| 1 | #pragma once |
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| 2 | |
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| 3 | #include <memory> |
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| 4 | |
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| 5 | namespace mbgl { |
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| 6 | |
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| 7 | class Mailbox; |
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| 8 | |
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| 9 | /* |
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| 10 | A `Scheduler` is responsible for coordinating the processing of messages by |
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| 11 | one or more actors via their mailboxes. It's an abstract interface. Currently, |
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| 12 | the following concrete implementations exist: |
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| 13 | |
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| 14 | * `ThreadPool` can coordinate an unlimited number of actors over any number of |
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| 15 | threads via a pool, preserving the following behaviors: |
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| 16 | |
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| 17 | - Messages from each individual mailbox are processed in order |
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| 18 | - Only a single message from a mailbox is processed at a time; there is no |
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| 19 | concurrency within a mailbox |
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| 20 | |
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| 21 | Subject to these constraints, processing can happen on whatever thread in the |
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| 22 | pool is available. |
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| 23 | |
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| 24 | * `Scheduler::GetCurrent()` is typically used to create a mailbox and `ActorRef` |
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| 25 | for an object that lives on the main thread and is not itself wrapped an |
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| 26 | `Actor`. The underlying implementation of this Scheduler should usually be |
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| 27 | a `RunLoop` |
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| 28 | auto mailbox = std::make_shared<Mailbox>(*Scheduler::Get()); |
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| 29 | Actor<Worker> worker(threadPool, ActorRef<Foo>(*this, mailbox)); |
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| 30 | */ |
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| 31 | class Scheduler { |
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| 32 | public: |
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| 33 | virtual ~Scheduler() = default; |
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| 34 | |
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| 35 | // Used by a Mailbox when it has a message in its queue to request that it |
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| 36 | // be scheduled. Specifically, the scheduler is expected to asynchronously |
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| 37 | // call `receive() on the given mailbox, provided it still exists at that |
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| 38 | // time. |
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| 39 | virtual void schedule(std::weak_ptr<Mailbox>) = 0; |
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| 40 | |
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| 41 | // Set/Get the current Scheduler for this thread |
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| 42 | static Scheduler* GetCurrent(); |
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| 43 | static void SetCurrent(Scheduler*); |
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| 44 | }; |
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| 45 | |
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| 46 | } // namespace mbgl |
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| 47 | |
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