[PATCH] Fix get-bytevector-all read redundant eof

[PATCH] Fix get-bytevector-all read redundant eof

[Nala Ginrut]

[-- Attachment #1: Type: text/plain, Size: 218 bytes --]

Attached the patch to fix get-bytevector-all.
You may check it like this:
(get-bytevector-all (current-input-port))

And try to input then type ctrl+d, the current implementation needs you
type ctrl+d twice.

Regards.

[-- Attachment #2: 0001-Fix-get-bytevector-all-read-redundant-eof.patch --]
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From 1e22ce9468a09a186ce77552bae310d2e4a6178d Mon Sep 17 00:00:00 2001
From: Nala Ginrut <nalaginrut@gmail.com>
Date: Thu, 14 Mar 2013 17:24:58 +0800
Subject: [PATCH] Fix get-bytevector-all read redundant eof.

---
 libguile/r6rs-ports.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libguile/r6rs-ports.c b/libguile/r6rs-ports.c
index e867429..c812979 100644
--- a/libguile/r6rs-ports.c
+++ b/libguile/r6rs-ports.c
@@ -644,7 +644,7 @@ SCM_DEFINE (scm_get_bytevector_all, "get-bytevector-all", 1, 0, 0,
   c_bv = (char *) scm_gc_malloc_pointerless (c_len, SCM_GC_BYTEVECTOR);
   c_total = c_read = 0;
 
-  do
+  while (!SCM_EOF_OBJECT_P (scm_peek_char (port)))
     {
       if (c_total + c_read > c_len)
 	{
@@ -660,7 +660,6 @@ SCM_DEFINE (scm_get_bytevector_all, "get-bytevector-all", 1, 0, 0,
       c_read = scm_c_read (port, c_bv + c_total, c_count);
       c_total += c_read, c_count -= c_read;
     }
-  while (!SCM_EOF_OBJECT_P (scm_peek_char (port)));
 
   if (c_total == 0)
     {
-- 
1.7.10.4

Re: [PATCH] Fix get-bytevector-all read redundant eof

[Nala Ginrut]

On Thu, 2013-03-14 at 17:30 +0800, Nala Ginrut wrote:
> Attached the patch to fix get-bytevector-all.
> You may check it like this:
> (get-bytevector-all (current-input-port))
> 
> And try to input then type ctrl+d, the current implementation needs you
> type ctrl+d twice.
> 
> Regards.


Sorry, but I realized that this patch only fixed when you type ctrl+d in
the beginning. But if you input something, the problem is still there.
I'll look deeper.

Re: [PATCH] Fix get-bytevector-all read redundant eof

[Mark H Weaver]

Nala Ginrut <nalaginrut@gmail.com> writes:

> On Thu, 2013-03-14 at 17:30 +0800, Nala Ginrut wrote:
>> Attached the patch to fix get-bytevector-all.
>> You may check it like this:
>> (get-bytevector-all (current-input-port))
>> 
>> And try to input then type ctrl+d, the current implementation needs you
>> type ctrl+d twice.
>> 
>> Regards.
>
>
> Sorry, but I realized that this patch only fixed when you type ctrl+d in
> the beginning. But if you input something, the problem is still there.
> I'll look deeper.

FWIW, I suspect you'll have to dig fairly deep to fix this properly.
AFAIK, the ports code was not designed to ensure that exactly one EOF is
reported to the user for each EOF returned by the kernel.  I hope to
look into this soon (possibly before 2.0.8), as part of my investigation
of <http://bugs.gnu.org/12216>.

    Thanks,
      Mark

Re: [PATCH] Fix get-bytevector-all read redundant eof

[Nala Ginrut]

On Fri, 2013-03-15 at 17:20 -0400, Mark H Weaver wrote:
> Nala Ginrut <nalaginrut@gmail.com> writes:
> 
> > On Thu, 2013-03-14 at 17:30 +0800, Nala Ginrut wrote:
> >> Attached the patch to fix get-bytevector-all.
> >> You may check it like this:
> >> (get-bytevector-all (current-input-port))
> >> 
> >> And try to input then type ctrl+d, the current implementation needs you
> >> type ctrl+d twice.
> >> 
> >> Regards.
> >
> >
> > Sorry, but I realized that this patch only fixed when you type ctrl+d in
> > the beginning. But if you input something, the problem is still there.
> > I'll look deeper.
> 
> FWIW, I suspect you'll have to dig fairly deep to fix this properly.
> AFAIK, the ports code was not designed to ensure that exactly one EOF is
> reported to the user for each EOF returned by the kernel.  I hope to
> look into this soon (possibly before 2.0.8), as part of my investigation
> of <http://bugs.gnu.org/12216>.
> 

Yes, I tried the bug-demo code of dwheeler, and found that EOF seems was
eaten in somewhere. 
I read the code on the calling-tree of scm_peek_char, but hardly find
the problem related. 
Maybe it's something about the 'port' implementation?

>     Thanks,
>       Mark

Re: [PATCH] Fix get-bytevector-all read redundant eof

[Mark H Weaver]

Nala Ginrut <nalaginrut@gmail.com> writes:
> You may check it like this:
> (get-bytevector-all (current-input-port))
>
> And try to input then type ctrl+d, the current implementation needs you
> type ctrl+d twice.

I just pushed a fix for this (and some other related problems) to
stable-2.0.

http://git.savannah.gnu.org/gitweb/?p=guile.git;a=commit;h=47f2bce5ae332c274270882c259776b8e4ea12f7

Thanks for bringing this to our attention!

      Mark