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

// Copyright 2023 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

pub use crate::errors::ParseError;
pub use crate::parse::{validate_package_path_segment, validate_resource_path};
use crate::{Scheme, UrlParts};

pub const SCHEME: &str = "fuchsia-builtin";

/// Decoded representation of a builtin URL.
///
/// fuchsia-builtin://#resource
///
/// Builtin component declarations are used to bootstrap the ELF runner.
/// They are never packaged.
///
/// The path in builtin URLs must be "/". Following that, they may contain a fragment.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct BuiltinUrl {
    resource: Option<String>,
}

impl BuiltinUrl {
    pub fn parse(input: &str) -> Result<Self, ParseError> {
        Self::try_from_parts(UrlParts::parse(input)?)
    }

    fn try_from_parts(
        UrlParts { scheme, host, path, hash, resource }: UrlParts,
    ) -> Result<Self, ParseError> {
        if scheme.ok_or(ParseError::MissingScheme)? != Scheme::Builtin {
            return Err(ParseError::InvalidScheme);
        }

        if host.is_some() {
            return Err(ParseError::HostMustBeEmpty);
        }

        if hash.is_some() {
            return Err(ParseError::CannotContainHash);
        }

        if path != "/" {
            return Err(ParseError::PathMustBeRoot);
        }

        Ok(Self { resource })
    }

    pub fn resource(&self) -> Option<&str> {
        self.resource.as_ref().map(|s| s.as_str())
    }
}

impl std::fmt::Display for BuiltinUrl {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}://", SCHEME)?;
        if let Some(ref resource) = self.resource {
            write!(f, "#{}", percent_encoding::utf8_percent_encode(resource, crate::FRAGMENT))?;
        }

        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::errors::{PackagePathSegmentError, ResourcePathError};
    use assert_matches::assert_matches;

    #[test]
    fn test_parse_ok() {
        assert_eq!(BuiltinUrl::parse("fuchsia-builtin://").unwrap().resource(), None);
        assert_eq!(BuiltinUrl::parse("fuchsia-builtin://#a").unwrap().resource(), Some("a"));
        assert_eq!(
            BuiltinUrl::parse("fuchsia-builtin://#elf_runner.cm").unwrap().resource(),
            Some("elf_runner.cm")
        );
    }

    #[test]
    fn test_parse_error_wrong_scheme() {
        assert_matches!(BuiltinUrl::parse("foobar://").unwrap_err(), ParseError::InvalidScheme);
        assert_matches!(
            BuiltinUrl::parse("fuchsia-boot://").unwrap_err(),
            ParseError::InvalidScheme
        );
        assert_matches!(
            BuiltinUrl::parse("fuchsia-pkg://").unwrap_err(),
            ParseError::InvalidScheme
        );
    }

    #[test]
    fn test_parse_error_missing_scheme() {
        assert_matches!(BuiltinUrl::parse("package").unwrap_err(), ParseError::MissingScheme);
    }

    #[test]
    fn test_parse_error_invalid_path() {
        assert_matches!(
            BuiltinUrl::parse("fuchsia-builtin:////").unwrap_err(),
            ParseError::InvalidPathSegment(PackagePathSegmentError::Empty)
        );
    }

    #[test]
    fn test_parse_error_invalid_character() {
        assert_matches!(
            BuiltinUrl::parse("fuchsia-builtin:///package:1234").unwrap_err(),
            ParseError::InvalidPathSegment(PackagePathSegmentError::InvalidCharacter {
                character: ':'
            })
        );
    }

    #[test]
    fn test_parse_error_host_must_be_empty() {
        assert_matches!(
            BuiltinUrl::parse("fuchsia-builtin://hello").unwrap_err(),
            ParseError::HostMustBeEmpty
        );
    }

    #[test]
    fn test_parse_error_resource_cannot_be_slash() {
        assert_matches!(
            BuiltinUrl::parse("fuchsia-builtin://#/").unwrap_err(),
            ParseError::InvalidResourcePath(ResourcePathError::PathStartsWithSlash)
        );
    }
}