mirror of
https://github.com/walles/moar.git
synced 2024-08-17 07:50:35 +03:00
425 lines
13 KiB
Go
425 lines
13 KiB
Go
package main
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import (
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"flag"
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"fmt"
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"io"
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"os"
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"os/exec"
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"path/filepath"
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"runtime"
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"strings"
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"time"
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"github.com/alecthomas/chroma/v2"
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"github.com/alecthomas/chroma/v2/formatters"
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"github.com/alecthomas/chroma/v2/styles"
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log "github.com/sirupsen/logrus"
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"golang.org/x/term"
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"github.com/walles/moar/m"
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"github.com/walles/moar/twin"
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)
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var versionString = "Should be set when building, please use build.sh to build"
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func printUsage(output io.Writer, flagSet *flag.FlagSet, printCommandline bool) {
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// This controls where PrintDefaults() prints, see below
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flagSet.SetOutput(output)
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// FIXME: Log if any printouts fail?
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moarEnv := os.Getenv("MOAR")
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if printCommandline {
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_, _ = fmt.Fprintln(output, "Commandline: moar", strings.Join(os.Args[1:], " "))
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_, _ = fmt.Fprintf(output, "Environment: MOAR=\"%v\"\n", moarEnv)
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_, _ = fmt.Fprintln(output)
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}
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_, _ = fmt.Fprintln(output, "Usage:")
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_, _ = fmt.Fprintln(output, " moar [options] <file>")
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_, _ = fmt.Fprintln(output, " ... | moar")
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_, _ = fmt.Fprintln(output, " moar < file")
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_, _ = fmt.Fprintln(output)
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_, _ = fmt.Fprintln(output, "Shows file contents. Compressed files will be transparently decompressed.")
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_, _ = fmt.Fprintln(output, "Input is expected to be (possibly compressed) UTF-8 encoded text. Invalid /")
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_, _ = fmt.Fprintln(output, "non-printable characters are by default rendered as '?'.")
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_, _ = fmt.Fprintln(output)
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_, _ = fmt.Fprintln(output, "More information + source code:")
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_, _ = fmt.Fprintln(output, " <https://github.com/walles/moar#readme>")
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_, _ = fmt.Fprintln(output)
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_, _ = fmt.Fprintln(output, "Environment:")
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if len(moarEnv) == 0 {
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_, _ = fmt.Fprintln(output, " Additional options are read from the MOAR environment variable if set.")
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_, _ = fmt.Fprintln(output, " But currently, the MOAR environment variable is not set.")
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} else {
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_, _ = fmt.Fprintln(output, " Additional options are read from the MOAR environment variable.")
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_, _ = fmt.Fprintf(output, " Current setting: MOAR=\"%s\"\n", moarEnv)
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}
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absMoarPath, err := absLookPath(os.Args[0])
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if err == nil {
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absPagerValue, err := absLookPath(os.Getenv("PAGER"))
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if err != nil {
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absPagerValue = ""
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}
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if absPagerValue != absMoarPath {
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// We're not the default pager
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_, _ = fmt.Fprintln(output)
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_, _ = fmt.Fprintln(output, "Making moar your default pager:")
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_, _ = fmt.Fprintln(output, " Put the following line in your ~/.bashrc, ~/.bash_profile or ~/.zshrc")
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_, _ = fmt.Fprintln(output, " and moar will be used as the default pager in all new terminal windows:")
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_, _ = fmt.Fprintln(output)
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_, _ = fmt.Fprintf(output, " export PAGER=%s\n", getMoarPath())
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}
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} else {
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log.Warn("Unable to find moar binary ", err)
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}
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_, _ = fmt.Fprintln(output)
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_, _ = fmt.Fprintln(output, "Options:")
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flagSet.PrintDefaults()
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}
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// "moar" if we're in the $PATH, otherwise an absolute path
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func getMoarPath() string {
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moarPath := os.Args[0]
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if filepath.IsAbs(moarPath) {
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return moarPath
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}
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if strings.Contains(moarPath, string(os.PathSeparator)) {
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// Relative path
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moarPath, err := filepath.Abs(moarPath)
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if err != nil {
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panic(err)
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}
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return moarPath
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}
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// Neither absolute nor relative, try PATH
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_, err := exec.LookPath(moarPath)
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if err != nil {
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panic("Unable to find in $PATH: " + moarPath)
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}
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return moarPath
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}
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func absLookPath(path string) (string, error) {
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lookedPath, err := exec.LookPath(path)
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if err != nil {
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return "", err
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}
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absLookedPath, err := filepath.Abs(lookedPath)
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if err != nil {
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return "", err
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}
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return absLookedPath, err
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}
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// printProblemsHeader prints bug reporting information to stderr
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func printProblemsHeader() {
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fmt.Fprintln(os.Stderr, "Please post the following report at <https://github.com/walles/moar/issues>,")
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fmt.Fprintln(os.Stderr, "or e-mail it to johan.walles@gmail.com.")
