hphp/hack/src/providers/provider_config.ml

   1 (*
   2  * Copyright (c) 2019, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the MIT license found in the
   6  * LICENSE file in the "hack" directory of this source tree.
   7  *
   8  *)
   9
  10 (* NOTE: we can't simply use a string as a key. In the case of a name conflict,
  11 we may put e.g. a function named 'foo' into the cache whose value is one type,
  12 and then later try to withdraw a class named 'foo' whose value is another type.
  13
  14 The problem can be solved with a GADT, but making a GADT with references to
  15 types like `Typing_defs.ty` causes dependency cycles, since `typing` ends up
  16 depending on `Provider_config` transitively.
  17 *)
  18 type decl_cache_key =
  19   | Fun_decl of string
  20   | Class_decl of string
  21   | Record_decl of string
  22   | Typedef_decl of string
  23   | Gconst_decl of string
  24
  25 type decl_cache = (decl_cache_key, Obj.t) Memory_bounded_lru_cache.t
  26
  27 type backend =
  28   | Lru_shared_memory
  29   | Shared_memory
  30   | Local_memory of { decl_cache: decl_cache }
  31   | Decl_service of unit
  32
  33 let backend_ref = ref Shared_memory
  34
  35 let set_lru_shared_memory_backend () : unit = backend_ref := Lru_shared_memory
  36
  37 let set_shared_memory_backend () : unit = backend_ref := Shared_memory
  38
  39 let set_local_memory_backend ~(max_size_in_words : int) : unit =
  40   backend_ref :=
  41     Local_memory
  42       { decl_cache = Memory_bounded_lru_cache.make ~max_size_in_words }
  43
  44 let set_decl_service_backend () : unit = backend_ref := Decl_service ()
  45
  46 let get_backend () : backend = !backend_ref