feat: job enhancements (#153)

* feat: add hilbish.job.add function

this is mainly to accomodate for the employer
handler (#152)

* feat!: add start function to jobs

the commit itself adds a few things but the
main purpose is to facilitate a lua side start
function that can restart the job

there is a breaking change in the hilbish.job.add
function; it is now required to provide an extra
table for arguments, since the first cmd
table isnt really what's actually ran

* fix: reuse standard files for jobs

* fix: deadlock in lua job add function and not taking proper amount of args

* fix: assign binary path to job

* feat: emit job.add hook when job is added

* chore: update modules

* fix: use setpgid on cmd procattr for background jobs

* fix: use right procattr on correct os

* fix: set bg proc attr in build tagged file

* feat: add disown function

* fix: stop jobs on exit

* feat: add disown command

* feat: add jobs.last function to get last job

* feat: make disown command get last job if id isnt suppied as arg

* chore: remove unused code

* feat: add job output

* chore: fix comments

* fix!: make exec path in job add explicit in lua side

* docs: add docs and changelogs relating to jobs

CHANGELOG.md

@@ -23,6 +23,17 @@ is for everything/anything as opposed to just adding a single command completion
 [#122](https://github.com/Rosettea/Hilbish/issues/122)
 - `fs.abs(path)` to get absolute path.
 - Nature module (`doc nature`)
+- `hilbish.jobs.add(cmdstr, args, execPath)` to add a job to the job table.
+`cmdstr` would be user input, `args` is the args for the command (includes arg0)
+and `execPath` is absolute path to command executable
+- `job.add` hook is thrown when a job is added. acts as a unique hook for
+jobs
+- `hilbish.jobs.disown(id)` and `disown` builtin to disown a job. `disown`
+without arguments will disown the last job.
+- `hilbish.jobs.last()` returns the last added job.
+- Job output (stdout/stderr) can now be obtained via the `stdout` and `stderr`
+fields on a job object.
+- Documentation for jobs is now available via `doc jobs`.
 
 ### Changed
 - **Breaking Change:** Upgraded to Lua 5.4.
@@ -57,6 +68,8 @@ certain color rules.
 - Cursor position with CJK characters. ([#145](https://github.com/Rosettea/Hilbish/pull/145))
 - Files with same name as parent folder in completions getting cut off [#136](https://github.com/Rosettea/Hilbish/issues/136))
 - `hilbish.which` now works with commanders and aliases.
+- Background jobs no longer take stdin so they do not interfere with shell
+input.
 
 ## [1.2.0] - 2022-03-17
 ### Added

docs/hooks/job.txt

@@ -1,11 +1,5 @@
-Note: A `job` is a table with the following keys:
+Note: `job` refers to a job object. YOu can check `doc jobs` for more
-- cmd: command string
+detail.
-- running: boolean whether the job is running
-- id: unique id for the job
-- pid: process id for the job
-- exitCode: exit code of the job
-In ordinary cases you'd prefer to use the id instead of pid. The id is unique to
-Hilbish and is how you get jobs with the `hilbish.jobs` interface.
 
 + `job.start` -> job > Thrown when a new background job starts.
 

docs/jobs.txt

@@ -0,0 +1,40 @@
+Hilbish has pretty standard job control. It's missing one or two things,
+but works well. One thing which is different from other shells
+(besides Hilbish) itself is the API for jobs, and of course it's in Lua.
+You can add jobs, stop and delete (disown) them and even get output.
+
+# Job Interface
+The job interface refers to `hilbish.jobs`.
+## Functions
+(Note that in the list here, they're called from `hilbish.jobs`, so
+a listing of `foo` would mean `hilbish.jobs.foo`)
+
+- `all()` -> {jobs}: Returns a table of all jobs.
+- `last()` -> job: Returns the last added job.
+- `get(id)` -> job: Get a job by its ID.
+- `add(cmdstr, args, execPath)` -> job: Adds a new job to the job table.
+Note that this does not run the command; You have to start it manually.
+`cmdstr` is the user's input for the job, `args` is a table of arguments
+for the command. It includes arg0 (don't set it as entry 0 in the table)
+and `execPath` is an absolute path for the command executable.
+- `disown(id)`: Removes a job by ID from the job table.
+
+# Job Object
+A job object on the Lua side is a table with some functions.
+On the under side it represents a job in the job table.
+You can still have a job object for a disowned job,
+it just won't be *working* anywhere. :^)
+
+## Properties
+- `cmd`: command string
+- `running`: boolean whether the job is running
+- `id`: unique id for the job
+- `pid`: process id for the job
+- `exitCode`: exit code of the job
+In ordinary cases you'd prefer to use the `id` instead of `pid`.
+The `id` is unique to Hilbish and is how you get jobs with the
+`hilbish.jobs` interface. It may also not describe the job entirely.
+
+## Functions
+- `stop()`: Stops the job.
+- `start()`: Starts the job.

