[UnifiedPDF] Handle PDF annotations actions that reset form fields.

https://bugs.webkit.org/show_bug.cgi?id=269122
rdar://problem/122680796

Reviewed by Tim Horton.

A certain type of PDF annotation action can reset various fields on a
form. PDFKit represents this type of action as a PDFKitActionResetForm.

Basically what we will do is check to see if an annotation has an action
associated with it and will handle it if it does. This first patch
supports the reset form action and will check to see if the action is
of that type when handling it. If it is, we will call into the
appropriate PDFKit SPI which will do the actual work for us.

Also, the PDF specification says that an action is composed of a type,
which specifies the type of action that it is, and a list of subsequent
actions that are supposed to be performed. So we need to handle this
scenario also by:
1.) Performing the action
2.) Store the subsequent actions on a stack in reverse order (so that
the first action is at the top of the stack).
We keep handling the action at the top of the stack until it is empty.

* Source/WebKit/Platform/spi/Cocoa/PDFKitSPI.h:
* Source/WebKit/Shared/Cocoa/PDFKitSoftLink.h:
* Source/WebKit/Shared/Cocoa/PDFKitSoftLink.mm:
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h:
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm:
(WebKit::UnifiedPDFPlugin::handleMouseEvent):
(WebKit::UnifiedPDFPlugin::handlePDFActionForAnnotation):

Canonical link: https://commits.webkit.org/274546@main

Source/WebKit/Platform/spi/Cocoa/PDFKitSPI.h

@@ -36,7 +36,15 @@
 #import <PDFKit/PDFHostViewController.h>
 #endif // PLATFORM(IOS_FAMILY)
 
+#import <PDFKit/PDFDocumentPriv.h>
 #import <PDFKit/PDFSelectionPriv.h>
+#if __has_include(<PDFKit/PDFActionPriv.h>)
+#import <PDFKit/PDFActionPriv.h>
+#else
+@interface PDFAction(SPI)
+- (NSArray *) nextActions;
+@end
+#endif // __has_include(PDFKIT/PDFActionPriv.h)
 
 #endif // HAVE(PDFKIT)
 
@@ -97,6 +105,7 @@
 @interface PDFDocument ()
 -(instancetype)initWithProvider:(CGDataProviderRef)dataProvider;
 -(void)preloadDataOfPagesInRange:(NSRange)range onQueue:(dispatch_queue_t)queue completion:(void (^)(NSIndexSet* loadedPageIndexes))completionBlock;
+-(void)resetFormFields:(PDFActionResetForm *) action;
 @property (readwrite, nonatomic) BOOL hasHighLatencyDataProvider;
 @end
 #endif // HAVE(INCREMENTAL_PDF_APIS)

Source/WebKit/Shared/Cocoa/PDFKitSoftLink.h

@@ -34,6 +34,7 @@
 SOFT_LINK_FRAMEWORK_FOR_HEADER(WebKit, PDFKit)
 
 ALLOW_DEPRECATED_DECLARATIONS_BEGIN
+SOFT_LINK_CLASS_FOR_HEADER(WebKit, PDFActionResetForm)
 SOFT_LINK_CLASS_FOR_HEADER(WebKit, PDFAnnotationButtonWidget)
 SOFT_LINK_CLASS_FOR_HEADER(WebKit, PDFAnnotationChoiceWidget)
 SOFT_LINK_CLASS_FOR_HEADER(WebKit, PDFAnnotationLink)

Source/WebKit/Shared/Cocoa/PDFKitSoftLink.mm

@@ -32,6 +32,7 @@
 SOFT_LINK_FRAMEWORK_FOR_SOURCE(WebKit, PDFKit)
 
 ALLOW_DEPRECATED_DECLARATIONS_BEGIN
+SOFT_LINK_CLASS_FOR_SOURCE(WebKit, PDFKit, PDFActionResetForm)
 SOFT_LINK_CLASS_FOR_SOURCE(WebKit, PDFKit, PDFAnnotationButtonWidget)
 SOFT_LINK_CLASS_FOR_SOURCE(WebKit, PDFKit, PDFAnnotationChoiceWidget)
 SOFT_LINK_CLASS_FOR_SOURCE(WebKit, PDFKit, PDFAnnotationLink)

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h

@@ -32,6 +32,7 @@
 #include <WebCore/GraphicsLayer.h>
 #include <wtf/OptionSet.h>
 
+OBJC_CLASS PDFAction;
 OBJC_CLASS PDFDestination;
 OBJC_CLASS WKPDFFormMutationObserver;
 
@@ -90,6 +91,7 @@ class UnifiedPDFPlugin final : public PDFPluginBase, public WebCore::GraphicsLay
     void focusPreviousAnnotation() final;
 #if PLATFORM(MAC)
     RetainPtr<PDFAnnotation> nextTextAnnotation(AnnotationSearchDirection) const;
+    void handlePDFActionForAnnotation(PDFAnnotation *);
 #endif
 
     void attemptToUnlockPDF(const String& password) final;

Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm

@@ -1358,6 +1358,10 @@ static bool isContextMenuEvent(const WebMouseEvent& event)
                 if (annotationIsLinkWithDestination(trackedAnnotation.get()))
                     followLinkAnnotation(trackedAnnotation.get());
 
+#if PLATFORM(MAC)
+                if (RetainPtr pdfAction = [trackedAnnotation action])
+                    handlePDFActionForAnnotation(trackedAnnotation.get());
+#endif
                 updateLayerHierarchy();
             }
 
@@ -2045,6 +2049,41 @@ static IntRect computeMarqueeSelectionRect(const WebCore::IntPoint& point1, cons
 #endif
 }
 
+#if PLATFORM(MAC)
+void UnifiedPDFPlugin::handlePDFActionForAnnotation(PDFAnnotation *annotation)
+{
+    if (!annotation)
+        return;
+    RetainPtr firstAction = [annotation action];
+    ASSERT(firstAction);
+    if (!firstAction)
+        return;
+
+    using PDFActionList = Vector<RetainPtr<PDFAction>>;
+    auto performPDFAction = [this](PDFAction *action) {
+        if (!action)
+            return;
+        if ([action isKindOfClass:getPDFActionResetFormClass()] && [m_pdfDocument respondsToSelector:@selector(resetFormFields:)])
+            [m_pdfDocument resetFormFields:static_cast<PDFActionResetForm *>(action)];
+    };
+
+    PDFActionList actionsForAnnotation;
+    actionsForAnnotation.append(firstAction);
+    while (!actionsForAnnotation.isEmpty()) {
+        RetainPtr currentAction = actionsForAnnotation.takeLast().get();
+        performPDFAction(currentAction.get());
+
+        if ([currentAction respondsToSelector:@selector(nextActions)]) {
+            RetainPtr reversedNextActions = [[currentAction nextActions] reverseObjectEnumerator];
+            while (RetainPtr nextAction = [reversedNextActions nextObject]) {
+                actionsForAnnotation.append(WTFMove(nextAction));
+                nextAction = [reversedNextActions nextObject];
+            }
+        }
+    }
+}
+#endif
+
 void AnnotationTrackingState::startAnnotationTracking(RetainPtr<PDFAnnotation>&& annotation, WebEventType mouseEventType, WebMouseEventButton mouseEventButton)
 {
     ASSERT(!m_trackedAnnotation);