feat(ui) webview impl on separate files (#32)

bindings/rust/tauri-sys/build.rs

@@ -2,12 +2,12 @@ use std::{env, path::PathBuf};
 
 fn main() {
   let tauri_path = PathBuf::from("../../../ui");
+  let mut tauri_impl_path = tauri_path.clone();
 
   let mut build = cc::Build::new();
 
   build
     .include(&tauri_path)
-    .file("tauri.c")
     .flag_if_supported("-std=c11")
     .flag_if_supported("-w");
 
@@ -20,11 +20,13 @@ fn main() {
   let target = env::var("TARGET").unwrap();
 
   if target.contains("windows") {
+    tauri_impl_path.push("tauri-windows.c");
     build.define("WEBVIEW_WINAPI", None);
     for &lib in &["ole32", "comctl32", "oleaut32", "uuid", "gdi32"] {
       println!("cargo:rustc-link-lib={}", lib);
     }
   } else if target.contains("linux") || target.contains("bsd") {
+    tauri_impl_path.push("tauri-gtk.c");
     let webkit = pkg_config::Config::new()
       .atleast_version("2.8")
       .probe("webkit2gtk-4.0")
@@ -35,6 +37,7 @@ fn main() {
     }
     build.define("WEBVIEW_GTK", None);
   } else if target.contains("apple") {
+    tauri_impl_path.push("tauri-cocoa.m");
     build
       .define("WEBVIEW_COCOA", None)
       .flag("-x")
@@ -45,5 +48,9 @@ fn main() {
     panic!("unsupported target");
   }
 
+  build
+    .file(tauri_impl_path.into_os_string().into_string().unwrap())
+    .file("tauri.c");
+
   build.compile("tauri");
 }

bindings/rust/tauri-sys/tauri.c

@@ -1,3 +1,14 @@
+#if defined(WEBVIEW_GTK)
+#include "tauri-gtk-webview.h"
+#elif defined(WEBVIEW_WINAPI)
+#define CINTERFACE
+#include "tauri-windows-webview.h"
+#elif defined(WEBVIEW_COCOA)
+#include "tauri-cocoa-webview.h"
+#else
+#error "Define one of: WEBVIEW_GTK, WEBVIEW_COCOA or WEBVIEW_WINAPI"
+#endif
+
 #define WEBVIEW_IMPLEMENTATION
 #include "tauri.h"
 

ui/tauri-cocoa-webview.h

@@ -0,0 +1,11 @@
+#include <objc/objc-runtime.h>
+#include <CoreGraphics/CoreGraphics.h>
+#include <limits.h>
+
+struct webview_priv {
+  id pool;
+  id window;
+  id webview;
+  id windowDelegate;
+  int should_exit;
+};

