(*
 * Copyright (c) 2017-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *)

open! IStd
module F = Format

module Access : sig
  (** Below [original] is the path used to create the access.  
      [path] may differ from [original] because of substitution of actuals *)
  type t =
    | Read of {path: AccessPath.t; original: AccessPath.t}  (** Field or array read *)
    | Write of {path: AccessPath.t; original: AccessPath.t}  (** Field or array write *)
    | ContainerRead of {path: AccessPath.t; original: AccessPath.t; pname: Typ.Procname.t}
        (** Read of container object *)
    | ContainerWrite of {path: AccessPath.t; original: AccessPath.t; pname: Typ.Procname.t}
        (** Write to container object *)
    | InterfaceCall of Typ.Procname.t
        (** Call to method of interface not annotated with @ThreadSafe *)
  [@@deriving compare]

  include PrettyPrintable.PrintableOrderedType with type t := t

  val matches : caller:t -> callee:t -> bool
  (** returns true if the caller access matches the callee access after accounting for mismatch
      between the formals and actuals *)

  val get_access_path : t -> AccessPath.t option
end

module TraceElem : sig
  include TraceElem.S with module Kind = Access

  val is_write : t -> bool

  val is_container_write : t -> bool

  val map : f:(AccessPath.t -> AccessPath.t) -> t -> t

  val is_direct : t -> bool
  (** return true if the given trace elem represents a direct access, not a call that eventually
      leads to an access *)

  val make_container_access : AccessPath.t -> Typ.Procname.t -> is_write:bool -> Location.t -> t

  val make_field_access : AccessPath.t -> is_write:bool -> Location.t -> t

  val make_unannotated_call_access : Typ.Procname.t -> Location.t -> t
end

module PathDomain :
  SinkTrace.S with module Source = Source.Dummy and module Sink = SinkTrace.MakeSink(TraceElem)

(** Overapproximation of number of locks that are currently held *)
module LocksDomain : sig
  include AbstractDomain.WithBottom

  val acquire_lock : t -> t
  (** record acquisition of a lock *)

  val release_lock : t -> t
  (** record release of a lock *)

  val integrate_summary : caller_astate:t -> callee_astate:t -> t
  (** integrate current state with a callee summary *)
end

(** Abstraction of threads that may run in parallel with the current thread.
    NoThread < AnyThreadExceptSelf < AnyThread *)
module ThreadsDomain : sig
  type t =
    | NoThread
        (** No threads can run in parallel with the current thread (concretization: empty set). We
        assume this by default unless we see evidence to the contrary (annotations, use of locks,
        etc.) *)
    | AnyThreadButSelf
        (** Current thread can run in parallel with other threads, but not with a copy of itself.
        (concretization : {% \{ t | t \in TIDs ^ t != t_cur \} %} ) *)
    | AnyThread
        (** Current thread can run in parallel with any thread, including itself (concretization:
            set of all TIDs ) *)

  include AbstractDomain.WithBottom with type t := t

  val can_conflict : t -> t -> bool
  (** return true if two accesses with these thread values can run concurrently *)

  val is_any : t -> bool

  val integrate_summary : caller_astate:t -> callee_astate:t -> t
  (** integrate current state with a callee summary *)
end

(** snapshot of the relevant state at the time of a heap access: concurrent thread(s), lock(s) held,
    ownership precondition *)
module AccessSnapshot : sig
  (** precondition for owned access; access is owned if it evaluates to true *)
  module OwnershipPrecondition : sig
    type t =
      | Conjunction of IntSet.t
          (** Conjunction of "formal index must be owned" predicates.
                                         true if empty *)
      | False

    include PrettyPrintable.PrintableOrderedType with type t := t

    val is_true : t -> bool
    (** return [true] if the precondition evaluates to true *)
  end

  type t = private
    { access: PathDomain.Sink.t
    ; thread: ThreadsDomain.t
    ; lock: bool
    ; ownership_precondition: OwnershipPrecondition.t }

  include PrettyPrintable.PrintableOrderedType with type t := t

  val make :
       PathDomain.Sink.t
    -> LocksDomain.t
    -> ThreadsDomain.t
    -> OwnershipPrecondition.t
    -> Procdesc.t
    -> t

  val make_from_snapshot : PathDomain.Sink.t -> t -> t

  val is_unprotected : t -> bool
  (** return true if not protected by lock, thread, or ownership *)
end

