From: Jeff King <peff@peff.net>
Date: Thu, 27 Apr 2017 06:21:14 GMT
Subject: Re: [PATCH 10/26] Check for EOF while parsing mails
Message-ID: <20170427062114.p367j6rojnw4aj5r@sigill.intra.peff.net>
In-Reply-To: <1fb841cee32996ee9194c2bd33b9dfe74cc37726.1493237937.git.johannes.schindelin@gmx.de>

On Wed, Apr 26, 2017 at 10:20:16PM +0200, Johannes Schindelin wrote:

> diff --git a/builtin/mailsplit.c b/builtin/mailsplit.c
> index 30681681c13..c0d88f97512 100644
> --- a/builtin/mailsplit.c
> +++ b/builtin/mailsplit.c
> @@ -232,7 +232,7 @@ static int split_mbox(const char *file, const char *dir, int allow_bare,
>  
>  	do {
>  		peek = fgetc(f);
> -	} while (isspace(peek));
> +	} while (peek >= 0 && isspace(peek));
>  	ungetc(peek, f);

Are we guaranteed that EOF is a negative number?  Also, what is the
behavior of ungetc when we pass it EOF?

It looks like POSIX does what we want (pushing EOF is a noop, and the
stream retains its feof() status), but I don't know if there are other
implementations to worry about.

Perhaps:

  /* soak up whitespace */
  while ((peek = fgetc(f)) != EOF) {
	if (!isspace(peek)) {
		ungetc(peek, f);
		break;
	}
  }

would be more portable.

-Peff