exec.go

@@ -239,7 +239,7 @@ func execCommand(cmd string, terminalOut bool) (io.Writer, io.Writer, error) {
 
 			stmtStr := buf.String()
 			buf.Reset()
-			jobs.add(stmtStr)
+			jobs.add(stmtStr, []string{}, "")
 		}
 
 		interp.ExecHandler(execHandle(bg))(runner)
@@ -357,13 +357,15 @@ func execHandle(bg bool) interp.ExecHandlerFunc {
 			Stderr: hc.Stderr,
 		}
 
-		err = cmd.Start()
 		var j *job
 		if bg {
 			j = jobs.getLatest()
-			j.setHandle(cmd.Process)
+			j.setHandle(&cmd)
-			j.start(cmd.Process.Pid)
+			err = j.start()
+		} else {
+			err = cmd.Start()
 		}
+
 		if err == nil {
 			if done := ctx.Done(); done != nil {
 				go func() {
@@ -388,35 +390,8 @@ func execHandle(bg bool) interp.ExecHandlerFunc {
 			err = cmd.Wait()
 		}
 
-		var exit uint8
+		exit := handleExecErr(err)
-		switch x := err.(type) {
+
-		case *exec.ExitError:
-			// started, but errored - default to 1 if OS
-			// doesn't have exit statuses
-			if status, ok := x.Sys().(syscall.WaitStatus); ok {
-				if status.Signaled() {
-					if ctx.Err() != nil {
-						return ctx.Err()
-					}
-					exit = uint8(128 + status.Signal())
-					goto end
-				}
-				exit = uint8(status.ExitStatus())
-				goto end
-			}
-			exit = 1
-			goto end
-		case *exec.Error:
-			// did not start
-			fmt.Fprintf(hc.Stderr, "%v\n", err)
-			exit = 127
-			goto end
-		case nil:
-			goto end
-		default:
-			return err
-		}
-		end:
 		if bg {
 			j.exitCode = int(exit)
 			j.finish()
@@ -425,6 +400,35 @@ func execHandle(bg bool) interp.ExecHandlerFunc {
 	}
 }
 
+func handleExecErr(err error) (exit uint8) {
+	ctx := context.TODO()
+
+	switch x := err.(type) {
+	case *exec.ExitError:
+		// started, but errored - default to 1 if OS
+		// doesn't have exit statuses
+		if status, ok := x.Sys().(syscall.WaitStatus); ok {
+			if status.Signaled() {
+				if ctx.Err() != nil {
+					return
+				}
+				exit = uint8(128 + status.Signal())
+				return
+			}
+			exit = uint8(status.ExitStatus())
+			return
+		}
+		exit = 1
+		return
+	case *exec.Error:
+		// did not start
+		//fmt.Fprintf(hc.Stderr, "%v\n", err)
+		exit = 127
+	default: return
+	}
+
+	return
+}
 func lookpath(file string) error { // custom lookpath function so we know if a command is found *and* is executable
 	var skip []string
 	if runtime.GOOS == "windows" {

execfile_unix.go

@@ -4,8 +4,13 @@ package main
 
 import (
 	"os"
+	"syscall"
 )
 
+var bgProcAttr *syscall.SysProcAttr = &syscall.SysProcAttr{
+	Setpgid: true,
+}
+
 func findExecutable(path string, inPath, dirs bool) error {
 	f, err := os.Stat(path)
 	if err != nil {

execfile_windows.go

@@ -5,8 +5,13 @@ package main
 import (
 	"path/filepath"
 	"os"
+	"syscall"
 )
 
