wolf-graph-dot 0.1.0

Adds support for generating Graphviz DOT files from wolf-graph graphs.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140

use wolf_graph::prelude::*;

use crate::{EdgeAttributes, GraphAttributes, GroupAttributes, NodeAttributes};

// Docs: https://graphviz.org/doc/info/lang.html
// Editor: http://magjac.com/graphviz-visual-editor/

pub trait DotEncodable<GData, NData, EData>: VisitableGraph + Sized {
    fn dot_graph_attributes(&self) -> Option<GraphAttributes> {
        None
    }

    fn dot_node_attributes(&self, _node: &NodeID) -> Option<NodeAttributes> {
        None
    }

    fn dot_edge_attributes(&self, _edge: &EdgeID) -> Option<EdgeAttributes> {
        None
    }

    // This should only return `true` if the graph is a compound graph.
    fn dot_is_compound(&self) -> bool {
        false
    }

    // This returns the children of a group node, or the roots of the forest if `node` is `nil`.
    fn dot_children(&self, _node: Option<&NodeID>) -> Nodes {
        Nodes::new()
    }

    // Default implementation presumes that if a node has children, it is a group.
    // Override if you wish to, for example, support empty groups.
    fn dot_is_group(&self, node: &NodeID) -> bool {
        !self.dot_children(Some(node)).is_empty()
    }

    fn dot_group_attributes(&self, _group: &NodeID) -> Option<GroupAttributes> {
        None
    }
}

pub trait DotFormat<GData, NData, EData>: DotEncodable<GData, NData, EData> {
    fn dot_format(&self) -> String {
        let mut lines = Vec::new();
        format_graph(self, &mut lines);
        format_lines(&lines)
    }
}

// Blanket implementation of `DotFormat` for all types that implement `DotEncodable`.
impl<GData, NData, EData, T> DotFormat<GData, NData, EData> for T where T: DotEncodable<GData, NData, EData> {}

fn format_graph<GData, NData, EData>(
    graph: &impl DotEncodable<GData, NData, EData>,
    lines: &mut Vec<(usize, String)>
) {
    let indent = 0;

    let graph_label = graph
        .dot_graph_attributes()
        .and_then(|attrs| attrs.label)
        .unwrap_or_else(|| "G".to_string());
    lines.push((indent, format!("digraph {} {{", graph_label)));
    if graph.dot_is_compound() {
        format_group(graph, lines, None, indent + 1);
    } else {
        format_nodes(graph, lines, &graph.all_nodes(), indent + 1);
    }
    format_edges(graph, lines, &graph.all_edges(), indent + 1);
    lines.push((indent, "}".to_string()));
}

fn format_group<GData, NData, EData>(
    graph: &impl DotEncodable<GData, NData, EData>,
    lines: &mut Vec<(usize, String)>,
    parent: Option<&NodeID>,
    indent: usize
) {
    if let Some(attrs) = parent
        .and_then(|parent| graph.dot_group_attributes(parent))
        .and_then(|attributes| attributes.attributes(false))
    {
        lines.push((indent, attrs));
    }
    format_nodes(graph, lines, &graph.dot_children(parent), indent);
}

fn format_subgraph<GData, NData, EData>(graph: &impl DotEncodable<GData, NData, EData>, lines: &mut Vec<(usize, String)>, parent: &NodeID, indent: usize) {
    lines.push((indent, format!("subgraph cluster_{} {{", parent)));
    format_group(graph, lines, Some(parent), indent + 1);
    lines.push((indent, "}".to_string()));
}

fn format_nodes<GData, NData, EData>(graph: &impl DotEncodable<GData, NData, EData>, lines: &mut Vec<(usize, String)>, nodes: &Nodes, indent: usize) {
    for node in nodes {
        if graph.dot_is_group(node) {
            format_subgraph(graph, lines, node, indent);
        } else {
            format_leaf_node(graph, lines, node, indent);
        }
    }
}

fn format_leaf_node<GData, NData, EData>(graph: &impl DotEncodable<GData, NData, EData>, lines: &mut Vec<(usize, String)>, node: &NodeID, indent: usize) {
    let mut line_components = vec![node.to_string()];
    line_components.push(" ".to_string());
    if let Some(attributes) = graph.dot_node_attributes(node) {
        if let Some(attrs) = attributes.attributes() {
            line_components.push(attrs);
        }
    }
    lines.push((indent, line_components.join("")));
}

fn format_edges<GData, NData, EData>(graph: &impl DotEncodable<GData, NData, EData>, lines: &mut Vec<(usize, String)>, edges: &Edges, indent: usize) {
    for edge in edges {
        format_edge(graph, lines, edge, indent);
    }
}

fn format_edge<GData, NData, EData>(graph: &impl DotEncodable<GData, NData, EData>, lines: &mut Vec<(usize, String)>, edge: &EdgeID, indent: usize) {
    let mut line_components = vec![graph.source(edge).unwrap().to_string()];
    line_components.push(" -> ".to_string());
    line_components.push(graph.target(edge).unwrap().to_string());
    line_components.push(" ".to_string());
    if let Some(attributes) = graph.dot_edge_attributes(edge) {
        if let Some(attrs) = attributes.attributes() {
            line_components.push(attrs);
        }
    }
    lines.push((indent, line_components.join("")));
}

fn format_lines(lines: &[(usize, String)]) -> String {
    lines
        .iter()
        .map(|(indent, s)| format!("{}{}", " ".repeat(indent * 4), s))
        .collect::<Vec<_>>()
        .join("\n")
}