draganddrop.cc

属性sosuo算法

    rv = event->GetTarget(getter_AddRefs(target));
    if (NS_FAILED(rv)) return rv;
    if(target == nsnull) return NS_OK;
    nsCOMPtr<nsIDOMNode> node (do_QueryInterface(target, &rv));
    if (NS_FAILED(rv)) return rv;

    nsAutoString dragDestTypeString = NS_ConvertUTF8toUTF16(
            nsDependentCString("dragdesttype"));
    nsAutoString dragDestType;
    nsCOMPtr <nsIDOMElement> currentElement;
    PRBool supported;
    while(1) {
        rv = searchUpForElementWithAttribute(node, dragDestTypeString,
                getter_AddRefs(currentElement));
        if(NS_FAILED(rv)) return rv;
        if(currentElement == nsnull) return NS_OK;
        rv = currentElement->GetAttribute(dragDestTypeString, dragDestType);
        if(NS_FAILED(rv)) return rv;
        rv = isDragTypeSupported(dragDestType, &supported, &singleDragType);
        if(NS_FAILED(rv)) return rv;
        if(supported) {
            *element = currentElement;
            (*element)->AddRef();
            return NS_OK;
        } 
        nsCOMPtr<nsIDOMNode> parent;
        rv = node->GetParentNode(getter_AddRefs(parent));
        if(NS_FAILED(rv)) return rv;
        if(parent == nsnull) return NS_OK;
        node = parent;
    }
}

class DemocracyDNDHook : public nsIClipboardDragDropHooks, nsIDOMEventListener {
protected:
    GtkMozEmbed* embed;

public:   
    DemocracyDNDHook(GtkMozEmbed* embed) {
        this->embed = embed;
    }

    NS_DECL_ISUPPORTS 

    nsresult AllowDrop(nsIDOMEvent *event, nsIDragSession *session, 
                    PRBool* retval) {
        nsresult rv;
        *retval = false;

        rv = removeCurrentHighlight();
        if(NS_FAILED(rv)) return rv;
        
        nsCOMPtr<nsIDOMElement> element;
        nsString singleDragType;
        rv = findDropElement(event, getter_AddRefs(element), singleDragType);
        if(NS_FAILED(rv)) return rv;
        if(element) {
            nsAutoString dragEffectStr = NS_ConvertUTF8toUTF16(
                    nsDependentCString("drageffect"));
            dragEffectStr.Append(singleDragType);
            nsAutoString dragEffect;
            rv = element->GetAttribute(dragEffectStr, dragEffect);
            if(NS_FAILED(rv)) return rv;
            *retval = true;
            rv = session->SetDragAction(stringToDragAction(dragEffect));
            if(NS_FAILED(rv)) return rv;
            rv = setNewHighlight(element, singleDragType);
            if(NS_FAILED(rv)) return rv;
        } else {
            PRBool hasURLs;
            rv = checkForURLs(&hasURLs);
            if(NS_FAILED(rv)) return rv;
            if(hasURLs) {
                rv = session->SetDragAction(
                        nsIDragService::DRAGDROP_ACTION_COPY);
                if(NS_FAILED(rv)) return rv;
                *retval = true;
                return NS_OK;
            }
        }
        return NS_OK;
    }

    nsresult AllowStartDrag(nsIDOMEvent *event, PRBool* retval) {
        *retval = true;

        nsCOMPtr<nsIDOMElement> element;
        nsAutoString dragSourceTypeStr = NS_ConvertUTF8toUTF16(
                nsDependentCString("dragsourcetype"));
        nsresult rv = searchUpForElementWithAttribute(event, 
                dragSourceTypeStr, getter_AddRefs(element));
        if (NS_FAILED(rv)) return rv;
        if(element) {
            nsCOMPtr<nsISupportsArray> dragArray(do_CreateInstance(
                        "@mozilla.org/supports-array;1", &rv));
            if (NS_FAILED(rv)) return rv;
            makeDragData(element, dragArray);
            rv = startDrag(dragArray);
            if (NS_FAILED(rv)) {
                printf("WARNING: startDrag failed\n");
                return rv;
            } else {
                event->StopPropagation();
                event->PreventDefault();
                *retval = false;
            }
        } 
        return NS_OK;
    }

    nsresult OnCopyOrDrag(nsIDOMEvent *event, nsITransferable *trans, 
                    PRBool* retval) {
        /* This gets called when the default drop handler needs to copy
         * something.  Don't mess with things in this case.
         */
        *retval = true;
        return NS_OK;
    }

