litequeue.rb in litequeue-0.2.0

- old
+ new
@@ -1,8 +1,103 @@
 # frozen_string_literal: true
 
 require_relative "litequeue/version"
 
-module Litequeue
-  class Error < StandardError; end
-  # Your code goes here...
+require "singleton"
+require "yaml"
+require "litedb"
+
+class Litequeue
+  include Singleton
+
+  DEFAULT_QUEUE = "default"
+
+  Configuration = Struct.new(:path, :synchronous, :mmap_size, :journal_size_limit)
+
+  def self.configuration
+    @configuration ||= Configuration.new(
+      _path = "queue.sqlite3",
+      _synchronous = :OFF,
+      _mmap_size = 32 * 1024
+    )
+  end
+
+  def self.configure
+    yield(configuration)
+  end
+
+  def self.migrations
+    YAML.load_file("#{__dir__}/litequeue/migrations.sql.yml")
+  end
+
+  def self.statements
+    YAML.load_file("#{__dir__}/litequeue/statements.sql.yml")
+  end
+
+  def initialize
+    configuration = self.class.configuration
+    file = configuration.path
+    options = configuration.to_h
+      .slice(:synchronous, :mmap_size, :journal_size_limit)
+      .merge(migrations: self.class.migrations,
+        statements: self.class.statements)
+
+    @db = Litedb::Connection.new(file, options)
+    # Once the instance has been initialized, don't allow the configuration to be changed
+    # as it won't have any effect.
+    configuration.freeze
+  end
+
+  def push(value, queue: DEFAULT_QUEUE, delay: 0)
+    results = @db.run_statement(:push, queue, delay, value) # [["{id}", "{name}"]]
+    extract_row(results)
+  end
+
+  def pop(queue: DEFAULT_QUEUE, limit: 1)
+    results = @db.run_statement(:pop, queue, limit)
+
+    return extract_row(results) if limit == 1
+
+    results
+  end
+
+  def repush(id, value, queue: DEFAULT_QUEUE, delay: 0)
+    results = @db.run_statement(:repush, id, queue, delay, value)
+    extract_value(results)
+  end
+
+  def delete(id)
+    results = @db.run_statement(:delete, id)
+    extract_value(results)
+  end
+
+  def count(queue: nil)
+    results = @db.run_statement(:count, queue)
+    extract_value(results)
+  end
+
+  def clear(queue: nil)
+    results = @db.run_statement(:clear, queue)
+    results.count
+  end
+
+  def empty?
+    count.zero?
+  end
+
+  private
+
+  def extract_value(results) # [["{value}"]] || []
+    return if results.empty?
+
+    results
+      .first # [[value]] -> [value]
+      .first # [value] -> value
+  end
+
+  def extract_row(results) # [[{value}, {value}]] || []
+    return if results.empty?
+
+    results
+      .first # [[value, value]] -> [value, value]
+  end
 end