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: mne_read_source_spaces.m
    path of file: ./repos/fieldtrip/external/mne
    
    the code of the file until where you have to start completion: function [src] = mne_read_source_spaces(source,add_geom,tree)
%
% [src] = mne_read_source_spaces(source,add_geom,tree)
%
% Reads source spaces from a fif file
%
% source      - The name of the file or an open file id
% add_geom 
    
function complete_source_space_info
        %
        %   Main triangulation
        %
        fprintf(1,'\tCompleting triangulation info...');
        this.tri_area = zeros(1,this.ntri);
        r1 = this.rr(this.tris(:,1),:);
        r2 = this.rr(this.tris(:,2),:);
        r3 = this.rr(this.tris(:,3),:);
        this.tri_cent = (r1+r2+r3)/3.0;
        this.tri_nn   = cross((r2-r1),(r3-r1));
        for p = 1:this.ntri
            size = sqrt(this.tri_nn(p,:)*this.tri_nn(p,:)');
            this.tri_area(p) = size/2.0;
            this.tri_nn(p,:) = this.tri_nn(p,:)/size;
        end