1 files changed, 458 insertions, 0 deletions
diff --git a/vendor/github.com/getlantern/golog/golog.go b/vendor/github.com/getlantern/golog/golog.go
new file mode 100644
index 0000000..143e904
--- /dev/null
+++ b/vendor/github.com/getlantern/golog/golog.go
@@ -0,0 +1,458 @@
+// Package golog implements logging functions that log errors to stderr and
+// debug messages to stdout. Trace logging is also supported.
+// Trace logs go to stdout as well, but they are only written if the program
+// is run with environment variable "TRACE=true".
+// A stack dump will be printed after the message if "PRINT_STACK=true".
+package golog
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+
+	"github.com/getlantern/errors"
+	"github.com/getlantern/hidden"
+	"github.com/getlantern/ops"
+	"github.com/oxtoacart/bpool"
+)
+
+const (
+	// ERROR is an error Severity
+	ERROR = 500
+
+	// FATAL is an error Severity
+	FATAL = 600
+)
+
+var (
+	outs           atomic.Value
+	reporters      []ErrorReporter
+	reportersMutex sync.RWMutex
+
+	bufferPool = bpool.NewBufferPool(200)
+
+	onFatal atomic.Value
+)
+
+// Severity is a level of error (higher values are more severe)
+type Severity int
+
+func (s Severity) String() string {
+	switch s {
+	case ERROR:
+		return "ERROR"
+	case FATAL:
+		return "FATAL"
+	default:
+		return "UNKNOWN"
+	}
+}
+
+func init() {
+	DefaultOnFatal()
+	ResetOutputs()
+}
+
+func SetOutputs(errorOut io.Writer, debugOut io.Writer) {
+	outs.Store(&outputs{
+		ErrorOut: errorOut,
+		DebugOut: debugOut,
+	})
+}
+
+func ResetOutputs() {
+	SetOutputs(os.Stderr, os.Stdout)
+}
+
+func GetOutputs() *outputs {
+	return outs.Load().(*outputs)
+}
+
+// RegisterReporter registers the given ErrorReporter. All logged Errors are
+// sent to this reporter.
+func RegisterReporter(reporter ErrorReporter) {
+	reportersMutex.Lock()
+	reporters = append(reporters, reporter)
+	reportersMutex.Unlock()
+}
+
+// OnFatal configures golog to call the given function on any FATAL error. By
+// default, golog calls os.Exit(1) on any FATAL error.
+func OnFatal(fn func(err error)) {
+	onFatal.Store(fn)
+}
+
+// DefaultOnFatal enables the default behavior for OnFatal
+func DefaultOnFatal() {
+	onFatal.Store(func(err error) {
+		os.Exit(1)
+	})
+}
+
+type outputs struct {
+	ErrorOut io.Writer
+	DebugOut io.Writer
+}
+
+// MultiLine is an interface for arguments that support multi-line output.
+type MultiLine interface {
+	// MultiLinePrinter returns a function that can be used to print the
+	// multi-line output. The returned function writes one line to the buffer and
+	// returns true if there are more lines to write. This function does not need
+	// to take care of trailing carriage returns, golog handles that
+	// automatically.
+	MultiLinePrinter() func(buf *bytes.Buffer) bool
+}
+
+// ErrorReporter is a function to which the logger will report errors.
+// It the given error and corresponding message along with associated ops
+// context. This should return quickly as it executes on the critical code
+// path. The recommended approach is to buffer as much as possible and discard
+// new reports if the buffer becomes saturated.
+type ErrorReporter func(err error, linePrefix string, severity Severity, ctx map[string]interface{})
+
+type Logger interface {
+	// Debug logs to stdout
+	Debug(arg interface{})
+	// Debugf logs to stdout
+	Debugf(message string, args ...interface{})
+
+	// Error logs to stderr
+	Error(arg interface{}) error
+	// Errorf logs to stderr. It returns the first argument that's an error, or
+	// a new error built using fmt.Errorf if none of the arguments are errors.
+	Errorf(message string, args ...interface{}) error
+
+	// Fatal logs to stderr and then exits with status 1
+	Fatal(arg interface{})
+	// Fatalf logs to stderr and then exits with status 1
+	Fatalf(message string, args ...interface{})
+
+	// Trace logs to stderr only if TRACE=true
+	Trace(arg interface{})
+	// Tracef logs to stderr only if TRACE=true
+	Tracef(message string, args ...interface{})
+
+	// TraceOut provides access to an io.Writer to which trace information can
+	// be streamed. If running with environment variable "TRACE=true", TraceOut
+	// will point to os.Stderr, otherwise it will point to a ioutil.Discared.
+	// Each line of trace information will be prefixed with this Logger's
+	// prefix.
