From 47368e1d048c62d085760d8144cde3ade64da8e7 Mon Sep 17 00:00:00 2001
From: Hadeed Ahmad <hadeedji@gmail.com>
Date: Tue, 3 Oct 2023 10:58:02 +0500
Subject: [PATCH] Add a way to report errors after exit

---
 include/kilo.h     |  3 +++
 include/terminal.h | 10 ----------
 src/kilo.c         | 18 ++++++++++++++++++
 src/terminal.c     | 46 +++++++++++++++++++++++++++++++---------------
 4 files changed, 52 insertions(+), 25 deletions(-)

diff --git a/include/kilo.h b/include/kilo.h
index 54ca860..f66f032 100644
--- a/include/kilo.h
+++ b/include/kilo.h
@@ -21,4 +21,7 @@ extern struct editor_state E;
 void editor_set_message(const char *fmt, ...);
 char *editor_prompt(const char *prompt);
 
+extern char *error_message;
+void error_set_message(const char *prefix);
+
 #endif // KILO_H
diff --git a/include/terminal.h b/include/terminal.h
index 616c13c..701fbd1 100644
--- a/include/terminal.h
+++ b/include/terminal.h
@@ -4,29 +4,19 @@
 #include "input.h"
 #include "utils.h"
 
-// Functions to perform low level terminal operations, using escape codes
-
 ERRCODE terminal_enable_raw(void);
-void terminal_disable_raw(void);
-
-// Cursor positioned at the start
 ERRCODE terminal_clear(void);
 
-// Hide or show the cursor
 enum cursor_visibility {
     CURSOR_SHOWN = 0,
     CURSOR_HIDDEN = 1
 };
 ERRCODE terminal_cursor_visibility(enum cursor_visibility visibility);
-
-// Calculate the current window size
 ERRCODE terminal_get_win_size(int *rows, int *cols);
 
-// Get and set the cursor position, 1-based indexing
 ERRCODE terminal_get_cursor_pos(int *row, int *col);
 ERRCODE terminal_set_cursor_pos(int, int);
 
-// Read input from the terminal and parse it into a KEY
 KEY terminal_read_key(void);
 
 #endif // TERMINAL_H
diff --git a/src/kilo.c b/src/kilo.c
index 40b730f..cea931f 100644
--- a/src/kilo.c
+++ b/src/kilo.c
@@ -1,6 +1,7 @@
 #define _POSIX_C_SOURCE 199309L
 
 #include <ctype.h>
+#include <errno.h>
 #include <signal.h>
 #include <stdarg.h>
 #include <stdbool.h>
@@ -51,6 +52,7 @@ void editor_init(char *filename) {
 
     editor_set_message("Welcome to kilo! | CTRL-Q: Quit | CTRL-S: SAVE");
     terminal_clear();
+    error_message = NULL;
 
     struct sigaction sa;
     sa.sa_handler = editor_resize;
@@ -126,3 +128,19 @@ void editor_resize() {
 
     ui_draw_screen();
 }
+
+/*****************************************************************************/
+
+char *error_message;
+
+void error_set_message(const char *prefix) {
+    if (error_message)
+        free(error_message);
+
+    const char *strerror_msg = strerror(errno);
+    const char *fmt = "%s: %s\n";
+    size_t len = strlen(prefix) + 2 + strlen(strerror_msg) + 2;
+
+    error_message = malloc(len);
+    snprintf(error_message, len, fmt, prefix, strerror_msg);
+}
diff --git a/src/terminal.c b/src/terminal.c
index 214b479..27d6a88 100644
--- a/src/terminal.c
+++ b/src/terminal.c
@@ -1,5 +1,7 @@
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/ioctl.h>
 #include <termios.h>
 #include <unistd.h>
@@ -9,6 +11,34 @@
 #include "terminal.h"
 #include "utils.h"
 
+static void terminal_disable_raw(void) {
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
+        die ("term_disable_raw");
+
+    write(STDIN_FILENO, "\x1b[?1049l", 8);
+
+    if (error_message) {
+        write(STDERR_FILENO, error_message, strlen(error_message));
+        free(error_message);
+    }
+}
+
+static char terminal_read_char(void) {
+    char c;
+
+    ssize_t read_return;
+    do {
+        read_return = read(STDIN_FILENO, &c, 1);
+    } while(read_return == 0 || (read_return == -1 && errno == EINTR));
+
+    if (read_return == -1) {
+        error_set_message("read");
+        exit(1);
+    }
+
+    return c;
+}
+
 ERRCODE terminal_enable_raw(void) {
     if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1)
         return -1;
@@ -27,13 +57,6 @@ ERRCODE terminal_enable_raw(void) {
     return tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw);
 }
 
-void terminal_disable_raw(void) {
-    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
-        die ("term_disable_raw");
-
-    write(STDIN_FILENO, "\x1b[?1049l", 8);
-}
-
 ERRCODE terminal_clear(void) {
     if (write(STDOUT_FILENO, "\x1b[2J", 4) != 4) return -1;
     if (write(STDOUT_FILENO, "\x1b[H", 3) != 3) return -1;
@@ -100,14 +123,7 @@ ERRCODE terminal_set_cursor_pos(int row, int col) {
 }
 
 KEY terminal_read_key(void) {
-    char c;
-
-    ssize_t read_return = 0;
-    while (read_return == 0)
-        read_return = read(STDIN_FILENO, &c, 1);
-
-    if (read_return == -1)
-        return NOP;
+    char c = terminal_read_char();
 
     if (c == '\x1b') {
         char buf[8] = { '\0' };