// Go support for leveled logs, analogous to https://code.google.com/p/google-glog/
//
// Copyright 2013 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 dbg provides some helper code for call traces.
package dbg

import (
	"runtime"
)

// Stacks is a wrapper for runtime.Stack that attempts to recover the data for
// all goroutines or the calling one.
func Stacks(all bool) []byte {
	// We don't know how big the traces are, so grow a few times if they don't fit. Start large, though.
	n := 10000
	if all {
		n = 100000
	}
	var trace []byte
	for i := 0; i < 5; i++ {
		trace = make([]byte, n)
		nbytes := runtime.Stack(trace, all)
		if nbytes < len(trace) {
			return trace[:nbytes]
		}
		n *= 2
	}
	return trace
}