[Summary view] [Print] [Text view]

   1  /**

   2   * @license Selection save and restore module for Rangy.

   3   * Saves and restores user selections using marker invisible elements in the DOM.

   4   *

   5   * Part of Rangy, a cross-browser JavaScript range and selection library

   6   * http://code.google.com/p/rangy/

   7   *

   8   * Depends on Rangy core.

   9   *

  10   * Copyright 2012, Tim Down

  11   * Licensed under the MIT license.

  12   * Version: 1.2.3

  13   * Build date: 26 February 2012

  14   */
  15  rangy.createModule("SaveRestore", function(api, module) {
  16      api.requireModules( ["DomUtil", "DomRange", "WrappedRange"] );
  17  
  18      var dom = api.dom;
  19  
  20      var markerTextChar = "\ufeff";
  21  
  22      function gEBI(id, doc) {
  23          return (doc || document).getElementById(id);
  24      }
  25  
  26      function insertRangeBoundaryMarker(range, atStart) {
  27          var markerId = "selectionBoundary_" + (+new Date()) + "_" + ("" + Math.random()).slice(2);
  28          var markerEl;
  29          var doc = dom.getDocument(range.startContainer);
  30  
  31          // Clone the Range and collapse to the appropriate boundary point

  32          var boundaryRange = range.cloneRange();
  33          boundaryRange.collapse(atStart);
  34  
  35          // Create the marker element containing a single invisible character using DOM methods and insert it

  36          markerEl = doc.createElement("span");
  37          markerEl.id = markerId;
  38          markerEl.style.lineHeight = "0";
  39          markerEl.style.display = "none";
  40          markerEl.className = "rangySelectionBoundary";
  41          markerEl.appendChild(doc.createTextNode(markerTextChar));
  42  
  43          boundaryRange.insertNode(markerEl);
  44          boundaryRange.detach();
  45          return markerEl;
  46      }
  47  
  48      function setRangeBoundary(doc, range, markerId, atStart) {
  49          var markerEl = gEBI(markerId, doc);
  50          if (markerEl) {
  51              range[atStart ? "setStartBefore" : "setEndBefore"](markerEl);
  52              markerEl.parentNode.removeChild(markerEl);
  53          } else {
  54              module.warn("Marker element has been removed. Cannot restore selection.");
  55          }
  56      }
  57  
  58      function compareRanges(r1, r2) {
  59          return r2.compareBoundaryPoints(r1.START_TO_START, r1);
  60      }
  61  
  62      function saveSelection(win) {
  63          win = win || window;
  64          var doc = win.document;
  65          if (!api.isSelectionValid(win)) {
  66              module.warn("Cannot save selection. This usually happens when the selection is collapsed and the selection document has lost focus.");
  67              return;
  68          }
  69          var sel = api.getSelection(win);
  70          var ranges = sel.getAllRanges();
  71          var rangeInfos = [], startEl, endEl, range;
  72  
  73          // Order the ranges by position within the DOM, latest first

  74          ranges.sort(compareRanges);
  75  
  76          for (var i = 0, len = ranges.length; i < len; ++i) {
  77              range = ranges[i];
  78              if (range.collapsed) {
  79                  endEl = insertRangeBoundaryMarker(range, false);
  80                  rangeInfos.push({
  81                      markerId: endEl.id,
  82                      collapsed: true
  83                  });
  84              } else {
  85                  endEl = insertRangeBoundaryMarker(range, false);
  86                  startEl = insertRangeBoundaryMarker(range, true);
  87  
  88                  rangeInfos[i] = {
  89                      startMarkerId: startEl.id,
  90                      endMarkerId: endEl.id,
  91                      collapsed: false,
  92                      backwards: ranges.length == 1 && sel.isBackwards()
  93                  };
  94              }
  95          }
  96  
  97          // Now that all the markers are in place and DOM manipulation over, adjust each range's boundaries to lie

