Wiki page revision comparison tool with diff displayed in modal dialog. Leverages Diff class from http://code.stephenmorley.org/php/diff-implementation with license CC0 1.0 universal http://creativecommons.org/publicdomain/zero/1.0/legalcode

5 files changed, 548 insertions, 17 deletions

diff --git a/Zotlabs/Module/Wiki.php b/Zotlabs/Module/Wiki.php
index 9e7d151b5..83fa0e337 100644
--- a/Zotlabs/Module/Wiki.php
+++ b/Zotlabs/Module/Wiki.php
@@ -136,6 +136,16 @@ class Wiki extends \Zotlabs\Web\Controller {
 		// Render the Markdown-formatted page content in HTML
 		require_once('library/markdown.php');	
 		
+		$wikiModalID = random_string(3);
+		$wikiModal = replace_macros(
+			get_markup_template('generic_modal.tpl'), array(
+				'$id' => $wikiModalID,
+				'$title' => t('Revision Comparison'),
+				'$ok' => t('Revert'),
+				'$cancel' => t('Cancel')
+			)
+		);
+		
 		$o .= replace_macros(get_markup_template('wiki.tpl'),array(
 			'$wikiheaderName' => $wikiheaderName,
 			'$wikiheaderPage' => $wikiheaderPage,
@@ -157,7 +167,10 @@ class Wiki extends \Zotlabs\Web\Controller {
 			'$pageName' => array('pageName', t('Enter the name of the new page:'), '', ''),
 			'$pageRename' => array('pageRename', t('Enter the new name:'), '', ''),
 			'$commitMsg' => array('commitMsg', '', '', '', '', 'placeholder="(optional) Enter a custom message when saving the page..."'),
-			'$pageHistory' => $pageHistory['history']
+			'$pageHistory' => $pageHistory['history'],
+			'$wikiModal' => $wikiModal,
+			'$wikiModalID' => $wikiModalID,
+			'$commit' => 'HEAD'
 		));
 		head_add_js('library/ace/ace.js');	// Ace Code Editor
 		return $o;
@@ -412,7 +425,7 @@ class Wiki extends \Zotlabs\Web\Controller {
 					json_return_and_die(array('success' => false));					
 				}
 			}
-			$reverted = wiki_revert_page(array('commitHash' => $commitHash, 'observer' => \App::get_observer(), 'resource_id' => $resource_id, 'pageUrlName' => $pageUrlName));
+			$reverted = wiki_revert_page(array('commitHash' => $commitHash, 'resource_id' => $resource_id, 'pageUrlName' => $pageUrlName));
 			if($reverted['success']) {
 				json_return_and_die(array('content' => $reverted['content'], 'message' => '', 'success' => true));					
 			} else {
@@ -420,6 +433,31 @@ class Wiki extends \Zotlabs\Web\Controller {
 			}
 		}
 		
+		// Compare page revisions
+		if ((argc() === 4) && (argv(2) === 'compare') && (argv(3) === 'page')) {
+			$resource_id = $_POST['resource_id']; 
+			$pageUrlName = $_POST['name'];
+			$compareCommit = $_POST['compareCommit'];
+			$currentCommit = $_POST['currentCommit'];
+			// Determine if observer has permission to revert pages
+			$nick = argv(1);
+			$channel = get_channel_by_nick($nick);			
+			if (local_channel() !== intval($channel['channel_id'])) {
+				$observer_hash = get_observer_hash();
+				$perms = wiki_get_permissions($resource_id, intval($channel['channel_id']), $observer_hash);
+				if(!$perms['read']) {
+					logger('Wiki read permission denied.' . EOL);
+					json_return_and_die(array('success' => false));					
+				}
+			}
+			$compare = wiki_compare_page(array('currentCommit' => $currentCommit, 'compareCommit' => $compareCommit, 'resource_id' => $resource_id, 'pageUrlName' => $pageUrlName));
+			if($compare['success']) {
+				json_return_and_die(array('diff' => $compare['diff'], 'message' => '', 'success' => true));					
+			} else {
+				json_return_and_die(array('diff' => '', 'message' => 'Error comparing page', 'success' => false));					
