On Tue, Feb 23, 2021 at 11:33:24AM -0800, Jonathan Tan wrote: > > > > > +/** > > > > + * This callback is called repeatedly 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. > > > > + * The contents of 'send' will be read into the pipe and passed to the pipe. > > > > + * > > > > + * Return nonzero to close the pipe. > > > > + */ > > > > +typedef int (*feed_pipe_fn)(struct strbuf *pipe, > > > > + void *pp_cb, > > > > + void *pp_task_cb); > > > > + > > > > > > As you mention above in the commit message, I think the clearest API to > > > support what we need is to just have a callback (that has access to > > > child_process) that is executed between process start and finish. > > > > > > As it is, I think this callback is too specific in that it takes a > > > struct strbuf. I think that this struct strbuf will just end up being > > > unnecessary copying much of the time, when the user could have just > > > written to the fd directly. > > > > Since the rest of the run_processes_parallel() API passes strings around > > with strbufs, I'd prefer to leave it as-is to match the general API > > expectations and style. > > > > - Emily > > By the rest of the run_processes_parallel() API, do you mean > get_next_task_fn, start_failure_fn, and task_finished_fn? If yes, I > think that it makes sense for them to be strbuf, because buffering is > needed to avoid outputs from individual child processes interleaving, > but that's not true here. > > Having said that, this is an internal API so we could just leave it > as-is and then refactor it if we ever need something more flexible. Yeah, with that in mind I'll leave it as it is. I don't like the idea of directly exposing the child's pipe via callback; to me it feels like bad object-oriented design, but that maybe doesn't apply here :) Anyway, like you say, we can change it later if someone doesn't like this, no problem.
