Handle exceptions in VFS C API.

PiperOrigin-RevId: 817688877
Change-Id: Ia2e306fe4cd1848eb5731212aa4e959080a9d377

src/user/user_util.cc

@@ -1140,7 +1140,13 @@ std::vector<uint8_t> FileToMemory(const char* filename) {
     return {};
   }
 
-  std::vector<uint8_t> buffer(long_filesize);
+  std::vector<uint8_t> buffer;
+  try {
+    buffer.resize(long_filesize);
+  } catch (...) {
+    fclose(fp);
+    return {};
+  }
 
   // go back to start of file
   if (fseek(fp, 0, SEEK_SET) != 0) {

src/user/user_vfs.cc

@@ -251,7 +251,12 @@ int mj_addBufferVFS(mjVFS* vfs, const char* name, const void* buffer,
   if (!(file = cvfs->AddFile(FilePath(name), std::move(inbuffer), 0))) {
     return 2;  // AddFile failed, repeated name
   }
-  file->filedata.reserve(nbuffer);
+  try {
+    file->filedata.reserve(nbuffer);
+  } catch (...) {
+    cvfs->DeleteFile(file->filename);  // delete file on error
+    return -1;
+  }
   file->filestamp = vfs_memcpy(file->filedata, buffer, nbuffer);
   return 0;
 }