modules/follow-relationship.js

   1 /**
   2  * (C) Copyright 2007-2008 Jeremy Maitin-Shepard
   3  * (C) Copyright 2012 John Foerch
   4  *
   5  * Portions of this file were derived from Vimperator,
   6  * (C) Copyright 2007 Doug Kearns
   7  * (C) Copyright 2007-2008 Martin Stubenschrott.
   8  *
   9  * Use, modification, and distribution are subject to the terms specified in the
  10  * COPYING file.
  11 **/
  12
  13 require("element.js");
  14
  15 const RELATIONSHIP_NEXT = 0;
  16 const RELATIONSHIP_PREVIOUS = 1;
  17
  18 var browser_relationship_rel_regexp = ["next", "prev|previous"];
  19 var browser_relationship_rev_regexp = ["prev|previous", "next"];
  20
  21 define_variable("browser_relationship_patterns", {},
  22     "Patterns used by `follow-next' and `follow-previous'. "+
  23     "User value may be overridden for specific websites by "+
  24     "page-modes.");
  25
  26 browser_relationship_patterns[RELATIONSHIP_NEXT] =
  27     [/^next$/i,
  28      new RegExp("^>$","i"),
  29      new RegExp("^(>>|»)$","i"),
  30      new RegExp("^(>|»)","i"),
  31      new RegExp("(>|»)$","i"),
  32      new RegExp("\\bnext","i")
  33     ];
  34
  35 browser_relationship_patterns[RELATIONSHIP_PREVIOUS] =
  36     [/^(prev|previous)$/i,
  37      new RegExp("^<$","i"),
  38      new RegExp("^(<<|«)$","i"),
  39      new RegExp("^(<|«)","i"),
  40      new RegExp("(<|«)$","i"),
  41      new RegExp("\\bprev|previous\\b","i")
  42     ];
  43
  44 function document_get_element_by_relationship (doc, patterns, relationship) {
  45     patterns = patterns[relationship];
  46     var rel_name = new RegExp(browser_relationship_rel_regexp[relationship], "i");
  47     var rev_name = new RegExp(browser_relationship_rev_regexp[relationship], "i");
  48
  49     var elems = doc.getElementsByTagName("link");
  50     // links have higher priority than anchors
  51     for (var i = 0, n = elems.length; i < n; i++) {
  52         if (rel_name.test(elems[i].rel) || rev_name.test(elems[i].rev))
  53             return elems[i];
  54     }
  55
  56     // no links? look for anchors
  57     elems = doc.getElementsByTagName("a");
  58     for (i = 0, n = elems.length; i < n; i++) {
  59         if (rel_name.test(elems[i].rel) || rev_name.test(elems[i].rev))
  60             return elems[i];
  61     }
  62
  63     for (var j = 0, p = patterns.length; j < p; ++j) {
  64         var pattern = patterns[j];
  65         if (pattern instanceof Function) {
  66             var elem = pattern(doc);
  67             if (elem)
  68                 return elem;
  69         } else {
  70             for (i = 0, n = elems.length; i < n; i++) { // loop through list of anchors again
  71                 if (pattern.test(elems[i].textContent))
  72                     return elems[i];
  73                 // images with alt text being href
  74                 var children = elems[i].childNodes;
  75                 for (var k = 0, c = children.length; k < c; k++) {
  76                     if (children[k].alt && pattern.test(children[k].alt))
  77                         return elems[i];
  78                 }
  79             }
  80         }
  81     }
  82     return null;
  83 }
  84
  85 define_browser_object_class("relationship-next", null,
  86     function (I, prompt) {
  87         var doc = I.buffer.document;
  88         for (let frame in frame_iterator(I.buffer.top_frame, I.buffer.focused_frame)) {
  89             let elem = document_get_element_by_relationship(
  90                 frame.document,
  91                 I.local.browser_relationship_patterns,
  92                 RELATIONSHIP_NEXT);
  93             if (elem)
  94                 yield co_return(elem);
  95         }
  96         throw interactive_error("No \"next\" link found.");
  97     });
  98
  99 define_browser_object_class("relationship-previous", null,
 100     function (I, prompt) {
 101         var doc = I.buffer.document;
 102         for (let frame in frame_iterator(I.buffer.top_frame, I.buffer.focused_frame)) {
 103             let elem = document_get_element_by_relationship(
 104                 frame.document,
 105                 I.local.browser_relationship_patterns,
 106                 RELATIONSHIP_PREVIOUS);
 107             if (elem)
 108                 yield co_return(elem);
 109         }
 110         throw interactive_error("No \"previous\" link found.");
 111     });
 112
 113 provide("follow-relationship");