1 files changed, 151 insertions, 0 deletions
diff --git a/components/newtab/drag.js b/components/newtab/drag.js
new file mode 100644
index 0000000..e3928eb
--- /dev/null
+++ b/components/newtab/drag.js
@@ -0,0 +1,151 @@
+#ifdef 0
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+#endif
+
+/**
+ * This singleton implements site dragging functionality.
+ */
+var gDrag = {
+  /**
+   * The site offset to the drag start point.
+   */
+  _offsetX: null,
+  _offsetY: null,
+
+  /**
+   * The site that is dragged.
+   */
+  _draggedSite: null,
+  get draggedSite() { return this._draggedSite; },
+
+  /**
+   * The cell width/height at the point the drag started.
+   */
+  _cellWidth: null,
+  _cellHeight: null,
+  get cellWidth() { return this._cellWidth; },
+  get cellHeight() { return this._cellHeight; },
+
+  /**
+   * Start a new drag operation.
+   * @param aSite The site that's being dragged.
+   * @param aEvent The 'dragstart' event.
+   */
+  start: function Drag_start(aSite, aEvent) {
+    this._draggedSite = aSite;
+
+    // Mark nodes as being dragged.
+    let selector = ".newtab-site, .newtab-control, .newtab-thumbnail";
+    let parentCell = aSite.node.parentNode;
+    let nodes = parentCell.querySelectorAll(selector);
+    for (let i = 0; i < nodes.length; i++)
+      nodes[i].setAttribute("dragged", "true");
+
+    parentCell.setAttribute("dragged", "true");
+
+    this._setDragData(aSite, aEvent);
+
+    // Store the cursor offset.
+    let node = aSite.node;
+    let rect = node.getBoundingClientRect();
+    this._offsetX = aEvent.clientX - rect.left;
+    this._offsetY = aEvent.clientY - rect.top;
+
+    // Store the cell dimensions.
+    let cellNode = aSite.cell.node;
+    this._cellWidth = cellNode.offsetWidth;
+    this._cellHeight = cellNode.offsetHeight;
+
+    gTransformation.freezeSitePosition(aSite);
+  },
+
+  /**
+   * Handles the 'drag' event.
+   * @param aSite The site that's being dragged.
+   * @param aEvent The 'drag' event.
+   */
+  drag: function Drag_drag(aSite, aEvent) {
+    // Get the viewport size.
+    let {clientWidth, clientHeight} = document.documentElement;
+
+    // We'll want a padding of 5px.
+    let border = 5;
+
+    // Enforce minimum constraints to keep the drag image inside the window.
+    let left = Math.max(scrollX + aEvent.clientX - this._offsetX, border);
+    let top = Math.max(scrollY + aEvent.clientY - this._offsetY, border);
+
+    // Enforce maximum constraints to keep the drag image inside the window.
+    left = Math.min(left, scrollX + clientWidth - this.cellWidth - border);
+    top = Math.min(top, scrollY + clientHeight - this.cellHeight - border);
+
+    // Update the drag image's position.
+    gTransformation.setSitePosition(aSite, {left: left, top: top});
+  },
+
+  /**
+   * Ends the current drag operation.
+   * @param aSite The site that's being dragged.
+   * @param aEvent The 'dragend' event.
+   */
+  end: function Drag_end(aSite, aEvent) {
+    let nodes = gGrid.node.querySelectorAll("[dragged]")
+    for (let i = 0; i < nodes.length; i++)
+      nodes[i].removeAttribute("dragged");
+
+    // Slide the dragged site back into its cell (may be the old or the new cell).
+    gTransformation.slideSiteTo(aSite, aSite.cell, {unfreeze: true});
+
+    this._draggedSite = null;
+  },
+
+  /**
+   * Checks whether we're responsible for a given drag event.
+   * @param aEvent The drag event to check.
+   * @return Whether we should handle this drag and drop operation.
+   */
+  isValid: function Drag_isValid(aEvent) {
+    let link = gDragDataHelper.getLinkFromDragEvent(aEvent);
+
+    // Check that the drag data is non-empty.
+    // Can happen when dragging places folders.
+    if (!link || !link.url) {
+      return false;
+    }
+
+    // Check that we're not accepting URLs which would inherit the caller's
+    // principal (such as javascript: or data:).
+    return gLinkChecker.checkLoadURI(link.url);
+  },
+
+  /**
+   * Initializes the drag data for the current drag operation.
+   * @param aSite The site that's being dragged.
+   * @param aEvent The 'dragstart' event.
+   */
+  _setDragData: function Drag_setDragData(aSite, aEvent) {
+    let {url, title} = aSite;
+
+    let dt = aEvent.dataTransfer;
+    dt.mozCursor = "default";
+    dt.effectAllowed = "move";
+    dt.setData("text/plain", url);
+    dt.setData("text/uri-list", url);
+    dt.setData("text/x-moz-url", url + "\n" + title);
+    dt.setData("text/html", "<a href=\"" + url + "\">" + url + "</a>");
+
+    // Create and use an empty drag element. We don't want to use the default
+    // drag image with its default opacity.
+    let dragElement = document.createElementNS(HTML_NAMESPACE, "div");
+    dragElement.classList.add("newtab-drag");
+    let scrollbox = document.getElementById("newtab-vertical-margin");
+    scrollbox.appendChild(dragElement);
+    dt.setDragImage(dragElement, 0, 0);
+
+    // After the 'dragstart' event has been processed we can remove the
+    // temporary drag element from the DOM.
+    setTimeout(() => scrollbox.removeChild(dragElement), 0);
+  }
+};