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// Package shell is the entry point for the terminal interface of Elvish.
package shell
import (
"fmt"
"io"
"os"
"os/signal"
"path/filepath"
"strconv"
"time"
"src.elv.sh/pkg/cli/term"
"src.elv.sh/pkg/daemon/daemondefs"
"src.elv.sh/pkg/env"
"src.elv.sh/pkg/eval"
"src.elv.sh/pkg/logutil"
"src.elv.sh/pkg/mods"
"src.elv.sh/pkg/parse"
"src.elv.sh/pkg/prog"
"src.elv.sh/pkg/sys"
"src.elv.sh/pkg/ui"
)
var logger = logutil.GetLogger("[shell] ")
// Program is the shell subprogram. It has two slightly different modes of
// operation:
//
// - When the command line argument contains a filename or "-c some-code", the
// shell is non-interactive. In this mode, it just evaluates the given file or
// code.
//
// - Otherwise, the shell is interactive, and launches a terminal [REPL]. This
// mode also initializes the storage backend, which in turn activates the
// storage daemon.
//
// To enable building a daemon-less version, the subprogram doesn't depend
// on pkg/daemon, and the caller should supply pkg/daemon.Activate in the
// ActivateDaemon field to enable functionalities. If it is nil, daemon
// functionalities are disabled.
//
// [REPL]: https://en.wikipedia.org/wiki/Read–eval–print_loop
type Program struct {
ActivateDaemon daemondefs.ActivateFunc
codeInArg bool
compileOnly bool
noRC bool
rc string
json *bool
daemonPaths *prog.DaemonPaths
}
func (p *Program) RegisterFlags(fs *prog.FlagSet) {
// script(1) (and possibly other programs) assume shells support -i
fs.Bool("i", false,
"A no-op flag, introduced for compatibility")
// termux (and possibly other programs) assume shells support -l
fs.Bool("l", false,
"A no-op flag, introduced for compatibility")
fs.BoolVar(&p.codeInArg, "c", false,
"Treat the first argument as code to execute")
fs.BoolVar(&p.compileOnly, "compileonly", false,
"Parse and compile Elvish code without executing it")
fs.BoolVar(&p.noRC, "norc", false,
"Don't read the RC file when running interactively")
fs.StringVar(&p.rc, "rc", "",
"Path to the RC file when running interactively")
p.json = fs.JSON()
if p.ActivateDaemon != nil {
p.daemonPaths = fs.DaemonPaths()
}
}
func (p *Program) Run(fds [3]*os.File, args []string) error {
cleanup1 := incSHLVL()
defer cleanup1()
cleanup2 := initSignal(fds)
defer cleanup2()
// https://no-color.org
ui.NoColor = os.Getenv(env.NO_COLOR) != ""
interactive := len(args) == 0
ev := p.makeEvaler(fds[2], interactive)
defer ev.PreExit()
if !interactive {
exit := script(
ev, fds, args, &scriptCfg{
Cmd: p.codeInArg, CompileOnly: p.compileOnly, JSON: *p.json})
return prog.Exit(exit)
}
var spawnCfg *daemondefs.SpawnConfig
if p.ActivateDaemon != nil {
var err error
spawnCfg, err = daemonPaths(p.daemonPaths)
if err != nil {
fmt.Fprintln(fds[2], "Warning:", err)
fmt.Fprintln(fds[2], "Storage daemon may not function.")
}
}
interact(ev, fds, &interactCfg{
RC: ev.EffectiveRcPath,
ActivateDaemon: p.ActivateDaemon, SpawnConfig: spawnCfg})
return nil
}
// Creates an Evaler, sets the module search directories and installs all the
// standard builtin modules.
//
// It writes a warning message to the supplied Writer if it could not initialize
// module search directories.
func (p *Program) makeEvaler(stderr io.Writer, interactive bool) *eval.Evaler {
ev := eval.NewEvaler()
var errRc error
ev.RcPath, errRc = rcPath()
switch {
case !interactive || p.noRC:
// Leave ev.ActualRcPath empty
case p.rc != "":
// Use explicit -rc flag value
var err error
ev.EffectiveRcPath, err = filepath.Abs(p.rc)
if err != nil {
fmt.Fprintln(stderr, "Warning:", err)
}
default:
if errRc == nil {
// Use default path stored in ev.RcPath
ev.EffectiveRcPath = ev.RcPath
} else {
fmt.Fprintln(stderr, "Warning:", errRc)
}
}
libs, err := libPaths()
if err != nil {
fmt.Fprintln(stderr, "Warning: resolving lib paths:", err)
} else {
ev.LibDirs = libs
}
mods.AddTo(ev)
return ev
}
// Increments the SHLVL environment variable. It returns a function to restore
// the original value of SHLVL.
func incSHLVL() func() {
oldValue, hadValue := os.LookupEnv(env.SHLVL)
i, err := strconv.Atoi(oldValue)
if err != nil {
i = 0
}
os.Setenv(env.SHLVL, strconv.Itoa(i+1))
if hadValue {
return func() { os.Setenv(env.SHLVL, oldValue) }
} else {
return func() { os.Unsetenv(env.SHLVL) }
}
}
func initSignal(fds [3]*os.File) func() {
sigCh := sys.NotifySignals()
go func() {
for sig := range sigCh {
logger.Println("signal", sig)
handleSignal(sig, fds[2])
}
}()
return func() {
signal.Stop(sigCh)
close(sigCh)
}
}
func evalInTTY(fds [3]*os.File, ev *eval.Evaler, ed editor, src parse.Source) error {
start := time.Now()
ports, cleanup := eval.PortsFromFiles(fds, ev.ValuePrefix())
defer cleanup()
restore := term.SetupForEval(fds[0], fds[1])
defer restore()
ctx, done := eval.ListenInterrupts()
err := ev.Eval(src, eval.EvalCfg{
Ports: ports, Interrupts: ctx, PutInFg: true})
done()
if ed != nil {
ed.RunAfterCommandHooks(src, time.Since(start).Seconds(), err)
}
return err
}
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