From bd473d325d6065bf05502afcd663c312702a2ba7 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Date: Tue, 1 Dec 2020 17:25:17 +0100
Subject: [PATCH] avcodec/bink: Make decoder init-threadsafe

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
---
 libavcodec/bink.c | 38 ++++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/libavcodec/bink.c b/libavcodec/bink.c
index 36d1ab6c0a..3eb767b83e 100644
--- a/libavcodec/bink.c
+++ b/libavcodec/bink.c
@@ -24,6 +24,7 @@
 #include "libavutil/imgutils.h"
 #include "libavutil/internal.h"
 #include "libavutil/mem_internal.h"
+#include "libavutil/thread.h"
 
 #define BITSTREAM_READER_LE
 #include "avcodec.h"
@@ -1309,6 +1310,19 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPac
     return pkt->size;
 }
 
+static av_cold void bink_init_vlcs(void)
+{
+    for (int i = 0; i < 16; i++) {
+        static VLC_TYPE table[16 * 128][2];
+        const int maxbits = bink_tree_lens[i][15];
+        bink_trees[i].table = table + i*128;
+        bink_trees[i].table_allocated = 1 << maxbits;
+        init_vlc(&bink_trees[i], maxbits, 16,
+                 bink_tree_lens[i], 1, 1,
+                 bink_tree_bits[i], 1, 1, INIT_VLC_USE_NEW_STATIC | INIT_VLC_LE);
+    }
+}
+
 /**
  * Calculate quantization tables for version b
  */
@@ -1343,11 +1357,10 @@ static av_cold void binkb_calc_quant(void)
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {
+    static AVOnce init_static_once = AV_ONCE_INIT;
     BinkContext * const c = avctx->priv_data;
-    static VLC_TYPE table[16 * 128][2];
-    static int binkb_initialised = 0;
     HpelDSPContext hdsp;
-    int i, ret;
+    int ret;
     int flags;
 
     c->version = avctx->codec_tag >> 24;
@@ -1358,16 +1371,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
     flags = AV_RL32(avctx->extradata);
     c->has_alpha = flags & BINK_FLAG_ALPHA;
     c->swap_planes = c->version >= 'h';
-    if (!bink_trees[15].table) {
-        for (i = 0; i < 16; i++) {
-            const int maxbits = bink_tree_lens[i][15];
-            bink_trees[i].table = table + i*128;
-            bink_trees[i].table_allocated = 1 << maxbits;
-            init_vlc(&bink_trees[i], maxbits, 16,
-                     bink_tree_lens[i], 1, 1,
-                     bink_tree_bits[i], 1, 1, INIT_VLC_USE_NEW_STATIC | INIT_VLC_LE);
-        }
-    }
     c->avctx = avctx;
 
     if ((ret = av_image_check_size(avctx->width, avctx->height, 0, avctx)) < 0)
@@ -1389,11 +1392,10 @@ static av_cold int decode_init(AVCodecContext *avctx)
         return ret;
 
     if (c->version == 'b') {
-        if (!binkb_initialised) {
-            binkb_calc_quant();
-            binkb_initialised = 1;
-        }
+        static AVOnce binkb_init_once = AV_ONCE_INIT;
+        ff_thread_once(&binkb_init_once, binkb_calc_quant);
     }
+    ff_thread_once(&init_static_once, bink_init_vlcs);
 
     return 0;
 }
@@ -1426,5 +1428,5 @@ const AVCodec ff_bink_decoder = {
     .decode         = decode_frame,
     .flush          = flush,
     .capabilities   = AV_CODEC_CAP_DR1,
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
 };