Eio backend for JavaScript environments

This provides:
- `eio_js_backend`, a simple backend;
- `js_of_ocaml-eio`, a counterpart to `js_of_ocaml-lwt`;
- `eio_brr`, Eio support for Brr (Eio variants of Brr functions
  that returns directly instead of returning a future).

dune-project

@@ -73,4 +73,24 @@
                (or (<> :os-distribution "centos") (> :os-version 7))))
   (eio_posix (and (= :version) (<> :os "win32")))
   (eio_windows (and (= :version) (= :os "win32")))))
+(package
+ (name eio_js_backend)
+ (synopsis "Simple Eio scheduler for JavaScript environments")
+ (description "An Eio scheduler suitable for JavaScript environments.")
+ (depends
+  (eio (= :version))))
+(package
+ (name eio_brr)
+ (synopsis "Eio support for Brr")
+ (description "This package provides Eio variants of Brr functions, which returns directly instead of returning a future.")
+ (depends
+  (eio_js_backend (= :version))
+  (brr (>= 0.0.4))))
+(package
+ (name js_of_ocaml-eio)
+ (synopsis "Eio-based JavaScript bindings")
+ (description "An Eio counterpart to package js_of_ocaml-lwt.")
+ (depends
+  (eio_js_backend (= :version))
+  (js_of_ocaml (>= 5.0.1))))
 (using mdx 0.2)

eio_brr.opam

@@ -0,0 +1,32 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+synopsis: "Eio support for Brr"
+description:
+  "This package provides Eio variants of Brr functions, which returns directly instead of returning a future."
+maintainer: ["anil@recoil.org"]
+authors: ["Anil Madhavapeddy" "Thomas Leonard"]
+license: "ISC"
+homepage: "https://github.com/ocaml-multicore/eio"
+doc: "https://ocaml-multicore.github.io/eio/"
+bug-reports: "https://github.com/ocaml-multicore/eio/issues"
+depends: [
+  "dune" {>= "3.9"}
+  "eio" {= version}
+  "brr" {>= "0.0.4"}
+  "odoc" {with-doc}
+]
+build: [
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
+]
+dev-repo: "git+https://github.com/ocaml-multicore/eio.git"

eio_js_backend.opam

@@ -0,0 +1,30 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+synopsis: "Simple Eio scheduler for JavaScript environments"
+description: "An Eio scheduler suitable for JavaScript environments."
+maintainer: ["anil@recoil.org"]
+authors: ["Anil Madhavapeddy" "Thomas Leonard"]
+license: "ISC"
+homepage: "https://github.com/ocaml-multicore/eio"
+doc: "https://ocaml-multicore.github.io/eio/"
+bug-reports: "https://github.com/ocaml-multicore/eio/issues"
+depends: [
+  "dune" {>= "3.9"}
+  "eio" {= version}
+  "odoc" {with-doc}
+]
+build: [
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
+]
+dev-repo: "git+https://github.com/ocaml-multicore/eio.git"

js_of_ocaml-eio.opam

@@ -0,0 +1,31 @@
+# This file is generated by dune, edit dune-project instead
+opam-version: "2.0"
+synopsis: "Eio-based JavaScript bindings"
+description: "An Eio counterpart of package js_of_ocaml-lwt."
+maintainer: ["anil@recoil.org"]
+authors: ["Anil Madhavapeddy" "Thomas Leonard"]
+license: "ISC"
+homepage: "https://github.com/ocaml-multicore/eio"
+doc: "https://ocaml-multicore.github.io/eio/"
+bug-reports: "https://github.com/ocaml-multicore/eio/issues"
+depends: [
+  "dune" {>= "3.9"}
+  "eio" {= version}
+  "js_of_ocaml" {>= "5.0.1"}
+  "odoc" {with-doc}
+]
+build: [
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
+]
+dev-repo: "git+https://github.com/ocaml-multicore/eio.git"

lib_eio_brr/dune

@@ -0,0 +1,6 @@
+(library
+ (name eio_brr)
+ (public_name eio_brr)
+ (wrapped false)
+ (modes byte)
+ (libraries eio_js_backend brr))

lib_eio_brr/eio_brr.ml

@@ -0,0 +1,46 @@
+let start = Eio_js_backend.start
+
+module Blob = struct
+  let array_buffer b = Eio_fut.await_exn (Brr.Blob.array_buffer b)
+  let text b = Eio_fut.await_exn (Brr.Blob.text b)
+  let data_uri b = Eio_fut.await_exn (Brr.Blob.data_uri b)
+end
+
+module Ev = struct
+  let next ?capture typ target = Eio_fut.await (Brr.Ev.next ?capture typ target)
+
+  module Data_transfer = struct
+    module Item = struct
+      let get_jstr i = Eio_fut.await (Brr.Ev.Data_transfer.Item.get_jstr i)
+    end
+  end
+
+  module Extendable = struct
+    let wait_until e ~sw f =
+      Brr.Ev.Extendable.wait_until e (Eio_fut.make_exn ~sw f)
+  end
+end
+
+module El = struct
+  let request_pointer_lock e = Eio_fut.await_exn (Brr.El.request_pointer_lock e)
+
+  let request_fullscreen ?opts e =
+    Eio_fut.await_exn (Brr.El.request_fullscreen ?opts e)
+end
+
+module Document = struct
+  let exit_pointer_lock e = Eio_fut.await (Brr.Document.exit_pointer_lock e)
+  let exit_fullscreen e = Eio_fut.await_exn (Brr.Document.exit_fullscreen e)
+end
+
+module G = struct
+  let set_timeout ~ms =
+    Eio_js_backend.await
+      ~setup:(fun ~resolve ~reject:_ -> Brr.G.set_timeout ~ms resolve)
+      ~cancel:Brr.G.stop_timer
+
+  let request_animation_frame () =
+    Eio_js_backend.await
+      ~setup:(fun ~resolve ~reject:_ -> Brr.G.request_animation_frame resolve)
+      ~cancel:Brr.G.cancel_animation_frame
+end

