minidom/
tree_builder.rs

1// Copyright (c) 2022 Astro <astro@spaceboyz.net>
2
3//! SAX events to DOM tree conversion
4
5use crate::prefixes::{Prefix, Prefixes};
6use crate::{Element, Error};
7use rxml::RawEvent;
8use std::collections::BTreeMap;
9
10/// Tree-building parser state
11pub struct TreeBuilder {
12    next_tag: Option<(Prefix, String, Prefixes, BTreeMap<String, String>)>,
13    /// Parsing stack
14    stack: Vec<Element>,
15    /// Namespace set stack by prefix
16    prefixes_stack: Vec<Prefixes>,
17    /// Document root element if finished
18    pub root: Option<Element>,
19}
20
21impl Default for TreeBuilder {
22    fn default() -> Self {
23        Self::new()
24    }
25}
26
27impl TreeBuilder {
28    /// Create a new one
29    pub fn new() -> Self {
30        TreeBuilder {
31            next_tag: None,
32            stack: vec![],
33            prefixes_stack: vec![],
34            root: None,
35        }
36    }
37
38    /// Allow setting prefixes stack.
39    ///
40    /// Useful to provide knowledge of namespaces that would have been declared on parent elements
41    /// not present in the reader.
42    pub fn with_prefixes_stack(mut self, prefixes_stack: Vec<Prefixes>) -> Self {
43        self.prefixes_stack = prefixes_stack;
44        self
45    }
46
47    /// Stack depth
48    pub fn depth(&self) -> usize {
49        self.stack.len()
50    }
51
52    /// Get the top-most element from the stack but don't remove it
53    pub fn top(&mut self) -> Option<&Element> {
54        self.stack.last()
55    }
56
57    /// Pop the top-most element from the stack
58    fn pop(&mut self) -> Option<Element> {
59        self.prefixes_stack.pop();
60        self.stack.pop()
61    }
62
63    /// Unshift the first child of the top element
64    pub fn unshift_child(&mut self) -> Option<Element> {
65        let depth = self.stack.len();
66        if depth > 0 {
67            self.stack[depth - 1].unshift_child()
68        } else {
69            None
70        }
71    }
72
73    /// Lookup XML namespace declaration for given prefix (or no prefix)
74    fn lookup_prefix(&self, prefix: &Option<String>) -> Option<&str> {
75        for nss in self.prefixes_stack.iter().rev() {
76            if let Some(ns) = nss.get(prefix) {
77                return Some(ns);
78            }
79        }
80
81        None
82    }
83
84    fn process_end_tag(&mut self) -> Result<(), Error> {
85        if let Some(el) = self.pop() {
86            if self.depth() > 0 {
87                let top = self.stack.len() - 1;
88                self.stack[top].append_child(el);
89            } else {
90                self.root = Some(el);
91            }
92        }
93
94        Ok(())
95    }
96
97    fn process_text(&mut self, text: String) {
98        if self.depth() > 0 {
99            let top = self.stack.len() - 1;
100            self.stack[top].append_text(text);
101        }
102    }
103
104    /// Process a Event that you got out of a RawParser
105    pub fn process_event(&mut self, event: RawEvent) -> Result<(), Error> {
106        match event {
107            RawEvent::XmlDeclaration(_, _) => {}
108
109            RawEvent::ElementHeadOpen(_, (prefix, name)) => {
110                self.next_tag = Some((
111                    prefix.map(|prefix| prefix.as_str().to_owned()),
112                    name.as_str().to_owned(),
113                    Prefixes::default(),
114                    BTreeMap::new(),
115                ))
116            }
117
118            RawEvent::Attribute(_, (prefix, name), value) => {
119                if let Some((_, _, ref mut prefixes, ref mut attrs)) = self.next_tag.as_mut() {
120                    match (prefix, name) {
121                        (None, xmlns) if xmlns == "xmlns" => prefixes.insert(None, value),
122                        (Some(xmlns), prefix) if xmlns.as_str() == "xmlns" => {
123                            prefixes.insert(Some(prefix.as_str().to_owned()), value);
124                        }
125                        (Some(prefix), name) => {
126                            attrs.insert(format!("{}:{}", prefix, name), value.as_str().to_owned());
127                        }
128                        (None, name) => {
129                            attrs.insert(name.as_str().to_owned(), value.as_str().to_owned());
130                        }
131                    }
132                }
133            }
134
135            RawEvent::ElementHeadClose(_) => {
136                if let Some((prefix, name, prefixes, attrs)) = self.next_tag.take() {
137                    self.prefixes_stack.push(prefixes.clone());
138
139                    let namespace = self
140                        .lookup_prefix(&prefix.clone().map(|prefix| prefix.as_str().to_owned()))
141                        .ok_or(Error::MissingNamespace)?
142                        .to_owned();
143                    let el =
144                        Element::new(name.as_str().to_owned(), namespace, prefixes, attrs, vec![]);
145                    self.stack.push(el);
146                }
147            }
148
149            RawEvent::ElementFoot(_) => self.process_end_tag()?,
150
151            RawEvent::Text(_, text) => self.process_text(text.as_str().to_owned()),
152        }
153
154        Ok(())
155    }
156}
minidom/tree_builder.rs

minidom/
tree_builder.rs
