Re: [PATCH] lib: another iterator-temporary/stale-pointer bug

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+From: Jani Nikula <jani@nikula.org>\r
+To: David Bremner <david@tethera.net>, notmuch@notmuchmail.org\r
+Subject: Re: [PATCH] lib: another iterator-temporary/stale-pointer bug\r
+In-Reply-To: <1419763508-11902-1-git-send-email-david@tethera.net>\r
+References: <20141226230655.GA41992@pamparam>\r
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+Date: Thu, 01 Jan 2015 16:49:31 +0200\r
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+On Sun, 28 Dec 2014, David Bremner <david@tethera.net> wrote:\r
+> Tamas Szakaly points out [1] that the bug fixed in 51b073c still\r
+> exists in at least one place. This change follows the suggestion of\r
+> [2] and creates a block scope temporary std::string to avoid the rules\r
+> of iterators temporaries.\r
+>\r
+> [1]: id:20141226113755.GA64154@pamparam\r
+> [2]: id:20141226230655.GA41992@pamparam\r
+> ---\r
+>\r
+> I decided to take a more minimalist approach than [2]. In particular\r
+> using "direntry" for two different things seemed slightly trickier\r
+> than necessary, for no obvious performance gain (calling .c_str()\r
+> should be cheap).\r
+>\r
+> lib/message.cc | 5 +++--\r
+>  1 file changed, 3 insertions(+), 2 deletions(-)\r
+>\r
+> diff --git a/lib/message.cc b/lib/message.cc\r
+> index a7a13cc..bacb4d4 100644\r
+> --- a/lib/message.cc\r
+> +++ b/lib/message.cc\r
+> @@ -641,15 +641,16 @@ _notmuch_message_add_directory_terms (void *ctx, notmuch_message_t *message)\r
+>      unsigned int directory_id;\r
+>      const char *direntry, *directory;\r
+>      char *colon;\r
+> +    const std::string term = *i;\r
+\r
+You could use a reference here like in [2]. Either way, LGTM.\r
+\r
+Jani.\r
+\r
+>  \r
+>      /* Terminate loop at first term without desired prefix. */\r
+> -    if (strncmp ((*i).c_str (), direntry_prefix, direntry_prefix_len))\r
+> +    if (strncmp (term.c_str (), direntry_prefix, direntry_prefix_len))\r
+>          break;\r
+>  \r
+>      /* Indicate that there are filenames remaining. */\r
+>      status = NOTMUCH_STATUS_DUPLICATE_MESSAGE_ID;\r
+>  \r
+> -    direntry = (*i).c_str ();\r
+> +    direntry = term.c_str ();\r
+>      direntry += direntry_prefix_len;\r
+>  \r
+>      directory_id = strtol (direntry, &colon, 10);\r
+> -- \r
+> 2.1.3\r
+>\r
+> _______________________________________________\r
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