66 lines
2.9 KiB
Clojure
66 lines
2.9 KiB
Clojure
(ns re-frame.events
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(:require [re-frame.db :refer [app-db]]
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[re-frame.utils :refer [first-in-vector]]
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[re-frame.interop :refer [empty-queue debug-enabled?]]
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[re-frame.registrar :refer [get-handler register-handler]]
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[re-frame.loggers :refer [console]]
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[re-frame.interceptor :as interceptor]
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[re-frame.trace :as trace :include-macros true]))
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(def kind :event)
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(assert (re-frame.registrar/kinds kind))
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(defn- flatten-and-remove-nils
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"`interceptors` might have nested collections, and contain nil elements.
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return a flat collection, with all nils removed.
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This function is 9/10 about giving good error messages"
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[id interceptors]
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(let [make-chain #(->> % flatten (remove nil?))]
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(if-not debug-enabled?
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(make-chain interceptors)
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(do ;; do a whole lot of development time checks
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(when-not (coll? interceptors)
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(console :error (str "re-frame: when registering " id ", expected a collection of interceptors, got:") interceptors))
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(let [chain (make-chain interceptors)]
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(when (empty? chain)
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(console :error (str "re-frame: when registering" id ", given an empty interceptor chain")))
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(when-let [not-i (first (remove interceptor/interceptor? chain))]
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(if (fn? not-i)
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(console :error (str "re-frame: when registering " id ", got a function instead of an interceptor. Did you provide old style middleware by mistake? Got:") not-i)
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(console :error (str "re-frame: when registering " id ", expected interceptors, but got:") not-i)))
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chain)))))
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(defn register
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"Associate the given event `id` with the given collection of `interceptors`.
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`interceptors` may contain nested collections and there may be nils
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at any level,so process this structure into a simple, nil-less vector
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before registration.
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An `event handler` will likely be at the end of the chain (wrapped in an interceptor)."
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[id interceptors]
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(register-handler kind id (flatten-and-remove-nils id interceptors)))
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;; -- handle event --------------------------------------------------------------------------------
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(def ^:dynamic *handling* nil) ;; remember what event we are currently handling
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(defn handle
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"Given an event vector, look up the associated intercepter chain, and execute it."
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[event-v]
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(let [event-id (first-in-vector event-v)]
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(if-let [interceptors (get-handler kind event-id true)]
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(if *handling*
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(console :error (str "re-frame: while handling \"" *handling* "\", dispatch-sync was called for \"" event-v "\". You can't call dispatch-sync within an event handler."))
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(binding [*handling* event-v]
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(trace/with-trace {:operation event-id
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:op-type kind
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:tags {:event event-v}}
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(interceptor/execute event-v interceptors)))))))
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