Fixed multi-volume RAR support.

The access now open itself the following rar volumes (only if needed). This
also allows to support rar embeded in rar or using other protocals than file.

It has been broken since the rar modules have been modified to
support multiple files.
(cherry picked from commit 25262a5ae65b2ce815a938fc53bab0602944921f)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/access/rar/access.c

@@ -72,6 +72,7 @@ static int Seek(access_t *access, uint64_t position)
         position = file->real_size;
 
     /* Search the chunk */
+    const rar_file_chunk_t *old_chunk = sys->chunk;
     for (int i = 0; i < file->chunk_count; i++) {
         sys->chunk = file->chunk[i];
         if (position < sys->chunk->cummulated_size + sys->chunk->size)
@@ -82,7 +83,13 @@ static int Seek(access_t *access, uint64_t position)
 
     const uint64_t offset = sys->chunk->offset +
                             (position - sys->chunk->cummulated_size);
-    return stream_Seek(sys->s, offset);
+
+    if (strcmp(old_chunk->mrl, sys->chunk->mrl)) {
+        if (sys->s)
+            stream_Delete(sys->s);
+        sys->s = stream_UrlNew(access, sys->chunk->mrl);
+    }
+    return sys->s ? stream_Seek(sys->s, offset) : VLC_EGENERIC;
 }
 
 static ssize_t Read(access_t *access, uint8_t *data, size_t size)
@@ -96,7 +103,7 @@ static ssize_t Read(access_t *access, uint8_t *data, size_t size)
         if (max <= 0)
             break;
 
-        int r = stream_Read(sys->s, data, max);
+        int r = sys->s ? stream_Read(sys->s, data, max) : -1;
         if (r <= 0)
             break;
 
@@ -117,6 +124,9 @@ static ssize_t Read(access_t *access, uint8_t *data, size_t size)
 static int Control(access_t *access, int query, va_list args)
 {
     stream_t *s = access->p_sys->s;
+    if (!s)
+        return VLC_EGENERIC;
+
     switch (query) {
     case ACCESS_CAN_SEEK: {
         bool *b = va_arg(args, bool *);
@@ -190,6 +200,10 @@ static int Open(vlc_object_t *object)
     access_InitFields(access);
     access->info.i_size = file->size;
 
+    rar_file_chunk_t dummy = {
+        .mrl = base,
+    };
+    sys->chunk = &dummy;
     Seek(access, 0);
 
     free(base);
@@ -207,6 +221,7 @@ static void Close(vlc_object_t *object)
     access_t *access = (access_t*)object;
     access_sys_t *sys = access->p_sys;
 
+    if (sys->s)
         stream_Delete(sys->s);
     RarFileDelete(sys->file);
     free(sys);

modules/access/rar/rar.c

@@ -45,8 +45,10 @@ static const int rar_marker_size = sizeof(rar_marker);
 
 void RarFileDelete(rar_file_t *file)
 {
-    for (int i = 0; i < file->chunk_count; i++)
+    for (int i = 0; i < file->chunk_count; i++) {
+        free(file->chunk[i]->mrl);
         free(file->chunk[i]);
+    }
     free(file->chunk);
     free(file->name);
     free(file);
@@ -153,7 +155,8 @@ static int SkipEnd(stream_t *s, const rar_block_t *hdr)
     return VLC_SUCCESS;
 }
 
-static int SkipFile(stream_t *s, int *count, rar_file_t ***file, const rar_block_t *hdr)
+static int SkipFile(stream_t *s, int *count, rar_file_t ***file,
+                    const rar_block_t *hdr, const char *volume_mrl)
 {
     const uint8_t *peek;
 
@@ -223,6 +226,7 @@ static int SkipFile(stream_t *s, int *count, rar_file_t ***file, const rar_block
     /* Append chunks */
     rar_file_chunk_t *chunk = malloc(sizeof(*chunk));
     if (chunk) {
+        chunk->mrl = strdup(volume_mrl);
         chunk->offset = stream_Tell(s) + hdr->size;
         chunk->size = hdr->add_size;
         chunk->cummulated_size = 0;
@@ -267,42 +271,119 @@ int RarProbe(stream_t *s)
     return VLC_SUCCESS;
 }
 
