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#pragma once
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#include <workerd/jsg/jsg.h>
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namespace workerd {
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class IoContext;
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// A TimeoutId is a positive non-zero integer value that explicitly identifies a timeout set on an
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// isolate.
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//
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// Lastly, timeout ids can experience integer roll over. It is expected that the
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// setTimeout/clearTimeout implementation will enforce id uniqueness for *active* timeouts. This
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// does not mean that an external user cannot have cached a timeout id for a long expired timeout.
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// However, clearTimeout implementations are expected to only have access to timeouts set via that
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// same implementation.
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class TimeoutId {
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 public:
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  // Use a double so that we can exceed the maximum value for uint32_t.
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  using NumberType = double;
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  // Store as a uint64_t so that we treat this id as an integer.
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  using ValueType = uint64_t;
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  class Generator;
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  // Convert an externally provided double into a TimeoutId. If you are making a new TimeoutId,
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  // use a Generator instead.
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  inline static TimeoutId fromNumber(NumberType id) {
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    return TimeoutId(static_cast<ValueType>(id));
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  }
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  // Convert a TimeoutId to an integer-convertable double for external consumption.
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  // Note that this is expected to be less than or equal to JavaScript Number.MAX_SAFE_INTEGER
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  // (2^53 - 1). To reach greater than that value in normal operation, we'd need a Generator to
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  // live far far longer than our normal release/restart cycle, be initialized with a large
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  // starting value, or experience active concurrency _somehow_.
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  inline NumberType toNumber() const {
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    return value;
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  }
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  inline bool operator<(TimeoutId id) const {
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    return value < id.value;
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  }
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 private:
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  constexpr explicit TimeoutId(ValueType value): value(value) {}
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  ValueType value;
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};
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class TimeoutId::Generator {
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 public:
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  Generator() = default;
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  KJ_DISALLOW_COPY_AND_MOVE(Generator);
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  // Get the next TimeoutId for this generator. This function will never return a TimeoutId <= 0.
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  TimeoutId getNext();
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 private:
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  // We always skip 0 per the spec:
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  // https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#timers.
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  TimeoutId::ValueType nextId = 1;
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};
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class TimeoutManager {
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 public:
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  // Upper bound on the number of timeouts a user can *ever* have active.
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  constexpr static auto MAX_TIMEOUTS = 10'000;
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  struct TimeoutParameters {
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    TimeoutParameters(bool repeat, int64_t msDelay, jsg::Function<void()> function);
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    bool repeat;
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    int64_t msDelay;
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    // This is a maybe to allow cancel to clear it and free the reference
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    // when it is no longer needed.
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    kj::Maybe<jsg::Function<void()>> function;
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  };
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  virtual TimeoutId setTimeout(
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      IoContext& context, TimeoutId::Generator& generator, TimeoutParameters params) = 0;
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  virtual void clearTimeout(IoContext& context, TimeoutId id) = 0;
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  virtual size_t getTimeoutCount() const = 0;
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  virtual kj::Maybe<kj::Date> getNextTimeout() const = 0;
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  virtual void cancelAll() = 0;
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};
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}  // namespace workerd