You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: dimension_mapping.rs
    path of file: ./repos/rerun/crates/re_space_view_tensor/src
    
    the code of the file until where you have to start completion: use re_types::datatypes::TensorDimension;

#[derive(Clone, Debug, PartialEq, Eq, Hash, serde::Deserialize, serde::Serialize)]
pub struct DimensionSelector {
    pub visible: bool,
    pub dim_idx: usize,
}

impl DimensionSelector {
    pub fn new(dim_idx: usize) -> Self {
        DimensionSelector {
            visible: true,
            dim_idx,
        }
    }
}

#[derive(Default, Clone, Debug, PartialEq, Eq, Hash, serde::Deserialize, serde::Serialize)]
pub struct DimensionMapping {
    /// 
    
fn longest_and_second_longest_dim_indices(shape: &[TensorDimension]) -> (usize, usize) {
    let mut longest_idx = 0;
    let mut second_longest_idx = 0;

    for (i, dim) in shape.iter().enumerate() {
        if dim.size > shape[longest_idx].size {
            second_longest_idx = longest_idx;
            longest_idx = i;
        } else if dim.size > shape[second_longest_idx].size {
            second_longest_idx = i;
        }
    }

    if longest_idx == second_longest_idx {
        (0, 1)
    } else {
        (longest_idx, second_longest_idx)
    }
}