Prevent nnn from waiting on open file process (#40)

* Prevent nnn from waiting on open file process

* Add env var flag to not wait for child process when opening file

* Set nowait flag once to skip bit-or every time we open a file

* Add documentation for NNN_NOWAIT

README.md

@@ -353,6 +353,12 @@ Any other value disables colored directories.
 
 The terminal screensaver is disabled by default. To set the wait time in seconds, use environment variable `NNN_IDLE_TIMEOUT`.
 
+#### open file in new process and make the nnn not block
+
+The desktop file opener should take care of opening files in new processes without causing `nnn` to block.
+If `nnn` does block/freeze when a file is open, then set the environment variable `NNN_NOWAIT` to any
+non-zero value.
+
 ### Why fork?
 
 I chose to fork because:

nnn.1

@@ -207,6 +207,12 @@ screensaver.
         echo -n $1 | xsel --clipboard --input
         -------------------------------------
 .Ed
+.Pp
+\fBNNN_NOWAIT:\fR make nnn not block while a file is open. Only necessary if
+nnn is blocking while a file is open.
+.Bd -literal
+	export NNN_NOWAIT=1
+.Ed
 .Sh KNOWN ISSUES
 If you are using urxvt you might have to set backspacekey to DEC.
 .Sh AUTHORS

nnn.c

@@ -222,6 +222,7 @@ static char *player;
 static char *copier;
 static char *editor;
 static char *desktop_manager;
+static char nowait;
 static blkcnt_t ent_blocks;
 static blkcnt_t dir_blocks;
 static ulong num_files;
@@ -2211,7 +2212,7 @@ nochange:
 				}
 
 				/* Invoke desktop opener as last resort */
-				spawn(utils[2], newpath, NULL, NULL, F_NOTRACE);
+				spawn(utils[2], newpath, NULL, NULL, nowait);
 				continue;
 			}
 			default:
@@ -2863,6 +2864,9 @@ main(int argc, char *argv[])
 	/* Get the default copier, if set */
 	copier = getenv("NNN_COPIER");
 
+	/* Get nowait flag */
+	nowait = F_NOTRACE | (getenv("NNN_NOWAIT") ? F_NOWAIT : 0);
+
 	signal(SIGINT, SIG_IGN);
 
 	/* Test initial path */