How to unzip more archive files

I have the following structure of archive file:

file.tar.gz --> file.war --> 10 directories --> subdirectories...

How to exctract the whole content of war file in tar file?

SrcFile = file("C:\\src\\file.tar.gz")
Src = tarTree(SrcFile) --> war file

If I manually extract tar file

SrcFile = file("C:\\src\\file.war")
Src = zipTree(SrcFile) --> directories

How to combine these 2 steps into 1 without manual extraction?

Thanks for help.