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   1  <?php
   2  // $Id: diff.module,v 1.23.2.3.2.20 2010/08/12 16:34:08 yhahn Exp $
   3  
   4  /**
   5   * @file
   6   * Provides functionality to show a diff between two node revisions.
   7   */
   8  
   9  /**
  10   * Number of items on one page of the revision list.
  11   */
  12  define('REVISION_LIST_SIZE', 50);
  13  
  14  /**
  15   * Implementation of hook_help().
  16   */
  17  function diff_help($path, $arg) {
  18    switch ($path) {
  19      case 'admin/help#diff':
  20        $output = '<p>'. t('The diff module overwrites the normal revisions view. The revisions table is enhanced with a possibility to view the difference between two node revisions. Users with the %view_revisions permission will also be able to view the changes between any two selected revisions. You may disable this for individual content types on the content type configuration page. This module also provides a nifty %preview_changes button while editing a post.', array('%preview_changes' => t('View changes'), '%view_revisions' => t('view revisions'))) .'</p>';
  21        return $output;
  22      case 'node/%/revisions/%/view':
  23        // the following string is copied from string copied from node_help('node/%/revisions')
  24        return '<p>'. t('The revisions let you track differences between multiple versions of a post.') .'</p>';
  25      case 'node/%/revisions/view/%/%':
  26        return '<p>'. t('Comparing two revisions:') .'</p>';
  27    }
  28  }
  29  
  30  /**
  31   * Implementation of hook_menu().
  32   */
  33  function diff_menu() {
  34    $items = array();
  35  
  36    /**
  37     * By using MENU_LOCAL_TASK (and 'tab_parent') we can get the various revision-views to
  38     * show the View|Edit|Revision-tabs of the node on top, and have the Revisions-tab open.
  39     * To avoid creating/showing any extra tabs or sub-tabs (tasks below top level) for the
  40     * various paths (i.e. "Diff", "Show latest" and "Show a specific revision") that need
  41     * a revision-id (vid) parameter, we make sure to set 'tab_parent' a bit odd.
  42     * This solution may not be the prettiest one, but by avoiding having two _LOCAL_TASKs
  43     * sharing a parent that can be accessed by its full path, it seems to work as desired.
  44     * Breadcrumbs work decently, at least the node link is among the crumbs. For some reason
  45     * any breadcrumbs "before/above" the node is only seen at 'node/%node/revisions/%/view'.
  46     */
  47    $items['node/%node/revisions/list'] = array(
  48      // Not used directly, but was created to get the other menu items to work well
  49      'title' => 'List revisions',
  50      'page callback' => 'diff_diffs_overview',
  51      'type' => MENU_DEFAULT_LOCAL_TASK,
  52      'access callback' => 'diff_node_revision_access',
  53      'access arguments' => array(1),
  54      'file' => 'diff.pages.inc',
  55    );
  56    $items['node/%node/revisions/view/%/%'] = array(
  57      'title' => 'Diff',
  58      'page callback' => 'diff_diffs_show',
  59      'page arguments' => array(1, 4, 5),
  60      'type' => MENU_LOCAL_TASK,
  61      'access callback' => 'diff_node_revision_access',
  62      'access arguments' => array(1),
  63      'tab_parent' => 'node/%/revisions/list',
  64      'file' => 'diff.pages.inc',
  65    );
  66    $items['node/%node/revisions/view/latest'] = array(
  67      'title' => 'Show latest diff',
  68      'page callback' => 'diff_latest',
  69      'page arguments' => array(1),
  70      'type' => MENU_LOCAL_TASK,
  71      'access callback' => 'diff_node_revision_access',
  72      'access arguments' => array(1),
  73      'tab_parent' => 'node/%/revisions/view',
  74      'file' => 'diff.pages.inc',
  75    );
  76    $items['node/%node/revisions/diff-inline'] = array(
  77      'page callback' => 'diff_inline_ahah',
  78      'page arguments' => array(1),
  79      'type' => MENU_CALLBACK,
  80      'access callback' => 'diff_node_revision_access',
  81      'access arguments' => array(1),
  82      'file' => 'diff.pages.inc',
  83    );
  84    return $items;
  85  }
  86  
  87  /**
  88   * Implementation of hook_menu_alter().
  89   */
  90  function diff_menu_alter(&$callbacks) {
  91    // Overwrite the default 'Revisions' page
  92    $callbacks['node/%node/revisions']['page callback'] = 'diff_diffs_overview';
  93    $callbacks['node/%node/revisions']['module'] = 'diff';
  94    $callbacks['node/%node/revisions']['file'] = 'diff.pages.inc';
  95  
  96    $callbacks['node/%node/revisions/%/view']['tab_parent'] = 'node/%/revisions/list';
  97    $callbacks['node/%node/revisions/%/revert']['tab_parent'] = 'node/%/revisions/%/view';
  98    $callbacks['node/%node/revisions/%/delete']['tab_parent'] = 'node/%/revisions/%/view';
  99  
 100    $callbacks['node/%node/revisions']['access callback'] =
 101    $callbacks['node/%node/revisions/%/view']['access callback'] =
 102    $callbacks['node/%node/revisions/%/revert']['access callback'] =
 103    $callbacks['node/%node/revisions/%/delete']['access callback'] = 'diff_node_revision_access';
 104    return;
 105  }
 106  
 107  /**
 108   * Access callback for the node revisions page.