lib_eio_brr/eio_brr.mli

@@ -0,0 +1,100 @@
+(** {1 Eio scheduler setup} *)
+
+val start : (unit -> unit) -> unit
+(** [start f] executes function [f] asynchronously in a context where
+    Eio operations can be performed.
+
+    This function is an alias for {!Eio_js_scheduler.start}.
+*)
+
+(** {1 Eio variants of Brr functions} *)
+
+(** {2:data Data containers and encodings} *)
+
+(** Blob objects. *)
+module Blob : sig
+  val array_buffer : Brr.Blob.t -> Brr.Tarray.Buffer.t
+  (** [array_buffer b] is an
+      {{:https://developer.mozilla.org/en-US/docs/Web/API/Blob/arrayBuffer}
+      array buffer} with the contents of [b]. *)
+
+  val text : Brr.Blob.t -> Jstr.t
+  (** [text b] is the
+      {{:https://developer.mozilla.org/en-US/docs/Web/API/Blob/text}string}
+      that results from UTF-8 decoding the contents of [b]. *)
+
+  val data_uri : Brr.Blob.t -> Jstr.t
+  (** [data_uri b] is [b] as a data URI (via the
+      {{:https://developer.mozilla.org/en-US/docs/Web/API/FileReader}
+      [FileReader]} API). *)
+end
+
+(** {2 DOM interaction} *)
+
+(** DOM events. *)
+module Ev : sig
+  val next : ?capture:bool -> 'a Brr.Ev.type' -> Brr.Ev.target -> 'a Brr.Ev.t
+  (** [next type' t] returns the next event of type [type'] on target [t]. *)
+
+  (** [DataTransfer] objects. *)
+  module Data_transfer : sig
+    (** [DataTransferItem] objects. *)
+    module Item : sig
+      val get_jstr : Brr.Ev.Data_transfer.Item.t -> Jstr.t
+      (** [get_jstr i] is the item's text. *)
+    end
+  end
+
+  module Extendable : sig
+    val wait_until :
+      Brr.Ev.Extendable.t -> sw:Eio.Switch.t -> (unit -> _) -> unit
+    (** [wait_until e ~sw fn] {{:https://developer.mozilla.org/en-US/docs/Web/API/ExtendableEvent/waitUntil}indicates} to the event dispatcher that work is ongoing. Function [fn] is run in a new fiber attached to [sw]. The work is considered completed when [fn] returns. *)
+  end
+end
+
+(** DOM elements. *)
+module El : sig
+  (** {1 Pointer locking} *)
+
+  val request_pointer_lock : Brr.El.t -> unit
+  (** [request_pointer_lock e] requests the pointer to be locked
+      to [e] in the document it belongs to. This listens on the
+      document for the next [Brr.Ev.pointerlockchange] and
+      [Brr.Ev.pointerlockerror] to resolve the future appropriately. *)
+
+  (** {1 Fullscreen} *)
+
+  val request_fullscreen : ?opts:Brr.El.fullscreen_opts -> Brr.El.t -> unit
+  (** [request_fullscreen e] requests to make the element
+      to be displayed in fullscreen mode. *)
+end
+
+(** [Document] objects *)
+module Document : sig
+  (** {1 Pointer locking} *)
+
+  val exit_pointer_lock : Brr.Document.t -> unit
+  (** [exit_pointer_lock d] {{:https://developer.mozilla.org/en-US/docs/Web/API/Document/exitPointerLock}exits} pointer lock mode. This returns
+      when the corresponding [Brr.Ev.pointerlockchange] on [d] has fired. *)
+
+  (** {1 Fullscreen}
+
+      Use {!El.request_fullscreen} to get into fullscreen mode. *)
+
+  val exit_fullscreen : Brr.Document.t -> unit
+  (** [exit_fullscreen d]
+      {{:https://developer.mozilla.org/en-US/docs/Web/API/Document/exitFullscreen}exits} fullscreen mode. *)
+end
+
+(** The global object, its global objects and functions. *)
+module G : sig
+  val set_timeout : ms:int -> unit
+  (** [set_timeout ~ms] is a timer waiting for [ms] milliseconds. It
+      can be cancelled. *)
+
+  val request_animation_frame : unit -> float
+  (** [request_animation_frame ()]
+      {{:https://developer.mozilla.org/en-US/docs/Web/API/Window/requestAnimationFrame}waits}
+      until right before the next repaint. It returns the current
+      point in time. It can be cancelled. *)
+end

lib_eio_brr/eio_brr_canvas.ml

@@ -0,0 +1,4 @@
+module Canvas = struct
+  let to_blob ?encode c =
+    Eio_fut.await_exn (Brr_canvas.Canvas.to_blob ?encode c)
+end

lib_eio_brr/eio_brr_canvas.mli

@@ -0,0 +1,10 @@
+(** Canvas element. *)
+module Canvas : sig
+  val to_blob :
+    ?encode:Brr_canvas.Canvas.image_encode ->
+    Brr_canvas.Canvas.t ->
+    Brr.Blob.t option
+  (** [to_blob ~encode t] is the canvas's image a blob object. [None]
+      is returned either if the canvas has no pixels or if an error
+      occurs during image serialisation. *)
+end