Bump version to 5.11.0

vendor/github.com/golang/glog/glog_flags.go

@@ -0,0 +1,398 @@
+// Go support for leveled logs, analogous to https://github.com/google/glog.
+//
+// Copyright 2023 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package glog
+
+import (
+	"bytes"
+	"errors"
+	"flag"
+	"fmt"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+
+	"github.com/golang/glog/internal/logsink"
+)
+
+// modulePat contains a filter for the -vmodule flag.
+// It holds a verbosity level and a file pattern to match.
+type modulePat struct {
+	pattern string
+	literal bool // The pattern is a literal string
+	full    bool // The pattern wants to match the full path
+	level   Level
+}
+
+// match reports whether the file matches the pattern. It uses a string
+// comparison if the pattern contains no metacharacters.
+func (m *modulePat) match(full, file string) bool {
+	if m.literal {
+		if m.full {
+			return full == m.pattern
+		}
+		return file == m.pattern
+	}
+	if m.full {
+		match, _ := filepath.Match(m.pattern, full)
+		return match
+	}
+	match, _ := filepath.Match(m.pattern, file)
+	return match
+}
+
+// isLiteral reports whether the pattern is a literal string, that is, has no metacharacters
+// that require filepath.Match to be called to match the pattern.
+func isLiteral(pattern string) bool {
+	return !strings.ContainsAny(pattern, `\*?[]`)
+}
+
+// isFull reports whether the pattern matches the full file path, that is,
+// whether it contains /.
+func isFull(pattern string) bool {
+	return strings.ContainsRune(pattern, '/')
+}
+
+// verboseFlags represents the setting of the -v and -vmodule flags.
+type verboseFlags struct {
+	// moduleLevelCache is a sync.Map storing the -vmodule Level for each V()
+	// call site, identified by PC. If there is no matching -vmodule filter,
+	// the cached value is exactly v. moduleLevelCache is replaced with a new
+	// Map whenever the -vmodule or -v flag changes state.
+	moduleLevelCache atomic.Value
+
+	// mu guards all fields below.
+	mu sync.Mutex
+
+	// v stores the value of the -v flag.  It may be read safely using
+	// sync.LoadInt32, but is only modified under mu.
+	v Level
+
+	// module stores the parsed -vmodule flag.
+	module []modulePat
+
+	// moduleLength caches len(module).  If greater than zero, it
+	// means vmodule is enabled. It may be read safely using sync.LoadInt32, but
+	// is only modified under mu.
+	moduleLength int32
+}
+
+// NOTE: For compatibility with the open-sourced v1 version of this
+// package (github.com/golang/glog) we need to retain that flag.Level
+// implements the flag.Value interface. See also go/log-vs-glog.
+
+// String is part of the flag.Value interface.
+func (l *Level) String() string {
+	return strconv.FormatInt(int64(l.Get().(Level)), 10)
+}
+
+// Get is part of the flag.Value interface.
+func (l *Level) Get() any {
+	if l == &vflags.v {
+		// l is the value registered for the -v flag.
+		return Level(atomic.LoadInt32((*int32)(l)))
+	}
+	return *l
+}
+
+// Set is part of the flag.Value interface.
+func (l *Level) Set(value string) error {
+	v, err := strconv.Atoi(value)
+	if err != nil {
+		return err
+	}
+	if l == &vflags.v {
+		// l is the value registered for the -v flag.
+		vflags.mu.Lock()
+		defer vflags.mu.Unlock()
+		vflags.moduleLevelCache.Store(&sync.Map{})
+		atomic.StoreInt32((*int32)(l), int32(v))
+		return nil
+	}
+	*l = Level(v)
+	return nil
+}
+
+// vModuleFlag is the flag.Value for the --vmodule flag.
+type vModuleFlag struct{ *verboseFlags }
+
+func (f vModuleFlag) String() string {
+	// Do not panic on the zero value.
+	// https://groups.google.com/g/golang-nuts/c/Atlr8uAjn6U/m/iId17Td5BQAJ.
+	if f.verboseFlags == nil {
+		return ""
+	}
+	f.mu.Lock()
+	defer f.mu.Unlock()
+
+	var b bytes.Buffer
+	for i, f := range f.module {
+		if i > 0 {
+			b.WriteRune(',')
+		}
+		fmt.Fprintf(&b, "%s=%d", f.pattern, f.level)
+	}
+	return b.String()
+}
+
+// Get returns nil for this flag type since the struct is not exported.
