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// Copyright 2019 The SwiftShader Authors. 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.
// strip_unneeded is a tool that attempts to remove unnecessary lines from a
// file by running a test script after each marked line is removed.
//
// strip_unneeded will scan the file specified by the --file argument for lines
// that contain the substring specified by the --marker argument. One-by-one
// those marked lines will be removed from the file, after which the test script
// specified by --test will be run. If the test passes (the process completes
// with a 0 return code), then the line will remain removed, otherwise it is
// restored. This will repeat for every line in the file containing the marker,
// until all lines are tested.
package main
import (
"flag"
"fmt"
"io/ioutil"
"os"
"os/exec"
"strings"
)
var (
file = flag.String("file", "", "file to modify")
marker = flag.String("marker", "CHECK_NEEDED", "line token")
test = flag.String("test", "", "test script to run with each change")
)
func main() {
if err := run(); err != nil {
fmt.Println(err.Error())
os.Exit(1)
}
}
func run() error {
flag.Parse()
if *file == "" {
return fmt.Errorf("Missing --file argument")
}
if *marker == "" {
return fmt.Errorf("Missing --marker argument")
}
if *test == "" {
return fmt.Errorf("Missing --test argument")
}
// make sure the test passes with no modifications
if err := runTest(); err != nil {
return fmt.Errorf("Test fails with no modifications.\n%v", err)
}
// load the test file
body, err := ioutil.ReadFile(*file)
if err != nil {
return fmt.Errorf("Couldn't load file '%v'", *file)
}
// gather all the lines
allLines := strings.Split(string(body), "\n")
// find all the lines with the marker
markerLines := make([]int, 0, len(allLines))
for i, l := range allLines {
if strings.Contains(l, *marker) {
markerLines = append(markerLines, i)
}
}
omit := map[int]bool{}
save := func() error {
f, err := os.Create(*file)
if err != nil {
return err
}
defer f.Close()
for i, l := range allLines {
if !omit[i] {
f.WriteString(l)
f.WriteString("\n")
}
}
return nil
}
for i, l := range markerLines {
omit[l] = true
if err := save(); err != nil {
return err
}
if err := runTest(); err != nil {
omit[l] = false
fmt.Printf("%d/%d: Test fails when removing line %v: %v\n", i, len(markerLines), l, allLines[l])
} else {
fmt.Printf("%d/%d: Test passes when removing line %v: %v\n", i, len(markerLines), l, allLines[l])
}
}
return save()
}
func runTest() error {
cmd := exec.Command("sh", "-c", *test)
out, err := cmd.CombinedOutput()
if err != nil {
return fmt.Errorf("Test failed with error: %v\n%v", err, string(out))
}
return nil
}