ui/tauri-cocoa.m

@@ -0,0 +1,636 @@
+#include "tauri-cocoa-webview.h"
+#include "tauri.h"
+
+#define NSAlertStyleWarning 0
+#define NSAlertStyleCritical 2
+#define NSWindowStyleMaskResizable 8
+#define NSWindowStyleMaskMiniaturizable 4
+#define NSWindowStyleMaskTitled 1
+#define NSWindowStyleMaskClosable 2
+#define NSWindowStyleMaskFullScreen (1 << 14)
+#define NSViewWidthSizable 2
+#define NSViewHeightSizable 16
+#define NSBackingStoreBuffered 2
+#define NSEventMaskAny ULONG_MAX
+#define NSEventModifierFlagCommand (1 << 20)
+#define NSEventModifierFlagOption (1 << 19)
+#define NSAlertStyleInformational 1
+#define NSAlertFirstButtonReturn 1000
+#define WKNavigationActionPolicyDownload 2
+#define NSModalResponseOK 1
+#define WKNavigationActionPolicyDownload 2
+#define WKNavigationResponsePolicyAllow 1
+#define WKUserScriptInjectionTimeAtDocumentStart 0
+#define NSApplicationActivationPolicyRegular 0
+
+static id get_nsstring(const char *c_str) {
+  return objc_msgSend((id)objc_getClass("NSString"),
+                      sel_registerName("stringWithUTF8String:"), c_str);
+}
+
+static id create_menu_item(id title, const char *action, const char *key) {
+  id item =
+      objc_msgSend((id)objc_getClass("NSMenuItem"), sel_registerName("alloc"));
+  objc_msgSend(item, sel_registerName("initWithTitle:action:keyEquivalent:"),
+               title, sel_registerName(action), get_nsstring(key));
+  objc_msgSend(item, sel_registerName("autorelease"));
+
+  return item;
+}
+
+static void webview_window_will_close(id self, SEL cmd, id notification) {
+  struct webview *w =
+      (struct webview *)objc_getAssociatedObject(self, "webview");
+  webview_terminate(w);
+}
+
+static void webview_external_invoke(id self, SEL cmd, id contentController,
+                                    id message) {
+  struct webview *w =
+      (struct webview *)objc_getAssociatedObject(contentController, "webview");
+  if (w == NULL || w->external_invoke_cb == NULL) {
+    return;
+  }
+
+  w->external_invoke_cb(w, (const char *)objc_msgSend(
+                               objc_msgSend(message, sel_registerName("body")),
+                               sel_registerName("UTF8String")));
+}
+
+static void run_open_panel(id self, SEL cmd, id webView, id parameters,
+                           id frame, void (^completionHandler)(id)) {
+
+  id openPanel = objc_msgSend((id)objc_getClass("NSOpenPanel"),
+                              sel_registerName("openPanel"));
+
+  objc_msgSend(
+      openPanel, sel_registerName("setAllowsMultipleSelection:"),
+      objc_msgSend(parameters, sel_registerName("allowsMultipleSelection")));
+
+  objc_msgSend(openPanel, sel_registerName("setCanChooseFiles:"), 1);
+  objc_msgSend(
+      openPanel, sel_registerName("beginWithCompletionHandler:"), ^(id result) {
+        if (result == (id)NSModalResponseOK) {
+          completionHandler(objc_msgSend(openPanel, sel_registerName("URLs")));
+        } else {
+          completionHandler(nil);
+        }
+      });
+}
+
+static void run_save_panel(id self, SEL cmd, id download, id filename,
+                           void (^completionHandler)(int allowOverwrite,
+                                                     id destination)) {
+  id savePanel = objc_msgSend((id)objc_getClass("NSSavePanel"),
+                              sel_registerName("savePanel"));
+  objc_msgSend(savePanel, sel_registerName("setCanCreateDirectories:"), 1);
+  objc_msgSend(savePanel, sel_registerName("setNameFieldStringValue:"),
+               filename);
+  objc_msgSend(savePanel, sel_registerName("beginWithCompletionHandler:"),
+               ^(id result) {
+                 if (result == (id)NSModalResponseOK) {
+                   id url = objc_msgSend(savePanel, sel_registerName("URL"));
+                   id path = objc_msgSend(url, sel_registerName("path"));
+                   completionHandler(1, path);
+                 } else {
+                   completionHandler(NO, nil);
+                 }
+               });
+}
+
+static void run_confirmation_panel(id self, SEL cmd, id webView, id message,
+                                   id frame, void (^completionHandler)(bool)) {
+
+  id alert =
+      objc_msgSend((id)objc_getClass("NSAlert"), sel_registerName("new"));
+  objc_msgSend(alert, sel_registerName("setIcon:"),
+               objc_msgSend((id)objc_getClass("NSImage"),
+                            sel_registerName("imageNamed:"),
+                            get_nsstring("NSCaution")));
+  objc_msgSend(alert, sel_registerName("setShowsHelp:"), 0);
+  objc_msgSend(alert, sel_registerName("setInformativeText:"), message);
+  objc_msgSend(alert, sel_registerName("addButtonWithTitle:"),
+               get_nsstring("OK"));
+  objc_msgSend(alert, sel_registerName("addButtonWithTitle:"),
+               get_nsstring("Cancel"));
+  if (objc_msgSend(alert, sel_registerName("runModal")) ==
+      (id)NSAlertFirstButtonReturn) {
+    completionHandler(true);
+  } else {
+    completionHandler(false);
+  }
+  objc_msgSend(alert, sel_registerName("release"));
+}
+
+static void run_alert_panel(id self, SEL cmd, id webView, id message, id frame,
+                            void (^completionHandler)(void)) {
+  id alert =
+      objc_msgSend((id)objc_getClass("NSAlert"), sel_registerName("new"));
+  objc_msgSend(alert, sel_registerName("setIcon:"),
+               objc_msgSend((id)objc_getClass("NSImage"),
+                            sel_registerName("imageNamed:"),
+                            get_nsstring("NSCaution")));
+  objc_msgSend(alert, sel_registerName("setShowsHelp:"), 0);
+  objc_msgSend(alert, sel_registerName("setInformativeText:"), message);
