Library iris.base_logic.lib.auth

From iris.proofmode Require Import tactics.
From iris.algebra Require Export auth.
From iris.algebra Require Import gmap.
From iris.base_logic.lib Require Export invariants.
Set Default Proof Using "Type".
Import uPred.

Class authG Σ (A : ucmraT) := AuthG {
  auth_inG :> inG Σ (authR A);
  auth_cmra_discrete :> CmraDiscrete A;
Definition authΣ (A : ucmraT) : gFunctors := #[ GFunctor (authR A) ].

Instance subG_authΣ Σ A : subG (authΣ A) Σ CmraDiscrete A authG Σ A.
Proof. solve_inG. Qed.

Section definitions.
  Context `{!invG Σ, !authG Σ A} {T : Type} (γ : gname).

  Definition auth_own (a : A) : iProp Σ :=
    own γ ( a).
  Definition auth_inv (f : T A) (φ : T iProp Σ) : iProp Σ :=
    ( t, own γ ( f t) φ t)%I.
  Definition auth_ctx (N : namespace) (f : T A) (φ : T iProp Σ) : iProp Σ :=
    inv N (auth_inv f φ).

  Global Instance auth_own_ne : NonExpansive auth_own.
  Proof. solve_proper. Qed.
  Global Instance auth_own_proper : Proper ((≡) ==> (⊣⊢)) auth_own.
  Proof. solve_proper. Qed.
  Global Instance auth_own_timeless a : Timeless (auth_own a).
  Proof. apply _. Qed.
  Global Instance auth_own_core_id a : CoreId a Persistent (auth_own a).
  Proof. apply _. Qed.

  Global Instance auth_inv_ne n :
    Proper (pointwise_relation T (dist n) ==>
            pointwise_relation T (dist n) ==> dist n) auth_inv.
  Proof. solve_proper. Qed.
  Global Instance auth_inv_proper :
    Proper (pointwise_relation T (≡) ==>
            pointwise_relation T (⊣⊢) ==> (⊣⊢)) auth_inv.
  Proof. solve_proper. Qed.
  Global Instance auth_ctx_ne N n :
    Proper (pointwise_relation T (dist n) ==>
            pointwise_relation T (dist n) ==> dist n) (auth_ctx N).
  Proof. solve_proper. Qed.
  Global Instance auth_ctx_proper N :
    Proper (pointwise_relation T (≡) ==>
            pointwise_relation T (⊣⊢) ==> (⊣⊢)) (auth_ctx N).
  Proof. solve_proper. Qed.
  Global Instance auth_ctx_persistent N f φ : Persistent (auth_ctx N f φ).
  Proof. apply _. Qed.
End definitions.

Typeclasses Opaque auth_own auth_inv auth_ctx.
Instance: Params (@auth_own) 4 := {}.
Instance: Params (@auth_inv) 5 := {}.
Instance: Params (@auth_ctx) 7 := {}.

Section auth.
  Context `{!invG Σ, !authG Σ A}.
  Context {T : Type} `{!Inhabited T}.
  Context (f : T A) (φ : T iProp Σ).
  Implicit Types N : namespace.
  Implicit Types P Q R : iProp Σ.
  Implicit Types a b : A.
  Implicit Types t u : T.
  Implicit Types γ : gname.

  Lemma auth_own_op γ a b : auth_own γ (a b) ⊣⊢ auth_own γ a auth_own γ b.
  Proof. by rewrite /auth_own -own_op auth_frag_op. Qed.

  Lemma auth_own_mono γ a b : a b auth_own γ b auth_own γ a.
  Proof. intros [? ->]. by rewrite auth_own_op sep_elim_l. Qed.
  Lemma auth_own_valid γ a : auth_own γ a a.
  Proof. by rewrite /auth_own own_valid auth_frag_validI. Qed.
  Global Instance auth_own_sep_homomorphism γ :
    WeakMonoidHomomorphism op uPred_sep (≡) (auth_own γ).
  Proof. split; try apply _. apply auth_own_op. Qed.

  Global Instance own_mono' γ : Proper (flip (≼) ==> (⊢)) (auth_own γ).
  Proof. intros a1 a2. apply auth_own_mono. Qed.

  Lemma auth_alloc_strong N E t (I : gname Prop) :
    pred_infinite I
     (f t) φ t ={E}=∗ γ, I γ auth_ctx γ N f φ auth_own γ (f t).
    iIntros (??) "Hφ". rewrite /auth_own /auth_ctx.
    iMod (own_alloc_strong ( f t f t) I) as (γ) "[% [Hγ Hγ']]";
      [done|by apply auth_both_valid|].
    iMod (inv_alloc N _ (auth_inv γ f φ) with "[-Hγ']") as "#?".
    { iNext. rewrite /auth_inv. iExists t. by iFrame. }

  Lemma auth_alloc_cofinite N E t (G : gset gname) :
     (f t) φ t ={E}=∗ γ, γ G auth_ctx γ N f φ auth_own γ (f t).
    intros ?. apply auth_alloc_strong=>//.
    apply (pred_infinite_set (C:=gset gname)) ⇒ E'.
     (fresh (G E')). apply not_elem_of_union, is_fresh.

  Lemma auth_alloc N E t :
     (f t) φ t ={E}=∗ γ, auth_ctx γ N f φ auth_own γ (f t).
    iIntros (?) "Hφ".
    iMod (auth_alloc_cofinite N E t with "Hφ") as (γ) "[_ ?]"; eauto.

  Lemma auth_empty γ : (|==> auth_own γ ε)%I.
  Proof. by rewrite /auth_own -own_unit. Qed.

  Lemma auth_acc E γ a :
     auth_inv γ f φ auth_own γ a ={E}=∗ t,
      a f t φ t u b,
      (f t, a) ¬l~> (f u, b) φ u ={E}=∗ auth_inv γ f φ auth_own γ b.
  Proof using Type×.
    iIntros "[Hinv Hγf]". rewrite /auth_inv /auth_own.
    iDestruct "Hinv" as (t) "[>Hγa Hφ]".
    iModIntro. iExists t.
    iDestruct (own_valid_2 with "Hγa Hγf") as % [? ?]%auth_both_valid.
    iSplit; first done. iFrame. iIntros (u b) "[% Hφ]".
    iMod (own_update_2 with "Hγa Hγf") as "[Hγa Hγf]".
    { eapply auth_update; eassumption. }
    iModIntro. iFrame. iExists u. iFrame.

  Lemma auth_open E N γ a :
    N E
    auth_ctx γ N f φ auth_own γ a ={E,EN}=∗ t,
      a f t φ t u b,
      (f t, a) ¬l~> (f u, b) φ u ={EN,E}=∗ auth_own γ b.
  Proof using Type×.
    iIntros (?) "[#? Hγf]". rewrite /auth_ctx. iInv N as "Hinv" "Hclose".
    iMod (auth_acc with "[$Hinv $Hγf]") as (t) "(?&?&HclAuth)".
    iModIntro. iExists t. iFrame. iIntros (u b) "H".
    iMod ("HclAuth" $! u b with "H") as "(Hinv & ?)". by iMod ("Hclose" with "Hinv").
End auth.

Arguments auth_open {_ _ _} [_] {_} [_] _ _ _ _ _ _ _.