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use super::dep_cache::RegistryQueryer;
use super::errors::ActivateResult;
use super::types::{ConflictMap, ConflictReason, FeaturesSet, ResolveOpts};
use super::RequestedFeatures;
use crate::core::{Dependency, PackageId, SourceId, Summary};
use crate::util::interning::InternedString;
use crate::util::Graph;
use anyhow::format_err;
use std::collections::HashMap;
use std::num::NonZeroU64;
use tracing::debug;
pub use super::encode::Metadata;
pub use super::encode::{EncodableDependency, EncodablePackageId, EncodableResolve};
pub use super::resolve::Resolve;
// A `Context` is basically a bunch of local resolution information which is
// kept around for all `BacktrackFrame` instances. As a result, this runs the
// risk of being cloned *a lot* so we want to make this as cheap to clone as
// possible.
#[derive(Clone)]
pub struct Context {
pub age: ContextAge,
pub activations: Activations,
/// list the features that are activated for each package
pub resolve_features: im_rc::HashMap<PackageId, FeaturesSet>,
/// get the package that will be linking to a native library by its links attribute
pub links: im_rc::HashMap<InternedString, PackageId>,
/// for each package the list of names it can see,
/// then for each name the exact version that name represents and whether the name is public.
pub public_dependency: Option<PublicDependency>,
/// a way to look up for a package in activations what packages required it
/// and all of the exact deps that it fulfilled.
pub parents: Graph<PackageId, im_rc::HashSet<Dependency>>,
}
/// When backtracking it can be useful to know how far back to go.
/// The `ContextAge` of a `Context` is a monotonically increasing counter of the number
/// of decisions made to get to this state.
/// Several structures store the `ContextAge` when it was added,
/// to be used in `find_candidate` for backtracking.
pub type ContextAge = usize;
/// Find the activated version of a crate based on the name, source, and semver compatibility.
/// By storing this in a hash map we ensure that there is only one
/// semver compatible version of each crate.
/// This all so stores the `ContextAge`.
pub type ActivationsKey = (InternedString, SourceId, SemverCompatibility);
pub type Activations = im_rc::HashMap<ActivationsKey, (Summary, ContextAge)>;
/// A type that represents when cargo treats two Versions as compatible.
/// Versions `a` and `b` are compatible if their left-most nonzero digit is the
/// same.
#[derive(Clone, Copy, Eq, PartialEq, Hash, Debug, PartialOrd, Ord)]
pub enum SemverCompatibility {
Major(NonZeroU64),
Minor(NonZeroU64),
Patch(u64),
}
impl From<&semver::Version> for SemverCompatibility {
fn from(ver: &semver::Version) -> Self {
if let Some(m) = NonZeroU64::new(ver.major) {
return SemverCompatibility::Major(m);
}
if let Some(m) = NonZeroU64::new(ver.minor) {
return SemverCompatibility::Minor(m);
}
SemverCompatibility::Patch(ver.patch)
}
}
impl PackageId {
pub fn as_activations_key(self) -> ActivationsKey {
(self.name(), self.source_id(), self.version().into())
}
}
impl Context {
pub fn new(check_public_visible_dependencies: bool) -> Context {
Context {
age: 0,
resolve_features: im_rc::HashMap::new(),
links: im_rc::HashMap::new(),
public_dependency: if check_public_visible_dependencies {
Some(PublicDependency::new())
} else {
None
},
parents: Graph::new(),
activations: im_rc::HashMap::new(),
}
}
/// Activate this summary by inserting it into our list of known activations.
///
/// The `parent` passed in here is the parent summary/dependency edge which
/// cased `summary` to get activated. This may not be present for the root
/// crate, for example.
///
/// Returns `true` if this summary with the given features is already activated.
pub fn flag_activated(
&mut self,
summary: &Summary,
opts: &ResolveOpts,
parent: Option<(&Summary, &Dependency)>,
) -> ActivateResult<bool> {
let id = summary.package_id();
let age: ContextAge = self.age;
match self.activations.entry(id.as_activations_key()) {
im_rc::hashmap::Entry::Occupied(o) => {
debug_assert_eq!(
&o.get().0,
summary,
"cargo does not allow two semver compatible versions"
);
}
im_rc::hashmap::Entry::Vacant(v) => {
if let Some(link) = summary.links() {
if self.links.insert(link, id).is_some() {
return Err(format_err!(
"Attempting to resolve a dependency with more than \
one crate with links={}.\nThis will not build as \
is. Consider rebuilding the .lock file.",
&*link
)
.into());
}
}
v.insert((summary.clone(), age));
// If we've got a parent dependency which activated us, *and*
// the dependency has a different source id listed than the
// `summary` itself, then things get interesting. This basically
// means that a `[patch]` was used to augment `dep.source_id()`
// with `summary`.
