1// Copyright 2015 Google Inc. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package android
16
17import (
18	"runtime"
19	"sort"
20	"strings"
21)
22
23func JoinWithPrefix(strs []string, prefix string) string {
24	if len(strs) == 0 {
25		return ""
26	}
27
28	if len(strs) == 1 {
29		return prefix + strs[0]
30	}
31
32	n := len(" ") * (len(strs) - 1)
33	for _, s := range strs {
34		n += len(prefix) + len(s)
35	}
36
37	ret := make([]byte, 0, n)
38	for i, s := range strs {
39		if i != 0 {
40			ret = append(ret, ' ')
41		}
42		ret = append(ret, prefix...)
43		ret = append(ret, s...)
44	}
45	return string(ret)
46}
47
48func sortedKeys(m map[string][]string) []string {
49	s := make([]string, 0, len(m))
50	for k := range m {
51		s = append(s, k)
52	}
53	sort.Strings(s)
54	return s
55}
56
57func indexList(s string, list []string) int {
58	for i, l := range list {
59		if l == s {
60			return i
61		}
62	}
63
64	return -1
65}
66
67func inList(s string, list []string) bool {
68	return indexList(s, list) != -1
69}
70
71// checkCalledFromInit panics if a Go package's init function is not on the
72// call stack.
73func checkCalledFromInit() {
74	for skip := 3; ; skip++ {
75		_, funcName, ok := callerName(skip)
76		if !ok {
77			panic("not called from an init func")
78		}
79
80		if funcName == "init" || strings.HasPrefix(funcName, "init·") {
81			return
82		}
83	}
84}
85
86// callerName returns the package path and function name of the calling
87// function.  The skip argument has the same meaning as the skip argument of
88// runtime.Callers.
89func callerName(skip int) (pkgPath, funcName string, ok bool) {
90	var pc [1]uintptr
91	n := runtime.Callers(skip+1, pc[:])
92	if n != 1 {
93		return "", "", false
94	}
95
96	f := runtime.FuncForPC(pc[0])
97	fullName := f.Name()
98
99	lastDotIndex := strings.LastIndex(fullName, ".")
100	if lastDotIndex == -1 {
101		panic("unable to distinguish function name from package")
102	}
103
104	if fullName[lastDotIndex-1] == ')' {
105		// The caller is a method on some type, so it's name looks like
106		// "pkg/path.(type).method".  We need to go back one dot farther to get
107		// to the package name.
108		lastDotIndex = strings.LastIndex(fullName[:lastDotIndex], ".")
109	}
110
111	pkgPath = fullName[:lastDotIndex]
112	funcName = fullName[lastDotIndex+1:]
113	ok = true
114	return
115}
116