plugins: Simplify plugin/codec API versioning

Replace the minimum version bound with a check on the size of
the API struct. The version only needs to be incremented for
ABI breaking changes. Additions to the API won't need to touch
the version number, resulting in fewer merge conflicts.

Change-Id: I916a04a7bf5890dcf5d615ce30087643165f8e1f

apps/codecs.c

···
         return CODEC_ERROR;
     }
 
-    if (hdr->api_version > CODEC_API_VERSION
-        || hdr->api_version < CODEC_MIN_API_VERSION) {
+    if (hdr->api_version != CODEC_API_VERSION ||
+        c_hdr->api_size > sizeof(struct codec_api))
+    {
         logf("codec api version error");
         lc_close(curr_handle);
         curr_handle = NULL;

apps/plugin.c

···
     }
 
     p_hdr = lc_get_header(current_plugin_handle);
-
     hdr = p_hdr ? &p_hdr->lc_hdr : NULL;
-
 
     if (hdr == NULL
         || hdr->magic != PLUGIN_MAGIC
···
         splash(HZ*2, ID2P(LANG_PLUGIN_WRONG_MODEL));
         return -1;
     }
-    if (hdr->api_version > PLUGIN_API_VERSION
-        || hdr->api_version < PLUGIN_MIN_API_VERSION)
+
+    if (hdr->api_version != PLUGIN_API_VERSION ||
+        p_hdr->api_size > sizeof(struct plugin_api))
     {
         lc_close(current_plugin_handle);
         splash(HZ*2, ID2P(LANG_PLUGIN_WRONG_VERSION));
         return -1;
     }
+
 #if (CONFIG_PLATFORM & PLATFORM_NATIVE)
     /* tlsf crashes observed on arm with 0x4 aligned addresses */
     plugin_size = ALIGN_UP(hdr->end_addr - pluginbuf, 0x8);

apps/plugin.h

···
 
 #define PLUGIN_MAGIC 0x526F634B /* RocK */
 
-/* increase this every time the api struct changes */
-#define PLUGIN_API_VERSION 265
-
-/* update this to latest version if a change to the api struct breaks
-   backwards compatibility (and please take the opportunity to sort in any
-   new function which are "waiting" at the end of the function table) */
-#define PLUGIN_MIN_API_VERSION 260
+/*
+ * Increment this whenever a change breaks the plugin ABI,
+ * when this happens please take the opportunity to sort in
+ * any new functions "waiting" at the end of the list.
+ */
+#define PLUGIN_API_VERSION 266
 
 /* 239 Marks the removal of ARCHOS HWCODEC and CHARCELL */
 
···
     struct lc_header lc_hdr; /* must be the first */
     enum plugin_status(*entry_point)(const void*);
     const struct plugin_api **api;
+    size_t api_size;
 };
 
 #ifdef PLUGIN
···
         const struct plugin_header __header \
         __attribute__ ((section (".header")))= { \
         { PLUGIN_MAGIC, TARGET_ID, PLUGIN_API_VERSION, \
-        plugin_start_addr, plugin_end_addr }, plugin__start, &rb };
+          plugin_start_addr, plugin_end_addr, }, \
+        plugin__start, &rb, sizeof(struct plugin_api) };
 #else /* PLATFORM_HOSTED */
 #define PLUGIN_HEADER \
         const struct plugin_api *rb DATA_ATTR; \
         const struct plugin_header __header \
         __attribute__((visibility("default"))) = { \
-        { PLUGIN_MAGIC, TARGET_ID, PLUGIN_API_VERSION, NULL, NULL }, \
-        plugin__start, &rb };
+            { PLUGIN_MAGIC, TARGET_ID, PLUGIN_API_VERSION, NULL, NULL }, \
+            plugin__start, &rb, sizeof(struct plugin_api) };
 #endif /* CONFIG_PLATFORM */
 #endif /* PLUGIN */
 

apps/plugins/imageviewer/image_decoder.c

···
         goto error_close;
     }
 
-    if (lc_hdr->api_version != IMGDEC_API_VERSION)
+    if (lc_hdr->api_version != IMGDEC_API_VERSION ||
+        hdr->img_api_size > sizeof(struct imgdec_api) ||
+        hdr->plugin_api_version != PLUGIN_API_VERSION ||
+        hdr->plugin_api_size > sizeof(struct plugin_api))
     {
         rb->splashf(2*HZ, "%s decoder: Incompatible version.", name);
         goto error_close;

apps/plugins/imageviewer/imageviewer.h

···
                             int x, int y, int width, int height);
 };
 
-#define IMGDEC_API_VERSION  (PLUGIN_API_VERSION << 4 | 0)
+#define IMGDEC_API_VERSION 1
 
