modules/follow-relationship.js

   1 /**
   2  * (C) Copyright 2007-2008 Jeremy Maitin-Shepard
   3  *
   4  * Portions of this file were derived from Vimperator,
   5  * (C) Copyright 2007 Doug Kearns
   6  * (C) Copyright 2007-2008 Martin Stubenschrott.
   7  *
   8  * Use, modification, and distribution are subject to the terms specified in the
   9  * COPYING file.
  10 **/
  11
  12 require("element.js");
  13
  14 const RELATIONSHIP_NEXT = 0;
  15 const RELATIONSHIP_PREVIOUS = 1;
  16
  17 var browser_relationship_rel_regexp = ["next", "prev|previous"];
  18 var browser_relationship_rev_regexp = ["prev|previous", "next"];
  19
  20 define_variable("browser_relationship_patterns", {},
  21     "Patterns used by `follow-next' and `follow-previous'. "+
  22     "User value may be overridden for specific websites by "+
  23     "page-modes.");
  24
  25 browser_relationship_patterns[RELATIONSHIP_NEXT] =
  26     [/^next$/i,
  27      new RegExp("^>$","i"),
  28      new RegExp("^(>>|»)$","i"),
  29      new RegExp("^(>|»)","i"),
  30      new RegExp("(>|»)$","i"),
  31      new RegExp("\\bnext","i")
  32     ];
  33
  34 browser_relationship_patterns[RELATIONSHIP_PREVIOUS] =
  35     [/^(prev|previous)$/i,
  36      new RegExp("^<$","i"),
  37      new RegExp("^(<<|«)$","i"),
  38      new RegExp("^(<|«)","i"),
  39      new RegExp("(<|«)$","i"),
  40      new RegExp("\\bprev|previous\\b","i")
  41     ];
  42
  43 function document_get_element_by_relationship (doc, patterns, relationship) {
  44     patterns = patterns[relationship];
  45     var rel_name = new RegExp(browser_relationship_rel_regexp[relationship], "i");
  46     var rev_name = new RegExp(browser_relationship_rev_regexp[relationship], "i");
  47
  48     var elems = doc.getElementsByTagName("link");
  49     // links have higher priority than anchors
  50     for (var i = 0, n = elems.length; i < n; i++) {
  51         if (rel_name.test(elems[i].rel) || rev_name.test(elems[i].rev))
  52             return elems[i];
  53     }
  54
  55     // no links? look for anchors
  56     elems = doc.getElementsByTagName("a");
  57     for (i = 0, n = elems.length; i < n; i++) {
  58         if (rel_name.test(elems[i].rel) || rev_name.test(elems[i].rev))
  59             return elems[i];
  60     }
  61
  62     for (var j = 0, p = patterns.length; j < p; ++j) {
  63         var pattern = patterns[j];
  64         if (pattern instanceof Function) {
  65             var elem = pattern(doc);
  66             if (elem)
  67                 return elem;
  68         } else {
  69             for (i = 0, n = elems.length; i < n; i++) { // loop through list of anchors again
  70                 if (pattern.test(elems[i].textContent))
  71                     return elems[i];
  72                 // images with alt text being href
  73                 var children = elems[i].childNodes;
  74                 for (var k = 0, c = children.length; k < c; k++) {
  75                     if (children[k].alt && pattern.test(children[k].alt))
  76                         return elems[i];
  77                 }
  78             }
  79         }
  80     }
  81     return null;
  82 }
  83
  84 define_browser_object_class("relationship-next", null,
  85     function (I, prompt) {
  86         var doc = I.buffer.document;
  87         for (let frame in frame_iterator(I.buffer.top_frame, I.buffer.focused_frame)) {
  88             let elem = document_get_element_by_relationship(
  89                 frame.document,
  90                 I.local.browser_relationship_patterns,
  91                 RELATIONSHIP_NEXT);
  92             if (elem)
  93                 yield co_return(elem);
  94         }
  95         throw interactive_error("No \"next\" link found.");
  96     });
  97
  98 define_browser_object_class("relationship-previous", null,
  99     function (I, prompt) {
 100         var doc = I.buffer.document;
 101         for (let frame in frame_iterator(I.buffer.top_frame, I.buffer.focused_frame)) {
 102             let elem = document_get_element_by_relationship(
 103                 frame.document,
 104                 I.local.browser_relationship_patterns,
 105                 RELATIONSHIP_PREVIOUS);
 106             if (elem)
 107                 yield co_return(elem);
 108         }
 109         throw interactive_error("No \"previous\" link found.");
 110     });
 111
 112 provide("follow-relationship");