+typedef struct {
+    const char *match;
+    const char *format;
+    int start;
+    int stop;
+} rar_pattern_t;
+
+static const rar_pattern_t *FindVolumePattern(const char *location)
+{
+    static const rar_pattern_t patterns[] = {
+        { ".part1.rar",   "%s.part%.1d.rar", 2,   9 },
+        { ".part01.rar",  "%s.part%.2d.rar", 2,  99, },
+        { ".part001.rar", "%s.part%.3d.rar", 2, 999 },
+        { ".rar",         "%s.r%.2d",        0,  99 },
+        { NULL, NULL, 0, 0 },
+    };
+
+    const size_t location_size = strlen(location);
+    for (int i = 0; patterns[i].match != NULL; i++) {
+        const size_t match_size = strlen(patterns[i].match);
+
+        if (location_size < match_size)
+            continue;
+        if (!strcmp(&location[location_size - match_size], patterns[i].match))
+            return &patterns[i];
+    }
+    return NULL;
+}
+
 int RarParse(stream_t *s, int *count, rar_file_t ***file)
 {
     *count = 0;
     *file = NULL;
 
-    /* Skip marker */
-    if (IgnoreBlock(s, RAR_BLOCK_MARKER))
+    const rar_pattern_t *pattern = FindVolumePattern(s->psz_path);
+    int volume_offset = 0;
+
+    char *volume_mrl;
+    if (asprintf(&volume_mrl, "%s://%s",
+                 s->psz_access, s->psz_path) < 0)
         return VLC_EGENERIC;
 
-    /* Skip archive  */
-    if (IgnoreBlock(s, RAR_BLOCK_ARCHIVE))
+    stream_t *vol = s;
+    for (;;) {
+        /* Skip marker & archive */
+        if (IgnoreBlock(vol, RAR_BLOCK_MARKER) ||
+            IgnoreBlock(vol, RAR_BLOCK_ARCHIVE)) {
+            if (vol != s)
+                stream_Delete(vol);
+            free(volume_mrl);
             return VLC_EGENERIC;
+        }
 
         /* */
+        bool has_next = false;
         for (;;) {
             rar_block_t bk;
             int ret;
 
-        if (PeekBlock(s, &bk))
+            if (PeekBlock(vol, &bk))
                 break;
 
             switch(bk.type) {
             case RAR_BLOCK_END:
-            ret = SkipEnd(s, &bk);
+                ret = SkipEnd(vol, &bk);
+                has_next = ret && (bk.flags & RAR_BLOCK_END_HAS_NEXT);
                 break;
             case RAR_BLOCK_FILE:
-            ret = SkipFile(s, count, file, &bk);
+                ret = SkipFile(vol, count, file, &bk, volume_mrl);
                 break;
             default:
-            ret = SkipBlock(s, &bk);
+                ret = SkipBlock(vol, &bk);
                 break;
             }
             if (ret)
                 break;
         }
+        if (vol != s)
+            stream_Delete(vol);
+
+        if (!has_next) {
+            free(volume_mrl);
+            return VLC_SUCCESS;
+        }
 
+        /* Open next volume */
+        const int volume_index = pattern->start + volume_offset++;
+        if (volume_index > pattern->stop) {
+            free(volume_mrl);
             return VLC_SUCCESS;
+        }
+
+        char *volume_base;
+        if (asprintf(&volume_base, "%s://%.*s",
+                     s->psz_access,
+                     (int)(strlen(s->psz_path) - strlen(pattern->match)), s->psz_path) < 0) {
+            free(volume_mrl);
+            return VLC_SUCCESS;
+        }
+
+        free(volume_mrl);
+        if (asprintf(&volume_mrl, pattern->format, volume_base, volume_index) < 0)
+            volume_mrl = NULL;
+        free(volume_base);
+
+        if (!volume_mrl)
+            return VLC_SUCCESS;
+        vol = stream_UrlNew(s, volume_mrl);
+
+        if (!vol) {
+            free(volume_mrl);
+            return VLC_SUCCESS;
+        }
+    }
 }
 

modules/access/rar/rar.h

@@ -22,6 +22,7 @@
  *****************************************************************************/
 
 typedef struct {
+    char     *mrl;
     uint64_t offset;
     uint64_t size;
     uint64_t cummulated_size;