+			}
+		}
+		
 		// Rename a page
 		if ((argc() === 4) && (argv(2) === 'rename') && (argv(3) === 'page')) {
 			$resource_id = $_POST['resource_id']; 
diff --git a/include/wiki.php b/include/wiki.php
index d60f4a3a7..a89db3358 100644
--- a/include/wiki.php
+++ b/include/wiki.php
@@ -347,7 +347,7 @@ function wiki_revert_page($arr) {
 	$resource_id = ((array_key_exists('resource_id',$arr)) ? $arr['resource_id'] : '');
 	$commitHash = ((array_key_exists('commitHash',$arr)) ? $arr['commitHash'] : null);
 	if (! $commitHash) {
-		return array('content' => $content, 'message' => 'No commit has provided', 'success' => false);
+		return array('content' => $content, 'message' => 'No commit was provided', 'success' => false);
 	}
 	$w = wiki_get_wiki($resource_id);
 	if (!$w['path']) {
@@ -378,6 +378,48 @@ function wiki_revert_page($arr) {
 	}
 }
 
+function wiki_compare_page($arr) {
+	$pageUrlName = ((array_key_exists('pageUrlName',$arr)) ? $arr['pageUrlName'] : '');
+	$resource_id = ((array_key_exists('resource_id',$arr)) ? $arr['resource_id'] : '');
+	$currentCommit = ((array_key_exists('currentCommit',$arr)) ? $arr['currentCommit'] : 'HEAD');
+	$compareCommit = ((array_key_exists('compareCommit',$arr)) ? $arr['compareCommit'] : null);
+	if (! $compareCommit) {
+		return array('message' => 'No compare commit was provided', 'success' => false);
+	}
+	$w = wiki_get_wiki($resource_id);
+	if (!$w['path']) {
+		return array('message' => 'Error reading wiki', 'success' => false);
+	}
+	$page_path = $w['path'].'/'.$pageUrlName.'.md';
+	if (is_readable($page_path) === true) {
+		$reponame = ((array_key_exists('title', $w['wiki'])) ? urlencode($w['wiki']['title']) : 'repo');
+		if($reponame === '') {
+			$reponame = 'repo';
+		}
+		$git = new GitRepo('', null, false, $w['wiki']['title'], $w['path']);
+		$compareContent = $currentContent = '';
+		try {
+			foreach ($git->git->tree($currentCommit) as $object) {
+				if ($object['type'] == 'blob' && $object['file'] === $pageUrlName.'.md' ) {
+						$currentContent = $git->git->cat->blob($object['hash']);						
+				}
+			}
+			foreach ($git->git->tree($compareCommit) as $object) {
+				if ($object['type'] == 'blob' && $object['file'] === $pageUrlName.'.md' ) {
+						$compareContent = $git->git->cat->blob($object['hash']);						
+				}
+			}
+			require_once('library/class.Diff.php');
+			$diff = Diff::toTable(Diff::compare($currentContent, $compareContent));
+		} catch (\PHPGit\Exception\GitException $e) {
+			return array('message' => 'GitRepo error thrown', 'success' => false);
+		}
+		return array('diff' => $diff, 'message' => '', 'success' => true);
+	} else {
+		return array('message' => 'Page file not writable', 'success' => false);
+	}
+}
+
 function wiki_git_commit($arr) {
 	$files = ((array_key_exists('files', $arr)) ? $arr['files'] : null);
 	$all = ((array_key_exists('all', $arr)) ? $arr['all'] : false);
diff --git a/library/class.Diff.php b/library/class.Diff.php
new file mode 100644
index 000000000..689abe9e7
--- /dev/null
+++ b/library/class.Diff.php
@@ -0,0 +1,386 @@
+<?php
+
+/*
+
+class.Diff.php
+
+A class containing a diff implementation
+
+Created by Stephen Morley - http://stephenmorley.org/ - and released under the
+terms of the CC0 1.0 Universal legal code:
+
+http://creativecommons.org/publicdomain/zero/1.0/legalcode
+
+*/
+
+// A class containing functions for computing diffs and formatting the output.