+func (f vModuleFlag) Get() any { return nil }
+
+var errVmoduleSyntax = errors.New("syntax error: expect comma-separated list of filename=N")
+
+// Syntax: -vmodule=recordio=2,foo/bar/baz=1,gfs*=3
+func (f vModuleFlag) Set(value string) error {
+	var filter []modulePat
+	for _, pat := range strings.Split(value, ",") {
+		if len(pat) == 0 {
+			// Empty strings such as from a trailing comma can be ignored.
+			continue
+		}
+		patLev := strings.Split(pat, "=")
+		if len(patLev) != 2 || len(patLev[0]) == 0 || len(patLev[1]) == 0 {
+			return errVmoduleSyntax
+		}
+		pattern := patLev[0]
+		v, err := strconv.Atoi(patLev[1])
+		if err != nil {
+			return errors.New("syntax error: expect comma-separated list of filename=N")
+		}
+		// TODO: check syntax of filter?
+		filter = append(filter, modulePat{pattern, isLiteral(pattern), isFull(pattern), Level(v)})
+	}
+
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.module = filter
+	atomic.StoreInt32((*int32)(&f.moduleLength), int32(len(f.module)))
+	f.moduleLevelCache.Store(&sync.Map{})
+	return nil
+}
+
+func (f *verboseFlags) levelForPC(pc uintptr) Level {
+	if level, ok := f.moduleLevelCache.Load().(*sync.Map).Load(pc); ok {
+		return level.(Level)
+	}
+
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	level := Level(f.v)
+	fn := runtime.FuncForPC(pc)
+	file, _ := fn.FileLine(pc)
+	// The file is something like /a/b/c/d.go. We want just the d for
+	// regular matches, /a/b/c/d for full matches.
+	file = strings.TrimSuffix(file, ".go")
+	full := file
+	if slash := strings.LastIndex(file, "/"); slash >= 0 {
+		file = file[slash+1:]
+	}
+	for _, filter := range f.module {
+		if filter.match(full, file) {
+			level = filter.level
+			break // Use the first matching level.
+		}
+	}
+	f.moduleLevelCache.Load().(*sync.Map).Store(pc, level)
+	return level
+}
+
+func (f *verboseFlags) enabled(callerDepth int, level Level) bool {
+	if atomic.LoadInt32(&f.moduleLength) == 0 {
+		// No vmodule values specified, so compare against v level.
+		return Level(atomic.LoadInt32((*int32)(&f.v))) >= level
+	}
+
+	pcs := [1]uintptr{}
+	if runtime.Callers(callerDepth+2, pcs[:]) < 1 {
+		return false
+	}
+	frame, _ := runtime.CallersFrames(pcs[:]).Next()
+	return f.levelForPC(frame.Entry) >= level
+}
+
+// traceLocation represents an entry in the -log_backtrace_at flag.
+type traceLocation struct {
+	file string
+	line int
+}
+
+var errTraceSyntax = errors.New("syntax error: expect file.go:234")
+
+func parseTraceLocation(value string) (traceLocation, error) {
+	fields := strings.Split(value, ":")
+	if len(fields) != 2 {
+		return traceLocation{}, errTraceSyntax
+	}
+	file, lineStr := fields[0], fields[1]
+	if !strings.Contains(file, ".") {
+		return traceLocation{}, errTraceSyntax
+	}
+	line, err := strconv.Atoi(lineStr)
+	if err != nil {
+		return traceLocation{}, errTraceSyntax
+	}
+	if line < 0 {
+		return traceLocation{}, errors.New("negative value for line")
+	}
+	return traceLocation{file, line}, nil
+}
+
+// match reports whether the specified file and line matches the trace location.
+// The argument file name is the full path, not the basename specified in the flag.
+func (t traceLocation) match(file string, line int) bool {
+	if t.line != line {
+		return false
+	}
+	if i := strings.LastIndex(file, "/"); i >= 0 {
+		file = file[i+1:]
+	}
+	return t.file == file
+}
+
+func (t traceLocation) String() string {
+	return fmt.Sprintf("%s:%d", t.file, t.line)
+}
+
+// traceLocations represents the -log_backtrace_at flag.
