From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-2.3 required=3.0 tests=AWL,BAYES_00,BODY_8BITS, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id 3B17C1F5AE for ; Sun, 9 May 2021 13:45:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229680AbhEINqU (ORCPT ); Sun, 9 May 2021 09:46:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229641AbhEINqS (ORCPT ); Sun, 9 May 2021 09:46:18 -0400 Received: from mail-il1-x132.google.com (mail-il1-x132.google.com [IPv6:2607:f8b0:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AC8BC061573 for ; Sun, 9 May 2021 06:45:14 -0700 (PDT) Received: by mail-il1-x132.google.com with SMTP id c3so11813664ils.5 for ; Sun, 09 May 2021 06:45:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=8z6hH4CMJIwMeLqc70Or/8g23kakDuABezHv1rgijrk=; b=pajlv7GhFjdS/TUEOx9GN6Pa/4f3H4q4atnSHMdans1GNCrT9fomwfaSYgcIeeYnNk inII40NKqPDhTw6HilpgJ1IV1qs1YdeEnaDBC9wpxc5bXNwb9nY0kg76wcXUv1q3xNzO J3K0zI3I+fugcu4GvYu9KbiPCtIgchLQdHQxCeJeA57oUaAiduUjxkO8sg5ghsh3JwdW uLqX22+ITqLPdpC8WwpuHF+S4CZIAJyzWog3vAPDWyYnUgR1j/6Guddth1Mf+XJK/E5R LfeRsRYZShsr/JB7ZdziZMpYf07DV9GQ+rRZybiUC5HC9HujIw5vu+e1orka9ZGemCCR y/gQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=8z6hH4CMJIwMeLqc70Or/8g23kakDuABezHv1rgijrk=; b=Rdq2vDsZq7wes6nA4pkgoslFIGrUKq1VbiJbCHcVyKb1snVqmlj1g6AtZrZZqi2PV7 tkpJyLOwsxriSADxGINdEiUPYp6w6BLeso2bv9mt/kNkTersUW7Q4vJoE3AT4MBW65UB bVJc3moXZ26cJxcYBxHtB+5rANttBKiVgshzVKfWAp7Cr4lnkiKW8Z40F5fCSgjbOPtv lAe+na2o9beQDeuUxRXN3SFS/yOBrRxQocX7VUk1AbnvTNcKoby4ebJIyLKrOufCkx+x GqSzTNimph7sO/cGX0UsLD/jtod7jf6E7gnAO60RAtYGTUmrZ4pTHl3XJRlW/oRv7AJK qQBw== X-Gm-Message-State: AOAM533FjnVZYvvkQV/syvyIjsb3TxpEWjRPLroQ//IVZc4suqUbFN49 MeQ3NaQLfjhc1lUCquopdc42g+gkf7nFSK6wSeM= X-Google-Smtp-Source: ABdhPJygzc5ZQHx5yf0jDUQW//Vqye+SqyI/BWak7hftvjSKm+VIU7xSGhZuuwIcscT/2ScLVVZajVbfA/ETjXkhfis= X-Received: by 2002:a92:c20e:: with SMTP id j14mr5255912ilo.259.1620567913915; Sun, 09 May 2021 06:45:13 -0700 (PDT) MIME-Version: 1.0 References: <3770df1829830229e768607b699730d2a7c21c5e.1620487353.git.gitgitgadget@gmail.com> In-Reply-To: From: ZheNing Hu Date: Sun, 9 May 2021 21:44:58 +0800 Message-ID: Subject: Re: [PATCH 2/2] [GSOC][RFC] ref-filter: introduce enum atom_type To: Junio C Hamano Cc: Christian Couder , ZheNing Hu via GitGitGadget , git , Jeff King , Christian Couder , Hariom Verma Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Junio C Hamano =E4=BA=8E2021=E5=B9=B45=E6=9C=889=E6=97= =A5=E5=91=A8=E6=97=A5 =E4=B8=8B=E5=8D=884:26=E5=86=99=E9=81=93=EF=BC=9A > > Christian Couder writes: > > > I am not sure it's worth having an atom_type field for each valid_atom > > element if the value of that field is already the index of the > > element, because then one would always be able to replace > > `valid_atom[i].atom_type` with just `i`. Or is it for some kind of > > type safety issue? > > > I wonder if the enum should be instead defined like this: > > > > enum atom_type { > > ATOM_UNKNOWN =3D 0, > > ATOM_REFNAME, > > ... > > ATOM_ELSE, > > ATOM_INVALID, /* should be last */ > > }; > > > > As a struct containing an atom_type would typically be initialized > > with 0 after being allocated, `ATOM_UNKNOWN =3D 0` could ensure that we > > can easily distinguish such a struct where the atom_type is known from > > such a struct where it is unknown yet. > > > > Having ATOM_INVALID as always the last enum value (even if some new > > ones are added later) could help us iterate over the valid atoms using > > something like: > > > > for (i =3D ATOM_UNKNOWN + 1; i < ATOM_INVALID; i++) > > /* do something with valid_atom[i] */; > > OK. > > As to "safety", I think it still makes sense to declare "enum", but > I agree that we do not necessarily have to have it in the valid_atom[] > struct. We could do something like this instead: > > static struct { > const char *name; > info_source source; > cmp_type cmp_type; > int (*parser)(const struct ref_format *format, struct used_at= om *atom, > const char *arg, struct strbuf *err); > } valid_atom[] =3D { > [ATOM_REFNAME] =3D { "refname", SOURCE_NONE, FIELD_STR, refnam= e_atom_parser }, > [ATOM_OBJECTTYPE] =3D { "objecttype", SOURCE_OTHER, FIELD_STR,= objecttype... > [ATOM_OBJECTSIZE] =3D { "objectsize", SOURCE_OTHER, FIELD_ULON= G, objectsi... > ... Thank! Good suggection. We hope that the atom_type and valid_atom items establish a clear connection. Maybe we should add some comments before the definition of the `enum atom_type` to remind the coder of the connection between atom_type and valid_atom. -- ZheNing Hu