+class Diff{
+
+  // define the constants
+  const UNMODIFIED = 0;
+  const DELETED    = 1;
+  const INSERTED   = 2;
+
+  /* Returns the diff for two strings. The return value is an array, each of
+   * whose values is an array containing two values: a line (or character, if
+   * $compareCharacters is true), and one of the constants DIFF::UNMODIFIED (the
+   * line or character is in both strings), DIFF::DELETED (the line or character
+   * is only in the first string), and DIFF::INSERTED (the line or character is
+   * only in the second string). The parameters are:
+   *
+   * $string1           - the first string
+   * $string2           - the second string
+   * $compareCharacters - true to compare characters, and false to compare
+   *                      lines; this optional parameter defaults to false
+   */
+  public static function compare(
+      $string1, $string2, $compareCharacters = false){
+
+    // initialise the sequences and comparison start and end positions
+    $start = 0;
+    if ($compareCharacters){
+      $sequence1 = $string1;
+      $sequence2 = $string2;
+      $end1 = strlen($string1) - 1;
+      $end2 = strlen($string2) - 1;
+    }else{
+      $sequence1 = preg_split('/\R/', $string1);
+      $sequence2 = preg_split('/\R/', $string2);
+      $end1 = count($sequence1) - 1;
+      $end2 = count($sequence2) - 1;
+    }
+
+    // skip any common prefix
+    while ($start <= $end1 && $start <= $end2
+        && $sequence1[$start] == $sequence2[$start]){
+      $start ++;
+    }
+
+    // skip any common suffix
+    while ($end1 >= $start && $end2 >= $start
+        && $sequence1[$end1] == $sequence2[$end2]){
+      $end1 --;
+      $end2 --;
+    }
+
+    // compute the table of longest common subsequence lengths
+    $table = self::computeTable($sequence1, $sequence2, $start, $end1, $end2);
+
+    // generate the partial diff
+    $partialDiff =
+        self::generatePartialDiff($table, $sequence1, $sequence2, $start);
+
+    // generate the full diff
+    $diff = array();
+    for ($index = 0; $index < $start; $index ++){
+      $diff[] = array($sequence1[$index], self::UNMODIFIED);
+    }
+    while (count($partialDiff) > 0) $diff[] = array_pop($partialDiff);
+    for ($index = $end1 + 1;
+        $index < ($compareCharacters ? strlen($sequence1) : count($sequence1));
+        $index ++){
+      $diff[] = array($sequence1[$index], self::UNMODIFIED);
+    }
+
+    // return the diff
+    return $diff;
+
+  }
+
+  /* Returns the diff for two files. The parameters are:
+   *
+   * $file1             - the path to the first file
+   * $file2             - the path to the second file
+   * $compareCharacters - true to compare characters, and false to compare
+   *                      lines; this optional parameter defaults to false
+   */
+  public static function compareFiles(
+      $file1, $file2, $compareCharacters = false){
+
+    // return the diff of the files
+    return self::compare(
+        file_get_contents($file1),
+        file_get_contents($file2),
+        $compareCharacters);
+
+  }
+
+  /* Returns the table of longest common subsequence lengths for the specified
+   * sequences. The parameters are:
+   *
+   * $sequence1 - the first sequence
+   * $sequence2 - the second sequence
+   * $start     - the starting index
+   * $end1      - the ending index for the first sequence
+   * $end2      - the ending index for the second sequence
+   */
+  private static function computeTable(
+      $sequence1, $sequence2, $start, $end1, $end2){
+
+    // determine the lengths to be compared
+    $length1 = $end1 - $start + 1;
+    $length2 = $end2 - $start + 1;
+
+    // initialise the table
+    $table = array(array_fill(0, $length2 + 1, 0));
+
+    // loop over the rows
+    for ($index1 = 1; $index1 <= $length1; $index1 ++){
+
+      // create the new row
+      $table[$index1] = array(0);
+
+      // loop over the columns
+      for ($index2 = 1; $index2 <= $length2; $index2 ++){
+
+        // store the longest common subsequence length
+        if ($sequence1[$index1 + $start - 1]
+            == $sequence2[$index2 + $start - 1]){
+          $table[$index1][$index2] = $table[$index1 - 1][$index2 - 1] + 1;
+        }else{
+          $table[$index1][$index2] =
+              max($table[$index1 - 1][$index2], $table[$index1][$index2 - 1]);
+        }
+
+      }
+    }
+
+    // return the table
+    return $table;
+
+  }
+
+  /* Returns the partial diff for the specificed sequences, in reverse order.
