gecko-dev/browser/actors/ClickHandlerChild.jsm

/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* 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/. */

var EXPORTED_SYMBOLS = ["ClickHandlerChild"];

const { ActorChild } = ChromeUtils.import(
  "resource://gre/modules/ActorChild.jsm"
);
const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");

ChromeUtils.defineModuleGetter(
  this,
  "BrowserUtils",
  "resource://gre/modules/BrowserUtils.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "PrivateBrowsingUtils",
  "resource://gre/modules/PrivateBrowsingUtils.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "WebNavigationFrames",
  "resource://gre/modules/WebNavigationFrames.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "E10SUtils",
  "resource://gre/modules/E10SUtils.jsm"
);

class ClickHandlerChild extends ActorChild {
  handleEvent(event) {
    if (
      !event.isTrusted ||
      event.defaultPrevented ||
      event.button == 2 ||
      (event.type == "click" && event.button == 1)
    ) {
      return;
    }
    // Don't do anything on editable things, we shouldn't open links in
    // contenteditables, and editor needs to possibly handle middlemouse paste
    let composedTarget = event.composedTarget;
    if (
      composedTarget.isContentEditable ||
      (composedTarget.ownerDocument &&
        composedTarget.ownerDocument.designMode == "on") ||
      ChromeUtils.getClassName(composedTarget) == "HTMLInputElement" ||
      ChromeUtils.getClassName(composedTarget) == "HTMLTextAreaElement"
    ) {
      return;
    }

    let originalTarget = event.originalTarget;
    let ownerDoc = originalTarget.ownerDocument;
    if (!ownerDoc) {
      return;
    }

    // Handle click events from about pages
    if (event.button == 0) {
      if (ownerDoc.documentURI.startsWith("about:blocked")) {
        return;
      }
    }

    let [href, node, principal] = this._hrefAndLinkNodeForClickEvent(event);

    let csp = ownerDoc.csp;
    if (csp) {
      csp = E10SUtils.serializeCSP(csp);
    }

    let referrerInfo = Cc["@mozilla.org/referrer-info;1"].createInstance(
      Ci.nsIReferrerInfo
    );
    if (node) {
      referrerInfo.initWithNode(node);
    } else {
      referrerInfo.initWithDocument(ownerDoc);
    }
    referrerInfo = E10SUtils.serializeReferrerInfo(referrerInfo);
    let frameOuterWindowID = WebNavigationFrames.getFrameId(
      ownerDoc.defaultView
    );

    let json = {
      button: event.button,
      shiftKey: event.shiftKey,
      ctrlKey: event.ctrlKey,
      metaKey: event.metaKey,
      altKey: event.altKey,
      href: null,
      title: null,
      frameOuterWindowID,
      triggeringPrincipal: principal,
      csp,
      referrerInfo,
      originAttributes: principal ? principal.originAttributes : {},
      isContentWindowPrivate: PrivateBrowsingUtils.isContentWindowPrivate(
        ownerDoc.defaultView
      ),
    };

    if (href) {
      try {
        BrowserUtils.urlSecurityCheck(href, principal);
      } catch (e) {
        return;
      }

      json.href = href;
      if (node) {
        json.title = node.getAttribute("title");
      }

      // Check if the link needs to be opened with mixed content allowed.
      // Only when the owner doc has |mixedContentChannel| and the same origin
      // should we allow mixed content.
      json.allowMixedContent = false;
      let docshell = ownerDoc.defaultView.docShell;
      if (this.mm.docShell.mixedContentChannel) {
        const sm = Services.scriptSecurityManager;
        try {
          let targetURI = Services.io.newURI(href);
          let isPrivateWin =
            ownerDoc.nodePrincipal.originAttributes.privateBrowsingId > 0;
          sm.checkSameOriginURI(
            docshell.mixedContentChannel.URI,
            targetURI,
            false,
            isPrivateWin
          );
          json.allowMixedContent = true;
        } catch (e) {}
      }
      json.originPrincipal = ownerDoc.nodePrincipal;
      json.originStoragePrincipal = ownerDoc.effectiveStoragePrincipal;
      json.triggeringPrincipal = ownerDoc.nodePrincipal;

      // If a link element is clicked with middle button, user wants to open
      // the link somewhere rather than pasting clipboard content.  Therefore,
      // when it's clicked with middle button, we should prevent multiple
      // actions here to avoid leaking clipboard content unexpectedly.
      // Note that whether the link will work actually or not does not matter
      // because in this case, user does not intent to paste clipboard content.
      if (event.button === 1) {
        event.preventMultipleActions();
      }

      this.mm.sendAsyncMessage("Content:Click", json);
      return;
    }

    // This might be middle mouse navigation.
    if (event.button == 1) {
      this.mm.sendAsyncMessage("Content:Click", json);
    }
  }

  /**
   * Extracts linkNode and href for the current click target.
   *
   * @param event
   *        The click event.
   * @return [href, linkNode, linkPrincipal].
   *
   * @note linkNode will be null if the click wasn't on an anchor
   *       element. This includes SVG links, because callers expect |node|
   *       to behave like an <a> element, which SVG links (XLink) don't.
   */
  _hrefAndLinkNodeForClickEvent(event) {
    let { content } = this.mm;
    function isHTMLLink(aNode) {
      // Be consistent with what nsContextMenu.js does.
      return (
        (aNode instanceof content.HTMLAnchorElement && aNode.href) ||
        (aNode instanceof content.HTMLAreaElement && aNode.href) ||
        aNode instanceof content.HTMLLinkElement
      );
    }

    let node = event.composedTarget;
    while (node && !isHTMLLink(node)) {
      node = node.flattenedTreeParentNode;
    }

    if (node) {
      return [node.href, node, node.ownerDocument.nodePrincipal];
    }

    // If there is no linkNode, try simple XLink.
    let href, baseURI;
    node = event.composedTarget;
    while (node && !href) {
      if (
        node.nodeType == content.Node.ELEMENT_NODE &&
        (node.localName == "a" ||
          node.namespaceURI == "http://www.w3.org/1998/Math/MathML")
      ) {
        href =
          node.getAttribute("href") ||
          node.getAttributeNS("http://www.w3.org/1999/xlink", "href");
        if (href) {
          baseURI = node.ownerDocument.baseURIObject;
          break;
        }
      }
      node = node.flattenedTreeParentNode;
    }

    // In case of XLink, we don't return the node we got href from since
    // callers expect <a>-like elements.
    // Note: makeURI() will throw if aUri is not a valid URI.
    return [
      href ? Services.io.newURI(href, null, baseURI).spec : null,
      null,
      node && node.ownerDocument.nodePrincipal,
    ];
  }
}