Add simple backspacing

.gitignore

@@ -4,3 +4,4 @@ kilo
 .cache
 .clangd
 compile_commands.json
+test_file

include/buffer.h

@@ -1,6 +1,8 @@
 #ifndef BUFFER_H
 #define BUFFER_H
 
+#include <stdbool.h>
+
 #include "utils.h"
 
 struct erow {
@@ -15,6 +17,7 @@ struct buffer {
     char *filename;
     struct erow *rows;
     int n_rows;
+    bool modified;
 };
 
 struct buffer *buffer_create(void);
@@ -24,6 +27,7 @@ ERRCODE buffer_write_file(struct buffer *buffer);
 
 void erow_update_rendering(struct erow *erow);
 void erow_insert_char(struct erow *erow, int at, char c);
+void erow_delete_char(struct erow *erow, int at);
 int erow_cx_to_rx(struct erow *erow, int cx);
 int erow_rx_to_cx(struct erow *erow, int rx);
 

include/commands.h

@@ -3,8 +3,10 @@
 
 #include "input.h"
 
+void command_quit(void);
 void command_move_cursor(KEY key);
 void command_insert_char(char c);
+void command_delete_char(void);
 void command_save_buffer(void);
 
 #endif // COMMANDS_H

include/kilo.h

@@ -11,6 +11,7 @@ struct editor_state {
     int cx, cy, rx;
     int row_off, col_off;
     int screenrows, screencols;
+    int quit_times;
 
     struct buffer *current_buf;
     struct termios orig_termios;

include/utils.h

@@ -7,6 +7,7 @@
 #define MIN(a,b) (((a)<(b))?(a):(b))
 
 typedef int ERRCODE;
+#define RETURN(code) do {errcode = code; goto END;} while(0)
 
 void die(const char *context);
 

src/buffer.c

@@ -10,15 +10,17 @@
 #include "utils.h"
 
 static void buffer_free_rows(struct buffer *buffer);
+static char *buffer_get_string(struct buffer *buffer, size_t *len_p);
 
 struct buffer *buffer_create(void) {
-    struct buffer *buf = malloc(sizeof(struct buffer));
+    struct buffer *buffer = malloc(sizeof(struct buffer));
 
-    buf->filename = NULL;
-    buf->rows = NULL;
-    buf->n_rows = 0;
+    buffer->filename = NULL;
+    buffer->rows = NULL;
+    buffer->n_rows = 0;
+    buffer->modified = false;
 
-    return buf;
+    return buffer;
 }
 
 // TODO: Handle file not existing
@@ -57,33 +59,40 @@ void buffer_read_file(struct buffer *buffer, const char *filename) {
 
     free(line_buffer);
     fclose(file);
+
+    buffer->modified = false;
 }
 
 ERRCODE buffer_write_file(struct buffer *buffer) {
+    ERRCODE errcode = 0;
+
+    int fd = -1;
+    char *write_buffer = NULL;
+
     if (buffer->filename == NULL)
-        return -1;
+        RETURN(-1);
 
-    size_t len = 0;
+    size_t len;
+    write_buffer = buffer_get_string(buffer, &len);
 
-    for (int i = 0; i < buffer->n_rows; i++)
-        len += buffer->rows[i].n_chars + 1;
+    fd = open(buffer->filename, O_RDWR | O_TRUNC | O_CREAT, 0644);
+    if (fd == -1)
+        RETURN(-2);
 
-    char *write_buffer = malloc(len);
-    char *p = write_buffer;
-    for (int i = 0; i < buffer->n_rows; i++) {
-        struct erow *row = buffer->rows+i;
-        memcpy(p, row->chars, row->n_chars);
-        p += row->n_chars;
-        *p = '\n';
-        p++;
-    }
+    if (write(fd, write_buffer, len) != (ssize_t) len)
+        RETURN(-3);
 
-    int fd = open(buffer->filename, O_RDWR | O_TRUNC | O_CREAT, 0644);
-    write(fd, write_buffer, len);
-    close(fd);
-    free(write_buffer);
+END:
+    if (fd != -1)
+        close(fd);
 
-    return 0;
+    if (write_buffer)
+        free(write_buffer);
+
+    if (errcode == 0)
+        buffer->modified = false;
+
+    return errcode;
 }
 
 void buffer_append_row(struct buffer *buffer, const char *chars, int n_chars) {
@@ -98,6 +107,8 @@ void buffer_append_row(struct buffer *buffer, const char *chars, int n_chars) {
     new_row->n_rchars = 0;
 
     erow_update_rendering(new_row);
+
+    buffer->modified = true;
 }
 
 void buffer_free(struct buffer *buffer) {
@@ -112,6 +123,25 @@ static void buffer_free_rows(struct buffer *buffer) {
     }
 }
 
