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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
|
//! Utilities for working with Protobuf paths.
use std::iter;
/// Maps a fully-qualified Protobuf path to a value using path matchers.
#[derive(Debug, Default)]
pub(crate) struct PathMap<T> {
// insertion order might actually matter (to avoid warning about legacy-derive-helpers)
// see: https://doc.rust-lang.org/rustc/lints/listing/warn-by-default.html#legacy-derive-helpers
pub(crate) matchers: Vec<(String, T)>,
}
impl<T> PathMap<T> {
/// Inserts a new matcher and associated value to the path map.
pub(crate) fn insert(&mut self, matcher: String, value: T) {
self.matchers.push((matcher, value));
}
/// Returns a iterator over all the value matching the given fd_path and associated suffix/prefix path
pub(crate) fn get(&self, fq_path: &str) -> Iter<'_, T> {
Iter::new(self, fq_path.to_string())
}
/// Returns a iterator over all the value matching the path `fq_path.field` and associated suffix/prefix path
pub(crate) fn get_field(&self, fq_path: &str, field: &str) -> Iter<'_, T> {
Iter::new(self, format!("{}.{}", fq_path, field))
}
/// Returns the first value found matching the given path
/// If nothing matches the path, suffix paths will be tried, then prefix paths, then the global path
#[allow(unused)]
pub(crate) fn get_first<'a>(&'a self, fq_path: &'_ str) -> Option<&'a T> {
self.find_best_matching(fq_path)
}
/// Returns the first value found matching the path `fq_path.field`
/// If nothing matches the path, suffix paths will be tried, then prefix paths, then the global path
pub(crate) fn get_first_field<'a>(&'a self, fq_path: &'_ str, field: &'_ str) -> Option<&'a T> {
self.find_best_matching(&format!("{}.{}", fq_path, field))
}
/// Removes all matchers from the path map.
pub(crate) fn clear(&mut self) {
self.matchers.clear();
}
/// Returns the first value found best matching the path
/// See [sub_path_iter()] for paths test order
fn find_best_matching(&self, full_path: &str) -> Option<&T> {
sub_path_iter(full_path).find_map(|path| {
self.matchers
.iter()
.find(|(p, _)| p == path)
.map(|(_, v)| v)
})
}
}
/// Iterator inside a PathMap that only returns values that matches a given path
pub(crate) struct Iter<'a, T> {
iter: std::slice::Iter<'a, (String, T)>,
path: String,
}
impl<'a, T> Iter<'a, T> {
fn new(map: &'a PathMap<T>, path: String) -> Self {
Self {
iter: map.matchers.iter(),
path,
}
}
fn is_match(&self, path: &str) -> bool {
sub_path_iter(self.path.as_str()).any(|p| p == path)
}
}
impl<'a, T> std::iter::Iterator for Iter<'a, T> {
type Item = &'a T;
fn next(&mut self) -> Option<Self::Item> {
loop {
match self.iter.next() {
Some((p, v)) => {
if self.is_match(p) {
return Some(v);
}
}
None => return None,
}
}
}
}
impl<'a, T> std::iter::FusedIterator for Iter<'a, T> {}
/// Given a fully-qualified path, returns a sequence of paths:
/// - the path itself
/// - the sequence of suffix paths
/// - the sequence of prefix paths
/// - the global path
///
/// Example: sub_path_iter(".a.b.c") -> [".a.b.c", "a.b.c", "b.c", "c", ".a.b", ".a", "."]
fn sub_path_iter(full_path: &str) -> impl Iterator<Item = &str> {
// First, try matching the path.
iter::once(full_path)
// Then, try matching path suffixes.
.chain(suffixes(full_path))
// Then, try matching path prefixes.
.chain(prefixes(full_path))
// Then, match the global path.
.chain(iter::once("."))
}
/// Given a fully-qualified path, returns a sequence of fully-qualified paths which match a prefix
/// of the input path, in decreasing path-length order.
///
/// Example: prefixes(".a.b.c.d") -> [".a.b.c", ".a.b", ".a"]
fn prefixes(fq_path: &str) -> impl Iterator<Item = &str> {
std::iter::successors(Some(fq_path), |path| {
#[allow(unknown_lints, clippy::manual_split_once)]
path.rsplitn(2, '.').nth(1).filter(|path| !path.is_empty())
})
.skip(1)
}
/// Given a fully-qualified path, returns a sequence of paths which match the suffix of the input
/// path, in decreasing path-length order.