+var bgProcAttr *syscall.SysProcAttr = &syscall.SysProcAttr{
+	CreationFlags: syscall.CREATE_NEW_PROCESS_GROUP,
+}
+
 func findExecutable(path string, inPath, dirs bool) error {
 	nameExt := filepath.Ext(path)
 	pathExts := filepath.SplitList(os.Getenv("PATHEXT"))

go.mod

@@ -29,4 +29,4 @@ replace github.com/maxlandon/readline => ./readline
 
 replace layeh.com/gopher-luar => github.com/layeh/gopher-luar v1.0.10
 
-replace github.com/arnodel/golua => github.com/Rosettea/golua v0.0.0-20220419183026-6d22d6fec5ac
+replace github.com/arnodel/golua => github.com/Rosettea/golua v0.0.0-20220518005949-116371948fe3

go.sum

@@ -1,5 +1,7 @@
 github.com/Rosettea/golua v0.0.0-20220419183026-6d22d6fec5ac h1:dtXrgjch8PQyf7C90anZUquB5U3dr8AcMGJofeuirrI=
 github.com/Rosettea/golua v0.0.0-20220419183026-6d22d6fec5ac/go.mod h1:9jzpYPiU2is0HVGCiuIOBSXdergHUW44IEjmuN1UrIE=
+github.com/Rosettea/golua v0.0.0-20220518005949-116371948fe3 h1:I/wWr40FFLFF9pbT3wLb1FAEZhKb/hUWE+nJ5uHBK2g=
+github.com/Rosettea/golua v0.0.0-20220518005949-116371948fe3/go.mod h1:9jzpYPiU2is0HVGCiuIOBSXdergHUW44IEjmuN1UrIE=
 github.com/Rosettea/sh/v3 v3.4.0-0.dev.0.20220306140409-795a84b00b4e h1:P2XupP8SaylWaudD1DqbWtZ3mIa8OsE9635LmR+Q+lg=
 github.com/Rosettea/sh/v3 v3.4.0-0.dev.0.20220306140409-795a84b00b4e/go.mod h1:R09vh/04ILvP2Gj8/Z9Jd0Dh0ZIvaucowMEs6abQpWs=
 github.com/acarl005/stripansi v0.0.0-20180116102854-5a71ef0e047d h1:licZJFw2RwpHMqeKTCYkitsPqHNxTmd4SNR5r94FGM8=

job.go

@@ -1,8 +1,13 @@
 package main
 
 import (
-	"sync"
+	"bytes"
+	"errors"
+	"io"
 	"os"
+	"os/exec"
+	"sync"
+	"syscall"
 
 	"hilbish/util"
 
@@ -17,18 +22,59 @@ type job struct {
 	id int
 	pid int
 	exitCode int
-	proc *os.Process
+	once bool
+	args []string
+	// save path for a few reasons, one being security (lmao) while the other
+	// would just be so itll be the same binary command always (path changes)
+	path string
+	handle *exec.Cmd
+	cmdout io.Writer
+	cmderr io.Writer
+	stdout *bytes.Buffer
+	stderr *bytes.Buffer
 }
 
-func (j *job) start(pid int) {
+func (j *job) start() error {
-	j.pid = pid
+	if j.handle == nil || j.once {
+		// cmd cant be reused so make a new one
+		cmd := exec.Cmd{
+			Path: j.path,
+			Args: j.args,
+		}
+		j.setHandle(&cmd)
+	}
+	// bgProcAttr is defined in execfile_<os>.go, it holds a procattr struct
+	// in a simple explanation, it makes signals from hilbish (sigint)
+	// not go to it (child process)
+	j.handle.SysProcAttr = bgProcAttr
+	// reset output buffers
+	j.stdout.Reset()
+	j.stderr.Reset()
+	// make cmd write to both standard output and output buffers for lua access
+	j.handle.Stdout = io.MultiWriter(j.cmdout, j.stdout)
+	j.handle.Stderr = io.MultiWriter(j.cmderr, j.stderr)
+
+	if !j.once {
+		j.once = true
+	}
+
+	err := j.handle.Start()
+	proc := j.getProc()
+
+	j.pid = proc.Pid
 	j.running = true
+
 	hooks.Em.Emit("job.start", j.lua())
+
+	return err
 }
 
 func (j *job) stop() {
 	// finish will be called in exec handle
-	j.proc.Kill()
+	proc := j.getProc()
+	if proc != nil {
+		proc.Kill()
+	}
 }
 
 func (j *job) finish() {
@@ -36,13 +82,35 @@ func (j *job) finish() {
 	hooks.Em.Emit("job.done", j.lua())
 }
 
