moniker/
extended_moniker.rs

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1// Copyright 2022 The Fuchsia Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5use crate::error::MonikerError;
6use crate::moniker::Moniker;
7use cm_rust::{FidlIntoNative, NativeIntoFidl};
8use core::cmp::Ord;
9use std::fmt;
10
11#[cfg(feature = "serde")]
12use serde::{Deserialize, Serialize};
13
14/// One of:
15/// - A moniker
16/// - A marker representing component manager's realm
17#[cfg_attr(feature = "serde", derive(Deserialize, Serialize), serde(rename_all = "snake_case"))]
18#[derive(Eq, Ord, PartialOrd, PartialEq, Debug, Clone, Hash)]
19pub enum ExtendedMoniker {
20    ComponentInstance(Moniker),
21    ComponentManager,
22}
23
24/// The string representation of ExtendedMoniker::ComponentManager
25pub const EXTENDED_MONIKER_COMPONENT_MANAGER_STR: &'static str = "<component_manager>";
26
27impl ExtendedMoniker {
28    pub fn unwrap_instance_moniker_or<E: std::error::Error>(
29        &self,
30        error: E,
31    ) -> Result<&Moniker, E> {
32        match self {
33            Self::ComponentManager => Err(error),
34            Self::ComponentInstance(moniker) => Ok(moniker),
35        }
36    }
37
38    pub fn has_prefix(&self, other: &Self) -> bool {
39        match (self, other) {
40            (_, Self::ComponentManager) => true,
41            (Self::ComponentManager, Self::ComponentInstance(_)) => false,
42            (Self::ComponentInstance(a), Self::ComponentInstance(b)) => a.has_prefix(b),
43        }
44    }
45
46    pub fn parse_str(rep: &str) -> Result<Self, MonikerError> {
47        if rep == EXTENDED_MONIKER_COMPONENT_MANAGER_STR {
48            Ok(ExtendedMoniker::ComponentManager)
49        } else {
50            Ok(ExtendedMoniker::ComponentInstance(Moniker::parse_str(rep)?))
51        }
52    }
53}
54
55impl TryFrom<&str> for ExtendedMoniker {
56    type Error = MonikerError;
57
58    fn try_from(input: &str) -> Result<Self, MonikerError> {
59        Self::parse_str(input)
60    }
61}
62
63impl std::str::FromStr for ExtendedMoniker {
64    type Err = MonikerError;
65    fn from_str(s: &str) -> Result<Self, Self::Err> {
66        Self::parse_str(s)
67    }
68}
69
70impl fmt::Display for ExtendedMoniker {
71    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
72        match self {
73            Self::ComponentInstance(m) => {
74                write!(f, "{}", m)?;
75            }
76            Self::ComponentManager => {
77                write!(f, "{}", EXTENDED_MONIKER_COMPONENT_MANAGER_STR)?;
78            }
79        }
80        Ok(())
81    }
82}
83
84impl From<Moniker> for ExtendedMoniker {
85    fn from(m: Moniker) -> Self {
86        Self::ComponentInstance(m)
87    }
88}
89
90impl FidlIntoNative<ExtendedMoniker> for String {
91    fn fidl_into_native(self) -> ExtendedMoniker {
92        self.parse().unwrap()
93    }
94}
95
96impl NativeIntoFidl<String> for ExtendedMoniker {
97    fn native_into_fidl(self) -> String {
98        self.to_string()
99    }
100}
101
102#[cfg(test)]
103mod tests {
104    use super::*;
105
106    #[test]
107    fn parse() {
108        assert_eq!(
109            ExtendedMoniker::parse_str(EXTENDED_MONIKER_COMPONENT_MANAGER_STR).unwrap(),
110            ExtendedMoniker::ComponentManager
111        );
112        assert_eq!(
113            ExtendedMoniker::parse_str("/foo/bar").unwrap(),
114            ExtendedMoniker::ComponentInstance(Moniker::parse_str("/foo/bar").unwrap())
115        );
116        assert!(ExtendedMoniker::parse_str("").is_err(), "cannot be empty");
117    }
118
119    #[test]
120    fn has_prefix() {
121        let cm = ExtendedMoniker::ComponentManager;
122        let root = ExtendedMoniker::ComponentInstance(Moniker::root());
123        let a = ExtendedMoniker::ComponentInstance(Moniker::parse_str("a").unwrap());
124        let ab = ExtendedMoniker::ComponentInstance(Moniker::parse_str("a/b").unwrap());
125
126        assert!(cm.has_prefix(&cm));
127        assert!(!cm.has_prefix(&root));
128        assert!(!cm.has_prefix(&a));
129        assert!(!cm.has_prefix(&ab));
130
131        assert!(root.has_prefix(&cm));
132        assert!(root.has_prefix(&root));
133        assert!(!root.has_prefix(&a));
134        assert!(!root.has_prefix(&ab));
135
136        assert!(a.has_prefix(&cm));
137        assert!(a.has_prefix(&root));
138        assert!(a.has_prefix(&a));
139        assert!(!a.has_prefix(&ab));
140
141        assert!(ab.has_prefix(&cm));
142        assert!(ab.has_prefix(&root));
143        assert!(ab.has_prefix(&a));
144        assert!(ab.has_prefix(&ab));
145    }
146
147    #[test]
148    fn to_string_functions() {
149        let cm_moniker =
150            ExtendedMoniker::parse_str(EXTENDED_MONIKER_COMPONENT_MANAGER_STR).unwrap();
151        let foobar_moniker = ExtendedMoniker::parse_str("foo/bar").unwrap();
152        let empty_moniker = ExtendedMoniker::parse_str(".").unwrap();
153
154        assert_eq!(format!("{}", cm_moniker), EXTENDED_MONIKER_COMPONENT_MANAGER_STR.to_string());
155        assert_eq!(cm_moniker.to_string(), EXTENDED_MONIKER_COMPONENT_MANAGER_STR.to_string());
156        assert_eq!(format!("{}", foobar_moniker), "foo/bar".to_string());
157        assert_eq!(foobar_moniker.to_string(), "foo/bar".to_string());
158        assert_eq!(format!("{}", empty_moniker), ".".to_string());
159        assert_eq!(empty_moniker.to_string(), ".".to_string());
160    }
161}
moniker/extended_moniker.rs

moniker/
extended_moniker.rs
