gosora/updater/main.go

package main

import (
    "bufio"
    "fmt"
    "os"
    "runtime"
    "runtime/debug"
    "syscall"

    "gopkg.in/src-d/go-git.v4"
)

func main() {
    scanner := bufio.NewScanner(os.Stdin)

    // Capture panics instead of closing the window at a superhuman speed before the user can read the message on Windows
    defer func() {
        if r := recover(); r != nil {
            fmt.Println(r)
            debug.PrintStack()
            pressAnyKey(scanner)
            return
        }
    }()

    updater(scanner)
}

func pressAnyKey(scanner *bufio.Scanner) {
    fmt.Println("Please press enter to exit...")
    for scanner.Scan() {
        _ = scanner.Text()
        return
    }
}

// The bool return is a little trick to condense two lines onto one
func logError(err error) bool {
    if err == nil {
        return true
    }
    fmt.Println(err)
    debug.PrintStack()
    return false
}

func updater(scanner *bufio.Scanner) bool {
    fmt.Println("Welcome to Gosora's Upgrader")
    fmt.Println("We're going to check for new updates, please wait patiently")

    repo, err := git.PlainOpen(".")
    if err != nil {
        return logError(err)
    }

    workTree, err := repo.Worktree()
    if err != nil {
        return logError(err)
    }

    err = workTree.Pull(&git.PullOptions{Force: true})
    if err == git.NoErrAlreadyUpToDate {
        fmt.Println("You are already up-to-date")
        return true
    } else if err != nil && err != git.ErrUnstagedChanges { // fixes a bug in git where it refuses to update the files
        return logError(err)
    }

    err = workTree.Reset(&git.ResetOptions{Mode: git.HardReset})
    if err != nil {
        return logError(err)
    }

    fmt.Println("Updated to the latest commit")
    headRef, err := repo.Head()
    if err != nil {
        return logError(err)
    }

    // Get information about the commit
    commit, err := repo.CommitObject(headRef.Hash())
    if err != nil {
        return logError(err)
    }
    fmt.Println("Commit details:", commit)

    switch runtime.GOOS {
    case "windows":
        err = syscall.Exec("./patcher.bat", []string{}, os.Environ()) // doesn't work, need something for windows
    default: //linux, etc.
        err = syscall.Exec("./patcher-linux", []string{}, os.Environ())
    }
    return logError(err)
}