+   * The parameters are:
+   *
+   * $table     - the table returned by the computeTable function
+   * $sequence1 - the first sequence
+   * $sequence2 - the second sequence
+   * $start     - the starting index
+   */
+  private static function generatePartialDiff(
+      $table, $sequence1, $sequence2, $start){
+
+    //  initialise the diff
+    $diff = array();
+
+    // initialise the indices
+    $index1 = count($table) - 1;
+    $index2 = count($table[0]) - 1;
+
+    // loop until there are no items remaining in either sequence
+    while ($index1 > 0 || $index2 > 0){
+
+      // check what has happened to the items at these indices
+      if ($index1 > 0 && $index2 > 0
+          && $sequence1[$index1 + $start - 1]
+              == $sequence2[$index2 + $start - 1]){
+
+        // update the diff and the indices
+        $diff[] = array($sequence1[$index1 + $start - 1], self::UNMODIFIED);
+        $index1 --;
+        $index2 --;
+
+      }elseif ($index2 > 0
+          && $table[$index1][$index2] == $table[$index1][$index2 - 1]){
+
+        // update the diff and the indices
+        $diff[] = array($sequence2[$index2 + $start - 1], self::INSERTED);
+        $index2 --;
+
+      }else{
+
+        // update the diff and the indices
+        $diff[] = array($sequence1[$index1 + $start - 1], self::DELETED);
+        $index1 --;
+
+      }
+
+    }
+
+    // return the diff
+    return $diff;
+
+  }
+
+  /* Returns a diff as a string, where unmodified lines are prefixed by '  ',
+   * deletions are prefixed by '- ', and insertions are prefixed by '+ '. The
+   * parameters are:
+   *
+   * $diff      - the diff array
+   * $separator - the separator between lines; this optional parameter defaults
+   *              to "\n"
+   */
+  public static function toString($diff, $separator = "\n"){
+
+    // initialise the string
+    $string = '';
+
+    // loop over the lines in the diff
+    foreach ($diff as $line){
+
+      // extend the string with the line
+      switch ($line[1]){
+        case self::UNMODIFIED : $string .= '  ' . $line[0];break;
+        case self::DELETED    : $string .= '- ' . $line[0];break;
+        case self::INSERTED   : $string .= '+ ' . $line[0];break;
+      }
+
+      // extend the string with the separator
+      $string .= $separator;
+
+    }
+
+    // return the string
+    return $string;
+
+  }
+
+  /* Returns a diff as an HTML string, where unmodified lines are contained
+   * within 'span' elements, deletions are contained within 'del' elements, and
+   * insertions are contained within 'ins' elements. The parameters are:
+   *
+   * $diff      - the diff array
+   * $separator - the separator between lines; this optional parameter defaults
+   *              to '<br>'
+   */
+  public static function toHTML($diff, $separator = '<br>'){
+
+    // initialise the HTML
+    $html = '';
+
+    // loop over the lines in the diff
+    foreach ($diff as $line){
+
+      // extend the HTML with the line
+      switch ($line[1]){
+        case self::UNMODIFIED : $element = 'span'; break;
+        case self::DELETED    : $element = 'del';  break;
+        case self::INSERTED   : $element = 'ins';  break;
+      }
+      $html .=
+          '<' . $element . '>'
+          . htmlspecialchars($line[0])
+          . '</' . $element . '>';
+
+      // extend the HTML with the separator
+      $html .= $separator;
+
+    }
+
+    // return the HTML
+    return $html;
+
+  }
+
+  /* Returns a diff as an HTML table. The parameters are:
+   *
+   * $diff        - the diff array
+   * $indentation - indentation to add to every line of the generated HTML; this
+   *                optional parameter defaults to ''
+   * $separator   - the separator between lines; this optional parameter
+   *                defaults to '<br>'
+   */
