lavfi: add query_func2()

It differs from query_func() in accepting arrays of input/output format
configurations to be filled as callback parameters. This allows to mark
the filter context as const, ensuring it is not modified by this
function, as it is not supposed to have any side effects beyond
returning the supported formats.

1 files changed, 43 insertions, 0 deletions

diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 68e392b826..c84dd3cf25 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -352,7 +352,50 @@ static int filter_query_formats(AVFilterContext *ctx)
                        ctx->name, av_err2str(ret));
             return ret;
         }
+    } else if (ctx->filter->formats_state == FF_FILTER_FORMATS_QUERY_FUNC2) {
+        AVFilterFormatsConfig *cfg_in_stack[64], *cfg_out_stack[64];
+        AVFilterFormatsConfig **cfg_in_dyn = NULL, **cfg_out_dyn = NULL;
+        AVFilterFormatsConfig **cfg_in, **cfg_out;
+
+        if (ctx->nb_inputs > FF_ARRAY_ELEMS(cfg_in_stack)) {
+            cfg_in_dyn = av_malloc_array(ctx->nb_inputs, sizeof(*cfg_in_dyn));
+            if (!cfg_in_dyn)
+                return AVERROR(ENOMEM);
+            cfg_in = cfg_in_dyn;
+        } else
+            cfg_in = ctx->nb_inputs ? cfg_in_stack : NULL;
+
+        for (unsigned i = 0; i < ctx->nb_inputs; i++) {
+            AVFilterLink *l = ctx->inputs[i];
+            cfg_in[i] = &l->outcfg;
+        }
+
+        if (ctx->nb_outputs > FF_ARRAY_ELEMS(cfg_out_stack)) {
+            cfg_out_dyn = av_malloc_array(ctx->nb_outputs, sizeof(*cfg_out_dyn));
+            if (!cfg_out_dyn)
+                return AVERROR(ENOMEM);
+            cfg_out = cfg_out_dyn;
+        } else
+            cfg_out = ctx->nb_outputs ? cfg_out_stack : NULL;
+
+        for (unsigned i = 0; i < ctx->nb_outputs; i++) {
+            AVFilterLink *l = ctx->outputs[i];
+            cfg_out[i] = &l->incfg;
+        }
+
+        ret = ctx->filter->formats.query_func2(ctx, cfg_in, cfg_out);
+        av_freep(&cfg_in_dyn);
+        av_freep(&cfg_out_dyn);
+        if (ret < 0) {
+            if (ret != AVERROR(EAGAIN))
+                av_log(ctx, AV_LOG_ERROR, "Query format failed for '%s': %s\n",
+                       ctx->name, av_err2str(ret));
+            return ret;
+        }
+    }
 
+    if (ctx->filter->formats_state == FF_FILTER_FORMATS_QUERY_FUNC ||
+        ctx->filter->formats_state == FF_FILTER_FORMATS_QUERY_FUNC2) {
         ret = filter_check_formats(ctx);
         if (ret < 0)
             return ret;