//
// In this scenario we want to consider the activation key, as
// viewed from the perspective of `dep.source_id()`, as being
// fulfilled. This means that we need to add a second entry in
// the activations map for the source that was patched, in
// addition to the source of the actual `summary` itself.
//
// Without this it would be possible to have both 1.0.0 and
// 1.1.0 "from crates.io" in a dependency graph if one of those
// versions came from a `[patch]` source.
if let Some((_, dep)) = parent {
if dep.source_id() != id.source_id() {
let key = (id.name(), dep.source_id(), id.version().into());
let prev = self.activations.insert(key, (summary.clone(), age));
if let Some((previous_summary, _)) = prev {
return Err(
(previous_summary.package_id(), ConflictReason::Semver).into()
);
}
}
}
return Ok(false);
}
}
debug!("checking if {} is already activated", summary.package_id());
match &opts.features {
// This returns `false` for CliFeatures just for simplicity. It
// would take a bit of work to compare since they are not in the
// same format as DepFeatures (and that may be expensive
// performance-wise). Also, it should only occur once for a root
// package. The only drawback is that it may re-activate a root
// package again, which should only affect performance, but that
// should be rare. Cycles should still be detected since those
// will have `DepFeatures` edges.
RequestedFeatures::CliFeatures(_) => Ok(false),
RequestedFeatures::DepFeatures {
features,
uses_default_features,
} => {
let has_default_feature = summary.features().contains_key("default");
Ok(match self.resolve_features.get(&id) {
Some(prev) => {
features.is_subset(prev)
&& (!uses_default_features
|| prev.contains("default")
|| !has_default_feature)
}
None => features.is_empty() && (!uses_default_features || !has_default_feature),
})
}
}
}
/// If the package is active returns the `ContextAge` when it was added
pub fn is_active(&self, id: PackageId) -> Option<ContextAge> {
self.activations
.get(&id.as_activations_key())
.and_then(|(s, l)| if s.package_id() == id { Some(*l) } else { None })
}
/// If the conflict reason on the package still applies returns the `ContextAge` when it was added
pub fn still_applies(&self, id: PackageId, reason: &ConflictReason) -> Option<ContextAge> {
self.is_active(id).and_then(|mut max| {
match reason {
ConflictReason::PublicDependency(name) => {
if &id == name {
return Some(max);
}
max = std::cmp::max(max, self.is_active(*name)?);
max = std::cmp::max(
max,
self.public_dependency
.as_ref()
.unwrap()
.can_see_item(*name, id)?,
);
}
ConflictReason::PubliclyExports(name) => {
if &id == name {
return Some(max);
}
max = std::cmp::max(max, self.is_active(*name)?);
max = std::cmp::max(
max,
self.public_dependency
.as_ref()
.unwrap()
.publicly_exports_item(*name, id)?,
);
}
_ => {}
}
Some(max)
})
}
/// Checks whether all of `parent` and the keys of `conflicting activations`
/// are still active.
/// If so returns the `ContextAge` when the newest one was added.
pub fn is_conflicting(
&self,
parent: Option<PackageId>,
conflicting_activations: &ConflictMap,
) -> Option<usize> {
let mut max = 0;
if let Some(parent) = parent {
max = std::cmp::max(max, self.is_active(parent)?);
}
for (id, reason) in conflicting_activations.iter() {
max = std::cmp::max(max, self.still_applies(*id, reason)?);
}
Some(max)
}
pub fn resolve_replacements(
&self,
registry: &RegistryQueryer<'_>,
) -> HashMap<PackageId, PackageId> {
self.activations
.values()
.filter_map(|(s, _)| registry.used_replacement_for(s.package_id()))
.collect()
}
pub fn graph(&self) -> Graph<PackageId, std::collections::HashSet<Dependency>> {
let mut graph: Graph<PackageId, std::collections::HashSet<Dependency>> = Graph::new();
self.activations
.values()
.for_each(|(r, _)| graph.add(r.package_id()));
for i in self.parents.iter() {
graph.add(*i);
for (o, e) in self.parents.edges(i) {
let old_link = graph.link(*o, *i);
assert!(old_link.is_empty());
*old_link = e.iter().cloned().collect();
}
}
graph
}
}
impl Graph<PackageId, im_rc::HashSet<Dependency>> {
pub fn parents_of(&self, p: PackageId) -> impl Iterator<Item = (PackageId, bool)> + '_ {
self.edges(&p)
.map(|(grand, d)| (*grand, d.iter().any(|x| x.is_public())))
}
}
#[derive(Clone, Debug, Default)]
pub struct PublicDependency {
/// For each active package the set of all the names it can see,
/// for each name the exact package that name resolves to,
/// the `ContextAge` when it was first visible,
/// and the `ContextAge` when it was first exported.
