124 lines
3.2 KiB
Go
124 lines
3.2 KiB
Go
package sort
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import (
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"fmt"
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"log"
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"os"
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"slices"
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"strings"
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cmdpkg "github.com/brtholomy/um/go/cmd"
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"github.com/brtholomy/um/go/flags"
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"github.com/brtholomy/um/go/pipe"
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)
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const cmd = cmdpkg.Sort
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type options struct {
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Source flags.Flag[string]
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Key flags.Flag[string]
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Write flags.Flag[bool]
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Help flags.Flag[bool]
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}
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func initOpts() options {
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return options{
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flags.Flag[string]{"--source", "-s", "", "path to source list. reads from stdin if omitted."},
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flags.Flag[string]{"--key", "-k", "", "path to sort key"},
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flags.Flag[bool]{"--write", "-w", false, "write sorted list back to --key file"},
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flags.Flag[bool]{"--help", "-h", false, "show help"},
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}
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}
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func parseArgs(args []string) options {
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opts := initOpts()
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for i := 0; i < len(args); i++ {
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arg := args[i]
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switch {
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case arg == opts.Source.Long || arg == opts.Source.Short:
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i, opts.Source.Val = flags.ValidateIncrementFetchOrExit(args, i)
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case arg == opts.Key.Long || arg == opts.Key.Short:
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i, opts.Key.Val = flags.ValidateIncrementFetchOrExit(args, i)
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case arg == opts.Write.Long || arg == opts.Write.Short:
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opts.Write.Val = true
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case arg == opts.Help.Long || arg == opts.Help.Short:
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flags.Help(cmd, opts)
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default:
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flags.HelpInvalidArg(cmd, arg)
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flags.Help(cmd, opts)
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}
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}
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if !opts.Key.IsSet() {
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flags.HelpRequired(cmd, opts.Key.Long)
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flags.Help(cmd, opts)
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}
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return opts
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}
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// reads files from stdin if present, otherwise from the filename:
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func fileListSplitMaybeStdin(f string) []string {
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filelist, err := pipe.GetStdin()
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if err != nil {
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filelist = fileListSplit(f)
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}
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return filelist
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}
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// opens the given filename and splits into lines:
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func fileListSplit(f string) []string {
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dat, err := os.ReadFile(f)
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if err != nil {
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// if this fails all is lost. just exit.
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log.Fatalf("um %s: error opening file: %s\n%s", cmd, f, err)
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}
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return strings.Split(string(dat), pipe.Newline)
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}
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// record the order of the given filelist.
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func kMap(kslice []string) map[string]int {
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m := make(map[string]int, 0)
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for i, l := range kslice {
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m[l] = i
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}
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return m
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}
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// write out the provided source slice while respecting the order provided by kmap
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func sort(sslice []string, kmap map[string]int) string {
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oslice := make([]string, max(len(sslice), len(kmap))+1)
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for _, l := range sslice {
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// lines not represented in the key get appended to the end:
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if _, ok := kmap[l]; !ok {
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// we don't care that this might leave empty strings between:
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oslice = append(oslice, l)
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continue
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}
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// NOTE: raison d'etre of this whole thang:
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// if present in the key, respect the order:
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oslice[kmap[l]] = l
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}
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// delete empties and add a final newline
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oslice = slices.DeleteFunc(oslice, func(e string) bool { return e == "" })
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return strings.Join(oslice, pipe.Newline) + pipe.Newline
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}
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func write(file string, content string) {
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if err := os.WriteFile(file, []byte(content), 0664); err != nil {
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log.Fatalf("um %s: error writing file: %s\n%s", cmd, file, err)
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}
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}
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func Sort(args []string) {
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opts := parseArgs(args)
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sslice := fileListSplitMaybeStdin(opts.Source.Val)
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kslice := fileListSplit(opts.Key.Val)
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kmap := kMap(kslice)
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out := sort(sslice, kmap)
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if opts.Write.IsSet() {
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write(opts.Key.Val, out)
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} else {
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// to stdout
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fmt.Print(out)
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}
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}
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