+  public static function toTable($diff, $indentation = '', $separator = '<br>'){
+
+    // initialise the HTML
+    $html = $indentation . "<table class=\"diff\">\n";
+
+    // loop over the lines in the diff
+    $index = 0;
+    while ($index < count($diff)){
+
+      // determine the line type
+      switch ($diff[$index][1]){
+
+        // display the content on the left and right
+        case self::UNMODIFIED:
+          $leftCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::UNMODIFIED);
+          $rightCell = $leftCell;
+          break;
+
+        // display the deleted on the left and inserted content on the right
+        case self::DELETED:
+          $leftCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::DELETED);
+          $rightCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::INSERTED);
+          break;
+
+        // display the inserted content on the right
+        case self::INSERTED:
+          $leftCell = '';
+          $rightCell =
+              self::getCellContent(
+                  $diff, $indentation, $separator, $index, self::INSERTED);
+          break;
+
+      }
+
+      // extend the HTML with the new row
+      $html .=
+          $indentation
+          . "  <tr>\n"
+          . $indentation
+          . '    <td class="diff'
+          . ($leftCell == $rightCell
+              ? 'Unmodified'
+              : ($leftCell == '' ? 'Blank' : 'Deleted'))
+          . '">'
+          . $leftCell
+          . "</td>\n"
+          . $indentation
+          . '    <td class="diff'
+          . ($leftCell == $rightCell
+              ? 'Unmodified'
+              : ($rightCell == '' ? 'Blank' : 'Inserted'))
+          . '">'
+          . $rightCell
+          . "</td>\n"
+          . $indentation
+          . "  </tr>\n";
+
+    }
+
+    // return the HTML
+    return $html . $indentation . "</table>\n";
+
+  }
+
+  /* Returns the content of the cell, for use in the toTable function. The
+   * parameters are:
+   *
+   * $diff        - the diff array
+   * $indentation - indentation to add to every line of the generated HTML
+   * $separator   - the separator between lines
+   * $index       - the current index, passes by reference
+   * $type        - the type of line
+   */
+  private static function getCellContent(
+      $diff, $indentation, $separator, &$index, $type){
+
+    // initialise the HTML
+    $html = '';
+
+    // loop over the matching lines, adding them to the HTML
+    while ($index < count($diff) && $diff[$index][1] == $type){
+      $html .=
+          '<span>'
+          . htmlspecialchars($diff[$index][0])
+          . '</span>'
+          . $separator;
+      $index ++;
+    }
+
+    // return the HTML
+    return $html;
+
+  }
+
+}
+
+?>
diff --git a/view/tpl/wiki.tpl b/view/tpl/wiki.tpl
index dc78aad9f..990e6c883 100644
--- a/view/tpl/wiki.tpl
+++ b/view/tpl/wiki.tpl
@@ -96,17 +96,6 @@
       </div>
       <div id="page-history-pane" class="tab-pane fade" {{if $hidePageHistory}}style="display: none;"{{/if}}>
         <div id="page-history-list" class="section-content-wrapper">
-          <table class="table-striped table-responsive table-hover" style="width: 100%;">
-          {{foreach $pageHistory as $commit}}
-            <tr><td>
-            <table>
-              <tr><td>Date</td><td>{{$commit.date}}</td></tr>
-              <tr><td>Name</td><td>{{$commit.name}}</td></tr>
-              <tr><td>Message</td><td>{{$commit.title}}</td></tr>
-            </table>
-            </td></tr>
-          {{/foreach}}          
-          </table>
         </div>
       </div>     
 
@@ -120,16 +109,22 @@
   {{/if}}
 </div>
 
+{{$wikiModal}}
+
 <script>
   window.wiki_resource_id = '{{$resource_id}}';
   window.wiki_page_name = '{{$page}}';
   window.wiki_page_content = {{$content}};
