Implement navigation event callback handler on gtk

src/webview/webkitgtk/mod.rs

@@ -14,10 +14,10 @@ use glib::signal::Inhibit;
 use gtk::prelude::*;
 use webkit2gtk::{
   traits::*, UserContentInjectedFrames, UserScript, UserScriptInjectionTime, WebView,
-  WebViewBuilder,
+  WebViewBuilder, PolicyDecisionType, NavigationPolicyDecision,
 };
 use webkit2gtk_sys::{
-  webkit_get_major_version, webkit_get_micro_version, webkit_get_minor_version,
+  webkit_get_major_version, webkit_get_micro_version, webkit_get_minor_version, webkit_policy_decision_ignore, webkit_policy_decision_use,
 };
 
 use web_context::WebContextExt;
@@ -198,6 +198,31 @@ impl InnerWebView {
       Inhibit(false)
     });
 
+    if let Some(nav_handler) = attributes.navigation_handler {
+      webview.connect_decide_policy(move |_webview, policy_decision, policy_type| {
+        if let PolicyDecisionType::NavigationAction = policy_type {
+          if let Some(policy) = policy_decision.dynamic_cast_ref::<NavigationPolicyDecision>() {
+            if let Some(nav_action) = policy.navigation_action() {
+              if let Some(uri_req) = nav_action.request() {
+                if let Some(uri) = uri_req.uri() {
+                  let cancel = nav_handler(uri.to_string());
+                  let pointer = policy_decision.as_ptr();
+                  unsafe {
+                    if cancel {
+                      webkit_policy_decision_ignore(pointer)
+                    } else {
+                      webkit_policy_decision_use(pointer)
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+        false
+      });
+    }
+
     // Gtk application window can only contain one widget at a time.
     // In tao, we add a GtkBox to pack menu bar. So we check if
     // there's a box widget here.