+static char *buffer_get_string(struct buffer *buffer, size_t *len_p) {
+    *len_p = 0;
+
+    for (int i = 0; i < buffer->n_rows; i++)
+        *len_p += buffer->rows[i].n_chars + 1;
+
+    char *write_buffer = malloc(*len_p);
+    char *p = write_buffer;
+    for (int i = 0; i < buffer->n_rows; i++) {
+        struct erow *row = buffer->rows+i;
+        memcpy(p, row->chars, row->n_chars);
+        p += row->n_chars;
+        *p = '\n';
+        p++;
+    }
+
+    return write_buffer;
+}
+
 /*****************************************************************************/
 
 void erow_update_rendering(struct erow *erow) {
@@ -160,6 +190,25 @@ void erow_insert_char(struct erow *erow, int at, char c) {
     erow->n_chars++;
 
     erow_update_rendering(erow);
+
+    // TODO: Seems like a bad idea
+    E.current_buf->modified = true;
+}
+
+void erow_delete_char(struct erow *erow, int at) {
+    if (at < 0) at = 0;
+    if (at > erow->n_chars) at = erow->n_chars;
+
+    if (at != 0) {
+        memmove(erow->chars + at, erow->chars + at + 1, erow->n_chars - at);
+        erow->n_chars--;
+        erow->chars = realloc(erow->chars, erow->n_chars);
+        E.cx--;
+        erow_update_rendering(erow);
+    }
+
+    // TODO
+    E.current_buf->modified = true;
 }
 
 int erow_cx_to_rx(struct erow *erow, int cx) {

src/commands.c

@@ -1,15 +1,29 @@
+#include <errno.h>
 #include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
 
+#include "buffer.h"
 #include "commands.h"
 #include "input.h"
 #include "kilo.h"
-#include "buffer.h"
+#include "terminal.h"
 #include "utils.h"
 
 static void cursor_adjust_viewport(void);
 static void cursor_check_file_bounds(bool horizontal);
 static void cursor_update_rx(bool horizontal);
 
+void command_quit(void) {
+    if (E.current_buf->modified && E.quit_times) {
+        editor_set_message("Unsaved changed! Press quit %d more time(s)", E.quit_times);
+        E.quit_times--;
+    } else {
+        terminal_clear();
+        exit(0);
+    }
+}
+
 void command_move_cursor(KEY key) {
     struct erow *rows = E.current_buf->rows;
     int n_rows = E.current_buf->n_rows;
@@ -47,9 +61,9 @@ void command_move_cursor(KEY key) {
     }
 
     bool horizontal = (key == ARROW_LEFT  || 
-                       key == ARROW_RIGHT ||
-                       key == HOME        ||
-                       key == END);
+        key == ARROW_RIGHT ||
+        key == HOME        ||
+        key == END);
 
     cursor_check_file_bounds(horizontal);
     cursor_update_rx(horizontal);
@@ -64,13 +78,24 @@ void command_insert_char(char c) {
     E.rx = erow_cx_to_rx(E.current_buf->rows+E.cy, E.cx);
 }
 
+void command_delete_char(void) {
+    struct erow *row = E.current_buf->rows + E.cy;
+
+    if (E.cx == 0) {
+        // TODO
+    } else
+        erow_delete_char(row, E.cx);
+
+    E.rx = erow_cx_to_rx(E.current_buf->rows+E.cy, E.cx);
+}
+
 void command_save_buffer(void) {
     ERRCODE errcode = buffer_write_file(E.current_buf);
 
     if (errcode == 0)
         editor_set_message("Saved file %s", E.current_buf->filename);
-    else if (errcode == -1)
-        editor_set_message("Save failed, no filename");
+    else
+        editor_set_message("Save failed: ERRCODE %d: %s", errcode, strerror(errno));
 }
 
 static void cursor_check_file_bounds(bool horizontal) {
@@ -87,7 +112,13 @@ static void cursor_check_file_bounds(bool horizontal) {
         E.cy = n_rows;
 
     if (E.cx < 0) {
-        if (E.cy > 0 && horizontal) E.cx = rows[--E.cy].n_chars;
+        if (E.cy > 0 && horizontal)
+        {
+            current_row = &rows[--E.cy];
+            max_x = current_row->n_chars;
+
+            E.cx = max_x;
+        }
         else E.cx = 0;
     }
 

src/input.c

@@ -1,8 +1,9 @@
 #include <stdlib.h>
 
-#include "input.h"
-#include "terminal.h"
 #include "commands.h"
+#include "input.h"
+#include "kilo.h"
+#include "terminal.h"
 #include "utils.h"
 
 void input_process_key(void) {
@@ -20,28 +21,31 @@ void input_process_key(void) {
             command_move_cursor(c);
             break;
 
+        case CTRL_KEY('Q'):
+            command_quit();
+            return;
+
         case CTRL_KEY('S'):
             command_save_buffer();
             break;
 
-        case CTRL_KEY('Q'):
-            terminal_clear();
-            exit(0);
-            break;
-
         case '\r':
+            // TODO
             break;
 
         case BACKSPACE:
         case CTRL_KEY('H'):
         case DEL:
+            command_delete_char();
             break;
 
         case CTRL_KEY('L'):
-        // case NOP:
+        case NOP:
             break;
 
         default:
             command_insert_char(c);
     }
+
+    E.quit_times = 3;
 }

src/kilo.c

@@ -40,6 +40,7 @@ void editor_init(char *filename) {
     if (terminal_get_win_size(&E.screenrows, &E.screencols) == -1)
         die("term_get_win_size");
     E.screenrows -= 2;
+    E.quit_times = 3;
 
     E.current_buf = buffer_create();
     if (filename)

src/ui.c

@@ -72,7 +72,9 @@ static void ui_draw_statusbar(struct append_buf *draw_buf) {
     ab_append(draw_buf, "\x1b[7m", 4);
 
     char *display = E.current_buf->filename ? E.current_buf->filename : "[NO NAME]";
-    len = sprintf(buf, "%s -- %d lines", display, E.current_buf->n_rows);
+    char *modified = E.current_buf->modified ? "(modified) " : "";
+    int n_rows = E.current_buf->n_rows;
+    len = sprintf(buf, "%s %s-- %d lines", display, modified, n_rows);
     memcpy(status_buf, buf, len);
 
     len = sprintf(buf, "%d:%d", E.cy + 1, E.rx + 1);