///
/// Example: suffixes(".a.b.c.d") -> ["a.b.c.d", "b.c.d", "c.d", "d"]
fn suffixes(fq_path: &str) -> impl Iterator<Item = &str> {
std::iter::successors(Some(fq_path), |path| {
#[allow(unknown_lints, clippy::manual_split_once)]
path.splitn(2, '.').nth(1).filter(|path| !path.is_empty())
})
.skip(1)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_prefixes() {
assert_eq!(
prefixes(".a.b.c.d").collect::<Vec<_>>(),
vec![".a.b.c", ".a.b", ".a"],
);
assert_eq!(prefixes(".a").count(), 0);
assert_eq!(prefixes(".").count(), 0);
}
#[test]
fn test_suffixes() {
assert_eq!(
suffixes(".a.b.c.d").collect::<Vec<_>>(),
vec!["a.b.c.d", "b.c.d", "c.d", "d"],
);
assert_eq!(suffixes(".a").collect::<Vec<_>>(), vec!["a"]);
assert_eq!(suffixes(".").collect::<Vec<_>>(), Vec::<&str>::new());
}
#[test]
fn test_get_matches_sub_path() {
let mut path_map = PathMap::default();
// full path
path_map.insert(".a.b.c.d".to_owned(), 1);
assert_eq!(Some(&1), path_map.get(".a.b.c.d").next());
assert_eq!(Some(&1), path_map.get_field(".a.b.c", "d").next());
// suffix
path_map.clear();
path_map.insert("c.d".to_owned(), 1);
assert_eq!(Some(&1), path_map.get(".a.b.c.d").next());
assert_eq!(Some(&1), path_map.get("b.c.d").next());
assert_eq!(Some(&1), path_map.get_field(".a.b.c", "d").next());
// prefix
path_map.clear();
path_map.insert(".a.b".to_owned(), 1);
assert_eq!(Some(&1), path_map.get(".a.b.c.d").next());
assert_eq!(Some(&1), path_map.get_field(".a.b.c", "d").next());
// global
path_map.clear();
path_map.insert(".".to_owned(), 1);
assert_eq!(Some(&1), path_map.get(".a.b.c.d").next());
assert_eq!(Some(&1), path_map.get("b.c.d").next());
assert_eq!(Some(&1), path_map.get_field(".a.b.c", "d").next());
}
#[test]
fn test_get_best() {
let mut path_map = PathMap::default();
// worst is global
path_map.insert(".".to_owned(), 1);
assert_eq!(Some(&1), path_map.get_first(".a.b.c.d"));
assert_eq!(Some(&1), path_map.get_first("b.c.d"));
assert_eq!(Some(&1), path_map.get_first_field(".a.b.c", "d"));
// then prefix
path_map.insert(".a.b".to_owned(), 2);
assert_eq!(Some(&2), path_map.get_first(".a.b.c.d"));
assert_eq!(Some(&2), path_map.get_first_field(".a.b.c", "d"));
// then suffix
path_map.insert("c.d".to_owned(), 3);
assert_eq!(Some(&3), path_map.get_first(".a.b.c.d"));
assert_eq!(Some(&3), path_map.get_first("b.c.d"));
assert_eq!(Some(&3), path_map.get_first_field(".a.b.c", "d"));
// best is full path
path_map.insert(".a.b.c.d".to_owned(), 4);
assert_eq!(Some(&4), path_map.get_first(".a.b.c.d"));
assert_eq!(Some(&4), path_map.get_first_field(".a.b.c", "d"));
}
#[test]
fn test_get_keep_order() {
let mut path_map = PathMap::default();
path_map.insert(".".to_owned(), 1);
path_map.insert(".a.b".to_owned(), 2);
path_map.insert(".a.b.c.d".to_owned(), 3);
let mut iter = path_map.get(".a.b.c.d");
assert_eq!(Some(&1), iter.next());
assert_eq!(Some(&2), iter.next());
assert_eq!(Some(&3), iter.next());
assert_eq!(None, iter.next());
path_map.clear();
path_map.insert(".a.b.c.d".to_owned(), 1);
path_map.insert(".a.b".to_owned(), 2);
path_map.insert(".".to_owned(), 3);
let mut iter = path_map.get(".a.b.c.d");
assert_eq!(Some(&1), iter.next());
assert_eq!(Some(&2), iter.next());
assert_eq!(Some(&3), iter.next());
assert_eq!(None, iter.next());
}
}
|
