- implement "revert-buffer", which reverts the current buffer to what's on disk

- split gotoline() into the argument handling part and the part that actually
  goes to the specified line number so it can be re-used by revertbuffer()

input/ok florian@ haesbaert@

5 files changed, 66 insertions, 9 deletions

diff --git a/usr.bin/mg/basic.c b/usr.bin/mg/basic.c
index 160d9c1c9e3..9b6af92ec6d 100644
--- a/usr.bin/mg/basic.c
+++ b/usr.bin/mg/basic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: basic.c,v 1.37 2012/06/18 09:26:03 lum Exp $	*/
+/*	$OpenBSD: basic.c,v 1.38 2012/10/12 21:13:46 jasper Exp $	*/
 
 /* This file is in the public domain */
 
@@ -485,7 +485,6 @@ swapmark(int f, int n)
 int
 gotoline(int f, int n)
 {
-	struct line  *clp;
 	char   buf[32], *bufp;
 	const char *err;
 
@@ -501,6 +500,17 @@ gotoline(int f, int n)
 			return (FALSE);
 		}
 	}
+	return(setlineno(n));
+}
+
+/*
+ * Set the line number and switch to it.
+ */
+int
+setlineno(int n)
+{
+	struct line  *clp;
+
 	if (n >= 0) {
 		if (n == 0)
 			n++;
diff --git a/usr.bin/mg/buffer.c b/usr.bin/mg/buffer.c
index 5a30aadbf0a..0cc85f20efe 100644
--- a/usr.bin/mg/buffer.c
+++ b/usr.bin/mg/buffer.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: buffer.c,v 1.81 2012/08/31 18:06:42 lum Exp $	*/
+/*	$OpenBSD: buffer.c,v 1.82 2012/10/12 21:13:46 jasper Exp $	*/
 
 /* This file is in the public domain. */
 
@@ -861,4 +861,46 @@ checkdirty(struct buffer *bp)
 
 	return (TRUE);
 }
-	
+
+/*
+ * Revert the current buffer to whatever is on disk.
+ */
+/* ARGSUSED */
+int
+revertbuffer(int f, int n)
+{
+	struct mgwin *wp = wheadp;
+	struct buffer *bp = wp->w_bufp;
+	char fbuf[NFILEN + 32];
+	int lineno;
+
+	if (bp->b_fname[0] == 0) {
+		ewprintf("Cannot revert buffer not associated with any files.");
+		return (FALSE);
+	}
+
+	snprintf(fbuf, sizeof(fbuf), "Revert buffer from file %s", bp->b_fname);
+
+	if (eyorn(fbuf)) {
+		if (access(bp->b_fname, F_OK|R_OK) != 0) {
+			if (errno == ENOENT)
+				ewprintf("File %s no longer exists!",
+				    bp->b_fname);
+			else
+				ewprintf("File %s is no longer readable!",
+				    bp->b_fname);
+			return (FALSE);
+		}
+
+		/* Save our current line, so we can go back after reloading. */
+		lineno = wp->w_dotline;
+
+		/* Prevent readin from asking if we want to kill the buffer. */
+		curbp->b_flag &= ~BFCHG;
+
+		if (readin(bp->b_fname))
+			return(setlineno(lineno));
+	}
+
+	return (FALSE);
+}
diff --git a/usr.bin/mg/def.h b/usr.bin/mg/def.h
index e00a0dd0b68..c24c8505a73 100644
--- a/usr.bin/mg/def.h
+++ b/usr.bin/mg/def.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: def.h,v 1.125 2012/08/31 18:06:42 lum Exp $	*/
+/*	$OpenBSD: def.h,v 1.126 2012/10/12 21:13:46 jasper Exp $	*/
 
 /* This file is in the public domain. */
 
@@ -414,6 +414,7 @@ int		 notmodified(int, int);
 int		 popbuftop(struct buffer *, int);
 int		 getbufcwd(char *, size_t);
 int		 checkdirty(struct buffer *);
+int		 revertbuffer(int, int);
 
 /* display.c */
 int		vtresize(int, int, int);
@@ -494,6 +495,7 @@ int		 setmark(int, int);
 int		 clearmark(int, int);
 int		 swapmark(int, int);
 int		 gotoline(int, int);
+int		 setlineno(int);
 
 /* random.c X */
 int		 showcpos(int, int);
diff --git a/usr.bin/mg/funmap.c b/usr.bin/mg/funmap.c
index aac58ce53e3..66dd4147f69 100644
--- a/usr.bin/mg/funmap.c
+++ b/usr.bin/mg/funmap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: funmap.c,v 1.40 2012/06/14 17:21:22 lum Exp $	*/
+/*	$OpenBSD: funmap.c,v 1.41 2012/10/12 21:13:46 jasper Exp $	*/
 
 /* This file is in the public domain */
 
@@ -196,7 +196,8 @@ static struct funmap functnames[] = {
 	{csprevmatch, "cscope-prev-symbol",},
 	{csnextfile, "cscope-next-file",},
 	{csprevfile, "cscope-prev-file",},
-	{cscreatelist, "cscope-create-list-of-files-to-index"},
+	{cscreatelist, "cscope-create-list-of-files-to-index",},
+	{revertbuffer, "revert-buffer",},
 	{NULL, NULL,}
 };
 
diff --git a/usr.bin/mg/mg.1 b/usr.bin/mg/mg.1
index bc120809014..baab1863ce1 100644
--- a/usr.bin/mg/mg.1
+++ b/usr.bin/mg/mg.1
@@ -1,7 +1,7 @@
-.\"	$OpenBSD: mg.1,v 1.68 2012/07/11 19:56:13 sobrado Exp $
+.\"	$OpenBSD: mg.1,v 1.69 2012/10/12 21:13:47 jasper Exp $
 .\" This file is in the public domain.
 .\"
-.Dd $Mdocdate: July 11 2012 $
+.Dd $Mdocdate: October 12 2012 $
 .Dt MG 1
 .Os
 .Sh NAME
@@ -752,6 +752,8 @@ is negative, it is that line from the bottom.
 .It redraw-display
 Refresh the display.
 Recomputes all window sizes in case something has changed.
+.It revert-buffer
+Revert the current buffer to the latest file on disk.
 .It save-buffer
 Save the contents of the current buffer if it has been changed,
 optionally creating a backup copy.