(*
 * Copyright (c) 2016 - present Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *)

open! IStd
module F = Format

module Access = struct
  type t =
    | Read of AccessPath.t
    | Write of AccessPath.t
    | ContainerRead of AccessPath.t * Typ.Procname.t
    | ContainerWrite of AccessPath.t * Typ.Procname.t
    | InterfaceCall of Typ.Procname.t
    [@@deriving compare]

  let suffix_matches (_, accesses1) (_, accesses2) =
    match (List.rev accesses1, List.rev accesses2) with
    | access1 :: _, access2 :: _ ->
        AccessPath.equal_access access1 access2
    | _ ->
        false


  let matches ~caller ~callee =
    match (caller, callee) with
    | Read ap1, Read ap2 | Write ap1, Write ap2 ->
        suffix_matches ap1 ap2
    | ContainerRead (ap1, pname1), ContainerRead (ap2, pname2)
    | ContainerWrite (ap1, pname1), ContainerWrite (ap2, pname2) ->
        Typ.Procname.equal pname1 pname2 && suffix_matches ap1 ap2
    | InterfaceCall pname1, InterfaceCall pname2 ->
        Typ.Procname.equal pname1 pname2
    | _ ->
        false


  let make_field_access access_path ~is_write =
    if is_write then Write access_path else Read access_path


  let get_access_path = function
    | Read access_path
    | Write access_path
    | ContainerWrite (access_path, _)
    | ContainerRead (access_path, _) ->
        Some access_path
    | InterfaceCall _ ->
        None


  let map ~f = function
    | Read access_path ->
        Read (f access_path)
    | Write access_path ->
        Write (f access_path)
    | ContainerWrite (access_path, pname) ->
        ContainerWrite (f access_path, pname)
    | ContainerRead (access_path, pname) ->
        ContainerRead (f access_path, pname)
    | InterfaceCall _ as intfcall ->
        intfcall


  let equal t1 t2 = Int.equal (compare t1 t2) 0

  let pp fmt = function
    | Read access_path ->
        F.fprintf fmt "Read of %a" AccessPath.pp access_path
    | Write access_path ->
        F.fprintf fmt "Write to %a" AccessPath.pp access_path
    | ContainerRead (access_path, pname) ->
        F.fprintf fmt "Read of container %a via %a" AccessPath.pp access_path Typ.Procname.pp pname
    | ContainerWrite (access_path, pname) ->
        F.fprintf fmt "Write to container %a via %a" AccessPath.pp access_path Typ.Procname.pp
          pname
    | InterfaceCall pname ->
        F.fprintf fmt "Call to un-annotated interface method %a" Typ.Procname.pp pname
end

module TraceElem = struct
  module Kind = Access

  type t = {site: CallSite.t; kind: Kind.t} [@@deriving compare]

  let is_write {kind} =
    match kind with
    | InterfaceCall _ | Read _ | ContainerRead _ ->
        false
    | ContainerWrite _ | Write _ ->
        true


  let is_container_write {kind} =
    match kind with
    | InterfaceCall _ | Read _ | Write _ | ContainerRead _ ->
        false
    | ContainerWrite _ ->
        true


  let call_site {site} = site

  let kind {kind} = kind

  let make ?indexes:_ kind site = {kind; site}

  let with_callsite t site = {t with site}

  let pp fmt {site; kind} = F.fprintf fmt "%a at %a" Access.pp kind CallSite.pp site

  let map ~f {site; kind} = {site; kind= Access.map ~f kind}

  module Set = PrettyPrintable.MakePPSet (struct
    type nonrec t = t

    let compare = compare

    let pp = pp
  end)

  let dummy_pname = Typ.Procname.empty_block

  let make_dummy_site = CallSite.make dummy_pname

  (* all trace elems are created with a dummy call site. any trace elem without a dummy call site
     represents a call that leads to an access rather than a direct access *)
  let is_direct {site} = Typ.Procname.equal (CallSite.pname site) dummy_pname

  let make_container_access access_path pname ~is_write loc =
    let site = make_dummy_site loc in
    let access =
      if is_write then Access.ContainerWrite (access_path, pname)
      else Access.ContainerRead (access_path, pname)
    in
    make access site


  let make_field_access access_path ~is_write loc =
    let site = make_dummy_site loc in
    make (Access.make_field_access access_path ~is_write) site


  let make_unannotated_call_access pname loc =
    let site = make_dummy_site loc in
    make (Access.InterfaceCall pname) site
end

