From 424efbe67a7e995dc7f9dc9a54dd584c3e48b36d Mon Sep 17 00:00:00 2001
From: Alex Shinn <ashinn@users.noreply.github.com>
Date: Thu, 22 Jan 2015 18:10:46 +0900
Subject: [PATCH] Closing a port should reset the offset and force an error on
 further access.

---
 sexp.c |  4 ++++
 vm.c   | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/sexp.c b/sexp.c
index 771e2ed9..61af879b 100644
--- a/sexp.c
+++ b/sexp.c
@@ -172,6 +172,8 @@ sexp sexp_finalize_port (sexp ctx, sexp self, sexp_sint_t n, sexp port) {
 #endif
         )
       free(sexp_port_buf(port));
+    sexp_port_offset(port) = 0;
+    sexp_port_size(port) = 0;
   }
   return res;
 }
@@ -1444,6 +1446,8 @@ int sexp_buffered_read_char (sexp ctx, sexp p) {
   int res = 0;
   if (sexp_port_offset(p) < sexp_port_size(p)) {
     return ((unsigned char*)sexp_port_buf(p))[sexp_port_offset(p)++];
+  } else if (!sexp_port_openp(p)) {
+    return EOF;
   } else if (sexp_port_stream(p)) {
     res = fread(sexp_port_buf(p), 1, SEXP_PORT_BUFFER_SIZE, sexp_port_stream(p));
     if (res >= 0) {
diff --git a/vm.c b/vm.c
index 829d4aaf..8b8ec5ed 100644
--- a/vm.c
+++ b/vm.c
@@ -1936,6 +1936,9 @@ sexp sexp_apply (sexp ctx, sexp proc, sexp args) {
 #endif
     i = sexp_write_char(ctx, sexp_unbox_character(_ARG1), _ARG2);
     if (i == EOF) {
+      if (!sexp_port_openp(_ARG2))
+        sexp_raise("write-char: port is closed", _ARG2);
+      else
 #if SEXP_USE_GREEN_THREADS
       if ((sexp_port_stream(_ARG2) ? ferror(sexp_port_stream(_ARG2)) : 1)
           && (errno == EAGAIN)) {
@@ -1973,6 +1976,8 @@ sexp sexp_apply (sexp ctx, sexp proc, sexp args) {
       sexp_raise("write-string: not a valid string count", sexp_list2(ctx, tmp1, _ARG2));
     if (! sexp_oportp(_ARG3))
       sexp_raise("write-string: not an output-port", sexp_list1(ctx, _ARG3));
+    if (!sexp_port_openp(_ARG3))
+      sexp_raise("write-string: port is closed", _ARG3);
     sexp_context_top(ctx) = top;
 #if SEXP_USE_GREEN_THREADS
     errno = 0;
@@ -2015,6 +2020,9 @@ sexp sexp_apply (sexp ctx, sexp proc, sexp args) {
     else
 #endif
     if (i == EOF) {
+      if (!sexp_port_openp(_ARG1))
+        sexp_raise("peek-char: port is closed", _ARG1);
+      else
 #if SEXP_USE_GREEN_THREADS
       if ((sexp_port_stream(_ARG1) ? ferror(sexp_port_stream(_ARG1)) : 1)
           && (errno == EAGAIN)) {
@@ -2042,6 +2050,9 @@ sexp sexp_apply (sexp ctx, sexp proc, sexp args) {
 #endif
     i = sexp_read_char(ctx, _ARG1);
     if (i == EOF) {
+      if (!sexp_port_openp(_ARG1))
+        sexp_raise("read-char: port is closed", _ARG1);
+      else
 #if SEXP_USE_GREEN_THREADS
       if ((sexp_port_stream(_ARG1) ? ferror(sexp_port_stream(_ARG1)) : 1)
           && (errno == EAGAIN)) {