From ec0becacc9847406f2b0147a81f62e023b006351 Mon Sep 17 00:00:00 2001 From: Emily Shaffer Date: Wed, 28 Jan 2026 23:39:18 +0200 Subject: run-command: add stdin callback for parallelization MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If a user of the run_processes_parallel() API wants to pipe a large amount of information to the stdin of each parallel command, that data could exceed the pipe buffer of the process's stdin and can be too big to store in-memory via strbuf & friends or to slurp to a file. Generally this is solved by repeatedly writing to child_process.in between calls to start_command() and finish_command(). For a specific pre-existing example of this, see transport.c:run_pre_push_hook(). This adds a generic callback API to run_processes_parallel() to do exactly that in a unified manner, similar to the existing callback APIs, which can then be used by hooks.h to convert the remaining hooks to the new, simpler parallel interface. Signed-off-by: Emily Shaffer Signed-off-by: Ævar Arnfjörð Bjarmason Signed-off-by: Adrian Ratiu Signed-off-by: Junio C Hamano --- run-command.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'run-command.h') diff --git a/run-command.h b/run-command.h index 0df25e445f..e1ca965b5b 100644 --- a/run-command.h +++ b/run-command.h @@ -420,6 +420,21 @@ typedef int (*start_failure_fn)(struct strbuf *out, void *pp_cb, void *pp_task_cb); +/** + * This callback is repeatedly called on every child process who requests + * start_command() to create a pipe by setting child_process.in < 0. + * + * pp_cb is the callback cookie as passed into run_processes_parallel, and + * pp_task_cb is the callback cookie as passed into get_next_task_fn. + * + * Returns < 0 for error + * Returns == 0 when there is more data to be fed (will be called again) + * Returns > 0 when finished (child closed fd or no more data to be fed) + */ +typedef int (*feed_pipe_fn)(int child_in, + void *pp_cb, + void *pp_task_cb); + /** * This callback is called on every child process that finished processing. * @@ -473,6 +488,12 @@ struct run_process_parallel_opts */ start_failure_fn start_failure; + /* + * feed_pipe: see feed_pipe_fn() above. This can be NULL to omit any + * special handling. + */ + feed_pipe_fn feed_pipe; + /** * task_finished: See task_finished_fn() above. This can be * NULL to omit any special handling. -- cgit v1.3