//! Type definitions for learning about the dependency formats of all upstream
//! crates (rlibs/dylibs/oh my).
//!
//! For all the gory details, see the provider of the `dependency_formats`
//! query.

use rustc_session::config::CrateType;

/// A list of dependencies for a certain crate type.
///
/// The length of this vector is the same as the number of external crates used.
/// The value is None if the crate does not need to be linked (it was found
/// statically in another dylib), or Some(kind) if it needs to be linked as
/// `kind` (either static or dynamic).
pub type DependencyList = Vec<Linkage>;

/// A mapping of all required dependencies for a particular flavor of output.
///
/// This is local to the tcx, and is generally relevant to one session.
pub type Dependencies = Vec<(CrateType, DependencyList)>;

#[derive(Copy, Clone, PartialEq, Debug, HashStable, Encodable, Decodable)]
pub enum Linkage {
    NotLinked,
    IncludedFromDylib,
    Static,
    Dynamic,
}