eio backend, second attempt (#95)

feat: `tiny_httpd_eio` library

provides a tiny_httpd server that relies on Eio for non-blocking
sockets and for concurrency using eio fibers.

Author: c-cube

.github/workflows/format.yml

@@ -6,6 +6,7 @@ on:
     branches:
       - main
 
+jobs:
   format:
     name: format
     strategy:

.github/workflows/gh-pages.yml

@@ -38,7 +38,15 @@ jobs:
 
       - run: opam install ./tiny_httpd.opam ./tiny_httpd_camlzip.opam --deps-only --with-test
 
-      - run: opam exec -- dune build @install -p tiny_httpd,tiny_httpd_camlzip
+      - name: Build (OCaml 4.x)
+        run: opam exec -- dune build @install -p tiny_httpd,tiny_httpd_camlzip
+        if: ${{ !startsWith(matrix.ocaml-compiler, '5.') }}
+
+      - name: Build (OCaml 5.x, includes eio)
+        run: |
+          opam install ./tiny_httpd.opam ./tiny_httpd_eio.opam --deps-only --with-test
+          opam exec -- dune build @install -p tiny_httpd,tiny_httpd_camlzip,tiny_httpd_eio
+        if: ${{ startsWith(matrix.ocaml-compiler, '5.') }}
 
       - run: opam exec -- dune build @src/runtest @examples/runtest @tests/runtest -p tiny_httpd
         if: ${{ matrix.os == 'ubuntu-latest' }}
@@ -50,4 +58,10 @@ jobs:
 
       - run: opam install logs magic-mime -y
 
-      - run: opam exec -- dune build @install -p tiny_httpd,tiny_httpd_camlzip
+      - name: Final build (OCaml 4.x)
+        run: opam exec -- dune build @install -p tiny_httpd,tiny_httpd_camlzip
+        if: ${{ !startsWith(matrix.ocaml-compiler, '5.') }}
+
+      - name: Final build (OCaml 5.x, includes eio)
+        run: opam exec -- dune build @install -p tiny_httpd,tiny_httpd_camlzip,tiny_httpd_eio
+        if: ${{ startsWith(matrix.ocaml-compiler, '5.') }}

.github/workflows/main.yml

@@ -28,7 +28,7 @@
     (logs :with-test)
     (conf-libcurl :with-test)
     (ptime :with-test)
-    (qcheck-core (and (>= 0.9) :with-test))))
+    (qcheck-core (and (>= 0.91) :with-test))))
 
 (package
   (name tiny_httpd_camlzip)
@@ -39,3 +39,13 @@
     (iostream-camlzip (>= 0.2.1))
     (logs :with-test)
     (odoc :with-doc)))
+
+(package
+  (name tiny_httpd_eio)
+  (synopsis "Use eio for tiny_httpd")
+  (depends
+    (tiny_httpd (= :version))
+    (eio (and (>= 1.0) (< 2.0)))
+    base-unix
+    (logs :with-test)
+    (odoc :with-doc)))

dune-project

@@ -0,0 +1,2 @@
+#!/bin/sh
+exec dune exec --display=quiet --profile=release "examples/echo_eio.exe" -- $@

echo_eio.sh

@@ -11,10 +11,27 @@
 (executable
  (name echo)
  (flags :standard -warn-error -a+8)
- (modules echo vfs)
+ (modules echo)
  (libraries
   tiny_httpd
   logs
+  echo_vfs
+  tiny_httpd_camlzip
+  tiny_httpd.multipart-form-data))
+
+(executable
+ (name echo_eio)
+ (flags :standard -warn-error -a+8)
+ (modules echo_eio)
+ (libraries
+  tiny_httpd
+  tiny_httpd_eio
+  eio
+  eio_main
+  logs
+  echo_vfs
+  trace.core
+  trace-tef
   tiny_httpd_camlzip
   tiny_httpd.multipart-form-data))
 
@@ -55,6 +72,12 @@
 
 ; produce an embedded FS
 
+(library
+ (name echo_vfs)
+ (modules vfs)
+ (wrapped false)
+ (libraries tiny_httpd))
+
 (rule
  (targets vfs.ml)
  (deps