+  objc_msgSend(alert, sel_registerName("addButtonWithTitle:"),
+               get_nsstring("OK"));
+  objc_msgSend(alert, sel_registerName("runModal"));
+  objc_msgSend(alert, sel_registerName("release"));
+  completionHandler();
+}
+
+static void download_failed(id self, SEL cmd, id download, id error) {
+  printf("%s",
+         (const char *)objc_msgSend(
+             objc_msgSend(error, sel_registerName("localizedDescription")),
+             sel_registerName("UTF8String")));
+}
+
+static void make_nav_policy_decision(id self, SEL cmd, id webView, id response,
+                                     void (^decisionHandler)(int)) {
+  if (objc_msgSend(response, sel_registerName("canShowMIMEType")) == 0) {
+    decisionHandler(WKNavigationActionPolicyDownload);
+  } else {
+    decisionHandler(WKNavigationResponsePolicyAllow);
+  }
+}
+
+WEBVIEW_API int webview_init(struct webview *w) {
+  w->priv.pool = objc_msgSend((id)objc_getClass("NSAutoreleasePool"),
+                              sel_registerName("new"));
+  objc_msgSend((id)objc_getClass("NSApplication"),
+               sel_registerName("sharedApplication"));
+
+  Class __WKScriptMessageHandler = objc_allocateClassPair(
+      objc_getClass("NSObject"), "__WKScriptMessageHandler", 0);
+  class_addMethod(
+      __WKScriptMessageHandler,
+      sel_registerName("userContentController:didReceiveScriptMessage:"),
+      (IMP)webview_external_invoke, "v@:@@");
+  objc_registerClassPair(__WKScriptMessageHandler);
+
+  id scriptMessageHandler =
+      objc_msgSend((id)__WKScriptMessageHandler, sel_registerName("new"));
+
+  /***
+   _WKDownloadDelegate is an undocumented/private protocol with methods called
+   from WKNavigationDelegate
+   References:
+   https://github.com/WebKit/webkit/blob/master/Source/WebKit/UIProcess/API/Cocoa/_WKDownload.h
+   https://github.com/WebKit/webkit/blob/master/Source/WebKit/UIProcess/API/Cocoa/_WKDownloadDelegate.h
+   https://github.com/WebKit/webkit/blob/master/Tools/TestWebKitAPI/Tests/WebKitCocoa/Download.mm
+   ***/
+
+  Class __WKDownloadDelegate = objc_allocateClassPair(
+      objc_getClass("NSObject"), "__WKDownloadDelegate", 0);
+  class_addMethod(
+      __WKDownloadDelegate,
+      sel_registerName("_download:decideDestinationWithSuggestedFilename:"
+                       "completionHandler:"),
+      (IMP)run_save_panel, "v@:@@?");
+  class_addMethod(__WKDownloadDelegate,
+                  sel_registerName("_download:didFailWithError:"),
+                  (IMP)download_failed, "v@:@@");
+  objc_registerClassPair(__WKDownloadDelegate);
+  id downloadDelegate =
+      objc_msgSend((id)__WKDownloadDelegate, sel_registerName("new"));
+
+  Class __WKPreferences = objc_allocateClassPair(objc_getClass("WKPreferences"),
+                                                 "__WKPreferences", 0);
+  objc_property_attribute_t type = {"T", "c"};
+  objc_property_attribute_t ownership = {"N", ""};
+  objc_property_attribute_t attrs[] = {type, ownership};
+  class_replaceProperty(__WKPreferences, "developerExtrasEnabled", attrs, 2);
+  objc_registerClassPair(__WKPreferences);
+  id wkPref = objc_msgSend((id)__WKPreferences, sel_registerName("new"));
+  objc_msgSend(wkPref, sel_registerName("setValue:forKey:"),
+               objc_msgSend((id)objc_getClass("NSNumber"),
+                            sel_registerName("numberWithBool:"), !!w->debug),
+               objc_msgSend((id)objc_getClass("NSString"),
+                            sel_registerName("stringWithUTF8String:"),
+                            "developerExtrasEnabled"));
+
+  id userController = objc_msgSend((id)objc_getClass("WKUserContentController"),
+                                   sel_registerName("new"));
+  objc_setAssociatedObject(userController, "webview", (id)(w),
+                           OBJC_ASSOCIATION_ASSIGN);
+  objc_msgSend(
+      userController, sel_registerName("addScriptMessageHandler:name:"),
+      scriptMessageHandler,
+      objc_msgSend((id)objc_getClass("NSString"),
+                   sel_registerName("stringWithUTF8String:"), "invoke"));
+
+  /***
+   In order to maintain compatibility with the other 'webviews' we need to
+   override window.external.invoke to call
+   webkit.messageHandlers.invoke.postMessage
+   ***/
+
+  id windowExternalOverrideScript = objc_msgSend(
+      (id)objc_getClass("WKUserScript"), sel_registerName("alloc"));
+  objc_msgSend(
+      windowExternalOverrideScript,
+      sel_registerName("initWithSource:injectionTime:forMainFrameOnly:"),
+      get_nsstring("window.external = this; invoke = function(arg){ "
+                   "webkit.messageHandlers.invoke.postMessage(arg); };"),
+      WKUserScriptInjectionTimeAtDocumentStart, 0);
+
+  objc_msgSend(userController, sel_registerName("addUserScript:"),
+               windowExternalOverrideScript);
+
+  id config = objc_msgSend((id)objc_getClass("WKWebViewConfiguration"),
+                           sel_registerName("new"));
+  id processPool = objc_msgSend(config, sel_registerName("processPool"));
+  objc_msgSend(processPool, sel_registerName("_setDownloadDelegate:"),
+               downloadDelegate);
+  objc_msgSend(config, sel_registerName("setProcessPool:"), processPool);
+  objc_msgSend(config, sel_registerName("setUserContentController:"),
+               userController);
+  objc_msgSend(config, sel_registerName("setPreferences:"), wkPref);
+
+  Class __NSWindowDelegate = objc_allocateClassPair(objc_getClass("NSObject"),
+                                                    "__NSWindowDelegate", 0);
+  class_addProtocol(__NSWindowDelegate, objc_getProtocol("NSWindowDelegate"));
+  class_replaceMethod(__NSWindowDelegate, sel_registerName("windowWillClose:"),
