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[2a01:4f8:120:2468::2]) by smtp.gmail.com with ESMTPSA id b1-20020a05600c4e0100b003a3170a7af9sm1280362wmq.4.2022.10.12.02.01.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Oct 2022 02:01:50 -0700 (PDT) From: =?utf-8?b?w4Z2YXIgQXJuZmrDtnLDsCBCamFybWFzb24=?= To: git@vger.kernel.org Cc: Junio C Hamano , Calvin Wan , Emily Shaffer , Phillip Wood , =?utf-8?b?w4Z2YXIgQXJuZmrDtnI=?= =?utf-8?b?w7AgQmphcm1hc29u?= Subject: [PATCH v2 11/22] run-command.c: use designated init for pp_init(), add "const" Date: Wed, 12 Oct 2022 11:01:19 +0200 Message-Id: X-Mailer: git-send-email 2.38.0.971.ge79ff6d20e7 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Use a designated initializer to initialize those parts of pp_init() that don't need any conditionals for their initialization, this sets us on a path to pp_init() itself into mostly a validation and allocation function. Since we're doing that we can add "const" to some of the members of the "struct parallel_processes", which helps to clarify and self-document this code. E.g. we never alter the "data" pointer we pass t user callbacks, nor (after the preceding change to stop invoking online_cpus()) do we change "max_processes", the same goes for the "ungroup" option. We can also do away with a call to strbuf_init() in favor of macro initialization, and to rely on other fields being NULL'd or zero'd. Making members of a struct "const" rather that the pointer to the struct itself is usually painful, as e.g. it precludes us from incrementally setting up the structure. In this case we only set it up with the assignment in run_process_parallel() and pp_init(), and don't pass the struct pointer around as "const", so making individual members "const" is worth the potential hassle for extra safety. Signed-off-by: Ævar Arnfjörð Bjarmason --- run-command.c | 34 ++++++++++++++-------------------- 1 file changed, 14 insertions(+), 20 deletions(-) diff --git a/run-command.c b/run-command.c index 21c00a48823..6acfd29d8c1 100644 --- a/run-command.c +++ b/run-command.c @@ -1496,9 +1496,9 @@ enum child_state { int run_processes_parallel_ungroup; struct parallel_processes { - void *data; + void *const data; - size_t max_processes; + const size_t max_processes; size_t nr_processes; get_next_task_fn get_next_task; @@ -1518,7 +1518,7 @@ struct parallel_processes { struct pollfd *pfd; unsigned shutdown : 1; - unsigned ungroup : 1; + const unsigned ungroup : 1; size_t output_owner; struct strbuf buffered_output; /* of finished children */ @@ -1556,21 +1556,18 @@ static void handle_children_on_signal(int signo) } static void pp_init(struct parallel_processes *pp, - size_t n, get_next_task_fn get_next_task, start_failure_fn start_failure, - task_finished_fn task_finished, - void *data, int ungroup) + task_finished_fn task_finished) { + const size_t n = pp->max_processes; + if (!n) BUG("you must provide a non-zero number of processes!"); - pp->max_processes = n; - trace_printf("run_processes_parallel: preparing to run up to %"PRIuMAX" tasks", (uintmax_t)n); - pp->data = data; if (!get_next_task) BUG("you need to specify a get_next_task function"); pp->get_next_task = get_next_task; @@ -1578,16 +1575,9 @@ static void pp_init(struct parallel_processes *pp, pp->start_failure = start_failure ? start_failure : default_start_failure; pp->task_finished = task_finished ? task_finished : default_task_finished; - pp->nr_processes = 0; - pp->output_owner = 0; - pp->shutdown = 0; - pp->ungroup = ungroup; CALLOC_ARRAY(pp->children, n); - if (pp->ungroup) - pp->pfd = NULL; - else + if (!pp->ungroup) CALLOC_ARRAY(pp->pfd, n); - strbuf_init(&pp->buffered_output, 0); for (size_t i = 0; i < n; i++) { strbuf_init(&pp->children[i].err, 0); @@ -1785,13 +1775,17 @@ void run_processes_parallel(size_t n, int output_timeout = 100; int spawn_cap = 4; int ungroup = run_processes_parallel_ungroup; - struct parallel_processes pp; + struct parallel_processes pp = { + .max_processes = n, + .data = pp_cb, + .buffered_output = STRBUF_INIT, + .ungroup = ungroup, + }; /* unset for the next API user */ run_processes_parallel_ungroup = 0; - pp_init(&pp, n, get_next_task, start_failure, task_finished, pp_cb, - ungroup); + pp_init(&pp, get_next_task, start_failure, task_finished); while (1) { for (int i = 0; i < spawn_cap && !pp.shutdown &&