+// Syntax: -log_backtrace_at=recordio.go:234,sstable.go:456
+// Note that unlike vmodule the file extension is included here.
+type traceLocations struct {
+	mu      sync.Mutex
+	locsLen int32 // Safe for atomic read without mu.
+	locs    []traceLocation
+}
+
+func (t *traceLocations) String() string {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	var buf bytes.Buffer
+	for i, tl := range t.locs {
+		if i > 0 {
+			buf.WriteString(",")
+		}
+		buf.WriteString(tl.String())
+	}
+	return buf.String()
+}
+
+// Get always returns nil for this flag type since the struct is not exported
+func (t *traceLocations) Get() any { return nil }
+
+func (t *traceLocations) Set(value string) error {
+	var locs []traceLocation
+	for _, s := range strings.Split(value, ",") {
+		if s == "" {
+			continue
+		}
+		loc, err := parseTraceLocation(s)
+		if err != nil {
+			return err
+		}
+		locs = append(locs, loc)
+	}
+
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	atomic.StoreInt32(&t.locsLen, int32(len(locs)))
+	t.locs = locs
+	return nil
+}
+
+func (t *traceLocations) match(file string, line int) bool {
+	if atomic.LoadInt32(&t.locsLen) == 0 {
+		return false
+	}
+
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	for _, tl := range t.locs {
+		if tl.match(file, line) {
+			return true
+		}
+	}
+	return false
+}
+
+// severityFlag is an atomic flag.Value implementation for logsink.Severity.
+type severityFlag int32
+
+func (s *severityFlag) get() logsink.Severity {
+	return logsink.Severity(atomic.LoadInt32((*int32)(s)))
+}
+func (s *severityFlag) String() string { return strconv.FormatInt(int64(*s), 10) }
+func (s *severityFlag) Get() any       { return s.get() }
+func (s *severityFlag) Set(value string) error {
+	threshold, err := logsink.ParseSeverity(value)
+	if err != nil {
+		// Not a severity name.  Try a raw number.
+		v, err := strconv.Atoi(value)
+		if err != nil {
+			return err
+		}
+		threshold = logsink.Severity(v)
+		if threshold < logsink.Info || threshold > logsink.Fatal {
+			return fmt.Errorf("Severity %d out of range (min %d, max %d).", v, logsink.Info, logsink.Fatal)
+		}
+	}
+	atomic.StoreInt32((*int32)(s), int32(threshold))
+	return nil
+}
+
+var (
+	vflags verboseFlags // The -v and -vmodule flags.
+
+	logBacktraceAt traceLocations // The -log_backtrace_at flag.
+
+	// Boolean flags. Not handled atomically because the flag.Value interface
+	// does not let us avoid the =true, and that shorthand is necessary for
+	// compatibility. TODO: does this matter enough to fix? Seems unlikely.
+	toStderr     bool // The -logtostderr flag.
+	alsoToStderr bool // The -alsologtostderr flag.
+
+	stderrThreshold severityFlag // The -stderrthreshold flag.
+)
+
+// verboseEnabled returns whether the caller at the given depth should emit
+// verbose logs at the given level, with depth 0 identifying the caller of
+// verboseEnabled.
+func verboseEnabled(callerDepth int, level Level) bool {
+	return vflags.enabled(callerDepth+1, level)
+}
+
+// backtraceAt returns whether the logging call at the given function and line
+// should also emit a backtrace of the current call stack.
+func backtraceAt(file string, line int) bool {
+	return logBacktraceAt.match(file, line)
+}
+
+func init() {
+	vflags.moduleLevelCache.Store(&sync.Map{})
+
+	flag.Var(&vflags.v, "v", "log level for V logs")
+	flag.Var(vModuleFlag{&vflags}, "vmodule", "comma-separated list of pattern=N settings for file-filtered logging")
+
+	flag.Var(&logBacktraceAt, "log_backtrace_at", "when logging hits line file:N, emit a stack trace")
+
+	stderrThreshold = severityFlag(logsink.Error)
+
+	flag.BoolVar(&toStderr, "logtostderr", false, "log to standard error instead of files")
+	flag.BoolVar(&alsoToStderr, "alsologtostderr", false, "log to standard error as well as files")
+	flag.Var(&stderrThreshold, "stderrthreshold", "logs at or above this threshold go to stderr")
+}