cabal-version:       >=1.10
name:                lazy-cache
synopsis:            Library for caching IO action that leverages on GHC RTS implementation
version:             0.2.0.0
author:              Alexander Vershilov
maintainer:          backend-dev@sirius.online
copyright:           2019-2022 (C) Фонд "Талант и Успех"
license:             MPL-2.0
license-file:        LICENSE
build-type:          Simple
category:            System
description:         The library provides an interface for caching the results of IO actions.
                     This library relies on a blackholing — mechanism that is used to implement lazy
                     evaluation for avoiding concurrent runs of the action
                     (this is where the name of the library comes from).
                     .
                     The library provides caching mechanismsl with the following properties:
                     .
                       1. when the function is called the successful result is cached by no more than a provided time;
                       2. if the function ends with an exception, it will be rethrown, and the result will not be cached;
                       3. if the function will be called with the same input value it immediately gets cached
                          result;
                       4. if functions are called concurrently with the different input values they will not
                          block each other;
                       5. if functions will be called concurrently with the same argument then only one will
                          act, others will wait until the first one is finished and will either return the
                          result once it's received, or will rethrow an exception if the first one
                          exits with an exception;
                       6. outdated values are cleared only on accesses to the cache, so if no action is called
                          the data will not be cleared.
                     .
                     The main entry point of the library is "System.Cache" module, it explains how to
                     use the library and provides the public API, that does not depend on the actual
                     store implementation.
                     .
                     The library provides an interface for caching, and three implementations:
                     .
                        1. "System.Cache.Impl.Ghc" — the main one based on GHC system;

                        2. "System.Cache.Impl.MVar" — implementation based on library functions;

                        3. "System.Cache.Impl.NoCache" — implementation that disables caching, but keeps the same interface 
                     .
                     If you want to implement your own caching mechanism, or use internal API, you
                     can refer to the "System.Cache.Internal.Interface" module for an additional documentation.
extra-source-files:
   CHANGELOG.md
   Readme.md

tested-with:
  GHC == 9.2.2
   || == 8.10.7

source-repository head
  type: git
  location: https://github.com/cheopslab/lazy-cache

library
  exposed-modules:
    System.Cache
    System.Cache.Impl.Ghc
    System.Cache.Impl.MVar
    System.Cache.Impl.NoCache
    System.Cache.Internal.Interface
  other-extensions:
    RecursiveDo
    TemplateHaskell
  build-depends:
    base >=4.12 && <5,
    hashable >=1.1.2.3 && <1.5,
    psqueues >=0.2 && <0.3,
    clock >= 0.8
  hs-source-dirs: src
  ghc-options: -Wall
  default-language: Haskell2010
  default-extensions:
    LambdaCase
    NumericUnderscores
    OverloadedStrings
    RecordWildCards
    ScopedTypeVariables

test-suite spec
  type: exitcode-stdio-1.0
  main-is: Spec.hs
  other-modules:
      Cheops.Cache.CacheSpec
  hs-source-dirs:
      test
  ghc-options: -Wall -threaded -rtsopts -with-rtsopts=-N
  build-tool-depends: hspec-discover:hspec-discover
  build-depends:
      HUnit
    , base >=4.7 && <5
    , lazy-cache
    , hashable
    , hspec
    , clock
  default-language: Haskell2010