foundationdb/recipes/ruby-recipes/micro_priority.rb

108 lines
2.3 KiB
Ruby

#
# micro_priority.rb
#
# This source file is part of the FoundationDB open source project
#
# Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require 'fdb'
require 'securerandom'
FDB.api_version 300
@db = FDB.open
@pq = FDB::Subspace.new(["P"])
def clear_subspace(db,subspace)
db.transact do |tr|
tr.clear_range_start_with(subspace.key)
end
end
def push(db,value, priority)
db.transact do |tr|
tr[@pq[priority][next_count(tr,priority)][SecureRandom.hex(20)]] = value
end
end
def next_count(db,priority)
value = 0
db.transact do |tr|
tr.snapshot.get_range(*@pq[priority].range(), :limit => 1, :reverse => true) do |kv|
value = @pq[priority].unpack(kv.key)[0] + 1
end
end
value
end
def pop(db,max=false)
db.transact do |tr|
tr.get_range(*@pq.range(), :limit => 1, :reverse => max) do |kv|
tr.clear(kv.key)
puts kv.value
end
end
end
def peek(db,max=false)
value = nil
db.transact do |tr|
tr.get_range(*@pq.range(), :limit => 1, :reverse => max) do |kv|
value = kv.value
end
end
value
end
def smoke_test()
clear_subspace(@db,@pq)
puts "peek none: " + peek(@db).to_s
push(@db,'a',1)
push(@db,'b',5)
push(@db,'c',2)
push(@db,'d',4)
push(@db,'e',3)
puts "peak in min order"
puts peek(@db)
puts peek(@db)
puts "pop in min order"
pop(@db)
pop(@db)
pop(@db)
pop(@db)
pop(@db)
puts "peek none: "
peek(@db,max=true)
push(@db,'a1',1)
push(@db,'a2',1)
push(@db,'a3',1)
push(@db,'a4',1)
push(@db,'b',5)
push(@db,'c',2)
push(@db,'d',4)
push(@db,'e',3)
puts "peek in max "
puts peek(@db,max=true)
puts peek(@db,max=true)
puts "pop in max "
pop(@db,max=true)
pop(@db,max=true)
pop(@db,max=true)
pop(@db,max=true)
pop(@db,max=true)
pop(@db,max=true)
end
smoke_test()