    nsresult OnPasteOrDrop(nsIDOMEvent *event, nsITransferable *trans, 
                    PRBool* retval) {
        if(event == nsnull) {
            // Event was a paste, let mozilla handle it.
            *retval = true;
            return NS_OK;
        }
        *retval = false;
        nsresult rv;
        rv = removeCurrentHighlight();
        if(NS_FAILED(rv)) return rv;
        nsCOMPtr<nsIDOMElement> element;
        nsString singleDragType;
        rv = findDropElement(event, getter_AddRefs(element), singleDragType);
        if(NS_FAILED(rv)) return rv;
        if(element) {
            nsAutoString dragDestDataString = NS_ConvertUTF8toUTF16(
                nsDependentCString("dragdestdata"));
            nsAutoString dragDestData;
            rv = element->GetAttribute(dragDestDataString, dragDestData);
            if(NS_FAILED(rv)) return rv;
            nsAutoString sourceData;
            rv = getDragSourceData(singleDragType, sourceData);
            if(NS_FAILED(rv)) return rv;
            *retval = true;
            nsCAutoString url = NS_ConvertUTF16toUTF8(dragDestData);
            url.Insert("action:handleDrop?data=", 0);
            url.Append("&type=");
            url.Append(NS_ConvertUTF16toUTF8(singleDragType));
            url.Append("&sourcedata=");
            url.Append(NS_ConvertUTF16toUTF8(sourceData));
            gtk_moz_embed_load_url(this->embed,
                    PromiseFlatCString(url).get());
            return rv;
        } else {
            PRBool hasURLs;
            rv = checkForURLs(&hasURLs);
            if(NS_FAILED(rv)) return rv;
            if(hasURLs) {
                nsCOMPtr<nsIDragService> dragService(do_GetService(
                            "@mozilla.org/widget/dragservice;1", &rv));
                if(NS_FAILED(rv)) return rv;
                nsCOMPtr<nsIDragSession> dragSession;
                rv = dragService->GetCurrentSession(getter_AddRefs(dragSession));
                if(NS_FAILED(rv)) return rv;
                PRUint32 urlCount;
                rv = dragSession->GetNumDropItems(&urlCount);
                if(NS_FAILED(rv)) return rv;

                nsAutoString data;
                nsCAutoString utf8Data, escapedData;
                if(NS_FAILED(rv)) return rv;
                nsCAutoString url("action:handleURIDrop?data=");
                for(int i = 0; i < urlCount; i++) {
                    rv = extractDragData(kURLMime, data, i);
                    if(NS_FAILED(rv)) return rv;
                    utf8Data = NS_ConvertUTF16toUTF8(data);
                    NS_EscapeURL(PromiseFlatCString(utf8Data).get(),
                            utf8Data.Length(), 
                            esc_Query | esc_Forced | esc_AlwaysCopy,
                            escapedData);
                    url.Append(escapedData);
                    url.Append("%0A"); // "\n" 
                }
                gtk_moz_embed_load_url(this->embed,
                        PromiseFlatCString(url).get());
            }
            return NS_OK;
        }
    }

    nsresult HandleEvent(nsIDOMEvent *event) {
        // This fires for dragexit events
        PRInt32 screenX, screenY;
        nsresult rv;
        nsCOMPtr<nsIDOMMouseEvent> mouseEvent(do_QueryInterface(event, &rv));
        if(NS_FAILED(rv)) return rv;
        rv = mouseEvent->GetScreenX(&screenX);
        if(NS_FAILED(rv)) return rv;
        rv = mouseEvent->GetScreenY(&screenY);
        if(NS_FAILED(rv)) return rv;
        if(screenX == 0 && screenY == 0) {
            rv = removeCurrentHighlight();
            if(NS_FAILED(rv)) return rv;
        }
        return NS_OK;
    }
};

NS_IMPL_ISUPPORTS2(DemocracyDNDHook, nsIClipboardDragDropHooks, nsIDOMEventListener)

nsresult setupDragAndDrop(GtkMozEmbed* gtkembed)
{
    nsresult rv;

    nsCOMPtr<nsIWebBrowser> browser;
    nsCOMPtr<nsIDOMWindow> domWindow;

    gtk_moz_embed_get_nsIWebBrowser(gtkembed, getter_AddRefs(browser));
    rv = browser->GetContentDOMWindow(getter_AddRefs(domWindow));
    if (NS_FAILED(rv)) return rv;

    nsCOMPtr<nsICommandManager> commandManager(do_GetService(
            "@mozilla.org/embedcomp/command-manager;1", &rv));

    if (NS_FAILED(rv)) return rv;

    nsIClipboardDragDropHooks *rawPtr = new DemocracyDNDHook(gtkembed);
    if (!rawPtr)
        return NS_ERROR_OUT_OF_MEMORY;
    nsCOMPtr<nsIClipboardDragDropHooks> democracyDNDHook(do_QueryInterface(
                rawPtr, &rv));
    if (NS_FAILED(rv)) return rv;
    nsCOMPtr<nsICommandParams> params(do_CreateInstance(
        "@mozilla.org/embedcomp/command-params;1", &rv));
    if (NS_FAILED(rv)) return rv;
    rv = params->SetISupportsValue("addhook", democracyDNDHook);
    if (NS_FAILED(rv)) return rv;
    rv = commandManager->DoCommand("cmd_clipboardDragDropHook", params,
            domWindow);
    nsCOMPtr<nsIDOMEventTarget> eventTarget(
            do_QueryInterface(domWindow, &rv));
    if(NS_FAILED(rv)) return rv;
    nsCOMPtr<nsIDOMEventListener> dndEventListener(
            do_QueryInterface(democracyDNDHook, &rv));
    if(NS_FAILED(rv)) return rv;
    nsAutoString type = NS_ConvertUTF8toUTF16(
            nsDependentCString("dragexit"));
    rv = eventTarget->AddEventListener(type, dndEventListener, true);
    if(NS_FAILED(rv)) return rv;
    return rv;
}