avformat/avio: Schedule AVIODirContext to become an opaque type

Users can't make anything with its content.
Making it opaque might allow us to avoid one level of indirection.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

doc/APIchanges

@@ -14,6 +14,9 @@ libavutil:     2021-04-27
 
 API changes, most recent first:
 
+2022-10-03 - xxxxxxxxxx - lavf 59.34.100 - avio.h
+  Make AVIODirContext an opaque type in a future major version bump.
+
 2022-09-27 - 0c0a3deb18 - lavu 57.38.100 - cpu.h
   Add CPU flags for RISC-V vector extensions:
   AV_CPU_FLAG_RVV_I32, AV_CPU_FLAG_RVV_F32, AV_CPU_FLAG_RVV_I64,

libavformat/avio.c

@@ -528,6 +528,12 @@ int ffurl_delete(const char *url)
     return ret;
 }
 
+#if !FF_API_AVIODIRCONTEXT
+struct AVIODirContext {
+    struct URLContext *url_context;
+};
+#endif
+
 int avio_open_dir(AVIODirContext **s, const char *url, AVDictionary **options)
 {
     URLContext *h = NULL;

libavformat/avio.h

@@ -101,9 +101,13 @@ typedef struct AVIODirEntry {
     int64_t filemode;                     /**< Unix file mode, -1 if unknown. */
 } AVIODirEntry;
 
+#if FF_API_AVIODIRCONTEXT
 typedef struct AVIODirContext {
     struct URLContext *url_context;
 } AVIODirContext;
+#else
+typedef struct AVIODirContext AVIODirContext;
+#endif
 
 /**
  * Different data types that can be returned via the AVIO

libavformat/version.h

@@ -31,7 +31,7 @@
 
 #include "version_major.h"
 
-#define LIBAVFORMAT_VERSION_MINOR  33
+#define LIBAVFORMAT_VERSION_MINOR  34
 #define LIBAVFORMAT_VERSION_MICRO 100
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \

libavformat/version_major.h

@@ -47,6 +47,7 @@
 #define FF_HLS_TS_OPTIONS               (LIBAVFORMAT_VERSION_MAJOR < 60)
 #define FF_API_AVSTREAM_CLASS           (LIBAVFORMAT_VERSION_MAJOR > 59)
 #define FF_API_GET_END_PTS              (LIBAVFORMAT_VERSION_MAJOR < 60)
+#define FF_API_AVIODIRCONTEXT           (LIBAVFORMAT_VERSION_MAJOR < 60)
 
 
 #define FF_API_R_FRAME_RATE            1