+  window.wiki_page_commit = '{{$commit}}';
   
   if (window.wiki_page_name === 'Home') {
     $('#delete-page').hide();
     $('#rename-page').hide();
   }
   
+  $("#generic-modal-ok-{{$wikiModalID}}").removeClass('btn-primary');
+  $("#generic-modal-ok-{{$wikiModalID}}").addClass('btn-danger');
+  
   $('#rename-page').click(function (ev) {
     $('#rename-page-form-wrapper').show();
   });
@@ -313,4 +308,34 @@ function wiki_delete_wiki(wikiHtmlName, resource_id) {
         }
       }, 'json');
   }
+  
+  function wiki_compare_page(compareCommit) {
+    if (window.wiki_resource_id === '' || window.wiki_page_name === '' || window.wiki_page_commit === '') {
+      window.console.log('You must have a wiki page open in order to revert pages.');
+      return false;
+    }
+    $.post("wiki/{{$channel}}/compare/page", 
+      {
+        compareCommit: compareCommit, 
+        currentCommit: window.wiki_page_commit, 
+        name: window.wiki_page_name, 
+        resource_id: window.wiki_resource_id
+      }, 
+      function (data) {
+        if (data.success) {
+          window.wiki_page_commit = compareCommit;
+          var modalBody = $('#generic-modal-body-{{$wikiModalID}}');
+          modalBody.html('<div class="descriptive-text">'+data.diff+'</div>');
+          $('.modal-dialog').width('80%');
+          $("#generic-modal-ok-{{$wikiModalID}}").off('click');
+          $("#generic-modal-ok-{{$wikiModalID}}").click(function () {
+            wiki_revert_page(compareCommit);
+            $('#generic-modal-{{$wikiModalID}}').modal('hide');
+          });
+          $('#generic-modal-{{$wikiModalID}}').modal();
+        } else {
+          window.console.log('Error comparing page.');
+        }
+      }, 'json');
+  }
 </script>
diff --git a/view/tpl/wiki_page_history.tpl b/view/tpl/wiki_page_history.tpl
index 6ce3ce204..fef5d93a5 100644
--- a/view/tpl/wiki_page_history.tpl
+++ b/view/tpl/wiki_page_history.tpl
@@ -1,12 +1,52 @@
+<style>
+  .diff td{
+    padding:0 0.667em;
+    vertical-align:top;
+    white-space:pre;
+    white-space:pre-wrap;
+    font-family:Consolas,'Courier New',Courier,monospace;
+    font-size:1.0em;
+    line-height:1.333;
+  }
+
+  .diff span{
+    display:block;
+    min-height:1.333em;
+    margin-top:-1px;
+    padding:0 3px;
+  }
+
+  * html .diff span{
+    height:1.333em;
+  }
+
+  .diff span:first-child{
+    margin-top:0;
+  }
+
+  .diffDeleted span{
+    border:1px solid rgb(255,192,192);
+    background:rgb(255,224,224);
+  }
+
+  .diffInserted span{
+    border:1px solid rgb(192,255,192);
+    background:rgb(224,255,224);
+  }
+</style>
 <table class="table-striped table-responsive table-hover" style="width: 100%;">
   {{foreach $pageHistory as $commit}}
   <tr><td>
       <table id="rev-{{$commit.hash}}" onclick="$('#details-{{$commit.hash}}').show()" width="100%">
-        <tr><td width="10%">Date</td><td width="70%">{{$commit.date}}</td><td rowspan="3" width="20%" align="right">
-            <button id="revert-{{$commit.hash}}" class="btn btn-danger btn-xs" onclick="wiki_revert_page('{{$commit.hash}}')">Revert</button></td></tr>
+        <tr><td width="10%">Date</td><td width="70%">{{$commit.date}}</td>
+            <td rowspan="3" width="20%" align="right">
+              <button id="revert-{{$commit.hash}}" class="btn btn-danger btn-xs" onclick="wiki_revert_page('{{$commit.hash}}')">Revert</button>
+              <br><br>
+              <button id="compare-{{$commit.hash}}" class="btn btn-warning btn-xs" onclick="wiki_compare_page('{{$commit.hash}}')">Compare</button>
+            </td></tr>
         <tr><td>Name</td><td>{{$commit.name}} &lt;{{$commit.email}}&gt;</td></tr>
         <tr><td>Message</td><td>{{$commit.title}}</td></tr>
       </table>
     </td></tr>
   {{/foreach}}          
-</table>
\ No newline at end of file
+</table>