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#pragma once
///@file
#include "types.hh"
#include "store-api.hh"
#include "build-result.hh"
namespace nix {
/**
* Forward definition.
*/
struct Goal;
class Worker;
/**
* A pointer to a goal.
*/
typedef std::shared_ptr<Goal> GoalPtr;
typedef std::weak_ptr<Goal> WeakGoalPtr;
struct CompareGoalPtrs {
bool operator() (const GoalPtr & a, const GoalPtr & b) const;
};
/**
* Set of goals.
*/
typedef std::set<GoalPtr, CompareGoalPtrs> Goals;
typedef std::set<WeakGoalPtr, std::owner_less<WeakGoalPtr>> WeakGoals;
/**
* A map of paths to goals (and the other way around).
*/
typedef std::map<StorePath, WeakGoalPtr> WeakGoalMap;
/**
* Used as a hint to the worker on how to schedule a particular goal. For example,
* builds are typically CPU- and memory-bound, while substitutions are I/O bound.
* Using this information, the worker might decide to schedule more or fewer goals
* of each category in parallel.
*/
enum struct JobCategory {
/**
* A build of a derivation; it will use CPU and disk resources.
*/
Build,
/**
* A substitution an arbitrary store object; it will use network resources.
*/
Substitution,
};
struct Goal : public std::enable_shared_from_this<Goal>
{
typedef enum {ecSuccess, ecFailed, ecNoSubstituters, ecIncompleteClosure} ExitCode;
/**
* Backlink to the worker.
*/
Worker & worker;
/**
* Goals that this goal is waiting for.
*/
Goals waitees;
/**
* Goals waiting for this one to finish. Must use weak pointers
* here to prevent cycles.
*/
WeakGoals waiters;
/**
* Number of goals we are/were waiting for that have failed.
*/
size_t nrFailed = 0;
/**
* Number of substitution goals we are/were waiting for that
* failed because there are no substituters.
*/
size_t nrNoSubstituters = 0;
/**
* Number of substitution goals we are/were waiting for that
* failed because they had unsubstitutable references.
*/
size_t nrIncompleteClosure = 0;
/**
* Name of this goal for debugging purposes.
*/
std::string name;
/**
* Whether the goal is finished.
*/
std::optional<ExitCode> exitCode;
/**
* Build result.
*/
BuildResult buildResult;
public:
struct [[nodiscard]] StillAlive {};
struct [[nodiscard]] WaitForSlot {};
struct [[nodiscard]] Finished {
ExitCode result;
std::unique_ptr<Error> ex;
};
struct [[nodiscard]] WorkResult : std::variant<StillAlive, WaitForSlot, Finished>
{
WorkResult() = delete;
using variant::variant;
};
/**
* Exception containing an error message, if any.
*/
std::unique_ptr<Error> ex;
Goal(Worker & worker, DerivedPath path)
: worker(worker)
{ }
virtual ~Goal() noexcept(false)
{
trace("goal destroyed");
}
virtual WorkResult work() = 0;
void addWaitee(GoalPtr waitee);
virtual void waiteeDone(GoalPtr waitee) { }
virtual WorkResult handleChildOutput(int fd, std::string_view data)
{
abort();
}
virtual void handleEOF(int fd)
{
}
void trace(std::string_view s);
std::string getName() const
{
return name;
}
/**
* Callback in case of a timeout. It should wake up its waiters,
* get rid of any running child processes that are being monitored
* by the worker (important!), etc.
*/
virtual Finished timedOut(Error && ex) = 0;
virtual std::string key() = 0;
virtual void cleanup() { }
/**
* @brief Hint for the scheduler, which concurrency limit applies.
* @see JobCategory
*/
virtual JobCategory jobCategory() const = 0;
};
}
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