mirror of
https://github.com/walles/moar.git
synced 2024-09-11 20:17:13 +03:00
551 lines
16 KiB
Go
551 lines
16 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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"math"
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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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"strconv"
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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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_, _ = fmt.Fprintln(output, " +1234")
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_, _ = fmt.Fprintln(output, " \tImmediately scroll to line 1234")
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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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}
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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.StatusBarStyleType, 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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hintAsLine := m.NewLine(scrollHint)
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parsedTokens := hintAsLine.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 parseShiftAmount(shiftAmount string) (uint, error) {
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value, err := strconv.ParseUint(shiftAmount, 10, 32)
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if err != nil {
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return 0, err
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}
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if value < 1 {
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return 0, fmt.Errorf("Shift amount must be at least 1, was %d", value)
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}
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// Let's add an upper bound as well if / when requested
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return uint(value), nil
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}
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func pumpToStdout(inputFilename *string) error {
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if inputFilename != nil {
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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. That's why we go for
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// the filename first.
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inputFile, err := os.Open(*inputFilename)
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if err != nil {
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return fmt.Errorf("Failed to open %s: %w", *inputFilename, err)
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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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return fmt.Errorf("Failed to copy %s to stdout: %w", *inputFilename, err)
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}
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return nil
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}
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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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return fmt.Errorf("Failed to copy stdin to stdout: %w", err)
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}
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return nil
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}
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// Duplicate of m/reader.go:tryOpen
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func tryOpen(filename string) error {
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// Try opening the file
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tryMe, err := os.Open(filename)
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if err != nil {
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return err
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}
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// Try reading a byte
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buffer := make([]byte, 1)
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_, err = tryMe.Read(buffer)
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if err != nil && err.Error() == "EOF" {
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// Empty file, this is fine
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err = nil
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}
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closeErr := tryMe.Close()
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if err == nil && closeErr != nil {
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// Everything worked up until Close(), report the Close() error
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return closeErr
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}
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return err
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}
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// Parses an argument like "+123" anywhere on the command line into a one-based
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// line number, and returns the remaining args.
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//
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// Returns 0 on no target line number specified.
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func getTargetLineNumberOneBased(args []string) (int, []string) {
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for i, arg := range args {
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if !strings.HasPrefix(arg, "+") {
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continue
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}
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lineNumber, err := strconv.ParseInt(arg[1:], 10, 32)
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if err != nil {
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// Let's pretend this is a file name
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continue
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}
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if lineNumber < 1 {
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// Pretend this is a file name
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continue
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}
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// Remove the target line number from the args
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//
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// Ref: https://stackoverflow.com/a/57213476/473672
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remainingArgs := make([]string, 0)
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remainingArgs = append(remainingArgs, args[:i]...)
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remainingArgs = append(remainingArgs, args[i+1:]...)
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return int(lineNumber), remainingArgs
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}
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return 0, args
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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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var loglines strings.Builder
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log.SetOutput(&loglines)
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defer func() {
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err := recover()
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if len(loglines.String()) == 0 && err == nil {
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// No problems
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return
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}
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printProblemsHeader()
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if len(loglines.String()) > 0 {
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fmt.Fprintln(os.Stderr)
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// Consider not printing duplicate log messages more than once
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fmt.Fprintf(os.Stderr, "%s", loglines.String())
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}
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if err != nil {
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fmt.Fprintln(os.Stderr)
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panic(err)
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}
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os.Exit(1)
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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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defaultFormatter, err := parseColorsOption("auto")
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if err != nil {
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panic(fmt.Errorf("Failed parsing default formatter: %w", err))
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}
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formatter := flagSetFunc(flagSet,
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"colors", defaultFormatter, "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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quitIfOneScreen := flagSet.Bool("quit-if-one-screen", false, "Don't page if contents fits on one screen")
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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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shift := flagSetFunc(flagSet, "shift", 16, "Horizontal scroll amount >=1, defaults to 16", parseShiftAmount)
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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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targetLineNumberOneBased, remainingArgs := getTargetLineNumberOneBased(flags)
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err = flagSet.Parse(remainingArgs)
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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.StampMicro,
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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.Args()[0]
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inputFilename = &word
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// Need to check before twin.NewScreen() below, otherwise the screen
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// will be cleared before we print the "No such file" error.
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err := tryOpen(*inputFilename)
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if err != nil {
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fmt.Fprintln(os.Stderr, "ERROR:", err)
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os.Exit(1)
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}
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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 stdoutIsRedirected {
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err := pumpToStdout(inputFilename)
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if err != nil {
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fmt.Fprintln(os.Stderr, "ERROR:", err)
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os.Exit(1)
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}
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os.Exit(0)
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}
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// INVARIANT: At this point, stdout is a terminal and we should proceed with
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// paging.
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stdoutIsTerminal := !stdoutIsRedirected
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if !stdoutIsTerminal {
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panic("Invariant broken: stdout is not a terminal")
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}
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screen, err := twin.NewScreen()
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if err != nil {
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// Ref: https://github.com/walles/moar/issues/149
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log.Debug("Failed to set up screen for paging, pumping to stdout instead: ", err)
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err := pumpToStdout(inputFilename)
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if err != nil {
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fmt.Fprintln(os.Stderr, "ERROR:", err)
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os.Exit(1)
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}
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return
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}
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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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// Display the input file contents
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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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pager := m.NewPager(reader)
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pager.WrapLongLines = *wrap
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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.QuitIfOneScreen = *quitIfOneScreen
|
|
pager.StatusBarStyleOption = *statusBarStyle
|
|
pager.UnprintableStyle = *unprintableStyle
|
|
pager.ScrollLeftHint = *scrollLeftHint
|
|
pager.ScrollRightHint = *scrollRightHint
|
|
pager.SideScrollAmount = int(*shift)
|
|
pager.ChromaStyle = style
|
|
pager.ChromaFormatter = formatter
|
|
|
|
pager.TargetLineNumberOneBased = targetLineNumberOneBased
|
|
if *follow && pager.TargetLineNumberOneBased == 0 {
|
|
pager.TargetLineNumberOneBased = math.MaxInt
|
|
}
|
|
|
|
startPaging(pager, screen)
|
|
}
|
|
|
|
// Define a generic flag with specified name, default value, and usage string.
|
|
// The return value is the address of a variable that stores the parsed value of
|
|
// the flag.
|
|
func flagSetFunc[T any](flagSet *flag.FlagSet, name string, defaultValue T, usage string, parser func(valueString string) (T, error)) *T {
|
|
parsed := defaultValue
|
|
|
|
flagSet.Func(name, usage, func(valueString string) error {
|
|
parseResult, err := parser(valueString)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
parsed = parseResult
|
|
return nil
|
|
})
|
|
|
|
return &parsed
|
|
}
|
|
|
|
func startPaging(pager *m.Pager, screen twin.Screen) {
|
|
defer func() {
|
|
// Restore screen...
|
|
screen.Close()
|
|
|
|
// ... before printing any panic() output, otherwise the output will
|
|
// have broken linefeeds and be hard to follow.
|
|
if err := recover(); err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
if !pager.DeInit {
|
|
err := pager.ReprintAfterExit()
|
|
if err != nil {
|
|
log.Error("Failed reprinting pager view after exit", err)
|
|
}
|
|
}
|
|
}()
|
|
|
|
pager.StartPaging(screen)
|
|
}
|