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fmt.Fprintln(os.Stderr)
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fmt.Fprintln(os.Stderr, "Version:", versionString)
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fmt.Fprintln(os.Stderr, "LANG :", os.Getenv("LANG"))
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fmt.Fprintln(os.Stderr, "TERM :", os.Getenv("TERM"))
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fmt.Fprintln(os.Stderr)
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fmt.Fprintln(os.Stderr, "GOOS :", runtime.GOOS)
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fmt.Fprintln(os.Stderr, "GOARCH :", runtime.GOARCH)
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fmt.Fprintln(os.Stderr, "Compiler:", runtime.Compiler)
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fmt.Fprintln(os.Stderr, "NumCPU :", runtime.NumCPU())
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fmt.Fprintln(os.Stderr)
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}
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func parseStyleOption(styleOption string) (chroma.Style, error) {
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style, ok := styles.Registry[styleOption]
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if !ok {
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return *styles.Fallback, fmt.Errorf(
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"Pick a style from here: https://xyproto.github.io/splash/docs/longer/all.html\n")
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}
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return *style, nil
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}
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func parseColorsOption(colorsOption string) (chroma.Formatter, error) {
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if strings.ToLower(colorsOption) == "auto" {
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colorsOption = "16M"
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if strings.Contains(os.Getenv("TERM"), "256") {
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// Covers "xterm-256color" as used by the macOS Terminal
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colorsOption = "256"
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}
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}
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switch strings.ToUpper(colorsOption) {
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case "8":
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return formatters.TTY8, nil
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case "16":
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return formatters.TTY16, nil
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case "256":
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return formatters.TTY256, nil
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case "16M":
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return formatters.TTY16m, nil
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}
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return nil, fmt.Errorf("Valid counts are 8, 16, 256, 16M or auto.")
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}
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func parseStatusBarStyle(styleOption string) (m.StatusBarStyle, error) {
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if styleOption == "inverse" {
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return m.STATUSBAR_STYLE_INVERSE, nil
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}
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if styleOption == "plain" {
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return m.STATUSBAR_STYLE_PLAIN, nil
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}
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if styleOption == "bold" {
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return m.STATUSBAR_STYLE_BOLD, nil
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}
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return 0, fmt.Errorf("good ones are inverse, plain and bold")
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}
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func parseUnprintableStyle(styleOption string) (m.UnprintableStyle, error) {
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if styleOption == "highlight" {
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return m.UNPRINTABLE_STYLE_HIGHLIGHT, nil
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}
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if styleOption == "whitespace" {
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return m.UNPRINTABLE_STYLE_WHITESPACE, nil
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}
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return 0, fmt.Errorf("Good ones are highlight or whitespace")
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}
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func parseScrollHint(scrollHint string) (twin.Cell, error) {
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scrollHint = strings.ReplaceAll(scrollHint, "ESC", "\x1b")
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hintParser := m.NewLine(scrollHint)
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parsedTokens := hintParser.HighlightedTokens(nil).Cells
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if len(parsedTokens) == 1 {
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return parsedTokens[0], nil
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}
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return twin.Cell{}, fmt.Errorf("Expected exactly one (optionally highlighted) character. For example: 'ESC[2m…'")
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}
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func main() {
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// FIXME: If we get a CTRL-C, get terminal back into a useful state before terminating
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defer func() {
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err := recover()
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if err == nil {
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return
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}
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printProblemsHeader()
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panic(err)
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}()
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flagSet := flag.NewFlagSet("",
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flag.ContinueOnError, // We want to do our own error handling
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)
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flagSet.SetOutput(io.Discard) // We want to do our own printing
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printVersion := flagSet.Bool("version", false, "Prints the moar version number")
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debug := flagSet.Bool("debug", false, "Print debug logs after exiting")