+                      (IMP)webview_window_will_close, "v@:@");
+  objc_registerClassPair(__NSWindowDelegate);
+
+  w->priv.windowDelegate =
+      objc_msgSend((id)__NSWindowDelegate, sel_registerName("new"));
+
+  objc_setAssociatedObject(w->priv.windowDelegate, "webview", (id)(w),
+                           OBJC_ASSOCIATION_ASSIGN);
+
+  id nsTitle =
+      objc_msgSend((id)objc_getClass("NSString"),
+                   sel_registerName("stringWithUTF8String:"), w->title);
+
+  CGRect r = CGRectMake(0, 0, w->width, w->height);
+
+  unsigned int style = NSWindowStyleMaskTitled | NSWindowStyleMaskClosable |
+                       NSWindowStyleMaskMiniaturizable;
+  if (w->resizable) {
+    style = style | NSWindowStyleMaskResizable;
+  }
+
+  w->priv.window =
+      objc_msgSend((id)objc_getClass("NSWindow"), sel_registerName("alloc"));
+  objc_msgSend(w->priv.window,
+               sel_registerName("initWithContentRect:styleMask:backing:defer:"),
+               r, style, NSBackingStoreBuffered, 0);
+
+  objc_msgSend(w->priv.window, sel_registerName("autorelease"));
+  objc_msgSend(w->priv.window, sel_registerName("setTitle:"), nsTitle);
+  objc_msgSend(w->priv.window, sel_registerName("setDelegate:"),
+               w->priv.windowDelegate);
+  objc_msgSend(w->priv.window, sel_registerName("center"));
+
+  Class __WKUIDelegate =
+      objc_allocateClassPair(objc_getClass("NSObject"), "__WKUIDelegate", 0);
+  class_addProtocol(__WKUIDelegate, objc_getProtocol("WKUIDelegate"));
+  class_addMethod(__WKUIDelegate,
+                  sel_registerName("webView:runOpenPanelWithParameters:"
+                                   "initiatedByFrame:completionHandler:"),
+                  (IMP)run_open_panel, "v@:@@@?");
+  class_addMethod(__WKUIDelegate,
+                  sel_registerName("webView:runJavaScriptAlertPanelWithMessage:"
+                                   "initiatedByFrame:completionHandler:"),
+                  (IMP)run_alert_panel, "v@:@@@?");
+  class_addMethod(
+      __WKUIDelegate,
+      sel_registerName("webView:runJavaScriptConfirmPanelWithMessage:"
+                       "initiatedByFrame:completionHandler:"),
+      (IMP)run_confirmation_panel, "v@:@@@?");
+  objc_registerClassPair(__WKUIDelegate);
+  id uiDel = objc_msgSend((id)__WKUIDelegate, sel_registerName("new"));
+
+  Class __WKNavigationDelegate = objc_allocateClassPair(
+      objc_getClass("NSObject"), "__WKNavigationDelegate", 0);
+  class_addProtocol(__WKNavigationDelegate,
+                    objc_getProtocol("WKNavigationDelegate"));
+  class_addMethod(
+      __WKNavigationDelegate,
+      sel_registerName(
+          "webView:decidePolicyForNavigationResponse:decisionHandler:"),
+      (IMP)make_nav_policy_decision, "v@:@@?");
+  objc_registerClassPair(__WKNavigationDelegate);
+  id navDel = objc_msgSend((id)__WKNavigationDelegate, sel_registerName("new"));
+
+  w->priv.webview =
+      objc_msgSend((id)objc_getClass("WKWebView"), sel_registerName("alloc"));
+  objc_msgSend(w->priv.webview,
+               sel_registerName("initWithFrame:configuration:"), r, config);
+  objc_msgSend(w->priv.webview, sel_registerName("setUIDelegate:"), uiDel);
+  objc_msgSend(w->priv.webview, sel_registerName("setNavigationDelegate:"),
+               navDel);
+
+  id nsURL = objc_msgSend((id)objc_getClass("NSURL"),
+                          sel_registerName("URLWithString:"),
+                          get_nsstring(webview_check_url(w->url)));
+
+  objc_msgSend(w->priv.webview, sel_registerName("loadRequest:"),
+               objc_msgSend((id)objc_getClass("NSURLRequest"),
+                            sel_registerName("requestWithURL:"), nsURL));
+  objc_msgSend(w->priv.webview, sel_registerName("setAutoresizesSubviews:"), 1);
+  objc_msgSend(w->priv.webview, sel_registerName("setAutoresizingMask:"),
+               (NSViewWidthSizable | NSViewHeightSizable));
+  objc_msgSend(objc_msgSend(w->priv.window, sel_registerName("contentView")),
+               sel_registerName("addSubview:"), w->priv.webview);
+  objc_msgSend(w->priv.window, sel_registerName("orderFrontRegardless"));
+
+  objc_msgSend(objc_msgSend((id)objc_getClass("NSApplication"),
+                            sel_registerName("sharedApplication")),
+               sel_registerName("setActivationPolicy:"),
+               NSApplicationActivationPolicyRegular);
+
+  objc_msgSend(objc_msgSend((id)objc_getClass("NSApplication"),
+                            sel_registerName("sharedApplication")),
+               sel_registerName("finishLaunching"));
+
+  objc_msgSend(objc_msgSend((id)objc_getClass("NSApplication"),
+                            sel_registerName("sharedApplication")),
+               sel_registerName("activateIgnoringOtherApps:"), 1);
+
+  id menubar =
+      objc_msgSend((id)objc_getClass("NSMenu"), sel_registerName("alloc"));
+  objc_msgSend(menubar, sel_registerName("initWithTitle:"), get_nsstring(""));
+  objc_msgSend(menubar, sel_registerName("autorelease"));
+
+  id appName = objc_msgSend(objc_msgSend((id)objc_getClass("NSProcessInfo"),
+                                         sel_registerName("processInfo")),
+                            sel_registerName("processName"));
+
+  id appMenuItem =
+      objc_msgSend((id)objc_getClass("NSMenuItem"), sel_registerName("alloc"));
+  objc_msgSend(appMenuItem,
+               sel_registerName("initWithTitle:action:keyEquivalent:"), appName,
+               NULL, get_nsstring(""));
+
+  id appMenu =
+      objc_msgSend((id)objc_getClass("NSMenu"), sel_registerName("alloc"));
+  objc_msgSend(appMenu, sel_registerName("initWithTitle:"), appName);
+  objc_msgSend(appMenu, sel_registerName("autorelease"));
+