inner: im_rc::HashMap<
PackageId,
im_rc::HashMap<InternedString, (PackageId, ContextAge, Option<ContextAge>)>,
>,
}
impl PublicDependency {
fn new() -> Self {
PublicDependency {
inner: im_rc::HashMap::new(),
}
}
fn publicly_exports(&self, candidate_pid: PackageId) -> Vec<PackageId> {
self.inner
.get(&candidate_pid) // if we have seen it before
.iter()
.flat_map(|x| x.values()) // all the things we have stored
.filter(|x| x.2.is_some()) // as publicly exported
.map(|x| x.0)
.chain(Some(candidate_pid)) // but even if not we know that everything exports itself
.collect()
}
fn publicly_exports_item(
&self,
candidate_pid: PackageId,
target: PackageId,
) -> Option<ContextAge> {
debug_assert_ne!(candidate_pid, target);
let out = self
.inner
.get(&candidate_pid)
.and_then(|names| names.get(&target.name()))
.filter(|(p, _, _)| *p == target)
.and_then(|(_, _, age)| *age);
debug_assert_eq!(
out.is_some(),
self.publicly_exports(candidate_pid).contains(&target)
);
out
}
pub fn can_see_item(&self, candidate_pid: PackageId, target: PackageId) -> Option<ContextAge> {
self.inner
.get(&candidate_pid)
.and_then(|names| names.get(&target.name()))
.filter(|(p, _, _)| *p == target)
.map(|(_, age, _)| *age)
}
pub fn add_edge(
&mut self,
candidate_pid: PackageId,
parent_pid: PackageId,
is_public: bool,
age: ContextAge,
parents: &Graph<PackageId, im_rc::HashSet<Dependency>>,
) {
// one tricky part is that `candidate_pid` may already be active and
// have public dependencies of its own. So we not only need to mark
// `candidate_pid` as visible to its parents but also all of its existing
// publicly exported dependencies.
for c in self.publicly_exports(candidate_pid) {
// for each (transitive) parent that can newly see `t`
let mut stack = vec![(parent_pid, is_public)];
while let Some((p, public)) = stack.pop() {
match self.inner.entry(p).or_default().entry(c.name()) {
im_rc::hashmap::Entry::Occupied(mut o) => {
// the (transitive) parent can already see something by `c`s name, it had better be `c`.
assert_eq!(o.get().0, c);
if o.get().2.is_some() {
// The previous time the parent saw `c`, it was a public dependency.
// So all of its parents already know about `c`
// and we can save some time by stopping now.
continue;
}
if public {
// Mark that `c` has now bean seen publicly
let old_age = o.get().1;
o.insert((c, old_age, if public { Some(age) } else { None }));
}
}
im_rc::hashmap::Entry::Vacant(v) => {
// The (transitive) parent does not have anything by `c`s name,
// so we add `c`.
v.insert((c, age, if public { Some(age) } else { None }));
}
}
// if `candidate_pid` was a private dependency of `p` then `p` parents can't see `c` thru `p`
if public {
// if it was public, then we add all of `p`s parents to be checked
stack.extend(parents.parents_of(p));
}
}
}
}
pub fn can_add_edge(
&self,
b_id: PackageId,
parent: PackageId,
is_public: bool,
parents: &Graph<PackageId, im_rc::HashSet<Dependency>>,
) -> Result<
(),
(
((PackageId, ConflictReason), (PackageId, ConflictReason)),
Option<(PackageId, ConflictReason)>,
),
> {
// one tricky part is that `candidate_pid` may already be active and
// have public dependencies of its own. So we not only need to check
// `b_id` as visible to its parents but also all of its existing
// publicly exported dependencies.
for t in self.publicly_exports(b_id) {
// for each (transitive) parent that can newly see `t`
let mut stack = vec![(parent, is_public)];
while let Some((p, public)) = stack.pop() {
// TODO: don't look at the same thing more than once
if let Some(o) = self.inner.get(&p).and_then(|x| x.get(&t.name())) {
if o.0 != t {
// the (transitive) parent can already see a different version by `t`s name.
// So, adding `b` will cause `p` to have a public dependency conflict on `t`.
return Err((
(o.0, ConflictReason::PublicDependency(p)), // p can see the other version and
(parent, ConflictReason::PublicDependency(p)), // p can see us
))
.map_err(|e| {
if t == b_id {
(e, None)
} else {
(e, Some((t, ConflictReason::PubliclyExports(b_id))))
}
});
}
if o.2.is_some() {
// The previous time the parent saw `t`, it was a public dependency.
// So all of its parents already know about `t`
// and we can save some time by stopping now.
continue;
}
}
// if `b` was a private dependency of `p` then `p` parents can't see `t` thru `p`
if public {
// if it was public, then we add all of `p`s parents to be checked
stack.extend(parents.parents_of(p));
}
}
}
Ok(())
}
}