(* In this domain true<=false. The intended denotations [[.]] are
    [[true]] = the set of all states where we know according, to annotations
               or assertions or lock instructions, that some lock is held.
    [[false]] = the empty set
   The use of && for join in this domain enforces that, to know a lock is held, one must hold in
   all branches.
*)
module LocksDomain = AbstractDomain.BooleanAnd

module ThreadsDomain = struct
  type astate = NoThread | AnyThreadButSelf | AnyThread [@@deriving compare]

  let empty = NoThread

  (* NoThread < AnyThreadButSelf < Any *)
  let ( <= ) ~lhs ~rhs =
    match (lhs, rhs) with
    | NoThread, _ ->
        true
    | _, NoThread ->
        false
    | _, AnyThread ->
        true
    | AnyThread, _ ->
        false
    | _ ->
        Int.equal 0 (compare_astate lhs rhs)


  let join astate1 astate2 =
    match (astate1, astate2) with
    | NoThread, astate | astate, NoThread ->
        astate
    | AnyThread, _ | _, AnyThread ->
        AnyThread
    | AnyThreadButSelf, AnyThreadButSelf ->
        AnyThreadButSelf


  let widen ~prev ~next ~num_iters:_ = join prev next

  let pp fmt astate =
    F.fprintf fmt
      ( match astate with
      | NoThread ->
          "NoThread"
      | AnyThreadButSelf ->
          "AnyThreadButSelf"
      | AnyThread ->
          "AnyThread" )


  let is_empty = function NoThread -> true | _ -> false

  let is_any_but_self = function AnyThreadButSelf -> true | _ -> false

  let is_any = function AnyThread -> true | _ -> false
end

module PathDomain = SinkTrace.Make (TraceElem)

module Choice = struct
  type t = OnMainThread | LockHeld [@@deriving compare]

  let pp fmt = function
    | OnMainThread ->
        F.fprintf fmt "OnMainThread"
    | LockHeld ->
        F.fprintf fmt "LockHeld"
end

module Attribute = struct
  type t = Functional | Choice of Choice.t [@@deriving compare]

  let pp fmt = function
    | Functional ->
        F.fprintf fmt "Functional"
    | Choice choice ->
        Choice.pp fmt choice


  module Set = PrettyPrintable.MakePPSet (struct
    type nonrec t = t

    let compare = compare

    let pp = pp
  end)
end

module AttributeSetDomain = AbstractDomain.InvertedSet (Attribute)

module OwnershipAbstractValue = struct
  type astate = Owned | OwnedIf of IntSet.t | Unowned [@@deriving compare]

  let owned = Owned

  let unowned = Unowned

  let make_owned_if formal_index = OwnedIf (IntSet.singleton formal_index)

  let ( <= ) ~lhs ~rhs =
    if phys_equal lhs rhs then true
    else
      match (lhs, rhs) with
      | _, Unowned ->
          true (* Unowned is top *)
      | Unowned, _ ->
          false
      | Owned, _ ->
          true (* Owned is bottom *)
      | OwnedIf s1, OwnedIf s2 ->
          IntSet.subset s1 s2
      | OwnedIf _, Owned ->
          false


  let join astate1 astate2 =
    if phys_equal astate1 astate2 then astate1
    else
      match (astate1, astate2) with
      | _, Unowned | Unowned, _ ->
          Unowned
      | astate, Owned | Owned, astate ->
          astate
      | OwnedIf s1, OwnedIf s2 ->
          OwnedIf (IntSet.union s1 s2)


  let widen ~prev ~next ~num_iters:_ = join prev next

  let pp fmt = function
    | Unowned ->
        F.fprintf fmt "Unowned"
    | OwnedIf s ->
        F.fprintf fmt "OwnedIf%a"
          (PrettyPrintable.pp_collection ~pp_item:Int.pp)
          (IntSet.elements s)
    | Owned ->
        F.fprintf fmt "Owned"
end

module OwnershipDomain = struct
  include AbstractDomain.Map (AccessPath) (OwnershipAbstractValue)

