From c5ea5670dc68f24edb1cc560d7d3d4fe2d15ba0c Mon Sep 17 00:00:00 2001
From: ivg <ivg@ieee.org>
Date: Wed, 17 Aug 2022 16:05:33 -0400
Subject: [PATCH] adds support for loading plugins in toplevels

Uses virtual libraries to select the proper dynamic linker
facility. To load in the toplevel add `dune-site.toplevel` library as
the dependency to your toplevel.

Signed-off-by: ivg <ivg@ieee.org>
Signed-off-by: Richard L Ford <richardlford@gmail.com>
---
 otherlibs/site/src/plugins/dune                      |  2 +-
 otherlibs/site/src/plugins/linker/dune               |  5 +++++
 otherlibs/site/src/plugins/linker/dynlink/dune       |  5 +++++
 otherlibs/site/src/plugins/linker/dynlink/linker.ml  |  1 +
 otherlibs/site/src/plugins/linker/linker.mli         |  1 +
 otherlibs/site/src/plugins/linker/toplevel/dune      |  6 ++++++
 otherlibs/site/src/plugins/linker/toplevel/linker.ml | 10 ++++++++++
 otherlibs/site/src/plugins/plugins.ml                |  2 +-
 8 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 otherlibs/site/src/plugins/linker/dune
 create mode 100644 otherlibs/site/src/plugins/linker/dynlink/dune
 create mode 100644 otherlibs/site/src/plugins/linker/dynlink/linker.ml
 create mode 100644 otherlibs/site/src/plugins/linker/linker.mli
 create mode 100644 otherlibs/site/src/plugins/linker/toplevel/dune
 create mode 100644 otherlibs/site/src/plugins/linker/toplevel/linker.ml

diff --git a/otherlibs/site/src/plugins/dune b/otherlibs/site/src/plugins/dune
index 378af3bb8750..7bed1ce9cbd6 100644
--- a/otherlibs/site/src/plugins/dune
+++ b/otherlibs/site/src/plugins/dune
@@ -6,6 +6,6 @@
   (dune_site
    (plugins)
    (data_module dune_site_plugins_data)))
- (libraries dune-site dune-private-libs.meta_parser dynlink)
+ (libraries dune-site dune-private-libs.meta_parser dune-site.linker)
  (instrumentation
   (backend bisect_ppx)))
diff --git a/otherlibs/site/src/plugins/linker/dune b/otherlibs/site/src/plugins/linker/dune
new file mode 100644
index 000000000000..acff16bb2002
--- /dev/null
+++ b/otherlibs/site/src/plugins/linker/dune
@@ -0,0 +1,5 @@
+(library
+ (name dune_site_backend)
+ (public_name dune-site.linker)
+ (virtual_modules linker)
+ (default_implementation dune-site.dynlink))
diff --git a/otherlibs/site/src/plugins/linker/dynlink/dune b/otherlibs/site/src/plugins/linker/dynlink/dune
new file mode 100644
index 000000000000..851802c02d98
--- /dev/null
+++ b/otherlibs/site/src/plugins/linker/dynlink/dune
@@ -0,0 +1,5 @@
+(library
+ (name dune_site_dynlink_linker)
+ (public_name dune-site.dynlink)
+ (implements dune-site.linker)
+ (libraries dynlink))
diff --git a/otherlibs/site/src/plugins/linker/dynlink/linker.ml b/otherlibs/site/src/plugins/linker/dynlink/linker.ml
new file mode 100644
index 000000000000..73bf7a03a50f
--- /dev/null
+++ b/otherlibs/site/src/plugins/linker/dynlink/linker.ml
@@ -0,0 +1 @@
+let load = Dynlink.loadfile
diff --git a/otherlibs/site/src/plugins/linker/linker.mli b/otherlibs/site/src/plugins/linker/linker.mli
new file mode 100644
index 000000000000..63fbb5a31860
--- /dev/null
+++ b/otherlibs/site/src/plugins/linker/linker.mli
@@ -0,0 +1 @@
+val load : string -> unit
diff --git a/otherlibs/site/src/plugins/linker/toplevel/dune b/otherlibs/site/src/plugins/linker/toplevel/dune
new file mode 100644
index 000000000000..c56cd49f8249
--- /dev/null
+++ b/otherlibs/site/src/plugins/linker/toplevel/dune
@@ -0,0 +1,6 @@
+(library
+ (name dune_site_toplevel_linker)
+ (modes byte)
+ (public_name dune-site.toplevel)
+ (implements dune-site.linker)
+ (libraries compiler-libs.toplevel))
diff --git a/otherlibs/site/src/plugins/linker/toplevel/linker.ml b/otherlibs/site/src/plugins/linker/toplevel/linker.ml
new file mode 100644
index 000000000000..3001b70181e8
--- /dev/null
+++ b/otherlibs/site/src/plugins/linker/toplevel/linker.ml
@@ -0,0 +1,10 @@
+let load filename =
+  let buf = Buffer.create 16 in
+  let ppf = Format.formatter_of_buffer buf in
+  match Toploop.load_file ppf filename with
+  | true -> ()
+  | false ->
+    Format.pp_print_flush ppf ();
+    failwith
+    @@ Format.asprintf "Failed to load file `%s': %s" filename
+         (Buffer.contents buf)
diff --git a/otherlibs/site/src/plugins/plugins.ml b/otherlibs/site/src/plugins/plugins.ml
index 581a8b9f803a..2fd2475b9554 100644
--- a/otherlibs/site/src/plugins/plugins.ml
+++ b/otherlibs/site/src/plugins/plugins.ml
@@ -256,7 +256,7 @@ let load_gen ~load_requires dirs name =
     List.iter
       (fun p ->
         let file = Filename.concat directory p in
-        Dynlink.loadfile file)
+        Dune_site_backend.Linker.load file)
       plugins)
 
 let rec load_requires name =