  98          // between its markers

  99          for (i = len - 1; i >= 0; --i) {
 100              range = ranges[i];
 101              if (range.collapsed) {
 102                  range.collapseBefore(gEBI(rangeInfos[i].markerId, doc));
 103              } else {
 104                  range.setEndBefore(gEBI(rangeInfos[i].endMarkerId, doc));
 105                  range.setStartAfter(gEBI(rangeInfos[i].startMarkerId, doc));
 106              }
 107          }
 108  
 109          // Ensure current selection is unaffected

 110          sel.setRanges(ranges);
 111          return {
 112              win: win,
 113              doc: doc,
 114              rangeInfos: rangeInfos,
 115              restored: false
 116          };
 117      }
 118  
 119      function restoreSelection(savedSelection, preserveDirection) {
 120          if (!savedSelection.restored) {
 121              var rangeInfos = savedSelection.rangeInfos;
 122              var sel = api.getSelection(savedSelection.win);
 123              var ranges = [];
 124  
 125              // Ranges are in reverse order of appearance in the DOM. We want to restore earliest first to avoid

 126              // normalization affecting previously restored ranges.

 127              for (var len = rangeInfos.length, i = len - 1, rangeInfo, range; i >= 0; --i) {
 128                  rangeInfo = rangeInfos[i];
 129                  range = api.createRange(savedSelection.doc);
 130                  if (rangeInfo.collapsed) {
 131                      var markerEl = gEBI(rangeInfo.markerId, savedSelection.doc);
 132                      if (markerEl) {
 133                          markerEl.style.display = "inline";
 134                          var previousNode = markerEl.previousSibling;
 135  
 136                          // Workaround for issue 17

 137                          if (previousNode && previousNode.nodeType == 3) {
 138                              markerEl.parentNode.removeChild(markerEl);
 139                              range.collapseToPoint(previousNode, previousNode.length);
 140                          } else {
 141                              range.collapseBefore(markerEl);
 142                              markerEl.parentNode.removeChild(markerEl);
 143                          }
 144                      } else {
 145                          module.warn("Marker element has been removed. Cannot restore selection.");
 146                      }
 147                  } else {
 148                      setRangeBoundary(savedSelection.doc, range, rangeInfo.startMarkerId, true);
 149                      setRangeBoundary(savedSelection.doc, range, rangeInfo.endMarkerId, false);
 150                  }
 151  
 152                  // Normalizing range boundaries is only viable if the selection contains only one range. For example,

 153                  // if the selection contained two ranges that were both contained within the same single text node,

 154                  // both would alter the same text node when restoring and break the other range.

 155                  if (len == 1) {
 156                      range.normalizeBoundaries();
 157                  }
 158                  ranges[i] = range;
 159              }
 160              if (len == 1 && preserveDirection && api.features.selectionHasExtend && rangeInfos[0].backwards) {
 161                  sel.removeAllRanges();
 162                  sel.addRange(ranges[0], true);
 163              } else {
 164                  sel.setRanges(ranges);
 165              }
 166  
 167              savedSelection.restored = true;
 168          }
 169      }
 170  
 171      function removeMarkerElement(doc, markerId) {
 172          var markerEl = gEBI(markerId, doc);
 173          if (markerEl) {
 174              markerEl.parentNode.removeChild(markerEl);
 175          }
 176      }
 177  
 178      function removeMarkers(savedSelection) {
 179          var rangeInfos = savedSelection.rangeInfos;
 180          for (var i = 0, len = rangeInfos.length, rangeInfo; i < len; ++i) {
 181              rangeInfo = rangeInfos[i];
 182              if (rangeInfo.collapsed) {
 183                  removeMarkerElement(savedSelection.doc, rangeInfo.markerId);
 184              } else {
 185                  removeMarkerElement(savedSelection.doc, rangeInfo.startMarkerId);
 186                  removeMarkerElement(savedSelection.doc, rangeInfo.endMarkerId);
 187              }
 188          }
 189      }
 190  
 191      api.saveSelection = saveSelection;
 192      api.restoreSelection = restoreSelection;
 193      api.removeMarkerElement = removeMarkerElement;
 194      api.removeMarkers = removeMarkers;
 195  });