 109   */
 110  function diff_node_revision_access($node, $op = 'view') {
 111    $may_revision_this_type = variable_get('enable_revisions_page_'. $node->type, TRUE) || user_access('administer nodes');
 112    return $may_revision_this_type && _node_revision_access($node, $op);
 113  }
 114  
 115  /**
 116   * Implementation of hook_block().
 117   */
 118  function diff_block($op = 'list', $delta = 0, $edit = array()) {
 119    if ($op === 'list') {
 120      return array('inline' => array('info' => t('Inline diff')));
 121    }
 122    elseif ($op === 'view' && $delta === 'inline' && user_access('view revisions') && $node = menu_get_object()) {
 123      $block = array();
 124      $revisions = node_revision_list($node);
 125      if (count($revisions) > 1) {
 126        $block['subject'] = t('Highlight changes');
 127        $block['content'] = drupal_get_form('diff_inline_form', $node, $revisions);
 128      }
 129      return $block;
 130    }
 131  }
 132  
 133  /**
 134   * Implementation of hook_nodeapi().
 135   */
 136  function diff_nodeapi(&$node, $op, $teaser, $page) {
 137    if ($page && $op == 'view' && user_access('view revisions') && variable_get('show_diff_inline_'. $node->type, FALSE)) {
 138      // Ugly but cheap way to check that we are viewing a node's revision page.
 139      if (arg(2) === 'revisions' && arg(3) === $node->vid) {
 140        module_load_include('inc', 'diff', 'diff.pages');
 141        $old_vid = _diff_get_previous_vid(node_revision_list($node), $node->vid);
 142        $node->content = array('#value' => diff_inline_show($node, $old_vid));
 143      }
 144      $node->content['#prefix'] = isset($node->content['#prefix']) ? "<div id='diff-inline-{$node->nid}'>" . $node->content['#prefix'] : "<div id='diff-inline-{$node->nid}'>";
 145      $node->content['#suffix'] = isset($node->content['#suffix']) ? $node->content['#suffix'] . "</div>" : "</div>";
 146    }
 147  }
 148  
 149  /**
 150   * Implementation of hook_form_alter().
 151   */
 152  function diff_form_alter(&$form, $form_state, $form_id) {
 153    if (isset($form['type']['#value']) && $form['type']['#value'] .'_node_form' == $form_id) {
 154      // Add a 'View changes' button on the node edit form.
 155      if (variable_get('show_preview_changes_'. $form['type']['#value'], TRUE) && $form['nid']['#value'] > 0) {
 156        $form['buttons']['preview_changes'] = array(
 157          '#type' => 'submit',
 158          '#value' => t('View changes'),
 159          '#weight' => 12,
 160          '#submit' => array('diff_node_form_build_preview_changes')
 161        );
 162      }
 163    }
 164    elseif ($form_id == 'node_type_form' && isset($form['identity']['type'])) {
 165      // Node type edit form.
 166      // Add checkbox to activate 'View changes' button per node type.
 167      $form['workflow']['diff'] = array(
 168        '#title' => t('Diff'),
 169        '#type' => 'item',
 170        '#tree' => FALSE,
 171      );
 172      $form['workflow']['diff']['show_preview_changes'] = array(
 173        '#type' => 'checkbox',
 174        '#title' => t('Show %preview_changes button on node edit form', array('%preview_changes' => t('View changes'))),
 175        '#weight' => 10,
 176        '#default_value' => variable_get('show_preview_changes_'. $form['#node_type']->type, TRUE),
 177      );
 178      $form['workflow']['diff']['show_diff_inline'] = array(
 179        '#type' => 'checkbox',
 180        '#title' => t('Show diffs inline for this content type'),
 181        '#description' => t("You must enable the 'Inline diff' block to use this feature"),
 182        '#weight' => 10,
 183        '#default_value' => variable_get('show_diff_inline_'. $form['#node_type']->type, FALSE),
 184      );
 185      $form['workflow']['diff']['enable_revisions_page'] = array(
 186        '#type' => 'checkbox',
 187        '#title' => t('Enable the %revisions page for this content type', array('%revisions' => t('Revisions'))),
 188        '#weight' => 11,
 189        '#default_value' => variable_get('enable_revisions_page_'. $form['#node_type']->type, TRUE),
 190      );
 191    }
 192  }
 193  
 194  /**
 195   * Callback if 'View changes' is pressed.
