modules/block-content-focus-change.js

   1 /**
   2  * (C) Copyright 2007-2008 Jeremy Maitin-Shepard
   3  * (C) Copyright 2008-2009 John J. Foerch
   4  *
   5  * Use, modification, and distribution are subject to the terms specified in the
   6  * COPYING file.
   7 **/
   8
   9 /**
  10  * block-content-focus-change-mode tries very hard to prevent
  11  * rude websites from changing the element focus via javascript.
  12  */
  13
  14 define_variable("block_content_focus_change_duration", 20,
  15     "Duration (in milliseconds) during which an element is "+
  16     "allowed to gain focus following a mouse click or key press, "+
  17     "if `block_content_focus_change_mode' is enabled.");;
  18
  19 function block_content_focus_change_track_input () {
  20     var browser = this;
  21     browser.block_content_focus_change_timestamp = Date.now();
  22 }
  23
  24 function block_content_focus_change_reset (buffer) {
  25     buffer.browser.block_content_focus_change_timestamp = null;
  26 }
  27
  28 function block_content_focus_change_test (buffer, event) {
  29     return !(event.target instanceof Ci.nsIDOMHTMLAnchorElement) &&
  30         (buffer.browser.block_content_focus_change_timestamp == null ||
  31          (Date.now() - buffer.browser.block_content_focus_change_timestamp)
  32          > block_content_focus_change_duration);
  33 }
  34
  35 function block_content_focus_change_buffer_setup (buffer) {
  36     if (! (buffer instanceof content_buffer) || buffer.dead)
  37         return;
  38     block_content_focus_change_reset(buffer);
  39     buffer.focusblocker = block_content_focus_change_test;
  40     buffer.browser.addEventListener("mousedown",
  41                                     block_content_focus_change_track_input,
  42                                     true);
  43     buffer.browser.addEventListener("keypress",
  44                                     block_content_focus_change_track_input,
  45                                     true);
  46 }
  47
  48 function block_content_focus_change_buffer_teardown (buffer) {
  49     if (! (buffer instanceof content_buffer) || buffer.dead)
  50         return;
  51     delete buffer.browser.block_content_focus_change_timestamp;
  52     buffer.focusblocker = null;
  53     buffer.browser.removeEventListener("mousedown",
  54                                        block_content_focus_change_track_input,
  55                                        true);
  56     buffer.browser.removeEventListener("keypress",
  57                                        block_content_focus_change_track_input,
  58                                        true);
  59 }
  60
  61 let (foo = browser_set_element_focus) {
  62     define_global_mode("block_content_focus_change_mode",
  63         function () { // enable
  64             for_each_buffer(function (buffer) {
  65                 block_content_focus_change_buffer_setup(buffer);
  66             });
  67             add_hook("create_buffer_hook",
  68                      block_content_focus_change_buffer_setup);
  69             add_hook("content_buffer_started_loading_hook",
  70                      block_content_focus_change_reset);
  71             add_hook("content_buffer_location_change_hook",
  72                      block_content_focus_change_reset);
  73             // this is a really sick hack, but still preferable to
  74             // considered alternatives.
  75             conkeror.browser_set_element_focus =
  76                 function (buffer, elem, prevent_scroll) {
  77                     buffer.browser.block_content_focus_change_timestamp = Date.now();
  78                     foo.call(this, buffer, elem, prevent_scroll);
  79                 };
  80         },
  81         function () { // disable
  82             for_each_buffer(function (buffer) {
  83                 block_content_focus_change_buffer_teardown(buffer);
  84             });
  85             remove_hook("create_buffer_hook",
  86                         block_content_focus_change_buffer_setup);
  87             remove_hook("content_buffer_started_loading_hook",
  88                         block_content_focus_change_reset);
  89             remove_hook("content_buffer_location_change_hook",
  90                         block_content_focus_change_reset);
  91             conkeror.browser_set_element_focus = foo;
  92         });
  93 }
  94
  95 block_content_focus_change_mode(true);
  96
  97 provide("block-content-focus-change");