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require "spec"
require "../support/fibers"
describe Mutex do
it "locks and unlocks" do
mutex = Mutex.new
mutex.lock
mutex.unlock
end
it "works with multiple threads" do
x = 0
mutex = Mutex.new
fibers = 10.times.map do
spawn do
100.times do
mutex.synchronize { x += 1 }
end
end
end.to_a
fibers.each do |f|
wait_until_finished f
end
x.should eq(1000)
end
describe "checked" do
it "raises if locked recursively" do
mutex = Mutex.new
mutex.lock
expect_raises(Exception, "Attempt to lock a mutex recursively (deadlock)") do
mutex.lock
end
end
it "raises if unlocks without lock" do
mutex = Mutex.new
expect_raises(Exception, "Attempt to unlock a mutex which is not locked") do
mutex.unlock
end
end
it "can't be unlocked by another fiber" do
mutex = nil
done = false
spawn do
mutex = Mutex.new
mutex.not_nil!.lock
done = true
end
until done
Fiber.yield
end
expect_raises(Exception, "Attempt to unlock a mutex locked by another fiber") do
mutex.not_nil!.unlock
end
end
end
describe "reentrant" do
it "can be locked many times from the same fiber" do
mutex = Mutex.new(:reentrant)
mutex.lock
mutex.lock
mutex.unlock
mutex.unlock
end
it "raises if unlocks without lock" do
mutex = Mutex.new(:reentrant)
expect_raises(Exception, "Attempt to unlock a mutex which is not locked") do
mutex.unlock
end
end
it "can't be unlocked by another fiber" do
mutex = nil
done = false
spawn do
mutex = Mutex.new(:reentrant)
mutex.not_nil!.lock
done = true
end
until done
Fiber.yield
end
expect_raises(Exception, "Attempt to unlock a mutex locked by another fiber") do
mutex.not_nil!.unlock
end
end
end
describe "unchecked" do
it "can lock and unlock from multiple fibers" do
mutex = Mutex.new(:unchecked)
a = 1
two = false
three = false
four = false
ch = Channel(Nil).new
spawn do
mutex.synchronize do
a = 2
Fiber.yield
two = a == 2
end
ch.send(nil)
end
spawn do
mutex.synchronize do
a = 3
Fiber.yield
three = a == 3
end
ch.send(nil)
end
spawn do
mutex.synchronize do
a = 4
Fiber.yield
four = a == 4
end
ch.send(nil)
end
3.times { ch.receive }
two.should be_true
three.should be_true
four.should be_true
end
end
end
|
