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

use std::{
    fmt::{Debug, Display},
    sync::Arc,
};

use wasmer_config::package::{PackageIdent, PackageSource};

use crate::runtime::resolver::PackageSummary;

/// Something that packages can be downloaded from.
#[async_trait::async_trait]
pub trait Source: Sync + Debug {
    /// Ask this source which packages would satisfy a particular
    /// [`Dependency`][dep] constraint.
    ///
    /// # Assumptions
    ///
    /// If this method returns a successful result, it is guaranteed that there
    /// will be at least one [`PackageSummary`], otherwise implementations
    /// should return [`QueryError::NotFound`] or [`QueryError::NoMatches`].
    ///
    /// [dep]: crate::runtime::resolver::Dependency
    async fn query(&self, package: &PackageSource) -> Result<Vec<PackageSummary>, QueryError>;

    /// Run [`Source::query()`] and get the [`PackageSummary`] for the latest
    /// version.
    async fn latest(&self, pkg: &PackageSource) -> Result<PackageSummary, QueryError> {
        let candidates = self.query(pkg).await?;

        match pkg {
            PackageSource::Ident(PackageIdent::Named(_)) => candidates
                .into_iter()
                .max_by(|left, right| {
                    let left_version = left.pkg.id.as_named().map(|x| &x.version);
                    let right_version = right.pkg.id.as_named().map(|x| &x.version);

                    left_version.cmp(&right_version)
                })
                .ok_or(QueryError::NoMatches {
                    query: pkg.clone(),
                    archived_versions: Vec::new(),
                }),
            _ => candidates
                .into_iter()
                .next()
                .ok_or_else(|| QueryError::NotFound { query: pkg.clone() }),
        }
    }
}

#[async_trait::async_trait]
impl<D, S> Source for D
where
    D: std::ops::Deref<Target = S> + Debug + Send + Sync,
    S: Source + ?Sized + Send + Sync + 'static,
{
    async fn query(&self, package: &PackageSource) -> Result<Vec<PackageSummary>, QueryError> {
        (**self).query(package).await
    }
}

#[derive(Clone, Debug)]
pub enum QueryError {
    Unsupported {
        query: PackageSource,
    },
    NotFound {
        query: PackageSource,
    },
    NoMatches {
        query: PackageSource,
        archived_versions: Vec<semver::Version>,
    },
    Timeout {
        query: PackageSource,
    },
    Other {
        query: PackageSource,
        // Arc to make it cloneable
        // Cloning is important for some use-cases.
        error: Arc<anyhow::Error>,
    },
}

impl QueryError {
    pub fn query(&self) -> &PackageSource {
        match self {
            Self::Unsupported { query }
            | Self::NotFound { query }
            | Self::NoMatches { query, .. }
            | Self::Timeout { query }
            | Self::Other { query, .. } => query,
        }
    }

    pub fn new_other(err: anyhow::Error, query: &PackageSource) -> Self {
        Self::Other {
            query: query.clone(),
            error: Arc::new(err),
        }
    }
}

impl Display for QueryError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "failed to query package '{}': ", self.query())?;

        match self {
            Self::Unsupported { .. } => f.write_str("unsupported package specifier"),
            Self::NotFound { .. } => f.write_str("not found"),
            Self::Timeout { .. } => f.write_str("timeout"),
            Self::NoMatches {
                query: _,
                archived_versions,
            } => match archived_versions.as_slice() {
                [] => f.write_str(
                    "the package was found, but no published versions matched the constraint",
                ),
                [version] => write!(
                    f,
                    "the only version satisfying the constraint, {version}, is archived"
                ),
                [first, rest @ ..] => {
                    let num_others = rest.len();
                    write!(
                        f,
                        "unable to satisfy the request - version {first}, and {num_others} are all archived"
                    )
                }
            },
            Self::Other { error: e, query: _ } => Display::fmt(e, f),
        }
    }
}

impl std::error::Error for QueryError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        match self {
            Self::Other { error, query: _ } => Some(&***error),
            Self::Unsupported { .. }
            | Self::NotFound { .. }
            | Self::NoMatches { .. }
            | Self::Timeout { .. } => None,
        }
    }
}