base/
print_tree.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5/// A struct that makes it easier to print out a pretty tree of data, which
6/// can be visually scanned more easily.
7pub struct PrintTree {
8    /// The current level of recursion.
9    level: u32,
10
11    /// An item which is queued up, so that we can determine if we need
12    /// a mid-tree prefix or a branch ending prefix.
13    queued_item: Option<String>,
14}
15
16impl PrintTree {
17    pub fn new(title: String) -> PrintTree {
18        println!("\u{250c} {}", title);
19        PrintTree {
20            level: 1,
21            queued_item: None,
22        }
23    }
24
25    /// Descend one level in the tree with the given title string.
26    pub fn new_level(&mut self, queued_title: String) {
27        self.flush_queued_item("\u{251C}\u{2500}");
28
29        self.print_level_prefix();
30
31        let items: Vec<&str> = queued_title.split('\n').collect();
32        println!("\u{251C}\u{2500} {}", items[0]);
33        for i in 1..items.len() {
34            self.print_level_child_indentation();
35            print!("{}", items[i]);
36            if i < items.len() {
37                println!();
38            }
39        }
40
41        self.level += 1;
42    }
43
44    /// Ascend one level in the tree.
45    pub fn end_level(&mut self) {
46        self.flush_queued_item("\u{2514}\u{2500}");
47        self.level -= 1;
48    }
49
50    /// Add an item to the current level in the tree.
51    pub fn add_item(&mut self, text: String) {
52        self.flush_queued_item("\u{251C}\u{2500}");
53        self.queued_item = Some(text);
54    }
55
56    fn print_level_prefix(&self) {
57        for _ in 0..self.level {
58            print!("\u{2502}  ");
59        }
60    }
61
62    fn print_level_child_indentation(&self) {
63        for _ in 0..(self.level + 1) {
64            print!("\u{2502}  ");
65        }
66        print!("{}", " ".repeat(7));
67    }
68
69    fn flush_queued_item(&mut self, prefix: &str) {
70        if let Some(queued_item) = self.queued_item.take() {
71            self.print_level_prefix();
72            let items: Vec<&str> = queued_item.split('\n').collect();
73            println!("{} {}", prefix, items[0]);
74            for i in 1..items.len() {
75                self.print_level_child_indentation();
76                print!("{}", items[i]);
77                if i < items.len() {
78                    println!();
79                }
80            }
81        }
82    }
83}
84
85impl Drop for PrintTree {
86    fn drop(&mut self) {
87        self.flush_queued_item("\u{2514}\u{2500}");
88    }
89}
base/print_tree.rs

base/
print_tree.rs
