From: Justus Winter <4winter@informatik.uni-hamburg.de> Date: Tue, 21 Feb 2012 08:29:21 +0000 (+0000) Subject: notmuch as a shared object aka library knigge X-Git-Url: http://git.tremily.us/gitweb.cgi?a=commitdiff_plain;h=bc980dd2ce7f755cb08762d7a8a38044a6315327;p=notmuch-archives.git notmuch as a shared object aka library knigge --- diff --git a/3e/55b63cdc7033db2fc3af9024dc75c20064abc0 b/3e/55b63cdc7033db2fc3af9024dc75c20064abc0 new file mode 100644 index 000000000..49e472e73 --- /dev/null +++ b/3e/55b63cdc7033db2fc3af9024dc75c20064abc0 @@ -0,0 +1,126 @@ +Return-Path: +X-Original-To: notmuch@notmuchmail.org +Delivered-To: notmuch@notmuchmail.org +Received: from localhost (localhost [127.0.0.1]) + by olra.theworths.org (Postfix) with ESMTP id 8B820431FAF + for ; Mon, 20 Feb 2012 16:29:30 -0800 (PST) +X-Virus-Scanned: Debian amavisd-new at olra.theworths.org +X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "Date" +X-Spam-Flag: NO +X-Spam-Score: 0.432 +X-Spam-Level: +X-Spam-Status: No, score=0.432 tagged_above=-999 required=5 + tests=[INVALID_DATE=0.432] autolearn=disabled +Received: from olra.theworths.org ([127.0.0.1]) + by localhost (olra.theworths.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id aSJ7quxRkytu for ; + Mon, 20 Feb 2012 16:29:29 -0800 (PST) +Received: from mail.cryptobitch.de (cryptobitch.de [88.198.7.68]) + (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) + (No client certificate requested) + by olra.theworths.org (Postfix) with ESMTPS id D22A9431FAE + for ; Mon, 20 Feb 2012 16:29:28 -0800 (PST) +Received: from mail.jade-hamburg.de (unknown [85.183.11.228]) + (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) + (No client certificate requested) + by mail.cryptobitch.de (Postfix) with ESMTPSA id 218E45312DC + for ; Tue, 21 Feb 2012 01:29:27 +0100 (CET) +Received: by mail.jade-hamburg.de (Postfix, from userid 401) + id 180BBDF2A4; Tue, 21 Feb 2012 01:29:26 +0100 (CET) +Received: from thinkbox.jade-hamburg.de + (dslb-088-075-032-221.pools.arcor-ip.net [88.75.32.221]) + (using TLSv1 with cipher AES256-SHA (256/256 bits)) + (No client certificate requested) (Authenticated sender: teythoon) + by mail.jade-hamburg.de (Postfix) with ESMTPSA id 46CD7DF2A1 + for ; Tue, 21 Feb 2012 01:29:25 +0100 (CET) +Received: from teythoon by thinkbox.jade-hamburg.de with local (Exim 4.77) + (envelope-from ) + id 1Rzdbd-0002Sp-Ss + for notmuch@notmuchmail.org; Tue, 21 Feb 2012 01:29:21 +0100 +Content-Type: text/plain; charset="utf-8" +MIME-Version: 1.0 +Content-Transfer-Encoding: quoted-printable +From: Justus Winter <4winter@informatik.uni-hamburg.de> +User-Agent: alot/0.21+ +To: notmuch mailing list , +Date: Tue, 21 Feb 2012 00:29:21 -0000 +Message-ID: <20120221002921.8534.57091@thinkbox.jade-hamburg.de> +Subject: notmuch as a shared object aka library knigge +Date: Tue, 21 Feb 2012 01:29:21 +0100 +X-BeenThere: notmuch@notmuchmail.org +X-Mailman-Version: 2.1.13 +Precedence: list +List-Id: "Use and development of the notmuch mail system." + +List-Unsubscribe: , + +List-Archive: +List-Post: +List-Help: +List-Subscribe: , + +X-List-Received-Date: Tue, 21 Feb 2012 00:29:30 -0000 + +Hi fellow notmuchrs, + +while going through the python bindings I recently came across the +following note in the documentation for the Database.get_directory +function [0]: + +~~~ snip ~~~ +Warning + +This call needs a writable database in Database.MODE.READ_WRITE +mode. The underlying library will exit the program if this method is +used on a read-only database! +~~~ snap ~~~ + +and indeed, the following program exits with an error: + +~~~ snip ~~~ +import os +import notmuch + +db_path =3D os.path.expanduser('~/Maildir') + +with notmuch.Database(db_path, mode=3Dnotmuch.Database.MODE.READ_ONLY) as d= +b: + db.get_directory('') +~~~ snap ~~~ + +% python temp/get_directory.py +Internal error: Failure to ensure database is writable (lib/directory.cc:10= +0). + +The line mentioned in the error message reads: + + if (notmuch->mode =3D=3D NOTMUCH_DATABASE_MODE_READ_ONLY) + INTERNAL_ERROR ("Failure to ensure database is writable"); + +with + +/* There's no point in continuing when we've detected that we've done + * something wrong internally (as opposed to the user passing in a + * bogus value). + * + * Note that __location__ comes from talloc.h. + */ +#define INTERNAL_ERROR(format, ...) \ + _internal_error (format " (%s).\n", \ + ##__VA_ARGS__, __location__) + +and _internal_error calling exit(3). + +If creating a shared library is the preferred way to increase the +startup time of the notmuch binary that's totally cool, but if +libnotmuch is to be used as a library for arbitrary programs it is not +acceptable to call exit(3). + +(And as mentioned before, neither is writing to any file descriptor +unless it has been specifically requested by the caller.) + +Cheers, +Justus + +0: http://notmuch.readthedocs.org/en/latest/index.html#notmuch.Database.get= +_directory