependency

// Reader is the interface that wraps the basic Read method.
//
// Read reads up to len(p) bytes into p. It returns the number of bytes
// read (0 <= n <= len(p)) and any error encountered. Even if Read
// returns n < len(p), it may use all of p as scratch space during the call.
// If some data is available but not len(p) bytes, Read conventionally
// returns what is available instead of waiting for more.
//
// When Read encounters an error or end-of-file condition after
// successfully reading n > 0 bytes, it returns the number of
// bytes read. It may return the (non-nil) error from the same call
// or return the error (and n == 0) from a subsequent call.
// An instance of this general case is that a Reader returning
// a non-zero number of bytes at the end of the input stream may
// return either err == EOF or err == nil. The next Read should
// return 0, EOF.
//
// Callers should always process the n > 0 bytes returned before
// considering the error err. Doing so correctly handles I/O errors
// that happen after reading some bytes and also both of the
// allowed EOF behaviors.
//
// Implementations of Read are discouraged from returning a
// zero byte count with a nil error, except when len(p) == 0.
// Callers should treat a return of 0 and nil as indicating that
// nothing happened; in particular it does not indicate EOF.
//
// Implementations must not retain p.
type Reader interface {
	Read(p []byte) (n int, err error)
}

// Writer is the interface that wraps the basic Write method.
//
// Write writes len(p) bytes from p to the underlying data stream.
// It returns the number of bytes written from p (0 <= n <= len(p))
// and any error encountered that caused the write to stop early.
// Write must return a non-nil error if it returns n < len(p).
// Write must not modify the slice data, even temporarily.
//
// Implementations must not retain p.
type Writer interface {
	Write(p []byte) (n int, err error)
}

// Closer is the interface that wraps the basic Close method.
//
// The behavior of Close after the first call is undefined.
// Specific implementations may document their own behavior.
type Closer interface {
	Close() error
}

// ReadWriter is the interface that groups the basic Read and Write methods.
type ReadWriter interface {
	Reader
	Writer
}

// ReadCloser is the interface that groups the basic Read and Close methods.
type ReadCloser interface {
	Reader
	Closer
}

// WriteCloser is the interface that groups the basic Write and Close methods.
type WriteCloser interface {
	Writer
	Closer
}

// ReadWriteCloser is the interface that groups the basic Read, Write and Close methods.
type ReadWriteCloser interface {
	Reader
	Writer
	Closer
}

// Discard is a Writer on which all Write calls succeed
// without doing anything.
// As of Go 1.16, this value is simply io.Discard.
// var Discard io.Writer = io.Discard
var Discard Writer = discard{}

type discard struct{}

// discard implements ReaderFrom as an optimization so Copy to
// io.Discard can avoid doing unnecessary work.
var _ ReaderFrom = discard{}

func (discard) Write(p []byte) (int, error) {
	return len(p), nil
}

func (discard) WriteString(s string) (int, error) {
	return len(s), nil
}

var blackHolePool = sync.Pool{
	New: func() any {
		b := make([]byte, 8192)
		return &b
	},
}

func (discard) ReadFrom(r Reader) (n int64, err error) {
	bufp := blackHolePool.Get().(*[]byte)
	readSize := 0
	for {
		readSize, err = r.Read(*bufp)
		n += int64(readSize)
		if err != nil {
			blackHolePool.Put(bufp)
			if err == EOF {
				return n, nil
			}
			return
		}
	}
}

// NopCloser returns a ReadCloser with a no-op Close method wrapping
// the provided Reader r.
//
// As of Go 1.16, this function simply calls io.NopCloser instead
// of ioutil.NopCloser
func NopCloser(r io.Reader) io.ReadCloser {
	return io.NopCloser(r)
}

type nopCloser struct {
	Reader
}

func (nopCloser) Close() error { return nil }

// ReadAll reads from r until an error or EOF and returns the data it read.
// A successful call returns err == nil, not err == EOF. Because ReadAll is
// defined to read from src until EOF, it does not treat an EOF from Read
// as an error to be reported.
func ReadAll(r Reader) ([]byte, error) {
	b := make([]byte, 0, 512)
	for {
		if len(b) == cap(b) {
			// Add more capacity (let append pick how much).
			b = append(b, 0)[:len(b)]
		}
		n, err := r.Read(b[len(b):cap(b)])
		b = b[:len(b)+n]
		if err != nil {
			if err == EOF {
				err = nil
			}
			return b, err
		}
	}
}

// ReaderFrom is the interface that wraps the ReadFrom method.
//
// ReadFrom reads data from r until EOF or error.
// The return value n is the number of bytes read.
// Any error except EOF encountered during the read is also returned.
//
// The Copy function uses ReaderFrom if available.
type ReaderFrom interface {
	ReadFrom(r Reader) (n int64, err error)
}

// WriterTo is the interface that wraps the WriteTo method.
//
// WriteTo writes data to w until there's no more data to write or
// when an error occurs. The return value n is the number of bytes
// written. Any error encountered during the write is also returned.
//
// The Copy function uses WriterTo if available.
type WriterTo interface {
	WriteTo(w Writer) (n int64, err error)
}

//////////////////////////////////// copied from io/fs to avoid dependency

// PathError records an error and the operation and file path that caused it.
type PathError struct {
	Op   string
	Path string
	Err  error
}

func (e *PathError) Error() string { return e.Op + " " + e.Path + ": " + e.Err.Error() }

func (e *PathError) Unwrap() error { return e.Err }

// Timeout reports whether this error represents a timeout.
func (e *PathError) Timeout() bool {
	t, ok := e.Err.(interface{ Timeout() bool })
	return ok && t.Timeout()
}

//////////////////////////////////// copied from os to avoid dependency

type timeout interface {
	Timeout() bool
}

// SyscallError records an error from a specific system call.
type SyscallError struct {
	Syscall string
	Err     error
}

func (e *SyscallError) Error() string { return e.Syscall + ": " + e.Err.Error() }

func (e *SyscallError) Unwrap() error { return e.Err }

// Timeout reports whether this error represents a timeout.
func (e *SyscallError) Timeout() bool {
	t, ok := e.Err.(timeout)
	return ok && t.Timeout()
}

// NewSyscallError returns, as an error, a new SyscallError
// with the given system call name and error details.
// As a convenience, if err is nil, NewSyscallError returns nil.
func NewSyscallError(syscall string, err error) error {
	if err == nil {
		return nil
	}
	return &SyscallError{syscall, err}
}