From 9a6954f9720784bc79668bcc6456f6a3f6a0c5a1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Haoran=20S=2E=20Diao=20=28=E5=88=81=E6=B5=A9=E7=84=B6=29?=
 <0@hairydiode.xyz>
Date: Fri, 12 Sep 2025 22:33:39 -0700
Subject: Made it so pressing escape twice sends an escape to the IM, fixed the
 status line persisting even on exit. Refactored main process exit

---
 escape.h |  9 ++++++++-
 im.h     |  7 ++++---
 ptyim.c  | 40 +++++++++++++++++++++++++---------------
 3 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/escape.h b/escape.h
index 8b5f0dd..d7c54a4 100644
--- a/escape.h
+++ b/escape.h
@@ -31,6 +31,8 @@ enum esc_state {
 	DECSC,
 	DECRC,
 	NORMAL,
+	//escape followed by an escape, has to be user generated
+	DOUBLE_ESC,
 };
 //global stdin -> pty ESC state
 enum esc_state in_state = NORMAL;
@@ -54,6 +56,7 @@ enum esc_state update_esc_state(char * buff,unsigned int buff_len, enum esc_stat
 			case C1:
 			case DECSC:
 			case DECRC:
+			case DOUBLE_ESC:
 			//all the sequences that have ended don't have an end
 			//and default to normal
 			case NORMAL:
@@ -91,8 +94,12 @@ enum esc_state update_esc_state(char * buff,unsigned int buff_len, enum esc_stat
 				}
 				else if (c == '8') {
 					state = DECSC;
+				}
+				else if (c == 0x1B) {
+					state = DOUBLE_ESC;
 				//deformed escape sequence
-				} else {
+				} 
+				else {
 					state = NORMAL;
 				}
 			break;
diff --git a/im.h b/im.h
index d92191c..47ae538 100644
--- a/im.h
+++ b/im.h
@@ -16,10 +16,10 @@
 //the one you desire
 #define BACKSPACE_KEY 0x7F
 #define BACKSPACE_KEY_2 0x08
-//setting it to the actual escape character interferes with arrow keys and
-//whatnot
-//#define ESCAPE_KEY 0x1B
+//the literal escape char is only fed into the im if it is pressed twice, see
+//escape.h
 #define ESCAPE_KEY '`'
+#define ESCAPE_KEY_2 0x1B
 //Vertical Tab Ctrl+K
 #define TOGGLE_KEY 0x0B
 #define IM_KEY_RANGE_LEN 3
@@ -146,6 +146,7 @@ int update_im_state(char input, char * output) {
 		if (im_buffer_pos > 0) {
 			switch (input) {
 				//escape, cancels
+				case ESCAPE_KEY_2:
 				case ESCAPE_KEY:
 					clear_im_buffer();
 					return 0;
diff --git a/ptyim.c b/ptyim.c
index 34fdbec..eedffd3 100644
--- a/ptyim.c
+++ b/ptyim.c
@@ -16,12 +16,6 @@
 #define WRITE_BUFFER_LEN 128
 //determines if the master process is running
 int running = 1;
-//hook for when the pty child process dies
-void childhook(int a) {
-	running = 0;
-	//this way it exists even if the loop is waiting for 1 last read char
-	_exit(0);
-}
 //pty master and slave fd
 int pty_slave = -1;
 int pty_master = -1;
@@ -45,6 +39,9 @@ void winchhook(int a) {
 	ioctl(pty_slave, TIOCSWINSZ, &sz);
 
 }
+//child process pids
+pid_t shell_pid;
+pid_t om_pid;
 //return 0 on success, -1 on error
 //sets the global vars pty_master and pty_slave
 int make_pty() {
@@ -88,6 +85,24 @@ void condition_stdin() {
 void restore_stdin() {
 	tcsetattr(STDIN_FILENO,TCSANOW,&stdin_termio_bk);
 }
+//main thread exit
+void exit_main() {
+	//kill shell , can not be blocked
+	kill(shell_pid, SIGKILL);
+	//exit, only the master process should reach this point
+	close(pty_master);
+	close(pty_slave);
+	restore_stdin();
+	//clears the screen so the im statusline goes away
+	write(STDIN_FILENO,"\033[2J", 4);
+	_exit(0);
+}
+//hook for when the pty child process dies
+void childhook(int a) {
+	running = 0;
+	//this way it exists even if the loop is waiting for 1 last read char
+	exit_main();
+}
 int main (int argc, char * argv[], char * envp[]) {
 	condition_stdin();
 	if (make_pty() != 0) {
@@ -98,7 +113,7 @@ int main (int argc, char * argv[], char * envp[]) {
 	//resize interrupt handler
 	winchhook(0);
 	//forks for running bash
-	pid_t shell_pid = fork();
+	shell_pid = fork();
 	if (shell_pid == 0) {
 		//shell child process
 		//set self to be session leader
@@ -137,7 +152,7 @@ int main (int argc, char * argv[], char * envp[]) {
 	} else {
 		//forks for read and write, master process handles im, child
 		//process just handles transfering pty output to stdout
-		pid_t om_pid = fork();
+		om_pid = fork();
 		if (om_pid == 0) {
 			//sets the name for cleaner ps output
 			prctl(PR_SET_NAME, "ptyim om thread");
@@ -179,7 +194,7 @@ int main (int argc, char * argv[], char * envp[]) {
 					fprintf(stderr, "%c: %d\n", read_buffer[0],in_state);
 					//skips if the char was anything but
 					//normal
-					if (in_state == NORMAL) {
+					if (in_state == NORMAL || in_state ==DOUBLE_ESC) {
 						//feeds the input char into the im state machine
 						char input_buffer[IM_TABLE_ENTRY_LEN+1] = {0};
 						int im_chars = update_im_state(read_buffer[0],
@@ -203,11 +218,6 @@ int main (int argc, char * argv[], char * envp[]) {
 			kill(om_pid, SIGKILL);
 		}
 	}
-	//kill shell , can not be blocked
-	kill(shell_pid, SIGKILL);
-	//exit, only the master process should reach this point
-	close(pty_master);
-	close(pty_slave);
-	restore_stdin();
+	exit_main();
 	return 0;
 }
-- 
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