WIP: Timeouts

README.md

@@ -52,6 +52,7 @@ is distributed under the [ISC license](LICENSE.md).
     - [A transactional lock-free queue](#a-transactional-lock-free-queue)
     - [Composing transactions](#composing-transactions)
     - [Blocking transactions](#blocking-transactions)
+    - [Timeouts](#timeouts)
     - [A transactional lock-free leftist heap](#a-transactional-lock-free-leftist-heap)
   - [Programming with transactional data structures](#programming-with-transactional-data-structures)
     - [The dining philosophers problem](#the-dining-philosophers-problem)
@@ -552,6 +553,61 @@ The retry mechanism essentially allows a transaction to wait for an arbitrary
 condition and can function as a fairly expressive communication and
 synchronization mechanism.
 
+#### Timeouts
+
+```ocaml
+# #require "domain-local-timeout"
+```
+
+```ocaml
+# #thread
+```
+
+```ocaml
+# Domain_local_timeout.set_system (module Thread) (module Unix)
+- : unit = ()
+```
+
+```ocaml
+type timeout = {
+  passed : 'x.xt:'x Xt.t -> bool;
+  cancel : unit -> unit;
+}
+```
+
+```ocaml
+# let timeoutf seconds =
+    let passed = Loc.make false in
+    let cancel =
+      Domain_local_timeout.set_timeoutf seconds @@ fun () ->
+      Loc.set passed true
+    in
+    { passed = Xt.get passed;
+      cancel = (cancel :> unit -> unit) }
+val timeoutf : float -> timeout = <fun>
+```
+
+```ocaml
+# let exit_if ~xt { passed; cancel } =
+    if passed ~xt then
+      raise Exit;
+    Xt.post_commit ~xt cancel;
+    Retry.later ()
+val exit_if : xt:'a Xt.t -> timeout -> 'b = <fun>
+```
+
+```ocaml
+# let an_empty_stack = stack () in
+  let timeout = timeoutf 0.1 in
+  Xt.commit { tx =
+    Xt.first [
+      pop an_empty_stack;
+      exit_if timeout;
+    ]
+  }
+Exception: Stdlib.Exit.
+```
+
 #### A transactional lock-free leftist heap
 
 Let's implement something a bit more complicated,

dune-project

@@ -11,6 +11,7 @@
  (depends 
   (ocaml (>= 5.0))
   (domain-local-await (>= 0.1.0))
+  domain-local-timeout
   (mdx (and (>= 1.10.0) :with-test))))
 (package (name kcas_data)
  (synopsis "Compositional lock-free data structures and primitives for communication and synchronization")

kcas.opam

@@ -11,6 +11,7 @@ depends: [
   "dune" {>= "3.3"}
   "ocaml" {>= "5.0"}
   "domain-local-await" {>= "0.1.0"}
+  "domain-local-timeout"
   "mdx" {>= "1.10.0" & with-test}
   "odoc" {with-doc}
 ]
@@ -29,3 +30,6 @@ build: [
   ]
 ]
 dev-repo: "git+https://github.com/ocaml-multicore/kcas.git"
+pin-depends: [
+  [ "domain-local-timeout.dev" "git+https://github.com/ocaml-multicore/domain-local-timeout#3c90d77a6b6f7ca77c21ec7be9f803ca2cadb138" ]
+]

kcas.opam.template

@@ -0,0 +1,3 @@
+pin-depends: [
+  [ "domain-local-timeout.dev" "git+https://github.com/ocaml-multicore/domain-local-timeout#3c90d77a6b6f7ca77c21ec7be9f803ca2cadb138" ]
+]