[FFmpeg-devel] [PATCH v3 3/4] lavfi: check the validity of formats lists.

[Nicolas George]

Part of the code expect valid lists, in particular no duplicates.
These tests allow to catch bugs in filters (unlikely but possible)
and to give a clear message when the error comes from the user
((a)formats) or the application (buffersink).

If we decide to switch for a more efficient merging algorithm,
possibly sorting the lists, these functions will be the prefered
place for pre-processing, and can be renamed accordingly.

Signed-off-by: Nicolas George <george at nsup.org>
---
 libavfilter/avfiltergraph.c | 50 ++++++++++++++++++++++++++
 libavfilter/formats.c       | 71 +++++++++++++++++++++++++++++++++++++
 libavfilter/formats.h       | 28 +++++++++++++++
 3 files changed, 149 insertions(+)


Extended commit message.


diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 7a85d94971..296920a046 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -313,6 +313,53 @@ static void sanitize_channel_layouts(void *log, AVFilterChannelLayouts *l)
     }
 }
 
+static int filter_link_check_formats(void *log, AVFilterLink *link, AVFilterFormatsConfig *cfg)
+{
+    int ret;
+
+    switch (link->type) {
+
+        case AVMEDIA_TYPE_VIDEO:
+            if ((ret = ff_formats_check_pixel_formats(log, cfg->formats)) < 0)
+                return ret;
+            break;
+
+        case AVMEDIA_TYPE_AUDIO:
+            if ((ret = ff_formats_check_sample_formats(log, cfg->formats)) < 0 ||
+                (ret = ff_formats_check_sample_rates(log, cfg->samplerates)) < 0 ||
+                (ret = ff_formats_check_channel_layouts(log, cfg->channel_layouts)) < 0)
+                return ret;
+            break;
+
+        default:
+            av_assert0(!"reached");
+    }
+    return 0;
+}
+
+/**
+ * Check the validity of the formats / etc. lists set by query_formats().
+ *
+ * In particular, check they do not contain any redundant element.
+ */
+static int filter_check_formats(AVFilterContext *ctx)
+{
+    unsigned i;
+    int ret;
+
+    for (i = 0; i < ctx->nb_inputs; i++) {
+        ret = filter_link_check_formats(ctx, ctx->inputs[i], &ctx->inputs[i]->outcfg);
+        if (ret < 0)
+            return ret;
+    }
+    for (i = 0; i < ctx->nb_outputs; i++) {
+        ret = filter_link_check_formats(ctx, ctx->outputs[i], &ctx->outputs[i]->incfg);
+        if (ret < 0)
+            return ret;
+    }
+    return 0;
+}
+
 static int filter_query_formats(AVFilterContext *ctx)
 {
     int ret, i;
@@ -329,6 +376,9 @@ static int filter_query_formats(AVFilterContext *ctx)
                    ctx->name, av_err2str(ret));
         return ret;
     }
+    ret = filter_check_formats(ctx);
+    if (ret < 0)
+        return ret;
 
     for (i = 0; i < ctx->nb_inputs; i++)
         sanitize_channel_layouts(ctx, ctx->inputs[i]->outcfg.channel_layouts);
diff --git a/libavfilter/formats.c b/libavfilter/formats.c
index 695d28ea8e..e575894e77 100644
--- a/libavfilter/formats.c
+++ b/libavfilter/formats.c
@@ -662,3 +662,74 @@ int ff_parse_channel_layout(int64_t *ret, int *nret, const char *arg,
 
     return 0;
 }
+
+static int check_list(void *log, const char *name, const AVFilterFormats *fmts)
+{
+    unsigned i, j;
+
+    if (!fmts)
+        return 0;
+    if (!fmts->nb_formats) {
+        av_log(log, AV_LOG_ERROR, "Empty %s list\n", name);
+        return AVERROR(EINVAL);
+    }
+    for (i = 0; i < fmts->nb_formats; i++) {
+        for (j = i + 1; j < fmts->nb_formats; j++) {
+            if (fmts->formats[i] == fmts->formats[j]) {
+                av_log(log, AV_LOG_ERROR, "Duplicated %s\n", name);
+                return AVERROR(EINVAL);
+            }
+        }
+    }
+    return 0;
+}
+
+int ff_formats_check_pixel_formats(void *log, const AVFilterFormats *fmts)
+{
+    return check_list(log, "pixel format", fmts);
+}
+
+int ff_formats_check_sample_formats(void *log, const AVFilterFormats *fmts)
+{
+    return check_list(log, "sample format", fmts);
+}
+
+int ff_formats_check_sample_rates(void *log, const AVFilterFormats *fmts)
+{
+    if (!fmts || !fmts->nb_formats)
+        return 0;
+    return check_list(log, "sample rate", fmts);
+}
+
+static int layouts_compatible(uint64_t a, uint64_t b)
+{
+    return a == b ||
+           (KNOWN(a) && !KNOWN(b) && av_get_channel_layout_nb_channels(a) == FF_LAYOUT2COUNT(b)) ||
+           (KNOWN(b) && !KNOWN(a) && av_get_channel_layout_nb_channels(b) == FF_LAYOUT2COUNT(a));
+}
+
+int ff_formats_check_channel_layouts(void *log, const AVFilterChannelLayouts *fmts)
+{
+    unsigned i, j;
+
+    if (!fmts)
+        return 0;
+    if (fmts->all_layouts < fmts->all_counts ||
+        (!fmts->all_layouts && !fmts->nb_channel_layouts)) {
+        av_log(log, AV_LOG_ERROR, "Inconsistent generic list\n");
+        return AVERROR(EINVAL);
+    }
+    if (!fmts->all_layouts && !fmts->nb_channel_layouts) {
+        av_log(log, AV_LOG_ERROR, "Empty channel layout list\n");
+        return AVERROR(EINVAL);
+    }
+    for (i = 0; i < fmts->nb_channel_layouts; i++) {
+        for (j = i + 1; j < fmts->nb_channel_layouts; j++) {
+            if (layouts_compatible(fmts->channel_layouts[i], fmts->channel_layouts[j])) {
+                av_log(log, AV_LOG_ERROR, "Duplicated or redundant channel layout\n");
+                return AVERROR(EINVAL);
+            }
+        }
+    }
+    return 0;
+}
diff --git a/libavfilter/formats.h b/libavfilter/formats.h
index a06e88722e..8378be4b9b 100644
--- a/libavfilter/formats.h
+++ b/libavfilter/formats.h
@@ -291,4 +291,32 @@ void ff_formats_unref(AVFilterFormats **ref);
  */
 void ff_formats_changeref(AVFilterFormats **oldref, AVFilterFormats **newref);
 
+/**
+ * Check that fmts is a valid pixel formats list.
+ *
+ * In particular, check for duplicates.
+ */
+int ff_formats_check_pixel_formats(void *log, const AVFilterFormats *fmts);
+
+/**
+ * Check that fmts is a valid sample formats list.
+ *
+ * In particular, check for duplicates.
+ */
+int ff_formats_check_sample_formats(void *log, const AVFilterFormats *fmts);
+
+/**
+ * Check that fmts is a valid sample rates list.
+ *
+ * In particular, check for duplicates.
+ */
+int ff_formats_check_sample_rates(void *log, const AVFilterFormats *fmts);
+
+/**
+ * Check that fmts is a valid channel layouts list.
+ *
+ * In particular, check for duplicates.
+ */
+int ff_formats_check_channel_layouts(void *log, const AVFilterChannelLayouts *fmts);
+
 #endif /* AVFILTER_FORMATS_H */
-- 
2.28.0