# HG changeset patch
# User Francisco J Ballesteros <nemo.mbox@gmail.com>
# Date 1330096589 -3600
# Node ID 9d88846ae23b2463252b1b8aef48f968edb7e34d
# Parent  1386cdce4771d4e0666ac42d115068e0c30ddda4
error: more debug help and stack resizing

R=nixiedev
CC=nix-dev
http://codereview.appspot.com/5695053

diff -r 1386cdce4771 -r 9d88846ae23b sys/include/error.h
--- a/sys/include/error.h	Fri Feb 24 11:02:36 2012 +0100
+++ b/sys/include/error.h	Fri Feb 24 16:16:29 2012 +0100
@@ -14,6 +14,7 @@
 
 void	errinit(int stack);
 void	noerror(void);
+int	nerrors(void);
 void	error(char* msg, ...);
 #define	catcherror()	setjmp((*__ep)->label[(*__ep)->nerr++])
 extern Error**	__ep;
diff -r 1386cdce4771 -r 9d88846ae23b sys/man/2/error
--- a/sys/man/2/error	Fri Feb 24 11:02:36 2012 +0100
+++ b/sys/man/2/error	Fri Feb 24 16:16:29 2012 +0100
@@ -19,6 +19,9 @@
 .br
 .B
 void	catcherror(void)
+.br
+.B
+int	nerrors(void)
 .SH DESCRIPTION
 These routiles are tools for error handling.
 .IR catcherror ,
@@ -46,6 +49,10 @@
 function in the kernel.
 .I Error
 raises an error. If the argument is nil, the error string is unaltered. See the example.
+.PP
+.I Nerrors
+returns the number of recovery points kept in the error stack. Useful to
+perform debug checks to see if the stack depth is what it should be.
 .SH SOURCE
 .B /sys/src/liberror
 .SH EXAMPLE
diff -r 1386cdce4771 -r 9d88846ae23b sys/src/liberror/error.c
--- a/sys/src/liberror/error.c	Fri Feb 24 11:02:36 2012 +0100
+++ b/sys/src/liberror/error.c	Fri Feb 24 16:16:29 2012 +0100
@@ -18,11 +18,26 @@
 	e->nlabel = stack;
 }
 
+int
+nerrors(void)
+{
+	return (*__ep)->nerr;
+}
+
 void
 noerror(void)
 {
-	if((*__ep)->nerr > (*__ep)->nlabel - 3)
-		sysfatal("error stack about to overflow");
+	Error *e;
+
+	e = *__ep;
+	if(e->nerr > e->nlabel - 3){
+		fprint(2, "error stack about to overflow. resizing");
+		e->nlabel *= 2;
+		(*__ep) = realloc(e, sizeof(Error) +
+				sizeof(e->label)*(e->nlabel-1));
+		if(*__ep == nil)
+			sysfatal("can't resize error stack: no memory");
+	}
 	if((*__ep)->nerr-- == 0)
 		sysfatal("noerror w/o catcherror");
 }