Windows/webkitgtk front-end support: build jsaddle-terminal on Windows, expose the WebView2 HWND

jsaddle-terminal/jsaddle-terminal.cabal

@@ -28,25 +28,27 @@ flag demo
 
 library
   hs-source-dirs:     src
-  exposed-modules:    Language.Javascript.JSaddle.Terminal
-                      Language.Javascript.JSaddle.Terminal.Protocol
+  exposed-modules:    Language.Javascript.JSaddle.Terminal.Protocol
                       Language.Javascript.JSaddle.Terminal.Bootstrap
   build-depends:      base >=4.16 && <5
-                    , aeson
                     , base64-bytestring
                     , bytestring
                     , jsaddle >=0.9.4 && <0.10
-                    , jsaddle-warp >=0.9.4 && <0.10
-                    , stm
-                    , text
-                    , unix
-                    , warp
-                    , websockets
   ghc-options:        -Wall
   default-language:   Haskell2010
-  -- Raw-mode stdin/termios: POSIX only.
-  if os(windows)
-    buildable: False
+  -- The tunnel runner needs raw-mode stdin/termios: POSIX only.  The framing
+  -- (Protocol) and iframe JS (Bootstrap) are pure and build everywhere, so
+  -- IDE-side consumers (leksah) can link this library on Windows too —
+  -- without the runner's warp-fallback deps (jsaddle-warp caps aeson).
+  if !os(windows)
+    exposed-modules:  Language.Javascript.JSaddle.Terminal
+    build-depends:      aeson
+                      , jsaddle-warp >=0.9.4 && <0.10
+                      , stm
+                      , text
+                      , unix
+                      , warp
+                      , websockets
 
 executable jsaddle-terminal-demo
   main-is:            Main.hs

jsaddle-webview2/cbits/WebView2Shim.c

@@ -371,6 +371,13 @@ static LRESULT CALLBACK wndProc(HWND hwnd, UINT msg, WPARAM wp, LPARAM lp)
 
 /* ------------------------------------------- API called from Haskell */
 
+/* The Win32 HWND of the window hosting the WebView2, so the embedding
+   application can do native window integration (menu bar, dialogs). */
+void *wv2GetHwnd(JSaddleWV2 *app)
+{
+    return (void *)app->hwnd;
+}
+
 void wv2SetHandlers(JSaddleWV2 *app, HsStablePtr start, HsStablePtr result, HsStablePtr sync)
 {
     app->startHandler = start;

jsaddle-webview2/src/Language/Javascript/JSaddle/WebView2.hs

@@ -20,6 +20,7 @@ module Language.Javascript.JSaddle.WebView2
     , run'
     , WebView2Config(..)
     , WebView2(..)
+    , webView2Hwnd
     ) where
 
 import Control.Monad (unless)
@@ -31,13 +32,22 @@ import Data.Text.Encoding (encodeUtf8)
 
 import Foreign.C.String (CString)
 import Foreign.C.Types (CInt(..))
+import Foreign.Ptr (Ptr)
 import Foreign.StablePtr (StablePtr, newStablePtr)
 
 import Language.Javascript.JSaddle (JSM)
 import Language.Javascript.JSaddle.WebView2.Internal
        (jsaddleMain, jsaddleMainHTML, jsaddleMainURL, WebView2(..))
 import System.Environment (getProgName)
 
+foreign import ccall wv2GetHwnd :: WebView2 -> IO (Ptr ())
+
+-- | The Win32 @HWND@ of the window hosting the WebView2, for native window
+--   integration (menu bar, dialogs) by the embedding application.  Only
+--   meaningful once the 'run'' callback has been entered.
+webView2Hwnd :: WebView2 -> IO (Ptr ())
+webView2Hwnd = wv2GetHwnd
+
 foreign import ccall runJsaddleWebView2
     :: StablePtr (WebView2 -> IO ())
     -> CString -- ^ window title (utf8)