- * Call the convert function of each filter.
- *
- * \param s Unused.
- * \param t The task identifying the filter chain.
- *
- * This is the core function of the filter subsystem. It loops over the list of
- * filter nodes determined by \a t and calls the filter's convert function if
- * there is input available for the filter node in question. If the convert
- * function consumed some or all of its input data, all registered input
- * callbacks are called. Similarly, if a convert function produced output, all
- * registered output callbacks get called.
- *
- * On errors a (negative) error code is stored in t->error.
- *
- * \sa filter_node, filter#convert, filter_callback.
- */
-void filter_pre_select(__a_unused struct sched *s, struct task *t)
-{
- struct filter_chain *fc = container_of(t, struct filter_chain, task);
- struct filter_node *fn;
- char *ib;
- size_t *loaded;
- int i, conv, conv_total = 0;
-
- if (fc->output_error && *fc->output_error < 0) {
- t->error = *fc->output_error;
- return;
- }
-again:
- ib = *fc->inbufp;
- loaded = fc->in_loaded;
- conv = 0;
- FOR_EACH_FILTER_NODE(fn, fc, i) {
- struct filter *f = filters + fn->filter_num;
- if (fn->loaded < fn->bufsize) {
- size_t size, old_fn_loaded = fn->loaded;
- t->error = f->convert(ib, *loaded, fn);
- if (t->error < 0)
- return;
- size = t->error;
- call_callbacks(fn, ib, size, fn->buf + old_fn_loaded,
- fn->loaded - old_fn_loaded);
- *loaded -= size;
- conv += size + fn->loaded - old_fn_loaded;
- if (*loaded && size)
- memmove(ib, ib + size, *loaded);
- }
- ib = fn->buf;
- loaded = &fn->loaded;
- }
- conv_total += conv;
- if (conv)
- goto again;
- if (conv_total) {
- /*
- * Other pre_select functions might have already been called by
- * now and decided to do nothing, e.g. because their output
- * buffer was full or the input buffer was empty. We just
- * converted something which caused these buffers to change but
- * we can't make the other tasks reconsider their decision at
- * this point. So force a minimal timeout for the next select
- * call to avoid unnecessary delays.
- */
- s->timeout.tv_sec = 0;
- s->timeout.tv_usec = 1;
- }
- if (*fc->input_error >= 0)
- return;
- if (*fc->out_loaded)
- return;
- if (*fc->in_loaded && conv_total)
- return;
- t->error = -E_FC_EOF;
-}
-
-/**
- * Close all filter nodes and their callbacks.
- *
- * \param fc The filter chain to close.
- *
- * For each filter node determined by \a fc, call the close function of each
- * registered filter callback as well as the close function of the
- * corresponding filter. Free all resources and destroy all callback lists and
- * the filter node list.
- *
- * \sa filter::close, filter_callback::close