  (* Helper function used by both is_owned and get_owned. Not exported.*)
  let get_owned_shallow access_path astate =
    try find access_path astate with Not_found -> OwnershipAbstractValue.Unowned


  (*deep ownership model where only a prefix needs to be owned in the astate*)
  let is_owned (base, accesses) astate =
    let is_owned_shallow access_path astate =
      match get_owned_shallow access_path astate with
      | OwnershipAbstractValue.Owned ->
          true
      | _ ->
          false
    in
    let rec helper = function
      | prefix, _ when is_owned_shallow (base, prefix) astate ->
          true
      | _, [] ->
          false
      | prefix, hd :: tl ->
          helper (List.append prefix [hd], tl)
    in
    helper ([], accesses)


  (*
returns Owned if any prefix is owned on any prefix, else OwnedIf if it is
OwnedIf in the astate, else UnOwned
*)
  let get_owned access_path astate =
    if is_owned access_path astate then OwnershipAbstractValue.Owned
    else try find access_path astate with Not_found -> OwnershipAbstractValue.Unowned


  let find = `Use_get_owned_instead
end

module AttributeMapDomain = struct
  include AbstractDomain.InvertedMap (AccessPath) (AttributeSetDomain)

  let add access_path attribute_set t =
    if AttributeSetDomain.is_empty attribute_set then t else add access_path attribute_set t


  let has_attribute access_path attribute t =
    try find access_path t |> AttributeSetDomain.mem attribute with Not_found -> false


  let get_choices access_path t =
    try
      let attributes = find access_path t in
      List.filter_map
        ~f:(function Attribute.Choice c -> Some c | _ -> None)
        (AttributeSetDomain.elements attributes)
    with Not_found -> []


  let add_attribute access_path attribute t =
    let attribute_set =
      (try find access_path t with Not_found -> AttributeSetDomain.empty)
      |> AttributeSetDomain.add attribute
    in
    add access_path attribute_set t
end

module AccessData = struct
  module Precondition = struct
    type t = Conjunction of IntSet.t | False [@@deriving compare]

    (* precondition is true if the conjunction of owned indexes is empty *)
    let is_true = function False -> false | Conjunction set -> IntSet.is_empty set

    let pp fmt = function
      | Conjunction indexes ->
          F.fprintf fmt "Owned(%a)"
            (PrettyPrintable.pp_collection ~pp_item:Int.pp)
            (IntSet.elements indexes)
      | False ->
          F.fprintf fmt "False"
  end

  type t = {thread: bool; lock: bool; ownership_precondition: Precondition.t} [@@deriving compare]

  let make locks threads ownership_precondition pdesc =
    (* shouldn't be creating metadata for accesses that are known to be owned; we should discard
       such accesses *)
    assert (not (Precondition.is_true ownership_precondition)) ;
    let thread = ThreadsDomain.is_any_but_self threads in
    let lock = locks || Procdesc.is_java_synchronized pdesc in
    {thread; lock; ownership_precondition}


  let is_unprotected {thread; lock; ownership_precondition} =
    not thread && not lock && not (Precondition.is_true ownership_precondition)


  let pp fmt {thread; lock; ownership_precondition} =
    F.fprintf fmt "Thread: %b Lock: %b Pre: %a" thread lock Precondition.pp ownership_precondition
end

module AccessDomain = struct
  include AbstractDomain.Map (AccessData) (PathDomain)

