#
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    /// If `Some`, the name of the dependency if renamed in toml.
    30    /// It's particularly interesting to artifact dependencies which rely on it
    31    /// for naming their environment variables. Note that the `extern_crate_name`
    32    /// cannot be used for this as it also may be the build target itself,
    33    /// which isn't always the renamed dependency name.
    34    pub dep_name: Option<InternedString>,
    35    /// Whether or not this is a public dependency.
    36    pub public: bool,
    37    /// If `true`, the dependency should not be added to Rust's prelude.
    38    pub noprelude: bool,
    39}
    40
    41const VERSION: u32 = 1;
    42
    43#[derive(serde::Serialize)]
    44struct SerializedUnitGraph<'a> {
    45    version: u32,
    46    units: Vec<SerializedUnit<'a>>,
    47    roots: Vec<usize>,
    48}
    49
    50#[derive(serde::Serialize)]
    51struct SerializedUnit<'a> {
    52    pkg_id: PackageIdSpec,
    53    target: &'a Target,
    54    profile: &'a Profile,
    55    platform: CompileKind,
    56    mode: CompileMode,
    57    features: &'a Vec<InternedString>,
    58    #[serde(skip_serializing_if = "std::ops::Not::not")] // hide for unstable build-std
    59    is_std: bool,
    60    dependencies: Vec<SerializedUnitDep>,
    61}
    62
    63#[derive(serde::Serialize)]
    64struct SerializedUnitDep {
    65    index: usize,
    66    extern_crate_name: InternedString,
    67    // This is only set on nightly since it is unstable.
    68    #[serde(skip_serializing_if = "Option::is_none")]
    69    public: Option<bool>,
    70    // This is only set on nightly since it is unstable.
    71    #[serde(skip_serializing_if = "Option::is_none")]
    72    noprelude: Option<bool>,
    73    // Intentionally not including `unit_for` because it is a low-level
    74    // internal detail that is mostly used for building the graph.
    75}
    76
    77/// Outputs a JSON serialization of [`UnitGraph`] for given `root_units`
    78/// to the standard output.
    79pub fn emit_serialized_unit_graph(
    80    root_units: &[Unit],
    81    unit_graph: &UnitGraph,
    82    gctx: &GlobalContext,
    83) -> CargoResult<()> {
    84    let mut units: Vec<(&Unit, &Vec<UnitDep>)> = unit_graph.iter().collect();
    85    units.sort_unstable();
    86    // Create a map for quick lookup for dependencies.
    87    let indices: HashMap<&Unit, usize> = units
    88        .iter()
    89        .enumerate()
    90        .map(|(i, val)| (val.0, i))
    91        .collect();
    92    let roots = root_units.iter().map(|root| indices[root]).collect();
    93    let ser_units = units
    94        .iter()
    95        .map(|(unit, unit_deps)| {
    96            let dependencies = unit_deps
    97                .iter()
    98                .map(|unit_dep| {
    99                    // https://github.com/rust-lang/rust/issues/64260 when stabilized.
    100                    let (public, noprelude) = if gctx.nightly_features_allowed {
    101                        (Some(unit_dep.public), Some(unit_dep.noprelude))
    102                    } else {
    103                        (None, None)
    104                    };
    105                    SerializedUnitDep {
    106                        index: indices[&unit_dep.unit],
    107                        extern_crate_name: unit_dep.extern_crate_name,
    108                        public,
    109                        noprelude,
    110                    }
    111                })
    112                .collect();
    113            SerializedUnit {
    114                pkg_id: unit.pkg.package_id().to_spec(),
    115                target: &unit.target,
    116                profile: &unit.profile,
    117                platform: unit.kind,
    118                mode: unit.mode,
    119                features: &unit.features,
    120                is_std: unit.is_std,
    121                dependencies,
    122            }
    123        })
    124        .collect();
    125
    126    gctx.shell().print_json(&SerializedUnitGraph {
    127        version: VERSION,
    128        units: ser_units,
    129        roots,
    130    })
    131}