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1// Copyright 2017 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 build
16
17import (
18	"os/exec"
19)
20
21// Cmd is a wrapper of os/exec.Cmd that integrates with the build context for
22// logging, the config's Environment for simpler environment modification, and
23// implements hooks for sandboxing
24type Cmd struct {
25	*exec.Cmd
26
27	Environment *Environment
28	Sandbox     Sandbox
29
30	ctx    Context
31	config Config
32	name   string
33}
34
35func Command(ctx Context, config Config, name string, executable string, args ...string) *Cmd {
36	ret := &Cmd{
37		Cmd:         exec.CommandContext(ctx.Context, executable, args...),
38		Environment: config.Environment().Copy(),
39		Sandbox:     noSandbox,
40
41		ctx:    ctx,
42		config: config,
43		name:   name,
44	}
45
46	return ret
47}
48
49func (c *Cmd) prepare() {
50	if c.Env == nil {
51		c.Env = c.Environment.Environ()
52	}
53	if c.sandboxSupported() {
54		c.wrapSandbox()
55	}
56
57	c.ctx.Verboseln(c.Path, c.Args)
58}
59
60func (c *Cmd) Start() error {
61	c.prepare()
62	return c.Cmd.Start()
63}
64
65func (c *Cmd) Run() error {
66	c.prepare()
67	err := c.Cmd.Run()
68	return err
69}
70
71func (c *Cmd) Output() ([]byte, error) {
72	c.prepare()
73	bytes, err := c.Cmd.Output()
74	return bytes, err
75}
76
77func (c *Cmd) CombinedOutput() ([]byte, error) {
78	c.prepare()
79	bytes, err := c.Cmd.CombinedOutput()
80	return bytes, err
81}
82
83// StartOrFatal is equivalent to Start, but handles the error with a call to ctx.Fatal
84func (c *Cmd) StartOrFatal() {
85	if err := c.Start(); err != nil {
86		c.ctx.Fatalf("Failed to run %s: %v", c.name, err)
87	}
88}
89
90func (c *Cmd) reportError(err error) {
91	if err == nil {
92		return
93	}
94	if e, ok := err.(*exec.ExitError); ok {
95		c.ctx.Fatalf("%s failed with: %v", c.name, e.ProcessState.String())
96	} else {
97		c.ctx.Fatalf("Failed to run %s: %v", c.name, err)
98	}
99}
100
101// RunOrFatal is equivalent to Run, but handles the error with a call to ctx.Fatal
102func (c *Cmd) RunOrFatal() {
103	c.reportError(c.Run())
104}
105
106// WaitOrFatal is equivalent to Wait, but handles the error with a call to ctx.Fatal
107func (c *Cmd) WaitOrFatal() {
108	c.reportError(c.Wait())
109}
110
111// OutputOrFatal is equivalent to Output, but handles the error with a call to ctx.Fatal
112func (c *Cmd) OutputOrFatal() []byte {
113	ret, err := c.Output()
114	c.reportError(err)
115	return ret
116}
117
118// CombinedOutputOrFatal is equivalent to CombinedOutput, but handles the error with
119// a call to ctx.Fatal
120func (c *Cmd) CombinedOutputOrFatal() []byte {
121	ret, err := c.CombinedOutput()
122	c.reportError(err)
123	return ret
124}
125
126// RunAndPrintOrFatal will run the command, then after finishing
127// print any output, then handling any errors with a call to
128// ctx.Fatal
129func (c *Cmd) RunAndPrintOrFatal() {
130	ret, err := c.CombinedOutput()
131	st := c.ctx.Status.StartTool()
132	if len(ret) > 0 {
133		if err != nil {
134			st.Error(string(ret))
135		} else {
136			st.Print(string(ret))
137		}
138	}
139	st.Finish()
140	c.reportError(err)
141}
142