commands: implement a no-quit mode

Add a mode that prevents aerc from quitting normally when an important
task is performed, i.e. when sending a message. The no-quit mode will be
ignored when quit is used with the -f option to force an exit.

Suggested-by: ph14nix[m]
Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

commands/mode/noquit.go

@@ -0,0 +1,26 @@
+package mode
+
+import "sync/atomic"
+
+// noquit is a counter for goroutines that requested the no-quit mode
+var noquit int32
+
+// NoQuit enters no-quit mode where aerc cannot be exited (unless the force
+// option is used)
+func NoQuit() {
+	atomic.AddInt32(&noquit, 1)
+}
+
+// NoQuitDone leaves the no-quit mode
+func NoQuitDone() {
+	atomic.AddInt32(&noquit, -1)
+}
+
+// QuitAllowed checks if aerc can exit normally (only when all goroutines that
+// requested a no-quit mode were done and called the NoQuitDone() function)
+func QuitAllowed() bool {
+	if atomic.LoadInt32(&noquit) > 0 {
+		return false
+	}
+	return true
+}

commands/quit.go

@@ -2,8 +2,11 @@ package commands
 
 import (
 	"errors"
+	"fmt"
 
+	"git.sr.ht/~rjarry/aerc/commands/mode"
 	"git.sr.ht/~rjarry/aerc/widgets"
+	"git.sr.ht/~sircmpwn/getopt"
 )
 
 type Quit struct{}
@@ -27,8 +30,22 @@ func (err ErrorExit) Error() string {
 }
 
 func (Quit) Execute(aerc *widgets.Aerc, args []string) error {
-	if len(args) != 1 {
-		return errors.New("Usage: quit")
+	force := false
+	opts, optind, err := getopt.Getopts(args, "f")
+	if err != nil {
+		return err
 	}
-	return ErrorExit(1)
+	for _, opt := range opts {
+		switch opt.Option {
+		case 'f':
+			force = true
+		}
+	}
+	if len(args) != optind {
+		return errors.New("Usage: quit [-f]")
+	}
+	if force || mode.QuitAllowed() {
+		return ErrorExit(1)
+	}
+	return fmt.Errorf("A task is not done yet. Use -f to force an exit.")
 }

doc/aerc.1.scd

@@ -113,8 +113,10 @@ These commands work in any context.
 *choose* -o <key> <text> <command> [-o <key> <text> <command>]...
 	Prompts the user to choose from various options.
 
-*quit*
-	Exits aerc.
+*quit* [-f]
+	Exits aerc. If a task is being performed that should not be interrupted
+	(like sending a message), a normal quit call might fail. In this case,
+	closing aerc can be forced with the -f option.
 
 ## MESSAGE COMMANDS