+  objc_msgSend(appMenuItem, sel_registerName("setSubmenu:"), appMenu);
+  objc_msgSend(menubar, sel_registerName("addItem:"), appMenuItem);
+
+  id title =
+      objc_msgSend(get_nsstring("Hide "),
+                   sel_registerName("stringByAppendingString:"), appName);
+  id item = create_menu_item(title, "hide:", "h");
+  objc_msgSend(appMenu, sel_registerName("addItem:"), item);
+
+  item = create_menu_item(get_nsstring("Hide Others"),
+                          "hideOtherApplications:", "h");
+  objc_msgSend(item, sel_registerName("setKeyEquivalentModifierMask:"),
+               (NSEventModifierFlagOption | NSEventModifierFlagCommand));
+  objc_msgSend(appMenu, sel_registerName("addItem:"), item);
+
+  item =
+      create_menu_item(get_nsstring("Show All"), "unhideAllApplications:", "");
+  objc_msgSend(appMenu, sel_registerName("addItem:"), item);
+
+  objc_msgSend(appMenu, sel_registerName("addItem:"),
+               objc_msgSend((id)objc_getClass("NSMenuItem"),
+                            sel_registerName("separatorItem")));
+
+  title = objc_msgSend(get_nsstring("Quit "),
+                       sel_registerName("stringByAppendingString:"), appName);
+  item = create_menu_item(title, "terminate:", "q");
+  objc_msgSend(appMenu, sel_registerName("addItem:"), item);
+
+id editMenuItem =
+      objc_msgSend((id)objc_getClass("NSMenuItem"), sel_registerName("alloc"));
+  objc_msgSend(editMenuItem,
+               sel_registerName("initWithTitle:action:keyEquivalent:"), get_nsstring("Edit"),
+               NULL, get_nsstring(""));
+
+  /***
+   Edit menu
+  ***/
+
+id editMenu =
+  objc_msgSend((id)objc_getClass("NSMenu"), sel_registerName("alloc"));
+  objc_msgSend(editMenu, sel_registerName("initWithTitle:"), get_nsstring("Edit"));
+  objc_msgSend(editMenu, sel_registerName("autorelease"));
+
+  objc_msgSend(editMenuItem, sel_registerName("setSubmenu:"), editMenu);
+  objc_msgSend(menubar, sel_registerName("addItem:"), editMenuItem);
+
+  item = create_menu_item(get_nsstring("Undo"), "undo:", "z");
+  objc_msgSend(editMenu, sel_registerName("addItem:"), item);
+
+  item = create_menu_item(get_nsstring("Redo"), "redo:", "y");
+  objc_msgSend(editMenu, sel_registerName("addItem:"), item);
+
+  item = objc_msgSend((id)objc_getClass("NSMenuItem"), sel_registerName("separatorItem"));
+  objc_msgSend(editMenu, sel_registerName("addItem:"), item);
+
+  item = create_menu_item(get_nsstring("Cut"), "cut:", "x");
+  objc_msgSend(editMenu, sel_registerName("addItem:"), item);
+
+  item = create_menu_item(get_nsstring("Copy"), "copy:", "c");
+  objc_msgSend(editMenu, sel_registerName("addItem:"), item);
+
+  item = create_menu_item(get_nsstring("Paste"), "paste:", "v");
+  objc_msgSend(editMenu, sel_registerName("addItem:"), item);
+
+  item = create_menu_item(get_nsstring("Select All"), "selectAll:", "a");
+  objc_msgSend(editMenu, sel_registerName("addItem:"), item);
+
+  /***
+   Finalize menubar
+  ***/
+
+  objc_msgSend(objc_msgSend((id)objc_getClass("NSApplication"),
+                            sel_registerName("sharedApplication")),
+               sel_registerName("setMainMenu:"), menubar);
+
+  w->priv.should_exit = 0;
+  return 0;
+}
+
+WEBVIEW_API int webview_loop(struct webview *w, int blocking) {
+  id until = (blocking ? objc_msgSend((id)objc_getClass("NSDate"),
+                                      sel_registerName("distantFuture"))
+                       : objc_msgSend((id)objc_getClass("NSDate"),
+                                      sel_registerName("distantPast")));
+
+  id event = objc_msgSend(
+      objc_msgSend((id)objc_getClass("NSApplication"),
+                   sel_registerName("sharedApplication")),
+      sel_registerName("nextEventMatchingMask:untilDate:inMode:dequeue:"),
+      ULONG_MAX, until,
+      objc_msgSend((id)objc_getClass("NSString"),
+                   sel_registerName("stringWithUTF8String:"),
+                   "kCFRunLoopDefaultMode"),
+      true);
+
+  if (event) {
+    objc_msgSend(objc_msgSend((id)objc_getClass("NSApplication"),
+                              sel_registerName("sharedApplication")),
+                 sel_registerName("sendEvent:"), event);
+  }
+
+  return w->priv.should_exit;
+}
+
+WEBVIEW_API int webview_eval(struct webview *w, const char *js) {
+  objc_msgSend(w->priv.webview,
+               sel_registerName("evaluateJavaScript:completionHandler:"),
+               get_nsstring(js), NULL);
+
+  return 0;
+}
+
+WEBVIEW_API void webview_set_title(struct webview *w, const char *title) {
+  objc_msgSend(w->priv.window, sel_registerName("setTitle"),
+               get_nsstring(title));
+}
+
+WEBVIEW_API void webview_set_fullscreen(struct webview *w, int fullscreen) {
+  unsigned long windowStyleMask = (unsigned long)objc_msgSend(
+      w->priv.window, sel_registerName("styleMask"));
+  int b = (((windowStyleMask & NSWindowStyleMaskFullScreen) ==
+            NSWindowStyleMaskFullScreen)
+               ? 1
+               : 0);
+  if (b != fullscreen) {
+    objc_msgSend(w->priv.window, sel_registerName("toggleFullScreen:"), NULL);
+  }
+}
+
+WEBVIEW_API void webview_set_color(struct webview *w, uint8_t r, uint8_t g,
+                                   uint8_t b, uint8_t a) {
+
+  id color = objc_msgSend((id)objc_getClass("NSColor"),
+                          sel_registerName("colorWithRed:green:blue:alpha:"),
+                          (float)r / 255.0, (float)g / 255.0, (float)b / 255.0,
+                          (float)a / 255.0);
+
+  objc_msgSend(w->priv.window, sel_registerName("setBackgroundColor:"), color);
+
+  if (0.5 >= ((r / 255.0 * 299.0) + (g / 255.0 * 587.0) + (b / 255.0 * 114.0)) /
+                 1000.0) {
