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 http://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.
7 pub 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 
16 impl PrintTree {
new(title: String) -> PrintTree17     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.
new_level(&mut self, queued_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                 print!("\n");
38             }
39         }
40 
41         self.level = self.level + 1;
42     }
43 
44     /// Ascend one level in the tree.
end_level(&mut self)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.
add_item(&mut self, text: String)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 
print_level_prefix(&self)56     fn print_level_prefix(&self) {
57         for _ in 0..self.level {
58             print!("\u{2502}  ");
59         }
60     }
61 
print_level_child_indentation(&self)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 
flush_queued_item(&mut self, prefix: &str)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                     print!("\n");
79                 }
80             }
81         }
82     }
83 }
84 
85 impl Drop for PrintTree {
drop(&mut self)86     fn drop(&mut self) {
87         self.flush_queued_item("\u{9492}\u{9472}");
88     }
89 }
90