cargo/core/compiler/
unit_graph.rs

1//! Serialization of [`UnitGraph`] for unstable option [`--unit-graph`].
2//!
3//! [`--unit-graph`]: https://doc.rust-lang.org/nightly/cargo/reference/unstable.html#unit-graph
4
5use cargo_util_schemas::core::PackageIdSpec;
6
7use crate::GlobalContext;
8use crate::core::Target;
9use crate::core::compiler::Unit;
10use crate::core::compiler::{CompileKind, CompileMode};
11use crate::core::profiles::{Profile, UnitFor};
12use crate::util::CargoResult;
13use crate::util::interning::InternedString;
14use std::collections::HashMap;
15
16/// The dependency graph of Units.
17pub type UnitGraph = HashMap<Unit, Vec<UnitDep>>;
18
19/// A unit dependency.
20#[derive(Debug, Clone, Hash, Eq, PartialEq, PartialOrd, Ord)]
21pub struct UnitDep {
22    /// The dependency unit.
23    pub unit: Unit,
24    /// The purpose of this dependency (a dependency for a test, or a build
25    /// script, etc.). Do not use this after the unit graph has been built.
26    pub unit_for: UnitFor,
27    /// The name the parent uses to refer to this dependency.
28    pub extern_crate_name: InternedString,
29    /// The dependency name as written in the manifest (including a rename).
30    ///
31    /// `None` means this edge does not carry a manifest dep name. For example,
32    /// std edges in build-std or synthetic edges for build script executions.
33    /// When `None`, the package name is typically used by callers as a fallback.
34    ///
35    /// This is mainly for Cargo-synthesized outputs
36    /// (artifact env vars and `CARGO_DEP_*` metadata env)
37    /// and is distinct from `extern_crate_name`.
38    pub dep_name: Option<InternedString>,
39    /// Whether or not this is a public dependency.
40    pub public: bool,
41    /// If `true`, the dependency should not be added to Rust's prelude.
42    pub noprelude: bool,
43}
44
45const VERSION: u32 = 1;
46
47#[derive(serde::Serialize)]
48struct SerializedUnitGraph<'a> {
49    version: u32,
50    units: Vec<SerializedUnit<'a>>,
51    roots: Vec<usize>,
52}
53
54#[derive(serde::Serialize)]
55struct SerializedUnit<'a> {
56    pkg_id: PackageIdSpec,
57    target: &'a Target,
58    profile: &'a Profile,
59    platform: CompileKind,
60    mode: CompileMode,
61    features: &'a Vec<InternedString>,
62    #[serde(skip_serializing_if = "std::ops::Not::not")] // hide for unstable build-std
63    is_std: bool,
64    dependencies: Vec<SerializedUnitDep>,
65}
66
67#[derive(serde::Serialize)]
68struct SerializedUnitDep {
69    index: usize,
70    extern_crate_name: InternedString,
71    // This is only set on nightly since it is unstable.
72    #[serde(skip_serializing_if = "Option::is_none")]
73    public: Option<bool>,
74    // This is only set on nightly since it is unstable.
75    #[serde(skip_serializing_if = "Option::is_none")]
76    noprelude: Option<bool>,
77    // Intentionally not including `unit_for` because it is a low-level
78    // internal detail that is mostly used for building the graph.
79}
80
81/// Outputs a JSON serialization of [`UnitGraph`] for given `root_units`
82/// to the standard output.
83pub fn emit_serialized_unit_graph(
84    root_units: &[Unit],
85    unit_graph: &UnitGraph,
86    gctx: &GlobalContext,
87) -> CargoResult<()> {
88    let mut units: Vec<(&Unit, &Vec<UnitDep>)> = unit_graph.iter().collect();
89    units.sort_unstable();
90    // Create a map for quick lookup for dependencies.
91    let indices: HashMap<&Unit, usize> = units
92        .iter()
93        .enumerate()
94        .map(|(i, val)| (val.0, i))
95        .collect();
96    let roots = root_units.iter().map(|root| indices[root]).collect();
97    let ser_units = units
98        .iter()
99        .map(|(unit, unit_deps)| {
100            let dependencies = unit_deps
101                .iter()
102                .map(|unit_dep| {
103                    // https://github.com/rust-lang/rust/issues/64260 when stabilized.
104                    let (public, noprelude) = if gctx.nightly_features_allowed {
105                        (Some(unit_dep.public), Some(unit_dep.noprelude))
106                    } else {
107                        (None, None)
108                    };
109                    SerializedUnitDep {
110                        index: indices[&unit_dep.unit],
111                        extern_crate_name: unit_dep.extern_crate_name,
112                        public,
113                        noprelude,
114                    }
115                })
116                .collect();
117            SerializedUnit {
118                pkg_id: unit.pkg.package_id().to_spec(),
119                target: &unit.target,
120                profile: &unit.profile,
121                platform: unit.kind,
122                mode: unit.mode,
123                features: &unit.features,
124                is_std: unit.is_std,
125                dependencies,
126            }
127        })
128        .collect();
129
130    gctx.shell().print_json(&SerializedUnitGraph {
131        version: VERSION,
132        units: ser_units,
133        roots,
134    })
135}
cargo/core/compiler/unit_graph.rs

cargo/core/compiler/
unit_graph.rs
