Add VFS handling logic to mj_openResource.

PiperOrigin-RevId: 653124909
Change-Id: I4d031eb0bfb0070f8493753d2aeaac60ac283b85

src/user/user_resource.h

@@ -30,7 +30,8 @@ extern "C" {
 
 // open the given resource; if the name doesn't have a prefix matching with a
 // resource provider, then the OS filesystem is used
-MJAPI mjResource* mju_openResource(const char* name, char* error, std::size_t nerror);
+MJAPI mjResource* mju_openResource(const char* name, const mjVFS* vfs,
+                                   char* error, std::size_t nerror);
 
 // close the given resource; no-op if resource is NULL
 MJAPI void mju_closeResource(mjResource* resource);
@@ -47,14 +48,8 @@ MJAPI void mju_getResourceDir(mjResource* resource, const char** dir, int* ndir)
 // return < 0 if the resource is older than the given timestamp
 MJAPI int mju_isModifiedResource(const mjResource* resource, const char* timestamp);
 
-// get the length of the dirname portion of a given path
-MJAPI int mju_dirnamelen(const char* path);
-
 #ifdef __cplusplus
 }
 #endif
 
-// read file into memory buffer (allocated here with mju_malloc)
-std::vector<uint8_t> mju_fileToMemory(const char* filename);
-
 #endif  // MUJOCO_SRC_ENGINE_ENGINE_RESOURCE_H_