+    objc_msgSend(w->priv.window, sel_registerName("setAppearance:"),
+                 objc_msgSend((id)objc_getClass("NSAppearance"),
+                              sel_registerName("appearanceNamed:"),
+                              get_nsstring("NSAppearanceNameVibrantDark")));
+  } else {
+    objc_msgSend(w->priv.window, sel_registerName("setAppearance:"),
+                 objc_msgSend((id)objc_getClass("NSAppearance"),
+                              sel_registerName("appearanceNamed:"),
+                              get_nsstring("NSAppearanceNameVibrantLight")));
+  }
+  objc_msgSend(w->priv.window, sel_registerName("setOpaque:"), 0);
+  objc_msgSend(w->priv.window,
+               sel_registerName("setTitlebarAppearsTransparent:"), 1);
+               objc_msgSend(w->priv.webview, sel_registerName("_setDrawsBackground:"), 0);
+}
+
+WEBVIEW_API void webview_dialog(struct webview *w,
+                                enum webview_dialog_type dlgtype, int flags,
+                                const char *title, const char *arg,
+                                char *result, size_t resultsz) {
+  if (dlgtype == WEBVIEW_DIALOG_TYPE_OPEN ||
+      dlgtype == WEBVIEW_DIALOG_TYPE_SAVE) {
+    id panel = (id)objc_getClass("NSSavePanel");
+    if (dlgtype == WEBVIEW_DIALOG_TYPE_OPEN) {
+      id openPanel = objc_msgSend((id)objc_getClass("NSOpenPanel"),
+                                  sel_registerName("openPanel"));
+      if (flags & WEBVIEW_DIALOG_FLAG_DIRECTORY) {
+        objc_msgSend(openPanel, sel_registerName("setCanChooseFiles:"), 0);
+        objc_msgSend(openPanel, sel_registerName("setCanChooseDirectories:"),
+                     1);
+      } else {
+        objc_msgSend(openPanel, sel_registerName("setCanChooseFiles:"), 1);
+        objc_msgSend(openPanel, sel_registerName("setCanChooseDirectories:"),
+                     0);
+      }
+      objc_msgSend(openPanel, sel_registerName("setResolvesAliases:"), 0);
+      objc_msgSend(openPanel, sel_registerName("setAllowsMultipleSelection:"),
+                   0);
+      panel = openPanel;
+    } else {
+      panel = objc_msgSend((id)objc_getClass("NSSavePanel"),
+                           sel_registerName("savePanel"));
+    }
+
+    objc_msgSend(panel, sel_registerName("setCanCreateDirectories:"), 1);
+    objc_msgSend(panel, sel_registerName("setShowsHiddenFiles:"), 1);
+    objc_msgSend(panel, sel_registerName("setExtensionHidden:"), 0);
+    objc_msgSend(panel, sel_registerName("setCanSelectHiddenExtension:"), 0);
+    objc_msgSend(panel, sel_registerName("setTreatsFilePackagesAsDirectories:"),
+                 1);
+    objc_msgSend(
+        panel, sel_registerName("beginSheetModalForWindow:completionHandler:"),
+        w->priv.window, ^(id result) {
+          objc_msgSend(objc_msgSend((id)objc_getClass("NSApplication"),
+                                    sel_registerName("sharedApplication")),
+                       sel_registerName("stopModalWithCode:"), result);
+        });
+
+    if (objc_msgSend(objc_msgSend((id)objc_getClass("NSApplication"),
+                                  sel_registerName("sharedApplication")),
+                     sel_registerName("runModalForWindow:"),
+                     panel) == (id)NSModalResponseOK) {
+      id url = objc_msgSend(panel, sel_registerName("URL"));
+      id path = objc_msgSend(url, sel_registerName("path"));
+      const char *filename =
+          (const char *)objc_msgSend(path, sel_registerName("UTF8String"));
+      strlcpy(result, filename, resultsz);
+    }
+  } else if (dlgtype == WEBVIEW_DIALOG_TYPE_ALERT) {
+    id a = objc_msgSend((id)objc_getClass("NSAlert"), sel_registerName("new"));
+    switch (flags & WEBVIEW_DIALOG_FLAG_ALERT_MASK) {
+    case WEBVIEW_DIALOG_FLAG_INFO:
+      objc_msgSend(a, sel_registerName("setAlertStyle:"),
+                   NSAlertStyleInformational);
+      break;
+    case WEBVIEW_DIALOG_FLAG_WARNING:
+      printf("Warning\n");
+      objc_msgSend(a, sel_registerName("setAlertStyle:"), NSAlertStyleWarning);
+      break;
+    case WEBVIEW_DIALOG_FLAG_ERROR:
+      printf("Error\n");
+      objc_msgSend(a, sel_registerName("setAlertStyle:"), NSAlertStyleCritical);
+      break;
+    }
+    objc_msgSend(a, sel_registerName("setShowsHelp:"), 0);
+    objc_msgSend(a, sel_registerName("setShowsSuppressionButton:"), 0);
+    objc_msgSend(a, sel_registerName("setMessageText:"), get_nsstring(title));
+    objc_msgSend(a, sel_registerName("setInformativeText:"), get_nsstring(arg));
+    objc_msgSend(a, sel_registerName("addButtonWithTitle:"),
+                 get_nsstring("OK"));
+    objc_msgSend(a, sel_registerName("runModal"));
+    objc_msgSend(a, sel_registerName("release"));
+  }
+}
+
+static void webview_dispatch_cb(void *arg) {
+  struct webview_dispatch_arg *context = (struct webview_dispatch_arg *)arg;
+  (context->fn)(context->w, context->arg);
+  free(context);
+}
+
+WEBVIEW_API void webview_dispatch(struct webview *w, webview_dispatch_fn fn,
+                                  void *arg) {
+  struct webview_dispatch_arg *context = (struct webview_dispatch_arg *)malloc(
+      sizeof(struct webview_dispatch_arg));
+  context->w = w;
+  context->arg = arg;
+  context->fn = fn;
+  dispatch_async_f(dispatch_get_main_queue(), context, webview_dispatch_cb);
+}
+
+WEBVIEW_API void webview_terminate(struct webview *w) {
+  w->priv.should_exit = 1;
+}
+
+WEBVIEW_API void webview_exit(struct webview *w) {
+  id app = objc_msgSend((id)objc_getClass("NSApplication"),
+                        sel_registerName("sharedApplication"));
+  objc_msgSend(app, sel_registerName("terminate:"), app);
+}
+
+WEBVIEW_API void webview_print_log(const char *s) { printf("%s\n", s); }