(** map of access metadata |-> set of accesses. the map should hold all accesses to a
    possibly-unowned access path *)
module AccessDomain : module type of AbstractDomain.FiniteSet (AccessSnapshot)

(** Powerset domain on the formal indexes in OwnedIf with a distinguished bottom element (Owned)
    and top element (Unowned) *)
module OwnershipAbstractValue : sig
  type t = private
    | Owned  (** Owned value; bottom of the lattice *)
    | OwnedIf of IntSet.t  (** Owned if the formals at the given indexes are owned in the caller *)
    | Unowned  (** Unowned value; top of the lattice *)
  [@@deriving compare]

  val owned : t

  val unowned : t

  val make_owned_if : int -> t

  include AbstractDomain.S with type t := t
end

module OwnershipDomain : sig
  include module type of AbstractDomain.Map (AccessPath) (OwnershipAbstractValue)

  val get_owned : AccessPath.t -> t -> OwnershipAbstractValue.t

  val is_owned : AccessPath.t -> t -> bool

  val find : [`Use_get_owned_instead] [@@warning "-32"]

  val propagate_assignment : AccessPath.t -> HilExp.t -> t -> t

  val propagate_return : AccessPath.t -> OwnershipAbstractValue.t -> HilExp.t list -> t -> t
end

(** attribute attached to a boolean variable specifying what it means when the boolean is true *)
module Choice : sig
  type t =
    | OnMainThread  (** the current procedure is running on the main thread *)
    | LockHeld  (** a lock is currently held *)

  include PrettyPrintable.PrintableOrderedType with type t := t
end

module Attribute : sig
  type t =
    | Functional  (** holds a value returned from a callee marked @Functional *)
    | Choice of Choice.t  (** holds a boolean choice variable *)

  include PrettyPrintable.PrintableOrderedType with type t := t
end

module AttributeSetDomain : module type of AbstractDomain.InvertedSet (Attribute)

module AttributeMapDomain : sig
  include module type of AbstractDomain.InvertedMap (AccessPath) (AttributeSetDomain)

  val add : AccessPath.t -> AttributeSetDomain.t -> t -> t

  val has_attribute : AccessPath.t -> Attribute.t -> t -> bool

  val get_choices : AccessPath.t -> t -> Choice.t list
  (** get the choice attributes associated with the given access path *)

  val add_attribute : AccessPath.t -> Attribute.t -> t -> t

  val propagate_assignment : AccessPath.t -> HilExp.t -> t -> t
  (** propagate attributes from the leaves to the root of an RHS Hil expression *)
end

type t =
  { threads: ThreadsDomain.t  (** current thread: main, background, or unknown *)
  ; locks: LocksDomain.t  (** boolean that is true if a lock must currently be held *)
  ; accesses: AccessDomain.t
        (** read and writes accesses performed without ownership permissions *)
  ; ownership: OwnershipDomain.t  (** map of access paths to ownership predicates *)
  ; attribute_map: AttributeMapDomain.t
        (** map of access paths to attributes such as owned, functional, ... *) }

(** same as astate, but without [attribute_map] (since these involve locals) and with the addition
    of the ownership/attributes associated with the return value as well as the set of formals which
    may escape *)
type summary =
  { threads: ThreadsDomain.t
  ; locks: LocksDomain.t
  ; accesses: AccessDomain.t
  ; return_ownership: OwnershipAbstractValue.t
  ; return_attributes: AttributeSetDomain.t }

val empty_summary : summary

include AbstractDomain.WithBottom with type t := t

val pp_summary : F.formatter -> summary -> unit