-func (j *job) setHandle(handle *os.Process) {
+func (j *job) wait() {
-	j.proc = handle
+	j.handle.Wait()
+}
+
+func (j *job) setHandle(handle *exec.Cmd) {
+	j.handle = handle
+	j.args = handle.Args
+	j.path = handle.Path
+	if handle.Stdout != nil {
+		j.cmdout = handle.Stdout
+	}
+	if handle.Stderr != nil {
+		j.cmderr = handle.Stderr
+	}
+}
+
+func (j *job) getProc() *os.Process {
+	handle := j.handle
+	if handle != nil {
+		return handle.Process
+	}
+
+	return nil
 }
 
 func (j *job) lua() rt.Value {
 	jobFuncs := map[string]util.LuaExport{
 		"stop": {j.luaStop, 0, false},
+		"start": {j.luaStart, 0, false},
 	}
 	luaJob := rt.NewTable()
 	util.SetExports(l, luaJob, jobFuncs)
@@ -52,10 +120,23 @@ func (j *job) lua() rt.Value {
 	luaJob.Set(rt.StringValue("id"), rt.IntValue(int64(j.id)))
 	luaJob.Set(rt.StringValue("pid"), rt.IntValue(int64(j.pid)))
 	luaJob.Set(rt.StringValue("exitCode"), rt.IntValue(int64(j.exitCode)))
+	luaJob.Set(rt.StringValue("stdout"), rt.StringValue(string(j.stdout.Bytes())))
+	luaJob.Set(rt.StringValue("stderr"), rt.StringValue(string(j.stderr.Bytes())))
 
 	return rt.TableValue(luaJob)
 }
 
+func (j *job) luaStart(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
+	if !j.running {
+		err := j.start()
+		exit := handleExecErr(err)
+		j.exitCode = int(exit)
+		j.finish()
+	}
+
+	return c.Next(), nil
+}
+
 func (j *job) luaStop(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 	if j.running {
 		j.stop()
@@ -79,7 +160,7 @@ func newJobHandler() *jobHandler {
 	}
 }
 
-func (j *jobHandler) add(cmd string) *job {
+func (j *jobHandler) add(cmd string, args []string, path string) *job {
 	j.mu.Lock()
 	defer j.mu.Unlock()
 
@@ -88,8 +169,15 @@ func (j *jobHandler) add(cmd string) *job {
 		cmd: cmd,
 		running: false,
 		id: j.latestID,
+		args: args,
+		path: path,
+		cmdout: os.Stdout,
+		cmderr: os.Stderr,
+		stdout: &bytes.Buffer{},
+		stderr: &bytes.Buffer{},
 	}
 	j.jobs[j.latestID] = jb
+	hooks.Em.Emit("job.add", jb.lua())
 
 	return jb
 }
@@ -101,11 +189,41 @@ func (j *jobHandler) getLatest() *job {
 	return j.jobs[j.latestID]
 }
 
+func (j *jobHandler) disown(id int) error {
+	j.mu.RLock()
+	if j.jobs[id] == nil {
+		return errors.New("job doesnt exist")
+	}
+	j.mu.RUnlock()
+
+	j.mu.Lock()
+	delete(j.jobs, id)
+	j.mu.Unlock()
+
+	return nil
+}
+
+func (j *jobHandler) stopAll() {
+	j.mu.RLock()
+	defer j.mu.RUnlock()
+
+	for _, jb := range j.jobs {
+		// on exit, unix shell should send sighup to all jobs
+		if jb.running {
+			proc := jb.getProc()
+			proc.Signal(syscall.SIGHUP)
+			jb.wait() // waits for program to exit due to sighup
+		}
+	}
+}
+
 func (j *jobHandler) loader(rtm *rt.Runtime) *rt.Table {
 	jobFuncs := map[string]util.LuaExport{
 		"all": {j.luaAllJobs, 0, false},
+		"last": {j.luaLastJob, 0, false},
 		"get": {j.luaGetJob, 1, false},
-		"add": {j.luaAddJob, 1, false},
+		"add": {j.luaAddJob, 3, false},
+		"disown": {j.luaDisownJob, 1, false},
 	}
 
