Interface WebView.DecidePolicyCallback

All Superinterfaces:

FunctionPointer

Enclosing class:

WebView

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public static interface WebView.DecidePolicyCallback
extends FunctionPointer

Functional interface declaration of the DecidePolicyCallback callback.

See Also:

• run(PolicyDecision, PolicyDecisionType)

Method Summary

Modifier and Type	Method	Description
boolean	run(@Nullable PolicyDecision decision, PolicyDecisionType decisionType)	This signal is emitted when WebKit is requesting the client to decide a policy decision, such as whether to navigate to a page, open a new window or whether or not to download a resource.
default MemorySegment	toCallback(Arena arena)	Creates a native function pointer to the upcall(MemorySegment, MemorySegment, int) method.
default int	upcall(MemorySegment sourceWebView, MemorySegment decision, int decisionType)	The upcall method is called from native code.

Method Details

run

boolean run(@Nullable PolicyDecision decision,
 PolicyDecisionType decisionType)

This signal is emitted when WebKit is requesting the client to decide a policy decision, such as whether to navigate to a page, open a new window or whether or not to download a resource. The WebKitNavigationPolicyDecision passed in the decision argument is a generic type, but should be casted to a more specific type when making the decision. For example:

static gboolean
decide_policy_cb (WebKitWebView *web_view,
                  WebKitPolicyDecision *decision,
                  WebKitPolicyDecisionType type)
{
    switch (type) {
    case WEBKIT_POLICY_DECISION_TYPE_NAVIGATION_ACTION: {
        WebKitNavigationPolicyDecision *navigation_decision = WEBKIT_NAVIGATION_POLICY_DECISION (decision);
        // Make a policy decision here
        break;
    }
    case WEBKIT_POLICY_DECISION_TYPE_NEW_WINDOW_ACTION: {
        WebKitNavigationPolicyDecision *navigation_decision = WEBKIT_NAVIGATION_POLICY_DECISION (decision);
        // Make a policy decision here
        break;
    }
    case WEBKIT_POLICY_DECISION_TYPE_RESPONSE:
        WebKitResponsePolicyDecision *response = WEBKIT_RESPONSE_POLICY_DECISION (decision);
        // Make a policy decision here
        break;
    default:
        // Making no decision results in webkit_policy_decision_use()
        return FALSE;
    }
    return TRUE;
}

It is possible to make policy decision asynchronously, by simply calling g_object_ref() on the decision argument and returning true to block the default signal handler. If the last reference is removed on a WebKitPolicyDecision and no decision has been made explicitly, webkit_policy_decision_use() will be the default policy decision. The default signal handler will simply call webkit_policy_decision_use(). Only the first policy decision chosen for a given WebKitPolicyDecision will have any affect.

upcall

default int upcall(MemorySegment sourceWebView,
 MemorySegment decision,
 int decisionType)

The upcall method is called from native code. The parameters are marshaled and run(PolicyDecision, PolicyDecisionType) is executed.

toCallback

default MemorySegment toCallback(Arena arena)

Creates a native function pointer to the upcall(MemorySegment, MemorySegment, int) method.

Specified by:

toCallback in interface FunctionPointer

Parameters:

arena - the arena in which the function pointer is allocated

Returns:

the native function pointer