cargo/core/compiler/
unit_graph.rs

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

cargo/core/compiler/
unit_graph.rs