+	TraceOut() io.Writer
+
+	// IsTraceEnabled() indicates whether or not tracing is enabled for this
+	// logger.
+	IsTraceEnabled() bool
+
+	// AsStdLogger returns an standard logger
+	AsStdLogger() *log.Logger
+}
+
+func LoggerFor(prefix string) Logger {
+	l := &logger{
+		prefix: prefix + ": ",
+		pc:     make([]uintptr, 10),
+	}
+
+	trace := os.Getenv("TRACE")
+	l.traceOn, _ = strconv.ParseBool(trace)
+	if !l.traceOn {
+		prefixes := strings.Split(trace, ",")
+		for _, p := range prefixes {
+			if prefix == strings.Trim(p, " ") {
+				l.traceOn = true
+				break
+			}
+		}
+	}
+	if l.traceOn {
+		l.traceOut = l.newTraceWriter()
+	} else {
+		l.traceOut = ioutil.Discard
+	}
+
+	printStack := os.Getenv("PRINT_STACK")
+	l.printStack, _ = strconv.ParseBool(printStack)
+
+	return l
+}
+
+type logger struct {
+	prefix     string
+	traceOn    bool
+	traceOut   io.Writer
+	printStack bool
+	outs       atomic.Value
+	pc         []uintptr
+	funcForPc  *runtime.Func
+}
+
+// attaches the file and line number corresponding to
+// the log message
+func (l *logger) linePrefix(skipFrames int) string {
+	runtime.Callers(skipFrames, l.pc)
+	funcForPc := runtime.FuncForPC(l.pc[0])
+	file, line := funcForPc.FileLine(l.pc[0] - 1)
+	return fmt.Sprintf("%s%s:%d ", l.prefix, filepath.Base(file), line)
+}
+
+func (l *logger) print(out io.Writer, skipFrames int, severity string, arg interface{}) string {
+	buf := bufferPool.Get()
+	defer bufferPool.Put(buf)
+
+	linePrefix := l.linePrefix(skipFrames)
+	writeHeader := func() {
+		buf.WriteString(severity)
+		buf.WriteString(" ")
+		buf.WriteString(linePrefix)
+	}
+	if arg != nil {
+		ml, isMultiline := arg.(MultiLine)
+		if !isMultiline {
+			writeHeader()
+			fmt.Fprintf(buf, "%v", arg)
+			printContext(buf, arg)
+			buf.WriteByte('\n')
+		} else {
+			mlp := ml.MultiLinePrinter()
+			first := true
+			for {
+				writeHeader()
+				more := mlp(buf)
+				if first {
+					printContext(buf, arg)
+					first = false
+				}
+				buf.WriteByte('\n')
+				if !more {
+					break
+				}
+			}
+		}
+	}
+	b := []byte(hidden.Clean(buf.String()))
+	_, err := out.Write(b)
+	if err != nil {
+		errorOnLogging(err)
+	}
+	if l.printStack {
+		l.doPrintStack()
+	}
+
+	return linePrefix
+}
+
+func (l *logger) printf(out io.Writer, skipFrames int, severity string, err error, message string, args ...interface{}) string {
+	buf := bufferPool.Get()
+	defer bufferPool.Put(buf)
+
+	linePrefix := l.linePrefix(skipFrames)
+	buf.WriteString(severity)
+	buf.WriteString(" ")
+	buf.WriteString(linePrefix)
+	fmt.Fprintf(buf, message, args...)
+	printContext(buf, err)
+	buf.WriteByte('\n')
+	b := []byte(hidden.Clean(buf.String()))
+	_, err2 := out.Write(b)
+	if err2 != nil {
+		errorOnLogging(err)
+	}
+	if l.printStack {
+		l.doPrintStack()
+	}
+	return linePrefix
+}
+
+func (l *logger) Debug(arg interface{}) {
+	l.print(GetOutputs().DebugOut, 4, "DEBUG", arg)
+}
+
+func (l *logger) Debugf(message string, args ...interface{}) {
+	l.printf(GetOutputs().DebugOut, 4, "DEBUG", nil, message, args...)