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trace := flagSet.Bool("trace", false, "Print trace logs after exiting")
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wrap := flagSet.Bool("wrap", false, "Wrap long lines")
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follow := flagSet.Bool("follow", false, "Follow piped input just like \"tail -f\"")
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style := flagSetFunc(flagSet,
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"style", *styles.Registry["native"],
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"Highlighting style from https://xyproto.github.io/splash/docs/longer/all.html", parseStyleOption)
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formatter := flagSetFunc(flagSet,
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"colors", formatters.TTY256, "Highlighting palette size: 8, 16, 256, 16M, auto", parseColorsOption)
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noLineNumbers := flagSet.Bool("no-linenumbers", false, "Hide line numbers on startup, press left arrow key to show")
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noStatusBar := flagSet.Bool("no-statusbar", false, "Hide the status bar, toggle with '='")
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noClearOnExit := flagSet.Bool("no-clear-on-exit", false, "Retain screen contents when exiting moar")
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statusBarStyle := flagSetFunc(flagSet, "statusbar", m.STATUSBAR_STYLE_INVERSE,
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"Status bar style: inverse, plain or bold", parseStatusBarStyle)
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unprintableStyle := flagSetFunc(flagSet, "render-unprintable", m.UNPRINTABLE_STYLE_HIGHLIGHT,
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"How unprintable characters are rendered: highlight or whitespace", parseUnprintableStyle)
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scrollLeftHint := flagSetFunc(flagSet, "scroll-left-hint",
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twin.NewCell('<', twin.StyleDefault.WithAttr(twin.AttrReverse)),
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"Shown when view can scroll left. One character with optional ANSI highlighting.", parseScrollHint)
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scrollRightHint := flagSetFunc(flagSet, "scroll-right-hint",
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twin.NewCell('>', twin.StyleDefault.WithAttr(twin.AttrReverse)),
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"Shown when view can scroll right. One character with optional ANSI highlighting.", parseScrollHint)
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// Combine flags from environment and from command line
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flags := os.Args[1:]
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moarEnv := strings.Trim(os.Getenv("MOAR"), " ")
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if len(moarEnv) > 0 {
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// FIXME: It would be nice if we could debug log that we're doing this,
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// but logging is not yet set up and depends on command line parameters.
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flags = append(strings.Fields(moarEnv), flags...)
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}
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err := flagSet.Parse(flags)
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if err != nil {
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if err == flag.ErrHelp {
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printUsage(os.Stdout, flagSet, false)
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return
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}
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boldErrorMessage := "\x1b[1m" + err.Error() + "\x1b[m"
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fmt.Fprintln(os.Stderr, "ERROR:", boldErrorMessage)
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fmt.Fprintln(os.Stderr)
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printUsage(os.Stderr, flagSet, true)
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os.Exit(1)
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}
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if *printVersion {
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fmt.Println(versionString)
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os.Exit(0)
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}
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log.SetLevel(log.InfoLevel)
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if *trace {
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log.SetLevel(log.TraceLevel)
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} else if *debug {
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log.SetLevel(log.DebugLevel)
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}
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log.SetFormatter(&log.TextFormatter{
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TimestampFormat: time.RFC3339Nano,
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})
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if len(flagSet.Args()) > 1 {
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fmt.Fprintln(os.Stderr, "ERROR: Expected exactly one filename, or data piped from stdin, got:", flagSet.Args())
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fmt.Fprintln(os.Stderr)
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printUsage(os.Stderr, flagSet, true)
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os.Exit(1)
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}
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stdinIsRedirected := !term.IsTerminal(int(os.Stdin.Fd()))
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stdoutIsRedirected := !term.IsTerminal(int(os.Stdout.Fd()))
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var inputFilename *string
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if len(flagSet.Args()) == 1 {
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word := flagSet.Arg(0)
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inputFilename = &word
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}
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if inputFilename == nil && !stdinIsRedirected {
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fmt.Fprintln(os.Stderr, "ERROR: Filename or input pipe required")
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fmt.Fprintln(os.Stderr)
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printUsage(os.Stderr, flagSet, true)
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os.Exit(1)
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}
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if inputFilename != nil && stdoutIsRedirected {
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// Pump file to stdout.