 196   */
 197  function diff_node_form_build_preview_changes($form, &$form_state) {
 198    module_load_include('inc', 'diff', 'diff.pages');
 199    $node = node_form_submit_build_node($form, $form_state);
 200  
 201    // Create diff of old node and edited node
 202    $rows = _diff_body_rows(node_load($form_state['values']['nid']), $node);
 203    $cols = _diff_default_cols();
 204    $header = _diff_default_header();
 205    $changes = theme('diff_table', $header, $rows, array('class' => 'diff'), NULL, $cols);
 206  
 207    // Prepend diff to edit form
 208    $form_state['node_preview'] = isset($form_state['node_preview']) ? $changes . $form_state['node_preview'] : $changes;
 209  }
 210  
 211  /**
 212   * Implementation of hook_theme().
 213   */
 214  function diff_theme() {
 215    return array(
 216      'diff_node_revisions' => array(
 217        'arguments' => array('form' => NULL),
 218        'file' => 'diff.theme.inc',
 219      ),
 220      'diff_table' => array(
 221        'arguments' => array('header' => NULL, 'rows' => NULL, 'attributes' => array(), 'caption' => NULL, 'cols' => array()),
 222        'file' => 'diff.theme.inc',
 223      ),
 224      'diff_header_line' => array(
 225        'arguments' => array('lineno' => NULL),
 226        'file' => 'diff.theme.inc',
 227      ),
 228      'diff_content_line' => array(
 229        'arguments' => array('line' => NULL),
 230        'file' => 'diff.theme.inc',
 231      ),
 232      'diff_empty_line' => array(
 233        'arguments' => array('line' => NULL),
 234        'file' => 'diff.theme.inc',
 235      ),
 236      'diff_inline_form' => array(
 237        'arguments' => array('form' => array()),
 238        'file' => 'diff.theme.inc',
 239      ),
 240      'diff_inline_metadata' => array(
 241        'arguments' => array(),
 242        'file' => 'diff.theme.inc',
 243      ),
 244      'diff_inline_chunk' => array(
 245        'arguments' => array('text' => '', 'type' => NULL),
 246        'file' => 'diff.theme.inc',
 247      ),
 248    );
 249  }
 250  
 251  /**
 252   * Render a diff of two strings to a $rows array suitable for use with
 253   * theme('table') or theme('diff_table').
 254   *
 255   * @param string $a
 256   *   The source string to compare from.
 257   * @param string $b
 258   *   The target string to compare to.
 259   * @param boolean $show_header
 260   *   Display diff context headers, e.g. "Line x".
 261   * @return
 262   *   Array of rows usable with theme('table').
 263   */
 264  function diff_get_rows($a, $b, $show_header = FALSE) {
 265    module_load_include('php', 'diff', 'DiffEngine');
 266    $formatter = new DrupalDiffFormatter();
 267    $formatter->show_header = $show_header;
 268    $diff = new Diff($a, $b);
 269    return $formatter->format($diff);
 270  }
 271  
 272  /**
 273   * Render a diff of two strings into HTML markup indicating additions, changes
 274   * and deletions.
 275   *
 276   * @param string $a
 277   *   The source string to compare from.
 278   * @param string $b
 279   *   The target string to compare to.
 280   * @return
 281   *   String containing HTML markup.
 282   */
 283  function diff_get_inline($a, $b) {
 284    module_load_include('php', 'diff', 'DiffEngine');
 285    $diff = new DrupalDiffInline($a, $b);
 286    return $diff->render();
 287  }
 288  
 289  /**
 290   * Form builder: Inline diff controls.
 291   */
 292  function diff_inline_form($form_state, $node, $revisions) {
 293    $form = array();
 294    $form['node'] = array(
 295      '#type' => 'value',
 296      '#value' => $node
 297    );
 298    $form['revision'] = array(
 299      '#type' => 'select',
 300      '#options' => array(0 => '< '. t('No highlighting') . ' >'),
 301      '#default_value' => (arg(2) === 'revisions' && arg(3) === $node->vid) ? $node->vid : 0,
 302      '#ahah' => array(
 303        'path' => "node/{$node->nid}/revisions/diff-inline",
 304        'wrapper' => "diff-inline-{$node->nid}",
 305        'method' => 'replace',
 306      ),
 307    );
 308    foreach ($revisions as $revision) {
 309      $form['revision']['#options'][$revision->vid] = t('@revision by @name', array(
 310        '@revision' => format_date($revision->timestamp, 'small'),
 311        '@name' => $revision->name,
 312      ));
 313    }
 314    $form['submit'] = array(
 315      '#type' => 'submit',
 316      '#value' => t('View'),
 317      '#submit' => array('diff_inline_form_submit'),
 318      '#attributes' => array('class' => 'diff-js-hidden'),
 319    );
 320    return $form;
 321  }
 322  
 323  /**
 324   * Form submission handler for diff_inline_form() for JS-disabled clients.
 325   */
 326  function diff_inline_form_submit(&$form, &$form_state) {
 327    if (isset($form_state['values']['revision'], $form_state['values']['node'])) {
 328      $node = $form_state['values']['node'];
 329      $vid = $form_state['values']['revision'];
 330      $form_state['redirect'] = "node/{$node->nid}/revisions/{$vid}/view";
 331    }
 332  }