+}
+
+func (l *logger) Error(arg interface{}) error {
+	return l.errorSkipFrames(arg, 1, ERROR)
+}
+
+func (l *logger) Errorf(message string, args ...interface{}) error {
+	return l.errorSkipFrames(errors.NewOffset(1, message, args...), 1, ERROR)
+}
+
+func (l *logger) Fatal(arg interface{}) {
+	fatal(l.errorSkipFrames(arg, 1, FATAL))
+}
+
+func (l *logger) Fatalf(message string, args ...interface{}) {
+	fatal(l.errorSkipFrames(errors.NewOffset(1, message, args...), 1, FATAL))
+}
+
+func fatal(err error) {
+	fn := onFatal.Load().(func(err error))
+	fn(err)
+}
+
+func (l *logger) errorSkipFrames(arg interface{}, skipFrames int, severity Severity) error {
+	var err error
+	switch e := arg.(type) {
+	case error:
+		err = e
+	default:
+		err = fmt.Errorf("%v", e)
+	}
+	linePrefix := l.print(GetOutputs().ErrorOut, skipFrames+4, severity.String(), err)
+	return report(err, linePrefix, severity)
+}
+
+func (l *logger) Trace(arg interface{}) {
+	if l.traceOn {
+		l.print(GetOutputs().DebugOut, 4, "TRACE", arg)
+	}
+}
+
+func (l *logger) Tracef(message string, args ...interface{}) {
+	if l.traceOn {
+		l.printf(GetOutputs().DebugOut, 4, "TRACE", nil, message, args...)
+	}
+}
+
+func (l *logger) TraceOut() io.Writer {
+	return l.traceOut
+}
+
+func (l *logger) IsTraceEnabled() bool {
+	return l.traceOn
+}
+
+func (l *logger) newTraceWriter() io.Writer {
+	pr, pw := io.Pipe()
+	br := bufio.NewReader(pr)
+
+	if !l.traceOn {
+		return pw
+	}
+	go func() {
+		defer func() {
+			if err := pr.Close(); err != nil {
+				errorOnLogging(err)
+			}
+		}()
+		defer func() {
+			if err := pw.Close(); err != nil {
+				errorOnLogging(err)
+			}
+		}()
+
+		for {
+			line, err := br.ReadString('\n')
+			if err == nil {
+				// Log the line (minus the trailing newline)
+				l.print(GetOutputs().DebugOut, 6, "TRACE", line[:len(line)-1])
+			} else {
+				l.printf(GetOutputs().DebugOut, 6, "TRACE", nil, "TraceWriter closed due to unexpected error: %v", err)
+				return
+			}
+		}
+	}()
+
+	return pw
+}
+
+type errorWriter struct {
+	l *logger
+}
+
+// Write implements method of io.Writer, due to different call depth,
+// it will not log correct file and line prefix
+func (w *errorWriter) Write(p []byte) (n int, err error) {
+	s := string(p)
+	if s[len(s)-1] == '\n' {
+		s = s[:len(s)-1]
+	}
+	w.l.print(GetOutputs().ErrorOut, 6, "ERROR", s)
+	return len(p), nil
+}
+
+func (l *logger) AsStdLogger() *log.Logger {
+	return log.New(&errorWriter{l}, "", 0)
+}
+
+func (l *logger) doPrintStack() {
+	var b []byte
+	buf := bytes.NewBuffer(b)
+	for _, pc := range l.pc {
+		funcForPc := runtime.FuncForPC(pc)
+		if funcForPc == nil {
+			break
+		}
+		name := funcForPc.Name()
+		if strings.HasPrefix(name, "runtime.") {
+			break
+		}
+		file, line := funcForPc.FileLine(pc)
+		fmt.Fprintf(buf, "\t%s\t%s: %d\n", name, file, line)
+	}
+	if _, err := buf.WriteTo(os.Stderr); err != nil {
+		errorOnLogging(err)
+	}
+}
+
+func errorOnLogging(err error) {
+	fmt.Fprintf(os.Stderr, "Unable to log: %v\n", err)
+}
+
+func printContext(buf *bytes.Buffer, err interface{}) {
+	// Note - we don't include globals when printing in order to avoid polluting the text log
+	values := ops.AsMap(err, false)
+	if len(values) == 0 {
+		return
+	}
+	buf.WriteString(" [")
+	var keys []string
+	for key := range values {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	for i, key := range keys {
+		value := values[key]
+		if i > 0 {
+			buf.WriteString(" ")
+		}
+		buf.WriteString(key)
+		buf.WriteString("=")
+		fmt.Fprintf(buf, "%v", value)
+	}
+	buf.WriteByte(']')
+}
+
+func report(err error, linePrefix string, severity Severity) error {
+	var reportersCopy []ErrorReporter
+	reportersMutex.RLock()
+	if len(reporters) > 0 {
+		reportersCopy = make([]ErrorReporter, len(reporters))
+		copy(reportersCopy, reporters)
+	}
+	reportersMutex.RUnlock()
+
+	if len(reportersCopy) > 0 {
+		ctx := ops.AsMap(err, true)
+		ctx["severity"] = severity.String()
+		for _, reporter := range reportersCopy {
+			// We include globals when reporting
+			reporter(err, linePrefix, severity, ctx)
+		}
+	}
+	return err
+}