implement trylock

Author: Krastanov

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## v1.0.1 - dev
 
-- Start using `Base`'s API: `lock`, `unlock`, `islocked`, `isready`, `get!` and deprecate `get`, `request`, `release`.
+- Start using `Base`'s API: `lock`, `trylock`, `unlock`, `islocked`, `isready`, `get!` and deprecate `get`, `request`, `release`.
 ## v1.0.0 - 2023-05-03
 
 - Rename from SimJulia.jl to ConcurrentSim.jl

src/ConcurrentSim.jl

@@ -7,7 +7,7 @@ module ConcurrentSim
   using Dates
   using ResumableFunctions
 
-  import Base: run, isless, show, yield, get, put!, isready, islocked, unlock, lock, &, |
+  import Base: run, isless, show, yield, get, put!, isready, islocked, unlock, lock, trylock, &, |
   import Dates: now
 
   export AbstractEvent, Environment, value, state, environment

src/resources/containers.jl

@@ -32,6 +32,30 @@ end
 
 lock(res::Resource; priority::Int=0) = put!(res, 1; priority=priority)
 
+"""
+    trylock(res::Resource)
+
+If the Resource is not locked, locks it and return the lock event.
+Returns `false` if the Resource is locked, similarly to the meaning of `trylock` for `Base.ReentrantLock`.
+
+```jldoctest
+julia> sim = Simulation(); res = Resource(sim);
+
+julia> ev = trylock(res)
+ConcurrentSim.Put 1
+
+julia> typeof(ev)
+ConcurrentSim.Put
+
+julia> trylock(res)
+false
+```
+"""
+function trylock(res::Resource; priority::Int=0)
+    islocked(res) && return false # TODO check priority
+    lock(res; priority)
+end
+
 function get(con::Container{N}, amount::N; priority::Int=0) where N<:Real
   get_ev = Get(con.env)
   con.get_queue[get_ev] = ContainerKey(priority, con.seid+=one(UInt), amount)

src/resources/stores.jl

@@ -102,3 +102,4 @@ islocked(sto::Store) = sto.load==sto.capacity
 
 unlock(::Store) = error("There is no well defined way to \"unlock\" a store. Instead of attempting `unlock` consider using `pop!(::Store)` or use a `Resource` instead of a `Store`.")
 lock(::Store) = error("There is no well defined way to \"lock\" a store. Instead of attempting `lock` consider using `put!(::Store, ...)` or use a `Resource` instead of a `Store`.")
+trylock(::Store) = error("There is no well defined way to \"lock\" a store. Instead of attempting `lock` consider using `put!(::Store, ...)` or use a `Resource` instead of a `Store`.")

test/test_resources_stores.jl

@@ -33,3 +33,4 @@ run(sim)
 
 @test_throws ErrorException unlock(sto)
 @test_throws ErrorException lock(sto)
+@test_throws ErrorException trylock(sto)