Add diff_target_files tool

blueprint_go_binary {

    name: "diff_target_files",

    srcs: [

        "compare.go",

        "diff_target_files.go",

        "glob.go",

        "target_files.go",

        "whitelist.go",

        "zip_artifact.go",

    ],

    testSrcs: [

        "compare_test.go",

        "glob_test.go",

        "whitelist_test.go",

    ],

}

// Copyright 2019 Google Inc. 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.

package main

import (

	"flag"

	"fmt"

	"os"

	"strings"

)

var (

	whitelists     = newMultiString("whitelist", "whitelist patterns in the form <pattern>[:<regex of line to ignore>]")

	whitelistFiles = newMultiString("whitelist_file", "files containing whitelist definitions")

	filters = newMultiString("filter", "filter patterns to apply to files in target-files.zip before comparing")

)

func newMultiString(name, usage string) *multiString {

	var f multiString

	flag.Var(&f, name, usage)

	return &f

}

type multiString []string

func (ms *multiString) String() string     { return strings.Join(*ms, ", ") }

func (ms *multiString) Set(s string) error { *ms = append(*ms, s); return nil }

func main() {

	flag.Parse()

	if flag.NArg() != 2 {

		fmt.Fprintf(os.Stderr, "Error, exactly two arguments are required\n")

		os.Exit(1)

	}

	whitelists, err := parseWhitelists(*whitelists, *whitelistFiles)

	if err != nil {

		fmt.Fprintf(os.Stderr, "Error parsing whitelists: %v\n", err)

		os.Exit(1)

	}

	priZip, err := NewLocalZipArtifact(flag.Arg(0))

	if err != nil {

		fmt.Fprintf(os.Stderr, "Error opening zip file %v: %v\n", flag.Arg(0), err)

		os.Exit(1)

	}

	defer priZip.Close()

	refZip, err := NewLocalZipArtifact(flag.Arg(1))

	if err != nil {

		fmt.Fprintf(os.Stderr, "Error opening zip file %v: %v\n", flag.Arg(1), err)

		os.Exit(1)

	}

	defer refZip.Close()

	diff, err := compareTargetFiles(priZip, refZip, targetFilesPattern, whitelists, *filters)

	if err != nil {

		fmt.Fprintf(os.Stderr, "Error comparing zip files: %v\n", err)

		os.Exit(1)

	}

	fmt.Print(diff.String())

	if len(diff.modified) > 0 || len(diff.onlyInA) > 0 || len(diff.onlyInB) > 0 {

		fmt.Fprintln(os.Stderr, "differences found")

		os.Exit(1)

	}

}