ui/tauri-gtk-webview.h

@@ -0,0 +1,14 @@
+#include <JavaScriptCore/JavaScript.h>
+#include <gtk/gtk.h>
+#include <webkit2/webkit2.h>
+
+struct webview_priv {
+  GtkWidget *window;
+  GtkWidget *scroller;
+  GtkWidget *webview;
+  GtkWidget *inspector_window;
+  GAsyncQueue *queue;
+  int ready;
+  int js_busy;
+  int should_exit;
+};

ui/tauri-gtk.c

@@ -0,0 +1,244 @@
+#include "tauri-gtk-webview.h"
+#include "tauri.h"
+
+static void external_message_received_cb(WebKitUserContentManager *m,
+                                         WebKitJavascriptResult *r,
+                                         gpointer arg) {
+  (void)m;
+  struct webview *w = (struct webview *)arg;
+  if (w->external_invoke_cb == NULL) {
+    return;
+  }
+  JSGlobalContextRef context = webkit_javascript_result_get_global_context(r);
+  JSValueRef value = webkit_javascript_result_get_value(r);
+  JSStringRef js = JSValueToStringCopy(context, value, NULL);
+  size_t n = JSStringGetMaximumUTF8CStringSize(js);
+  char *s = g_new(char, n);
+  JSStringGetUTF8CString(js, s, n);
+  w->external_invoke_cb(w, s);
+  JSStringRelease(js);
+  g_free(s);
+}
+
+static void webview_load_changed_cb(WebKitWebView *webview,
+                                    WebKitLoadEvent event, gpointer arg) {
+  (void)webview;
+  struct webview *w = (struct webview *)arg;
+  if (event == WEBKIT_LOAD_FINISHED) {
+    w->priv.ready = 1;
+  }
+}
+
+static void webview_destroy_cb(GtkWidget *widget, gpointer arg) {
+  (void)widget;
+  struct webview *w = (struct webview *)arg;
+  webview_terminate(w);
+}
+
+static gboolean webview_context_menu_cb(WebKitWebView *webview,
+                                        GtkWidget *default_menu,
+                                        WebKitHitTestResult *hit_test_result,
+                                        gboolean triggered_with_keyboard,
+                                        gpointer userdata) {
+  (void)webview;
+  (void)default_menu;
+  (void)hit_test_result;
+  (void)triggered_with_keyboard;
+  (void)userdata;
+  return TRUE;
+}
+
+WEBVIEW_API int webview_init(struct webview *w) {
+  if (gtk_init_check(0, NULL) == FALSE) {
+    return -1;
+  }
+
+  w->priv.ready = 0;
+  w->priv.should_exit = 0;
+  w->priv.queue = g_async_queue_new();
+  w->priv.window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+  gtk_window_set_title(GTK_WINDOW(w->priv.window), w->title);
+
+  if (w->resizable) {
+    gtk_window_set_default_size(GTK_WINDOW(w->priv.window), w->width,
+                                w->height);
+  } else {
+    gtk_widget_set_size_request(w->priv.window, w->width, w->height);
+  }
+  gtk_window_set_resizable(GTK_WINDOW(w->priv.window), !!w->resizable);
+  gtk_window_set_position(GTK_WINDOW(w->priv.window), GTK_WIN_POS_CENTER);
+
+  w->priv.scroller = gtk_scrolled_window_new(NULL, NULL);
+  gtk_container_add(GTK_CONTAINER(w->priv.window), w->priv.scroller);
+
+  WebKitUserContentManager *m = webkit_user_content_manager_new();
+  webkit_user_content_manager_register_script_message_handler(m, "external");
+  g_signal_connect(m, "script-message-received::external",
+                   G_CALLBACK(external_message_received_cb), w);
+
+  w->priv.webview = webkit_web_view_new_with_user_content_manager(m);
+  webkit_web_view_load_uri(WEBKIT_WEB_VIEW(w->priv.webview),
+                           webview_check_url(w->url));
+  g_signal_connect(G_OBJECT(w->priv.webview), "load-changed",
+                   G_CALLBACK(webview_load_changed_cb), w);
+  gtk_container_add(GTK_CONTAINER(w->priv.scroller), w->priv.webview);
+
+  if (w->debug) {
+    WebKitSettings *settings =
+        webkit_web_view_get_settings(WEBKIT_WEB_VIEW(w->priv.webview));
+    webkit_settings_set_enable_write_console_messages_to_stdout(settings, true);
+    webkit_settings_set_enable_developer_extras(settings, true);
+  } else {
+    g_signal_connect(G_OBJECT(w->priv.webview), "context-menu",
+                     G_CALLBACK(webview_context_menu_cb), w);
+  }
+
+  gtk_widget_show_all(w->priv.window);
+
+  webkit_web_view_run_javascript(
+      WEBKIT_WEB_VIEW(w->priv.webview),
+      "window.external={invoke:function(x){"
+      "window.webkit.messageHandlers.external.postMessage(x);}}",
+      NULL, NULL, NULL);
+
+  g_signal_connect(G_OBJECT(w->priv.window), "destroy",
+                   G_CALLBACK(webview_destroy_cb), w);
+  return 0;
+}
+
+WEBVIEW_API int webview_loop(struct webview *w, int blocking) {
+  gtk_main_iteration_do(blocking);
+  return w->priv.should_exit;
+}
+
+WEBVIEW_API void webview_set_title(struct webview *w, const char *title) {
+  gtk_window_set_title(GTK_WINDOW(w->priv.window), title);
+}
+
+WEBVIEW_API void webview_set_fullscreen(struct webview *w, int fullscreen) {
+  if (fullscreen) {
+    gtk_window_fullscreen(GTK_WINDOW(w->priv.window));
+  } else {
+    gtk_window_unfullscreen(GTK_WINDOW(w->priv.window));
