import { SelectionMode } from "./selection-mode";
export declare const CLIPBOARD_NS = "http://mangalamresearch.org/ns/wed/clipboard";
/**
 * An internal clipboard for wed editors.
 *
 * Due to the limitations of the clipboard API, wed maintains an internal
 * clipboard which allows it to transfer data in a way meaningful to wed.
 */
export declare class Clipboard {
    private readonly tree;
    private readonly top;
    private _mode;
    /**
     * The clipboard switches selection mode on the basis of how data is added to
     * it, and the mode remains in effect until data is added in a way that
     * changes the mode.
     *
     * Note that this property is **independent** of what the GUI is showing to
     * the user. The property "remembers", so to speak, how the clipboard has been
     * used.
     */
    readonly mode: SelectionMode;
    /**
     * Sets the selection mode of this clipboard.
     *
     * @param vale The new mode.
     */
    private setMode(value);
    /**
     * Clear the clipboard.
     *
     * Note that this clears only the contents of this object. **IT DOES NOT
     * AFFECT THE BROWSER'S CLIPBOARD!**
     */
    clear(): void;
    /**
     * Puts a span of nodes into the clipboard. This method switches the clipboard
     * to the span mode.
     *
     * Note that the clipboard is cleared before adding the nodes.
     *
     * @param nodes The nodes to put. These nodes become property of the clipboard
     * after being added. If you want to keep the nodes in another document, clone
     * them first.
     */
    putSpan(span: Node[] | string): void;
    /**
     * Check whether a node can be added to this clipboard's data. Clipboards
     * cannot contain heterogenous data. An attribute can be added only if the
     * clipboard is empty or contains attributes. Another type of node can be
     * added only if the clipboard does not contain attributes.
     *
     * @param node The node to check.
     *
     * @returns Whether the node can be added to this clipboard's data.
     */
    canAddUnit(node: Node): boolean;
    /**
     * Puts a DOM node in the clipboard. This method switches the clipboard to
     * unit mode.
     *
     * Note that the clipboard is cleared before adding the node.
     *
     * @param node The node to put. This node becomes property of the clipboard
     * after being added. If you want to keep it in another document, clone it
     * first.
     *
     * @param add Add to the clipboard, rather than replace the contents.
     */
    putUnit(node: Node, add: boolean): void;
    /**
     * Determines whether, in a paste operation, the tree that is stored in this
     * clipboard, serialized, is equal to some text.
     *
     * This can be used as an optimization to avoid parsing anew ``text`` if the
     * tree in the clipboard is already a parsed representation of that text.
     *
     * @param text The text to test against.
     */
    isSerializedTree(text: string): boolean;
    /**
     * @returns A deep copy of the tree in this clipboard.
     */
    cloneTree(): Element;
    /**
     * Set the DOM clipboard data to reflect what is stored in this wed-internal
     * clipboard. Note that any old data in the DOM clipboard data is cleared
     * before setting the new data.
     *
     * @param clipboardData The object to set.
     */
    setupDOMClipboardData(clipboardData: DataTransfer): void;
}
/**
 * Check whether the element has a single child element which is a collection of
 * attributes.
 *
 * @param el The element to check.
 *
 * @returns Whether the element contains an attribute collection.
 */
export declare function containsClipboardAttributeCollection(el: Element): boolean;