 	luaJob := rt.NewTable()
@@ -135,18 +253,30 @@ func (j *jobHandler) luaGetJob(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 }
 
 func (j *jobHandler) luaAddJob(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
-	j.mu.RLock()
+	if err := c.CheckNArgs(3); err != nil {
-	defer j.mu.RUnlock()
-
-	if err := c.Check1Arg(); err != nil {
 		return nil, err
 	}
 	cmd, err := c.StringArg(0)
 	if err != nil {
 		return nil, err
 	}
+	largs, err := c.TableArg(1)
+	if err != nil {
+		return nil, err
+	}
+	execPath, err := c.StringArg(2)
+	if err != nil {
+		return nil, err
+	}
 
-	jb := j.add(cmd)
+	var args []string
+	util.ForEach(largs, func(k rt.Value, v rt.Value) {
+		if v.Type() == rt.StringType {
+			args = append(args, v.AsString())
+		}
+	})
+
+	jb := j.add(cmd, args, execPath)
 
 	return c.PushingNext1(t.Runtime, jb.lua()), nil
 }
@@ -162,3 +292,32 @@ func (j *jobHandler) luaAllJobs(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 
 	return c.PushingNext1(t.Runtime, rt.TableValue(jobTbl)), nil
 }
+
+func (j *jobHandler) luaDisownJob(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
+	if err := c.Check1Arg(); err != nil {
+		return nil, err
+	}
+	jobID, err := c.IntArg(0)
+	if err != nil {
+		return nil, err
+	}
+
+	err = j.disown(int(jobID))
+	if err != nil {
+		return nil, err
+	}
+
+	return c.Next(), nil
+}
+
+func (j *jobHandler) luaLastJob(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
+	j.mu.RLock()
+	defer j.mu.RUnlock()
+
+	job := j.jobs[j.latestID]
+	if job == nil { // incase we dont have any jobs yet
+		return c.Next(), nil
+	}
+
+	return c.PushingNext1(t.Runtime, job.lua()), nil
+}

main.go

@@ -221,6 +221,8 @@ input:
 		}
 		fmt.Printf("\u001b[7m∆\u001b[0m" + strings.Repeat(" ", termwidth - 1) + "\r")
 	}
+
+	exit(0)
 }
 
 func continuePrompt(prev string) (string, error) {
@@ -294,7 +296,11 @@ func contains(s []string, e string) bool {
 }
 
 func exit(code int) {
-	// wait for all timers to finish before exiting
+	jobs.stopAll()
+
+	// wait for all timers to finish before exiting.
+	// only do that when not interactive
+	if !interactive {
 		for {
 			if timers.running == 0 {
 				os.Exit(code)
@@ -302,6 +308,9 @@ func exit(code int) {
 		}
 	}
 
+	os.Exit(code)
+}
+
 func getVersion() string {
 	v := strings.Builder{}
 

nature/commands/disown.lua

@@ -0,0 +1,25 @@
+local commander = require 'commander'
+
+commander.register('disown', function(args)
+	if #hilbish.jobs.all() == 0 then
+		print 'disown: no current job'
+		return 1
+	end
+
+	local id
+	if #args < 0 then
+		id = tonumber(args[1])
+		if not id then
+			print 'disown: invalid id for job'
+			return 1
+		end
+	else
+		id = hilbish.jobs.last().id
+	end
+
+	local ok = pcall(hilbish.jobs.disown, id)
+	if not ok then
+		print 'disown: job does not exist'
+		return 2
+	end
+end)

nature/commands/init.lua

@@ -4,3 +4,4 @@ require 'nature.commands.cdr'
 require 'nature.commands.doc'
 require 'nature.commands.exit'
 require 'nature.commands.guide'
+require 'nature.commands.disown'