Function svn_fs_get_file_delta_stream 

pub unsafe extern "C" fn svn_fs_get_file_delta_stream(
    stream_p: *mut *mut svn_txdelta_stream_t,
    source_root: *mut svn_fs_root_t,
    source_path: *const c_char,
    target_root: *mut svn_fs_root_t,
    target_path: *const c_char,
    pool: *mut apr_pool_t,
) -> *mut svn_error_t

Set @a *stream_p to a pointer to a delta stream that will turn the contents of the file @a source into the contents of the file @a target. If @a source_root is zero, use a file with zero length as the source.

This function does not compare the two files’ properties.

Allocate @a *stream_p, and do any necessary temporary allocation, in @a pool.