Require Export algebra.cmra. Require Import prelude.sets algebra.dra. Local Arguments valid _ _ !_ /. Local Arguments op _ _ !_ !_ /. Local Arguments unit _ _ !_ /. Inductive sts {A B} (R : relation A) (tok : A → set B) := | auth : A → set B → sts R tok | frag : set A → set B → sts R tok. Arguments auth {_ _ _ _} _ _. Arguments frag {_ _ _ _} _ _. Module sts. Section sts_core. Context {A B : Type} (R : relation A) (tok : A → set B). Infix "≼" := dra_included. Inductive sts_equiv : Equiv (sts R tok) := | auth_equiv s T1 T2 : T1 ≡ T2 → auth s T1 ≡ auth s T2 | frag_equiv S1 S2 T1 T2 : T1 ≡ T2 → S1 ≡ S2 → frag S1 T1 ≡ frag S2 T2. Global Existing Instance sts_equiv. Inductive step : relation (A * set B) := | Step s1 s2 T1 T2 : R s1 s2 → tok s1 ∩ T1 ≡ ∅ → tok s2 ∩ T2 ≡ ∅ → tok s1 ∪ T1 ≡ tok s2 ∪ T2 → step (s1,T1) (s2,T2). Hint Resolve Step. Inductive frame_step (T : set B) (s1 s2 : A) : Prop := | Frame_step T1 T2 : T1 ∩ (tok s1 ∪ T) ≡ ∅ → step (s1,T1) (s2,T2) → frame_step T s1 s2. Hint Resolve Frame_step. Record closed (T : set B) (S : set A) : Prop := Closed { closed_ne : S ≢ ∅; closed_disjoint s : s ∈ S → tok s ∩ T ≡ ∅; closed_step s1 s2 : s1 ∈ S → frame_step T s1 s2 → s2 ∈ S }. Lemma closed_steps S T s1 s2 : closed T S → s1 ∈ S → rtc (frame_step T) s1 s2 → s2 ∈ S. Proof. induction 3; eauto using closed_step. Qed. Global Instance sts_valid : Valid (sts R tok) := λ x, match x with auth s T => tok s ∩ T ≡ ∅ | frag S' T => closed T S' end. Definition up (T : set B) (s : A) : set A := mkSet (rtc (frame_step T) s). Definition up_set (T : set B) (S : set A) : set A := S ≫= up T. Global Instance sts_unit : Unit (sts R tok) := λ x, match x with | frag S' _ => frag (up_set ∅ S') ∅ | auth s _ => frag (up ∅ s) ∅ end. Inductive sts_disjoint : Disjoint (sts R tok) := | frag_frag_disjoint S1 S2 T1 T2 : S1 ∩ S2 ≢ ∅ → T1 ∩ T2 ≡ ∅ → frag S1 T1 ⊥ frag S2 T2 | auth_frag_disjoint s S T1 T2 : s ∈ S → T1 ∩ T2 ≡ ∅ → auth s T1 ⊥ frag S T2 | frag_auth_disjoint s S T1 T2 : s ∈ S → T1 ∩ T2 ≡ ∅ → frag S T1 ⊥ auth s T2. Global Existing Instance sts_disjoint. Global Instance sts_op : Op (sts R tok) := λ x1 x2, match x1, x2 with | frag S1 T1, frag S2 T2 => frag (S1 ∩ S2) (T1 ∪ T2) | auth s T1, frag _ T2 => auth s (T1 ∪ T2) | frag _ T1, auth s T2 => auth s (T1 ∪ T2) | auth s T1, auth _ T2 => auth s (T1 ∪ T2) (* never happens *) end. Global Instance sts_minus : Minus (sts R tok) := λ x1 x2, match x1, x2 with | frag S1 T1, frag S2 T2 => frag (up_set (T1 ∖ T2) S1) (T1 ∖ T2) | auth s T1, frag _ T2 => auth s (T1 ∖ T2) | frag _ T2, auth s T1 => auth s (T1 ∖ T2) (* never happens *) | auth s T1, auth _ T2 => frag (up (T1 ∖ T2) s) (T1 ∖ T2) end. Hint Extern 10 (equiv (A:=set _) _ _) => solve_elem_of : sts. Hint Extern 10 (¬(equiv (A:=set _) _ _)) => solve_elem_of : sts. Hint Extern 10 (_ ∈ _) => solve_elem_of : sts. Hint Extern 10 (_ ⊆ _) => solve_elem_of : sts. Instance: Equivalence ((≡) : relation (sts R tok)). Proof. split. * by intros []; constructor. * by destruct 1; constructor. * destruct 1; inversion_clear 1; constructor; etransitivity; eauto. Qed. Instance framestep_proper : Proper ((≡) ==> (=) ==> (=) ==> impl) frame_step. Proof. intros ?? HT ?? <- ?? <-; destruct 1; econstructor; eauto with sts. Qed. Instance closed_proper' : Proper ((≡) ==> (≡) ==> impl) closed. Proof. intros ?? HT ?? HS; destruct 1; constructor; intros until 0; rewrite -?HS -?HT; eauto. Qed. Instance closed_proper : Proper ((≡) ==> (≡) ==> iff) closed. Proof. by split; apply closed_proper'. Qed. Lemma closed_op T1 T2 S1 S2 : closed T1 S1 → closed T2 S2 → T1 ∩ T2 ≡ ∅ → S1 ∩ S2 ≢ ∅ → closed (T1 ∪ T2) (S1 ∩ S2). Proof. intros [_ ? Hstep1] [_ ? Hstep2] ?; split; [done|solve_elem_of|]. intros s3 s4; rewrite !elem_of_intersection; intros [??] [T3 T4 ?]; split. * apply Hstep1 with s3, Frame_step with T3 T4; auto with sts. * apply Hstep2 with s3, Frame_step with T3 T4; auto with sts. Qed. Instance up_preserving : Proper (flip (⊆) ==> (=) ==> (⊆)) up. Proof. intros T T' HT s ? <-; apply elem_of_subseteq. induction 1 as [|s1 s2 s3 [T1 T2]]; [constructor|]. eapply rtc_l; [eapply Frame_step with T1 T2|]; eauto with sts. Qed. Instance up_proper : Proper ((≡) ==> (=) ==> (≡)) up. Proof. by intros ?? [??] ???; split; apply up_preserving. Qed. Instance up_set_proper : Proper ((≡) ==> (≡) ==> (≡)) up_set. Proof. by intros T1 T2 HT S1 S2 HS; rewrite /up_set HS HT. Qed. Lemma elem_of_up s T : s ∈ up T s. Proof. constructor. Qed. Lemma subseteq_up_set S T : S ⊆ up_set T S. Proof. intros s ?; apply elem_of_bind; eauto using elem_of_up. Qed. Lemma closed_up_set S T : (∀ s, s ∈ S → tok s ∩ T ≡ ∅) → S ≢ ∅ → closed T (up_set T S). Proof. intros HS Hne; unfold up_set; split. * assert (∀ s, s ∈ up T s) by eauto using elem_of_up. solve_elem_of. * intros s; rewrite !elem_of_bind; intros (s'&Hstep&Hs'). specialize (HS s' Hs'); clear Hs' Hne S. induction Hstep as [s|s1 s2 s3 [T1 T2 ? Hstep] ? IH]; auto. inversion_clear Hstep; apply IH; clear IH; auto with sts. * intros s1 s2; rewrite !elem_of_bind; intros (s&?&?) ?; exists s. split; [eapply rtc_r|]; eauto. Qed. Lemma closed_up_set_empty S : S ≢ ∅ → closed ∅ (up_set ∅ S). Proof. eauto using closed_up_set with sts. Qed. Lemma closed_up s T : tok s ∩ T ≡ ∅ → closed T (up T s). Proof. intros; rewrite -(collection_bind_singleton (up T) s). apply closed_up_set; solve_elem_of. Qed. Lemma closed_up_empty s : closed ∅ (up ∅ s). Proof. eauto using closed_up with sts. Qed. Lemma up_closed S T : closed T S → up_set T S ≡ S. Proof. intros; split; auto using subseteq_up_set; intros s. unfold up_set; rewrite elem_of_bind; intros (s'&Hstep&?). induction Hstep; eauto using closed_step. Qed. Global Instance sts_dra : DRA (sts R tok). Proof. split. * apply _. * by do 2 destruct 1; constructor; setoid_subst. * by destruct 1; constructor; setoid_subst. * by intros ? [|]; destruct 1; inversion_clear 1; constructor; setoid_subst. * by do 2 destruct 1; constructor; setoid_subst. * assert (∀ T T' S s, closed T S → s ∈ S → tok s ∩ T' ≡ ∅ → tok s ∩ (T ∪ T') ≡ ∅). { intros S T T' s [??]; solve_elem_of. } destruct 3; simpl in *; auto using closed_op with sts. * intros []; simpl; eauto using closed_up, closed_up_set, closed_ne with sts. * intros ???? (z&Hy&?