Implement suspending the app using ctrl-z

Co-authored-by: Stefan Haller <[email protected]>

Author: cowboy8625

go.mod

@@ -37,6 +37,7 @@ require (
 	github.com/xo/terminfo v0.0.0-20210125001918-ca9a967f8778
 	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56
 	golang.org/x/sync v0.16.0
+	golang.org/x/sys v0.34.0
 	gopkg.in/ozeidan/fuzzy-patricia.v3 v3.0.0
 	gopkg.in/yaml.v3 v3.0.1
 )
@@ -77,7 +78,6 @@ require (
 	github.com/xanzy/ssh-agent v0.3.3 // indirect
 	golang.org/x/crypto v0.37.0 // indirect
 	golang.org/x/net v0.39.0 // indirect
-	golang.org/x/sys v0.34.0 // indirect
 	golang.org/x/term v0.33.0 // indirect
 	golang.org/x/text v0.27.0 // indirect
 	gopkg.in/fsnotify.v1 v1.4.7 // indirect

pkg/config/user_config.go

@@ -390,6 +390,7 @@ type KeybindingConfig struct {
 type KeybindingUniversalConfig struct {
 	Quit                              string   `yaml:"quit"`
 	QuitAlt1                          string   `yaml:"quit-alt1"`
+	SuspendApp                        string   `yaml:"suspendApp"`
 	Return                            string   `yaml:"return"`
 	QuitWithoutChangingDirectory      string   `yaml:"quitWithoutChangingDirectory"`
 	TogglePanel                       string   `yaml:"togglePanel"`
@@ -854,6 +855,7 @@ func GetDefaultConfig() *UserConfig {
 			Universal: KeybindingUniversalConfig{
 				Quit:                              "q",
 				QuitAlt1:                          "<c-c>",
+				SuspendApp:                        "<c-z>",
 				Return:                            "<esc>",
 				QuitWithoutChangingDirectory:      "Q",
 				TogglePanel:                       "<tab>",

pkg/gui/controllers.go

@@ -109,6 +109,7 @@ func (gui *Gui) resetHelpersAndControllers() {
 		AmendHelper:     helpers.NewAmendHelper(helperCommon, gpgHelper),
 		FixupHelper:     helpers.NewFixupHelper(helperCommon),
 		Commits:         commitsHelper,
+		SuspendResume:   helpers.NewSuspendResumeHelper(helperCommon),
 		Snake:           helpers.NewSnakeHelper(helperCommon),
 		Diff:            diffHelper,
 		Repos:           reposHelper,

pkg/gui/controllers/global_controller.go

@@ -123,6 +123,20 @@ func (self *GlobalController) GetKeybindings(opts types.KeybindingsOpts) []*type
 			Modifier: gocui.ModNone,
 			Handler:  self.quitWithoutChangingDirectory,
 		},
+		{
+			Key:         opts.GetKey(opts.Config.Universal.SuspendApp),
+			Modifier:    gocui.ModNone,
+			Handler:     self.c.Helpers().SuspendResume.SuspendApp,
+			Description: self.c.Tr.SuspendApp,
+			GetDisabledReason: func() *types.DisabledReason {
+				if !self.c.Helpers().SuspendResume.CanSuspendApp() {
+					return &types.DisabledReason{
+						Text: self.c.Tr.CannotSuspendApp,
+					}
+				}
+				return nil
+			},
+		},
 		{
 			Key:         opts.GetKey(opts.Config.Universal.ToggleWhitespaceInDiffView),
 			Handler:     self.toggleWhitespace,

pkg/gui/controllers/helpers/helpers.go

@@ -35,6 +35,7 @@ type Helpers struct {
 	AmendHelper    *AmendHelper
 	FixupHelper    *FixupHelper
 	Commits        *CommitsHelper
+	SuspendResume  *SuspendResumeHelper
 	Snake          *SnakeHelper
 	// lives in context package because our contexts need it to render to main
 	Diff              *DiffHelper

pkg/gui/controllers/helpers/signal_handling.go

@@ -0,0 +1,59 @@
+//go:build !windows
+
+package helpers
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+)
+
+func canSuspendApp() bool {
+	return true
+}
+
+func sendStopSignal() error {
+	return syscall.Kill(0, syscall.SIGSTOP)
+}
+
+// setForegroundPgrp sets the current process group as the foreground process group
+// for the terminal, allowing the program to read input after resuming from suspension.
+func setForegroundPgrp() error {
+	fd, err := unix.Open("/dev/tty", unix.O_RDWR, 0)
+	if err != nil {
+		return err
+	}
+	defer unix.Close(fd)
+
+	pgid := syscall.Getpgrp()
+
+	return unix.IoctlSetPointerInt(fd, unix.TIOCSPGRP, pgid)
+}
+
+func handleResumeSignal(log *logrus.Entry, onResume func() error) {
+	if err := setForegroundPgrp(); err != nil {
+		log.Warning(err)
+		return
+	}
+
+	if err := onResume(); err != nil {
+		log.Warning(err)
+	}
+}
+
+func installResumeSignalHandler(log *logrus.Entry, onResume func() error) {
+	go func() {
+		sigs := make(chan os.Signal, 1)
+		signal.Notify(sigs, syscall.SIGCONT)
+
+		for sig := range sigs {
+			switch sig {
+			case syscall.SIGCONT:
+				handleResumeSignal(log, onResume)
+			}
+		}
+	}()
+}

pkg/gui/controllers/helpers/signal_handling_windows.go

@@ -0,0 +1,16 @@
+package helpers
+
+import (
+	"github.com/sirupsen/logrus"
+)
+
+func canSuspendApp() bool {
+	return false
+}
+
+func sendStopSignal() error {
+	return nil
+}
+
+func installResumeSignalHandler(log *logrus.Entry, onResume func() error) {
+}

pkg/gui/controllers/helpers/suspend_resume_helper.go

@@ -0,0 +1,31 @@
+package helpers
+
+type SuspendResumeHelper struct {
+	c *HelperCommon
+}
+
+func NewSuspendResumeHelper(c *HelperCommon) *SuspendResumeHelper {
+	return &SuspendResumeHelper{
+		c: c,
+	}
+}
+
+func (s *SuspendResumeHelper) CanSuspendApp() bool {
+	return canSuspendApp()
+}
+
+func (s *SuspendResumeHelper) SuspendApp() error {
+	if !canSuspendApp() {
+		return nil
+	}
+
+	if err := s.c.Suspend(); err != nil {
+		return err
+	}
+
+	return sendStopSignal()
+}
+
+func (s *SuspendResumeHelper) InstallResumeSignalHandler() {
+	installResumeSignalHandler(s.c.Log, s.c.Resume)
+}

pkg/gui/gui.go

@@ -848,6 +848,8 @@ func (gui *Gui) Run(startArgs appTypes.StartArgs) error {
 
 	gui.BackgroundRoutineMgr.startBackgroundRoutines()
 
+	gui.Helpers().SuspendResume.InstallResumeSignalHandler()
+
 	gui.c.Log.Info("starting main loop")
 
 	// setting here so we can use it in layout.go

pkg/gui/gui_common.go

@@ -42,6 +42,14 @@ func (self *guiCommon) RunSubprocess(cmdObj *oscommands.CmdObj) (bool, error) {
 	return self.gui.runSubprocessWithSuspense(cmdObj)
 }
 
+func (self *guiCommon) Suspend() error {
+	return self.gui.suspend()
+}
+
+func (self *guiCommon) Resume() error {
+	return self.gui.resume()
+}
+
 func (self *guiCommon) Context() types.IContextMgr {
 	return self.gui.State.ContextMgr
 }