1// Copyright 2019 The SwiftShader Authors. 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 15// strip_unneeded is a tool that attempts to remove unnecessary lines from a 16// file by running a test script after each marked line is removed. 17// 18// strip_unneeded will scan the file specified by the --file argument for lines 19// that contain the substring specified by the --marker argument. One-by-one 20// those marked lines will be removed from the file, after which the test script 21// specified by --test will be run. If the test passes (the process completes 22// with a 0 return code), then the line will remain removed, otherwise it is 23// restored. This will repeat for every line in the file containing the marker, 24// until all lines are tested. 25package main 26 27import ( 28 "flag" 29 "fmt" 30 "io/ioutil" 31 "os" 32 "os/exec" 33 "strings" 34) 35 36var ( 37 file = flag.String("file", "", "file to modify") 38 marker = flag.String("marker", "CHECK_NEEDED", "line token") 39 test = flag.String("test", "", "test script to run with each change") 40) 41 42func main() { 43 if err := run(); err != nil { 44 fmt.Println(err.Error()) 45 os.Exit(1) 46 } 47} 48 49func run() error { 50 flag.Parse() 51 if *file == "" { 52 return fmt.Errorf("Missing --file argument") 53 } 54 if *marker == "" { 55 return fmt.Errorf("Missing --marker argument") 56 } 57 if *test == "" { 58 return fmt.Errorf("Missing --test argument") 59 } 60 61 // make sure the test passes with no modifications 62 if err := runTest(); err != nil { 63 return fmt.Errorf("Test fails with no modifications.\n%v", err) 64 } 65 66 // load the test file 67 body, err := ioutil.ReadFile(*file) 68 if err != nil { 69 return fmt.Errorf("Couldn't load file '%v'", *file) 70 } 71 72 // gather all the lines 73 allLines := strings.Split(string(body), "\n") 74 75 // find all the lines with the marker 76 markerLines := make([]int, 0, len(allLines)) 77 for i, l := range allLines { 78 if strings.Contains(l, *marker) { 79 markerLines = append(markerLines, i) 80 } 81 } 82 83 omit := map[int]bool{} 84 85 save := func() error { 86 f, err := os.Create(*file) 87 if err != nil { 88 return err 89 } 90 defer f.Close() 91 for i, l := range allLines { 92 if !omit[i] { 93 f.WriteString(l) 94 f.WriteString("\n") 95 } 96 } 97 return nil 98 } 99 100 for i, l := range markerLines { 101 omit[l] = true 102 if err := save(); err != nil { 103 return err 104 } 105 if err := runTest(); err != nil { 106 omit[l] = false 107 fmt.Printf("%d/%d: Test fails when removing line %v: %v\n", i, len(markerLines), l, allLines[l]) 108 } else { 109 fmt.Printf("%d/%d: Test passes when removing line %v: %v\n", i, len(markerLines), l, allLines[l]) 110 } 111 } 112 113 return save() 114} 115 116func runTest() error { 117 cmd := exec.Command("sh", "-c", *test) 118 out, err := cmd.CombinedOutput() 119 if err != nil { 120 return fmt.Errorf("Test failed with error: %v\n%v", err, string(out)) 121 } 122 return nil 123} 124