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 in_module(null);
  15
  16 define_variable("block_content_focus_change_duration", 20,
  17     "Duration (in milliseconds) during which an element is "+
  18     "allowed to gain focus following a mouse click or key press, "+
  19     "if `block_content_focus_change_mode' is enabled.");;
  20
  21 function block_content_focus_change_track_input () {
  22     var browser = this;
  23     browser.block_content_focus_change_timestamp = Date.now();
  24 }
  25
  26 function block_content_focus_change_reset (buffer) {
  27     buffer.browser.block_content_focus_change_timestamp = null;
  28 }
  29
  30 function block_content_focus_change_test (buffer, event) {
  31     return !(event.target instanceof Ci.nsIDOMHTMLAnchorElement) &&
  32         (buffer.browser.block_content_focus_change_timestamp == null ||
  33          (Date.now() - buffer.browser.block_content_focus_change_timestamp)
  34          > block_content_focus_change_duration);
  35 }
  36
  37 function block_content_focus_change_buffer_setup (buffer) {
  38     if (! (buffer instanceof content_buffer) || buffer.dead)
  39         return;
  40     block_content_focus_change_reset(buffer);
  41     buffer.focusblocker = block_content_focus_change_test;
  42     buffer.browser.addEventListener("mousedown",
  43                                     block_content_focus_change_track_input,
  44                                     true);
  45     buffer.browser.addEventListener("keypress",
  46                                     block_content_focus_change_track_input,
  47                                     true);
  48 }
  49
  50 function block_content_focus_change_buffer_teardown (buffer) {
  51     if (! (buffer instanceof content_buffer) || buffer.dead)
  52         return;
  53     delete buffer.browser.block_content_focus_change_timestamp;
  54     buffer.focusblocker = null;
  55     buffer.browser.removeEventListener("mousedown",
  56                                        block_content_focus_change_track_input,
  57                                        true);
  58     buffer.browser.removeEventListener("keypress",
  59                                        block_content_focus_change_track_input,
  60                                        true);
  61 }
  62
  63 let (foo = browser_set_element_focus) {
  64     define_global_mode("block_content_focus_change_mode",
  65         function () { // enable
  66             for_each_buffer(function (buffer) {
  67                 block_content_focus_change_buffer_setup(buffer);
  68             });
  69             add_hook("create_buffer_hook",
  70                      block_content_focus_change_buffer_setup);
  71             add_hook("content_buffer_started_loading_hook",
  72                      block_content_focus_change_reset);
  73             add_hook("content_buffer_location_change_hook",
  74                      block_content_focus_change_reset);
  75             // this is a really sick hack, but still preferable to
  76             // considered alternatives.
  77             conkeror.browser_set_element_focus =
  78                 function (buffer, elem, prevent_scroll) {
  79                     buffer.browser.block_content_focus_change_timestamp = Date.now();
  80                     foo.call(this, buffer, elem, prevent_scroll);
  81                 };
  82         },
  83         function () { // disable
  84             for_each_buffer(function (buffer) {
  85                 block_content_focus_change_buffer_teardown(buffer);
  86             });
  87             remove_hook("create_buffer_hook",
  88                         block_content_focus_change_buffer_setup);
  89             remove_hook("content_buffer_started_loading_hook",
  90                         block_content_focus_change_reset);
  91             remove_hook("content_buffer_location_change_hook",
  92                         block_content_focus_change_reset);
  93             conkeror.browser_set_element_focus = foo;
  94         });
  95 }
  96
  97 block_content_focus_change_mode(true);
  98
  99 provide("block-content-focus-change");