Initial commit

vendor/github.com/cockroachdb/errors/withstack/stack.go

@@ -0,0 +1,59 @@
+// Copyright 2019 The Cockroach Authors.
+//
+// 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 withstack
+
+import (
+	"fmt"
+	"runtime"
+
+	"github.com/cockroachdb/errors/errbase"
+)
+
+// stack represents a stack of program counters.
+// This mirrors the (non-exported) type of the same name in github.com/pkg/errors.
+type stack []uintptr
+
+// Format mirrors the code in github.com/pkg/errors.
+func (s *stack) Format(st fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		switch {
+		case st.Flag('+'):
+			for _, pc := range *s {
+				f := errbase.StackFrame(pc)
+				fmt.Fprintf(st, "\n%+v", f)
+			}
+		}
+	}
+}
+
+// StackTrace mirrors the code in github.com/pkg/errors.
+func (s *stack) StackTrace() errbase.StackTrace {
+	f := make([]errbase.StackFrame, len(*s))
+	for i := 0; i < len(f); i++ {
+		f[i] = errbase.StackFrame((*s)[i])
+	}
+	return f
+}
+
+// callers mirrors the code in github.com/pkg/errors,
+// but makes the depth customizable.
+func callers(depth int) *stack {
+	const numFrames = 32
+	var pcs [numFrames]uintptr
+	n := runtime.Callers(2+depth, pcs[:])
+	var st stack = pcs[0:n]
+	return &st
+}