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//
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// If we get both redirected stdin and an input filename, we must prefer
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// to copy the file, because that's how less works.
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inputFile, err := os.Open(*inputFilename)
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if err != nil {
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fmt.Fprintln(os.Stderr, "ERROR: Failed to open", inputFile, ": ")
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os.Exit(1)
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}
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_, err = io.Copy(os.Stdout, inputFile)
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if err != nil {
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log.Fatal("Failed to copy ", inputFilename, " to stdout: ", err)
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}
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os.Exit(0)
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}
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if stdinIsRedirected && stdoutIsRedirected {
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// Must be done after trying to pump the input filename to stdout to be
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// compatible with less, see above.
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_, err := io.Copy(os.Stdout, os.Stdin)
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if err != nil {
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log.Fatal("Failed to copy stdin to stdout: ", err)
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}
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os.Exit(0)
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}
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// INVARIANT: At this point, stdoutIsRedirected is false and we should
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// proceed with paging.
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var reader *m.Reader
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if stdinIsRedirected {
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// Display input pipe contents
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reader = m.NewReaderFromStream("", os.Stdin)
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} else {
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reader, err = m.NewReaderFromFilename(*inputFilename, *style, *formatter)
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if err != nil {
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fmt.Fprintf(os.Stderr, "ERROR: %v\n", err)
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os.Exit(1)
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}
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}
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// Display the input file contents
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pager := m.NewPager(reader)
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pager.WrapLongLines = *wrap
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pager.Following = *follow
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pager.ShowLineNumbers = !*noLineNumbers
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pager.ShowStatusBar = !*noStatusBar
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pager.DeInit = !*noClearOnExit
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pager.StatusBarStyle = *statusBarStyle
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pager.UnprintableStyle = *unprintableStyle
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pager.ScrollLeftHint = *scrollLeftHint
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pager.ScrollRightHint = *scrollRightHint
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startPaging(pager)
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}
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// Define a generic flag with specified name, default value, and usage string.
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// The return value is the address of a variable that stores the parsed value of
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// the flag.
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func flagSetFunc[T any](flagSet *flag.FlagSet, name string, defaultValue T, usage string, parser func(valueString string) (T, error)) *T {
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parsed := defaultValue
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flagSet.Func(name, usage, func(valueString string) error {
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parseResult, err := parser(valueString)
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if err != nil {
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return err
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}
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parsed = parseResult
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return nil
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})
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return &parsed
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}
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func startPaging(pager *m.Pager) {
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screen, e := twin.NewScreen()
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if e != nil {
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panic(e)
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}
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var loglines strings.Builder
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log.SetOutput(&loglines)
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defer func() {
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// Restore screen...
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screen.Close()
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// ... before printing panic() output, otherwise the output will have
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// broken linefeeds and be hard to follow.
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if err := recover(); err != nil {
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panic(err)
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}
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if !pager.DeInit {
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err := pager.ReprintAfterExit()
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if err != nil {
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log.Error("Failed reprinting pager view after exit", err)
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}
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}
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if len(loglines.String()) > 0 {
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printProblemsHeader()
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// FIXME: Don't print duplicate log messages more than once,
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// maybe invent our own logger for this?
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fmt.Fprintf(os.Stderr, "%s", loglines.String())
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os.Exit(1)
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}
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}()
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pager.StartPaging(screen)
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}
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