From e14432eae4ee28abb56fe530039f7fa10d0d99a2 Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Tue, 20 Aug 2019 10:24:00 -0400
Subject: [PATCH] Saving and backspacing

---
 kilo.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 120 insertions(+), 6 deletions(-)

diff --git a/kilo.c b/kilo.c
index 1c0ec8b..e77bb73 100644
--- a/kilo.c
+++ b/kilo.c
@@ -6,6 +6,7 @@
 
 #include <ctype.h>
 #include <errno.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -19,7 +20,8 @@
 /*** defines ***/
 
 #define KILO_VERSION "0.0.1"
-#define KILO_TAB_STOP 8
+#define KILO_TAB_STOP 4
+#define KILO_QUIT_TIMES 3
 
 #define CTRL_KEY(k) ((k) & 0x1f)
 
@@ -54,6 +56,7 @@ struct editorConfig {
 	int screencols;
 	int numrows;
 	erow *row;
+	int dirty;
 	char *filename;
 	char statusmsg[80];
 	time_t statusmsg_time;
@@ -62,6 +65,10 @@ struct editorConfig {
 
 struct editorConfig E;
 
+/*** prototypes ***/
+
+void editorSetStatusMessage(const char *fmt, ...);
+
 /*** terminal ***/
 
 void die(const char *s)
@@ -311,6 +318,7 @@ void editorAppendRow(char *s, size_t len)
 	editorUpdateRow(&E.row[at]);
 
 	E.numrows++;
+	E.dirty++;
 }
 
 void editorRowInsertChar(erow *row, int at, int c)
@@ -325,6 +333,20 @@ void editorRowInsertChar(erow *row, int at, int c)
 	row->size++;
 	row->chars[at] = c;
 	editorUpdateRow(row);
+	E.dirty++;
+}
+
+void editorRowDelChar(erow *row, int at)
+{
+	if (at < 0 || at >= row->size)
+	{
+		return;
+	}
+
+	memmove(&row->chars[at], &row->chars[at + 1], row->size - at);
+	row->size--;
+	editorUpdateRow(row);
+	E.dirty++;
 }
 
 /*** editor operations ***/
@@ -339,7 +361,46 @@ void editorInsertChar(int c)
 	E.cx++;
 }
 
+void editorDelChar()
+{
+	if (E.cy == E.numrows)
+	{
+		return;
+	}
+
+	erow *row = &E.row[E.cy];
+	if (E.cx > 0)
+	{
+		editorRowDelChar(row, E.cx - 1);
+		E.cx--;
+	}
+}
+
 /*** file i/o ***/
+
+char *editorRowsToString(int *buflen)
+{
+	int totlen = 0;
+	int j;
+	for (j = 0; j < E.numrows; j++)
+	{
+		totlen += E.row[j].size + 1;
+	}
+	*buflen = totlen;
+
+	char *buf = malloc(totlen);
+	char *p = buf;
+	for (j = 0; j < E.numrows; j++)
+	{
+		memcpy(p, E.row[j].chars, E.row[j].size);
+		p += E.row[j].size;
+		*p = '\n';
+		p++;
+	}
+
+	return buf;
+}
+
 void editorOpen(char *filename)
 {
 	free(E.filename);
@@ -367,6 +428,37 @@ void editorOpen(char *filename)
 
 	free(line);
 	fclose(fp);
+	E.dirty = 0;
+}
+
+void editorSave()
+{
+	if (E.filename == NULL)
+	{
+		return;
+	}
+
+	int len;
+	char *buf = editorRowsToString(&len);
+
+	int fd = open(E.filename, O_RDWR | O_CREAT, 0644);
+	if (fd != -1)
+	{
+		if (ftruncate(fd, len) != -1)
+		{
+			if (write(fd, buf, len) == len)
+			{
+				close(fd);
+				free(buf);
+				E.dirty = 0;
+				editorSetStatusMessage("%d bytes written to disk", len);
+				return;
+			}
+		}
+		close(fd);
+	}
+	free(buf);
+	editorSetStatusMessage("Can't save! I/O error: %s", strerror(errno));
 }
 
 /*** append buffer ***/
@@ -491,8 +583,9 @@ void editorDrawStatusBar(struct abuf *ab)
 {
 	abAppend(ab, "\x1b[7m", 4);
 	char status[80], rstatus[80];
-	int len = snprintf(status, sizeof(status), "%.20s - %d lines",
-			E.filename ? E.filename : "[No Name]", E.numrows);
+	int len = snprintf(status, sizeof(status), "%.20s - %d lines %s",
+			E.filename ? E.filename : "[No Name]", E.numrows,
+			E.dirty ? "(modified)" : "");
 	int rlen = snprintf(rstatus, sizeof(rstatus), "%d/%d",
 			E.cy + 1, E.numrows);
 
@@ -626,6 +719,8 @@ void editorMoveCursor(int key)
 
 void editorProcessKeypress()
 {
+	static int quit_times = KILO_QUIT_TIMES;
+
 	int c = editorReadKey();
 
 	switch (c)
@@ -635,11 +730,22 @@ void editorProcessKeypress()
 		break;
 
 		case CTRL_KEY('q'):
+			if (E.dirty && quit_times > 0)
+			{
+				editorSetStatusMessage("WARNING!!! File has unsaved changes ."
+						   "Press Ctrl-Q %d more time(s) to quit.", quit_times);
+				quit_times--;
+				return;
+			}
 			write(STDOUT_FILENO, "\x1b[2J", 4);
 			write(STDOUT_FILENO, "\x1b[H", 3);
 			exit(0);
 		break;
 
+		case CTRL_KEY('s'):
+			editorSave();
+		break;
+
 		case HOME_KEY:
 			E.cx = 0;
 		break;
@@ -654,11 +760,16 @@ void editorProcessKeypress()
 		case BACKSPACE:
 		case CTRL_KEY('h'):
 		case DEL_KEY:
-			/* TODO */
+			if (c == DEL_KEY)
+			{
+				editorMoveCursor(ARROW_RIGHT);
+			}
+			editorDelChar();
 		break;
 
 		case PAGE_UP:
-		case PAGE_DOWN: {
+		case PAGE_DOWN:
+		{
 			if (c == PAGE_UP)
 			{
 				E.cy = E.rowoff;
@@ -695,6 +806,8 @@ void editorProcessKeypress()
 			editorInsertChar(c);
 		break;
 	}
+
+	quit_times = KILO_QUIT_TIMES;
 }
 
 /*** init ***/
@@ -708,6 +821,7 @@ void initEditor()
 	E.coloff = 0;
 	E.numrows = 0;
 	E.row = NULL;
+	E.dirty = 0;
 	E.filename = NULL;
 	E.statusmsg[0] = '\0';
 	E.statusmsg_time = 0;
@@ -729,7 +843,7 @@ int main(int argc, char *argv[])
 		editorOpen(argv[1]);
 	}
 
-	editorSetStatusMessage("HELP: Ctrl-Q = quit");
+	editorSetStatusMessage("HELP: Ctrl-S = save | Ctrl-Q = quit");
 
 	while (1)
 	{