&Hxz); destruct Hxz; inversion Hy;clear Hy; setoid_subst; rewrite ?disjoint_union_difference; auto using closed_up with sts. eapply closed_up_set; eauto 2 using closed_disjoint with sts. * intros [] [] []; constructor; rewrite ?(associative _); auto with sts. * destruct 4; inversion_clear 1; constructor; auto with sts. * destruct 4; inversion_clear 1; constructor; auto with sts. * destruct 1; constructor; auto with sts. * destruct 3; constructor; auto with sts. * intros [|S T]; constructor; auto using elem_of_up with sts. assert (S ⊆ up_set ∅ S ∧ S ≢ ∅) by eauto using subseteq_up_set, closed_ne. solve_elem_of. * intros [|S T]; constructor; auto with sts. assert (S ⊆ up_set ∅ S); auto using subseteq_up_set with sts. * intros [s T|S T]; constructor; auto with sts. + rewrite (up_closed (up _ _)); auto using closed_up with sts. + rewrite (up_closed (up_set _ _)); eauto using closed_up_set, closed_ne with sts. * intros x y ?? (z&Hy&?&Hxz); exists (unit (x ⋅ y)); split_ands. + destruct Hxz;inversion_clear Hy;constructor;unfold up_set; solve_elem_of. + destruct Hxz; inversion_clear Hy; simpl; auto using closed_up_set_empty, closed_up_empty with sts. + destruct Hxz; inversion_clear Hy; constructor; repeat match goal with | |- context [ up_set ?T ?S ] => unless (S ⊆ up_set T S) by done; pose proof (subseteq_up_set S T) | |- context [ up ?T ?s ] => unless (s ∈ up T s) by done; pose proof (elem_of_up s T) end; auto with sts. * intros x y ?? (z&Hy&_&Hxz); destruct Hxz; inversion_clear Hy; constructor; repeat match goal with | |- context [ up_set ?T ?S ] => unless (S ⊆ up_set T S) by done; pose proof (subseteq_up_set S T) | |- context [ up ?T ?s ] => unless (s ∈ up T s) by done; pose proof (elem_of_up s T) end; auto with sts. * intros x y ?? (z&Hy&?&Hxz); destruct Hxz as [S1 S2 T1 T2| |]; inversion Hy; clear Hy; constructor; setoid_subst; rewrite ?disjoint_union_difference; auto. split; [|apply intersection_greatest; auto using subseteq_up_set with sts]. apply intersection_greatest; [auto with sts|]. intros s2; rewrite elem_of_intersection. unfold up_set; rewrite elem_of_bind; intros (?&s1&?&?&?). apply closed_steps with T2 s1; auto with sts. Qed. Lemma step_closed s1 s2 T1 T2 S Tf : step (s1,T1) (s2,T2) → closed Tf S → s1 ∈ S → T1 ∩ Tf ≡ ∅ → s2 ∈ S ∧ T2 ∩ Tf ≡ ∅ ∧ tok s2 ∩ T2 ≡ ∅. Proof. inversion_clear 1 as [???? HR Hs1 Hs2]; intros [?? Hstep]??; split_ands; auto. * eapply Hstep with s1, Frame_step with T1 T2; auto with sts. * solve_elem_of -Hstep Hs1 Hs2. Qed. End sts_core. End sts. Section stsRA. Context {A B : Type} (R : relation A) (tok : A → set B). Canonical Structure stsRA := validityRA (sts R tok). Definition sts_auth (s : A) (T : set B) : stsRA := to_validity (auth s T). Definition sts_frag (S : set A) (T : set B) : stsRA := to_validity (frag S T). Lemma sts_update s1 s2 T1 T2 : sts.step R tok (s1,T1) (s2,T2) → sts_auth s1 T1 ~~> sts_auth s2 T2. Proof. intros ?; apply validity_update; inversion 3 as [|? S ? Tf|]; subst. destruct (sts.step_closed R tok s1 s2 T1 T2 S Tf) as (?&?&?); auto. repeat (done || constructor). Qed. End stsRA.