#
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}