  let add_access precondition access_path t =
    let precondition_accesses = try find precondition t with Not_found -> PathDomain.empty in
    let precondition_accesses' = PathDomain.add_sink access_path precondition_accesses in
    add precondition precondition_accesses' t


  let get_accesses precondition t = try find precondition t with Not_found -> PathDomain.empty
end

type astate =
  { threads: ThreadsDomain.astate
  ; locks: LocksDomain.astate
  ; accesses: AccessDomain.astate
  ; ownership: OwnershipDomain.astate
  ; attribute_map: AttributeMapDomain.astate }

let empty =
  let threads = ThreadsDomain.empty in
  let locks = false in
  let accesses = AccessDomain.empty in
  let ownership = OwnershipDomain.empty in
  let attribute_map = AttributeMapDomain.empty in
  {threads; locks; accesses; ownership; attribute_map}


let is_empty {threads; locks; accesses; ownership; attribute_map} =
  ThreadsDomain.is_empty threads && not locks && AccessDomain.is_empty accesses
  && OwnershipDomain.is_empty ownership && AttributeMapDomain.is_empty attribute_map


let ( <= ) ~lhs ~rhs =
  if phys_equal lhs rhs then true
  else
    ThreadsDomain.( <= ) ~lhs:lhs.threads ~rhs:rhs.threads
    && LocksDomain.( <= ) ~lhs:lhs.locks ~rhs:rhs.locks
    && AccessDomain.( <= ) ~lhs:lhs.accesses ~rhs:rhs.accesses
    && AttributeMapDomain.( <= ) ~lhs:lhs.attribute_map ~rhs:rhs.attribute_map


let join astate1 astate2 =
  if phys_equal astate1 astate2 then astate1
  else
    let threads = ThreadsDomain.join astate1.threads astate2.threads in
    let locks = LocksDomain.join astate1.locks astate2.locks in
    let accesses = AccessDomain.join astate1.accesses astate2.accesses in
    let ownership = OwnershipDomain.join astate1.ownership astate2.ownership in
    let attribute_map = AttributeMapDomain.join astate1.attribute_map astate2.attribute_map in
    {threads; locks; accesses; ownership; attribute_map}


let widen ~prev ~next ~num_iters =
  if phys_equal prev next then prev
  else
    let threads = ThreadsDomain.widen ~prev:prev.threads ~next:next.threads ~num_iters in
    let locks = LocksDomain.widen ~prev:prev.locks ~next:next.locks ~num_iters in
    let accesses = AccessDomain.widen ~prev:prev.accesses ~next:next.accesses ~num_iters in
    let ownership = OwnershipDomain.widen ~prev:prev.ownership ~next:next.ownership ~num_iters in
    let attribute_map =
      AttributeMapDomain.widen ~prev:prev.attribute_map ~next:next.attribute_map ~num_iters
    in
    {threads; locks; accesses; ownership; attribute_map}


type summary =
  { threads: ThreadsDomain.astate
  ; locks: LocksDomain.astate
  ; accesses: AccessDomain.astate
  ; return_ownership: OwnershipAbstractValue.astate
  ; return_attributes: AttributeSetDomain.astate }

let pp_summary fmt {threads; locks; accesses; return_ownership; return_attributes} =
  F.fprintf fmt
    "@\nThreads: %a, Locks: %a @\nAccesses %a @\nOwnership: %a @\nReturn Attributes: %a @\n"
    ThreadsDomain.pp threads LocksDomain.pp locks AccessDomain.pp accesses
    OwnershipAbstractValue.pp return_ownership AttributeSetDomain.pp return_attributes


let pp fmt {threads; locks; accesses; ownership; attribute_map} =
  F.fprintf fmt "Threads: %a, Locks: %a @\nAccesses %a @\n Ownership: %a @\nAttributes: %a @\n"
    ThreadsDomain.pp threads LocksDomain.pp locks AccessDomain.pp accesses OwnershipDomain.pp
    ownership AttributeMapDomain.pp attribute_map