+  }
+}
+
+WEBVIEW_API void webview_set_color(struct webview *w, uint8_t r, uint8_t g,
+                                   uint8_t b, uint8_t a) {
+  GdkRGBA color = {r / 255.0, g / 255.0, b / 255.0, a / 255.0};
+  webkit_web_view_set_background_color(WEBKIT_WEB_VIEW(w->priv.webview),
+                                       &color);
+}
+
+WEBVIEW_API void webview_dialog(struct webview *w,
+                                enum webview_dialog_type dlgtype, int flags,
+                                const char *title, const char *arg,
+                                char *result, size_t resultsz) {
+  GtkWidget *dlg;
+  if (result != NULL) {
+    result[0] = '\0';
+  }
+  if (dlgtype == WEBVIEW_DIALOG_TYPE_OPEN ||
+      dlgtype == WEBVIEW_DIALOG_TYPE_SAVE) {
+    dlg = gtk_file_chooser_dialog_new(
+        title, GTK_WINDOW(w->priv.window),
+        (dlgtype == WEBVIEW_DIALOG_TYPE_OPEN
+             ? (flags & WEBVIEW_DIALOG_FLAG_DIRECTORY
+                    ? GTK_FILE_CHOOSER_ACTION_SELECT_FOLDER
+                    : GTK_FILE_CHOOSER_ACTION_OPEN)
+             : GTK_FILE_CHOOSER_ACTION_SAVE),
+        "_Cancel", GTK_RESPONSE_CANCEL,
+        (dlgtype == WEBVIEW_DIALOG_TYPE_OPEN ? "_Open" : "_Save"),
+        GTK_RESPONSE_ACCEPT, NULL);
+    gtk_file_chooser_set_local_only(GTK_FILE_CHOOSER(dlg), FALSE);
+    gtk_file_chooser_set_select_multiple(GTK_FILE_CHOOSER(dlg), FALSE);
+    gtk_file_chooser_set_show_hidden(GTK_FILE_CHOOSER(dlg), TRUE);
+    gtk_file_chooser_set_do_overwrite_confirmation(GTK_FILE_CHOOSER(dlg), TRUE);
+    gtk_file_chooser_set_create_folders(GTK_FILE_CHOOSER(dlg), TRUE);
+    gint response = gtk_dialog_run(GTK_DIALOG(dlg));
+    if (response == GTK_RESPONSE_ACCEPT) {
+      gchar *filename = gtk_file_chooser_get_filename(GTK_FILE_CHOOSER(dlg));
+      g_strlcpy(result, filename, resultsz);
+      g_free(filename);
+    }
+    gtk_widget_destroy(dlg);
+  } else if (dlgtype == WEBVIEW_DIALOG_TYPE_ALERT) {
+    GtkMessageType type = GTK_MESSAGE_OTHER;
+    switch (flags & WEBVIEW_DIALOG_FLAG_ALERT_MASK) {
+    case WEBVIEW_DIALOG_FLAG_INFO:
+      type = GTK_MESSAGE_INFO;
+      break;
+    case WEBVIEW_DIALOG_FLAG_WARNING:
+      type = GTK_MESSAGE_WARNING;
+      break;
+    case WEBVIEW_DIALOG_FLAG_ERROR:
+      type = GTK_MESSAGE_ERROR;
+      break;
+    }
+    dlg = gtk_message_dialog_new(GTK_WINDOW(w->priv.window), GTK_DIALOG_MODAL,
+                                 type, GTK_BUTTONS_OK, "%s", title);
+    gtk_message_dialog_format_secondary_text(GTK_MESSAGE_DIALOG(dlg), "%s",
+                                             arg);
+    gtk_dialog_run(GTK_DIALOG(dlg));
+    gtk_widget_destroy(dlg);
+  }
+}
+
+static void webview_eval_finished(GObject *object, GAsyncResult *result,
+                                  gpointer userdata) {
+  (void)object;
+  (void)result;
+  struct webview *w = (struct webview *)userdata;
+  w->priv.js_busy = 0;
+}
+
+WEBVIEW_API int webview_eval(struct webview *w, const char *js) {
+  while (w->priv.ready == 0) {
+    g_main_context_iteration(NULL, TRUE);
+  }
+  w->priv.js_busy = 1;
+  webkit_web_view_run_javascript(WEBKIT_WEB_VIEW(w->priv.webview), js, NULL,
+                                 webview_eval_finished, w);
+  while (w->priv.js_busy) {
+    g_main_context_iteration(NULL, TRUE);
+  }
+  return 0;
+}
+
+static gboolean webview_dispatch_wrapper(gpointer userdata) {
+  struct webview *w = (struct webview *)userdata;
+  for (;;) {
+    struct webview_dispatch_arg *arg =
+        (struct webview_dispatch_arg *)g_async_queue_try_pop(w->priv.queue);
+    if (arg == NULL) {
+      break;
+    }
+    (arg->fn)(w, arg->arg);
+    g_free(arg);
+  }
+  return FALSE;
+}
+
+WEBVIEW_API void webview_dispatch(struct webview *w, webview_dispatch_fn fn,
+                                  void *arg) {
+  struct webview_dispatch_arg *context =
+      (struct webview_dispatch_arg *)g_new(struct webview_dispatch_arg, 1);
+  context->w = w;
+  context->arg = arg;
+  context->fn = fn;
+  g_async_queue_lock(w->priv.queue);
+  g_async_queue_push_unlocked(w->priv.queue, context);
+  if (g_async_queue_length_unlocked(w->priv.queue) == 1) {
+    gdk_threads_add_idle(webview_dispatch_wrapper, w);
+  }
+  g_async_queue_unlock(w->priv.queue);
+}
+
+WEBVIEW_API void webview_terminate(struct webview *w) {
+  w->priv.should_exit = 1;
+}
+
+WEBVIEW_API void webview_exit(struct webview *w) { (void)w; }
+WEBVIEW_API void webview_print_log(const char *s) {
+  fprintf(stderr, "%s\n", s);
+}

ui/tauri-windows-webview.h

@@ -0,0 +1,19 @@
+#define CINTERFACE
+#include <windows.h>
+
+#include <commctrl.h>
+#include <exdisp.h>
+#include <mshtmhst.h>
+#include <mshtml.h>
+#include <shobjidl.h>
+
+#include <stdio.h>
+
+struct webview_priv {
+  HWND hwnd;
+  IOleObject **browser;
+  BOOL is_fullscreen;
+  DWORD saved_style;
+  DWORD saved_ex_style;
+  RECT saved_rect;
+};