ipc: add --no-ipc flag to completely disable IPC

Running aerc mailto:... and aerc mbox:... can be confusing; if there's
another aerc instance already open, the action will be performed in the
other instance, which may not be visible. Add a --no-ipc flag that runs
these actions, and aerc-internal commands (i.e., aerc :<command>), in
the new aerc instance instead.

Also, if --no-ipc is passed, don't listen on a socket for IPC calls from
other aerc instances.

Changelog-added: Add `--no-ipc` flag to run `aerc mailto:...`,
 `aerc mbox:...`, and `aerc :<command...>` within the current aerc
 instance and prevent listening for IPC calls from other aerc instances.
Signed-off-by: Jason Cox <me@jasoncarloscox.com>
Acked-by: Robin Jarry <robin@jarry.cc>

2 files changed, 30 insertions, 9 deletions

diff --git a/doc/aerc.1.scd b/doc/aerc.1.scd
index 3f52fbac..5511e79e 100644
--- a/doc/aerc.1.scd
+++ b/doc/aerc.1.scd
@@ -36,11 +36,20 @@ from your terminal.
 	Instead of using _$XDG_CONFIG_HOME/aerc/binds.conf_ use the file at the
 	specified path for configuring binds.
 
+*--no-ipc*
+	Run commands (*mailto:*_..._, *:*_<command...>_, *mbox:*_<file>_) directly
+	in this instance rather than over IPC in an existing aerc instance. Also
+	disable creation of an IPC server for subsequent aerc instances to
+	communicate with this one.
+
 *mailto:*_address[,address][?query[&query]]_
 	Open the composer with the address(es) in the To field. These
 	addresses must not be percent encoded.
-	If aerc is already running, the composer is started in this instance,
-	otherwise aerc will be started.
+
+	If aerc is already running (and *--no-ipc* is not passed), the composer is
+	started in that instance; otherwise a new instance is started with the
+	composer.
+
 	The following (optional) query parameters are supported:
 
 [[ *Query*
@@ -75,9 +84,15 @@ from your terminal.
 	directly on aerc's command line. This latter form can be helpful for
 	commands that don't interpret quotes in their arguments.
 
+	If aerc is already running (and *--no-ipc* is not passed), the command is
+	run in that instance; otherwise a new instance is started with the command.
+
 *mbox:*_<file>_
 	Open the specified mbox file as a virtual temporary account.
 
+	If aerc is already running (and *--no-ipc* is not passed), the file is
+	opened in that instance; otherwise a new instance is started with the file.
+
 # RUNTIME COMMANDS
 
 To execute a command, press *:* to bring up the command interface. Commands may
diff --git a/main.go b/main.go
index cc65dc44..9558382b 100644
--- a/main.go
+++ b/main.go
@@ -102,6 +102,7 @@ type Opts struct {
 	ConfAerc     string   `opt:"--aerc-conf"`
 	ConfAccounts string   `opt:"--accounts-conf"`
 	ConfBinds    string   `opt:"--binds-conf"`
+	NoIPC        bool     `opt:"--no-ipc"`
 	Command      []string `opt:"..." required:"false" metavar:"mailto:<address> | mbox:<file> | :<command...>"`
 }
 
@@ -121,6 +122,8 @@ Options:
   --aerc-conf        Path to configuration file to be used instead of the default.
   --accounts-conf    Path to configuration file to be used instead of the default.
   --binds-conf       Path to configuration file to be used instead of the default.
+  --no-ipc           Run any commands in this aerc instance, and don't create a
+                     socket for other aerc instances to communicate with this one.
   mailto:<address>   Open the composer with the address(es) in the To field.
                      If aerc is already running, the composer is started in
                      this instance, otherwise aerc will be started.
@@ -159,7 +162,7 @@ func main() {
 		die("%s", err)
 	}
 
-	if len(opts.Command) > 0 {
+	if len(opts.Command) > 0 && !opts.NoIPC {
 		response, err := ipc.ConnectAndExec(opts.Command)
 		if err == nil {
 			if response.Error != "" {
@@ -202,11 +205,13 @@ func main() {
 
 	startup, startupDone := context.WithCancel(context.Background())
 
-	as, err := ipc.StartServer(app.IPCHandler(), startup)
-	if err != nil {
-		log.Warnf("Failed to start Unix server: %v", err)
-	} else {
-		defer as.Close()
+	if !opts.NoIPC {
+		as, err := ipc.StartServer(app.IPCHandler(), startup)
+		if err != nil {
+			log.Warnf("Failed to start Unix server: %v", err)
+		} else {
+			defer as.Close()
+		}
 	}
 
 	// set the aerc version so that we can use it in the template funcs
@@ -218,7 +223,8 @@ func main() {
 			return
 		}
 		// Retry execution. Since IPC has already failed, we know no
-		// other aerc instance is running; run the command directly.
+		// other aerc instance is running (or IPC was explicitly
+		// disabled); run the command directly.
 		err := app.Command(opts.Command)
 		if err != nil {
 			// no other aerc instance is running, so let