1 <?php
  2 /**
  3  * Utility class to render views of the differences between two data objects (or two versions of the
  4  * same data object).
  5  * 
  6  * Construcing a diff object is done as follows:
  7  * <code>
  8  * $fromRecord = Versioned::get_version('SiteTree', $pageID, $fromVersion);
  9  * $toRecord = Versioned::get_version('SiteTree, $pageID, $toVersion);
 10  * $diff = new DataDifferencer($fromRecord, $toRecord);
 11  * </code>
 12  * 
 13  * And then it can be used in a number of ways.  You can use the ChangedFields() method in a template:
 14  * <pre>
 15  * <dl class="diff">
 16  * <% control Diff.ChangedFields %>
 17  *    <dt>$Title</dt>
 18  *    <dd>$Diff</dd>
 19  * <% end_control %>
 20  * </dl>
 21  * </pre>
 22  * 
 23  * Or you can get the diff'ed content as another DataObject, that you can insert into a form.
 24  * <code>
 25  * $form->loadDataFrom($diff->diffedData());
 26  * </code>
 27  * 
 28  * If there are fields whose changes you aren't interested in, you can ignore them like so:
 29  * <code>
 30  * $diff->ignoreFields('AuthorID', 'Status');
 31  * </code>
 32  * 
 33  * @package sapphire
 34  * @subpackage misc
 35  */
 36 class DataDifferencer extends ViewableData {
 37     protected $fromRecord;
 38     protected $toRecord;
 39     
 40     protected $ignoredFields = array("ID","Version","RecordID");
 41     
 42     /**
 43      * Construct a DataDifferencer to show the changes between $fromRecord and $toRecord.
 44      * If $fromRecord is null, this will represent a "creation".
 45      */
 46     function __construct($fromRecord, $toRecord) {
 47         if(!$toRecord) user_error("DataDifferencer constructed without a toRecord", E_USER_WARNING);
 48         $this->fromRecord = $fromRecord;
 49         $this->toRecord = $toRecord;
 50         parent::__construct();
 51     }
 52     
 53     /**
 54      * Specify some fields to ignore changes from.  Repeated calls are cumulative.
 55      * @param $ignoredFields An array of field names to ignore.  Alternatively, pass the field names as
 56      * separate args.
 57      */
 58     function ignoreFields($ignoredFields) {
 59         if(!is_array($ignoredFields)) $ignoredFields = func_get_args();
 60         $this->ignoredFields = array_merge($this->ignoredFields, $ignoredFields);
 61     }
 62     
 63     /**
 64      * Get a DataObject with altered values replaced with HTML diff strings, incorporating
 65      * <ins> and <del> tags.
 66      */
 67     function diffedData() {
 68         if($this->fromRecord) {
 69             $diffed = clone $this->fromRecord;
 70             $fields = array_keys($diffed->getAllFields() + $this->toRecord->getAllFields());
 71         } else {
 72             $diffed = clone $this->toRecord;
 73             $fields = array_keys($this->toRecord->getAllFields());
 74         }
 75         
 76         foreach($fields as $field) {
 77             if(in_array($field, $this->ignoredFields)) continue;
 78             
 79             if(!$this->fromRecord) {
 80                 $diffed->$field = "<ins>" . $this->toRecord->$field . "</ins>";
 81             } else if($this->fromRecord->$field != $this->toRecord->$field) {           
 82                 $diffed->$field = Diff::compareHTML($this->fromRecord->$field, $this->toRecord->$field);
 83             }
 84         }
 85         
 86         return $diffed;
 87     }
 88     
 89     /**
 90      * Get a DataObjectSet of the changed fields.
 91      * Each element is an array data containing
 92      *  - Name: The field name
 93      *  - Title: The human-readable field title
 94      *  - Diff: An HTML diff showing the changes
 95      *  - From: The older version of the field
 96      *  - To: The newer version of the field
 97      */
 98     function ChangedFields() {
 99         $changedFields = new DataObjectSet();
100 
101         if($this->fromRecord) {
102             $base = $this->fromRecord;
103             $fields = array_keys($this->fromRecord->getAllFields());
104         } else {
105             $base = $this->toRecord;
106             $fields = array_keys($this->toRecord->getAllFields());
107         }
108         
109         foreach($fields as $field) {
110             if(in_array($field, $this->ignoredFields)) continue;
111 
112             if(!$this->fromRecord || $this->fromRecord->$field != $this->toRecord->$field) {            
113                 $changedFields->push(new ArrayData(array(
114                     'Name' => $field,
115                     'Title' => $base->fieldLabel($field),
116                     'Diff' => $this->fromRecord
117                         ? Diff::compareHTML($this->fromRecord->$field, $this->toRecord->$field)
118                         : "<ins>" . $this->toRecord->$field . "</ins>",
119                     'From' => $this->fromRecord ? $this->fromRecord->$field : null,
120                     'To' => $this->toRecord ? $this->toRecord->$field : null,
121                 )));
122             }
123         }
124         
125         return $changedFields;
126     }
127 
128     /**
129      * Get an array of the names of every fields that has changed.
130      * This is simpler than {@link ChangedFields()}
131      */
132     function changedFieldNames() {
133         $diffed = clone $this->fromRecord;
134         $fields = array_keys($diffed->getAllFields());
135         
136         $changedFields = array();
137         
138         foreach($fields as $field) {
139             if(in_array($field, $this->ignoredFields)) continue;
140             if($this->fromRecord->$field != $this->toRecord->$field) {          
141                 $changedFields[] = $field;
142             }
143         }
144         
145         return $changedFields;
146     }
147 }
148