1 files changed, 238 insertions, 0 deletions
diff --git a/modules/PageMenu.jsm b/modules/PageMenu.jsm
new file mode 100644
index 0000000..d01f626
--- /dev/null
+++ b/modules/PageMenu.jsm
@@ -0,0 +1,238 @@
+/* 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/. */
+
+this.EXPORTED_SYMBOLS = ["PageMenu"];
+
+this.PageMenu = function PageMenu() {
+}
+
+PageMenu.prototype = {
+  PAGEMENU_ATTR: "pagemenu",
+  GENERATEDITEMID_ATTR: "generateditemid",
+
+  _popup: null,
+  _builder: null,
+
+  // Given a target node, get the context menu for it or its ancestor.
+  getContextMenu: function(aTarget) {
+    let target = aTarget;
+    while (target) {
+      let contextMenu = target.contextMenu;
+      if (contextMenu) {
+        return contextMenu;
+      }
+      target = target.parentNode;
+    }
+
+    return null;
+  },
+
+  // Given a target node, generate a JSON object for any context menu
+  // associated with it, or null if there is no context menu.
+  maybeBuild: function(aTarget) {
+    let pageMenu = this.getContextMenu(aTarget);
+    if (!pageMenu) {
+      return null;
+    }
+
+    pageMenu.QueryInterface(Components.interfaces.nsIHTMLMenu);
+    pageMenu.sendShowEvent();
+    // the show event is not cancelable, so no need to check a result here
+
+    this._builder = pageMenu.createBuilder();
+    if (!this._builder) {
+      return null;
+    }
+
+    pageMenu.build(this._builder);
+
+    // This serializes then parses again, however this could be avoided in
+    // the single-process case with further improvement.
+    let menuString = this._builder.toJSONString();
+    if (!menuString) {
+      return null;
+    }
+
+    return JSON.parse(menuString);
+  },
+
+  // Given a JSON menu object and popup, add the context menu to the popup.
+  buildAndAttachMenuWithObject: function(aMenu, aBrowser, aPopup) {
+    if (!aMenu) {
+      return false;
+    }
+
+    let insertionPoint = this.getInsertionPoint(aPopup);
+    if (!insertionPoint) {
+      return false;
+    }
+
+    let fragment = aPopup.ownerDocument.createDocumentFragment();
+    this.buildXULMenu(aMenu, fragment);
+
+    let pos = insertionPoint.getAttribute(this.PAGEMENU_ATTR);
+    if (pos == "start") {
+      insertionPoint.insertBefore(fragment,
+                                  insertionPoint.firstChild);
+    } else if (pos.startsWith("#")) {
+      insertionPoint.insertBefore(fragment, insertionPoint.querySelector(pos));
+    } else {
+      insertionPoint.appendChild(fragment);
+    }
+
+    this._popup = aPopup;
+
+    this._popup.addEventListener("command", this);
+    this._popup.addEventListener("popuphidden", this);
+
+    return true;
+  },
+
+  // Construct the XUL menu structure for a given JSON object.
+  buildXULMenu: function(aNode, aElementForAppending) {
+    let document = aElementForAppending.ownerDocument;
+
+    let children = aNode.children;
+    for (let child of children) {
+      let menuitem;
+      switch (child.type) {
+        case "menuitem":
+          if (!child.id) {
+            continue; // Ignore children without ids
+          }
+
+          menuitem = document.createElement("menuitem");
+          if (child.checkbox) {
+            menuitem.setAttribute("type", "checkbox");
+            if (child.checked) {
+              menuitem.setAttribute("checked", "true");
+            }
+          }
+
+          if (child.label) {
+            menuitem.setAttribute("label", child.label);
+          }
+          if (child.icon) {
+            menuitem.setAttribute("image", child.icon);
+            menuitem.className = "menuitem-iconic";
+          }
+          if (child.disabled) {
+            menuitem.setAttribute("disabled", true);
+          }
+
+          break;
+
+        case "separator":
+          menuitem = document.createElement("menuseparator");
+          break;
+
+        case "menu":
+          menuitem = document.createElement("menu");
+          if (child.label) {
+            menuitem.setAttribute("label", child.label);
+          }
+
+          let menupopup = document.createElement("menupopup");
+          menuitem.appendChild(menupopup);
+
+          this.buildXULMenu(child, menupopup);
+          break;
+      }
+
+      menuitem.setAttribute(this.GENERATEDITEMID_ATTR, child.id ? child.id : 0);
+      aElementForAppending.appendChild(menuitem);
+    }
+  },
+
+  // Called when the generated menuitem is executed.
+  handleEvent: function(event) {
+    let type = event.type;
+    let target = event.target;
+    if (type == "command" && target.hasAttribute(this.GENERATEDITEMID_ATTR)) {
+      // If a builder is assigned, call click on it directly. Otherwise, this is
+      // likely a menu with data from another process, so send a message to the
+      // browser to execute the menuitem.
+      if (this._builder) {
+        this._builder.click(target.getAttribute(this.GENERATEDITEMID_ATTR));
+      }
+    } else if (type == "popuphidden" && this._popup == target) {
+      this.removeGeneratedContent(this._popup);
+
+      this._popup.removeEventListener("popuphidden", this);
+      this._popup.removeEventListener("command", this);
+
+      this._popup = null;
+      this._builder = null;
+    }
+  },
+
+  // Get the first child of the given element with the given tag name.
+  getImmediateChild: function(element, tag) {
+    let child = element.firstChild;
+    while (child) {
+      if (child.localName == tag) {
+        return child;
+      }
+      child = child.nextSibling;
+    }
+    return null;
+  },
+
+  // Return the location where the generated items should be inserted into the
+  // given popup. They should be inserted as the next sibling of the returned
+  // element.
+  getInsertionPoint: function(aPopup) {
+    if (aPopup.hasAttribute(this.PAGEMENU_ATTR))
+      return aPopup;
+
+    let element = aPopup.firstChild;
+    while (element) {
+      if (element.localName == "menu") {
+        let popup = this.getImmediateChild(element, "menupopup");
+        if (popup) {
+          let result = this.getInsertionPoint(popup);
+          if (result) {
+            return result;
+          }
+        }
+      }
+      element = element.nextSibling;
+    }
+
+    return null;
+  },
+
+  // Returns true if custom menu items were present.
+  maybeBuildAndAttachMenu: function(aTarget, aPopup) {
+    let menuObject = this.maybeBuild(aTarget);
+    if (!menuObject) {
+      return false;
+    }
+
+    return this.buildAndAttachMenuWithObject(menuObject, null, aPopup);
+  },
+
+  // Remove the generated content from the given popup.
+  removeGeneratedContent: function(aPopup) {
+    let ungenerated = [];
+    ungenerated.push(aPopup);
+
+    let count;
+    while (0 != (count = ungenerated.length)) {
+      let last = count - 1;
+      let element = ungenerated[last];
+      ungenerated.splice(last, 1);
+
+      let i = element.childNodes.length;
+      while (i-- > 0) {
+        let child = element.childNodes[i];
+        if (!child.hasAttribute(this.GENERATEDITEMID_ATTR)) {
+          ungenerated.push(child);
+          continue;
+        }
+        element.removeChild(child);
+      }
+    }
+  }
+}