 /* image decoder header */
 struct imgdec_header {
     struct lc_header lc_hdr; /* must be the first */
     const struct image_decoder *decoder;
     const struct plugin_api **api;
+    unsigned short plugin_api_version;
+    size_t plugin_api_size;
     const struct imgdec_api **img_api;
+    size_t img_api_size;
 };
 
 #ifdef IMGDEC
···
         const struct imgdec_header __header \
         __attribute__ ((section (".header")))= { \
         { PLUGIN_MAGIC, TARGET_ID, IMGDEC_API_VERSION, \
-        plugin_start_addr, plugin_end_addr }, &image_decoder, &rb, &iv };
+          plugin_start_addr, plugin_end_addr, }, &image_decoder, \
+          &rb, PLUGIN_API_VERSION, sizeof(struct plugin_api), \
+          &iv, sizeof(struct imgdec_api) };
 #else /* PLATFORM_HOSTED */
 #define IMGDEC_HEADER \
         const struct plugin_api *rb DATA_ATTR; \
         const struct imgdec_api *iv DATA_ATTR; \
         const struct imgdec_header __header \
         __attribute__((visibility("default"))) = { \
-        { PLUGIN_MAGIC, TARGET_ID, IMGDEC_API_VERSION, \
-        NULL, NULL }, &image_decoder, &rb, &iv };
+        { PLUGIN_MAGIC, TARGET_ID, IMGDEC_API_VERSION, NULL, NULL }, \
+          &image_decoder, &rb, PLUGIN_API_VERSION, sizeof(struct plugin_api), \
+          &iv, sizeof(struct imgdec_api), };
 #endif /* CONFIG_PLATFORM */
 #endif
 

apps/plugins/lib/overlay.c

···
         goto error_close;
     }
 
-    
-    if (hdr->api_version > PLUGIN_API_VERSION
-        || hdr->api_version < PLUGIN_MIN_API_VERSION)
+    if (hdr->api_version != PLUGIN_API_VERSION ||
+        p_hdr->api_size > sizeof(struct plugin_api))
     {
         rb->splashf(2*HZ, "%s overlay: Incompatible version.", name);
         goto error_close;

lib/rbcodec/codecs/codecs.h

···
 /* magic for encoder codecs */
 #define CODEC_ENC_MAGIC 0x52454E43 /* RENC */
 
-/* increase this every time the api struct changes */
-#define CODEC_API_VERSION 49
-
-/* update this to latest version if a change to the api struct breaks
-   backwards compatibility (and please take the opportunity to sort in any
-   new function which are "waiting" at the end of the function table) */
-#define CODEC_MIN_API_VERSION 49
+/*
+ * Increment this whenever a change breaks the codec ABI,
+ * when this happens please take the opportunity to sort in
+ * any new functions "waiting" at the end of the list.
+ */
+#define CODEC_API_VERSION 50
 
 /* reasons for calling codec main entrypoint */
 enum codec_entry_call_reason {
···
     enum codec_status(*entry_point)(enum codec_entry_call_reason reason);
     enum codec_status(*run_proc)(void);
     struct codec_api **api;
+    size_t api_size;
     void * rec_extension[]; /* extension for encoders */
 };
 
···
         const struct codec_header __header \
         __attribute__ ((section (".header")))= { \
         { CODEC_MAGIC, TARGET_ID, CODEC_API_VERSION, \
-        plugin_start_addr, plugin_end_addr }, codec_start, \
-        codec_run, &ci };
+          plugin_start_addr, plugin_end_addr }, \
+        codec_start, codec_run, &ci, sizeof(struct codec_api) };
 /* encoders */
 #define CODEC_ENC_HEADER \
         const struct codec_header __header \
         __attribute__ ((section (".header")))= { \
         { CODEC_ENC_MAGIC, TARGET_ID, CODEC_API_VERSION, \
-        plugin_start_addr, plugin_end_addr }, codec_start, \
-        codec_run, &ci, { enc_callback } };
+          plugin_start_addr, plugin_end_addr }, \
+        codec_start, codec_run, &ci, sizeof(struct codec_api), \
+        { enc_callback } };
 
 #else /* def SIMULATOR */
 /* decoders */
···
         const struct codec_header __header \
         __attribute__((visibility("default"))) = { \
         { CODEC_MAGIC, TARGET_ID, CODEC_API_VERSION, NULL, NULL }, \
-        codec_start, codec_run, &ci };
+        codec_start, codec_run, &ci, sizeof(struct codec_api) };
 /* encoders */
 #define CODEC_ENC_HEADER \
         const struct codec_header __header \
         __attribute__((visibility("default"))) = { \
         { CODEC_ENC_MAGIC, TARGET_ID, CODEC_API_VERSION, NULL, NULL }, \
-        codec_start, codec_run, &ci, { enc_callback } };
+        codec_start, codec_run, &ci, sizeof(struct codec_api), \
+        { enc_callback } };
 #endif /* SIMULATOR */
 #endif /* CODEC */