Support blame on blame for svn

Summary:
add the column for the blame on blame for svn. We will support
git once we have the 'parent' info of the commits saved in the database
for git.

Test Plan:
in svn it should work. In git is doesn't break things.

Reviewed By: epriestley
Reviewers: epriestley
CC: epriestley
Differential Revision: 95

src/applications/diffusion/controller/file/DiffusionBrowseFileController.php

@@ -26,6 +26,7 @@ class DiffusionBrowseFileController extends DiffusionController {
     'jpeg'=> 'image/jpeg'
   );
 
+
   public function processRequest() {
 
     // Build the view selection form.
@@ -90,6 +91,20 @@ class DiffusionBrowseFileController extends DiffusionController {
   }
 
 
+  /*
+   * Returns a content-type corrsponding to an image file extension
+   *
+   * @param string $path File path
+   * @return mixed A content-type string or NULL if path doesn't end with a
+   *               recognized image extension
+   */
+  public function getImageType($path) {
+    $ext = pathinfo($path);
+    $ext = $ext['extension'];
+    return idx($this->imageTypes, $ext);
+  }
+
+
   private function buildCorpus($selected) {
     $needs_blame = ($selected == 'blame' || $selected == 'plainblame');
 
@@ -166,7 +181,7 @@ class DiffusionBrowseFileController extends DiffusionController {
           implode("\n", $text_list)));
 
         $rows = $this->buildDisplayRows($text_list, $rev_list, $blame_dict,
-          $needs_blame, $drequest);
+          $needs_blame, $drequest, $file_query, $selected);
 
         $corpus_table = phutil_render_tag(
           'table',
@@ -189,7 +204,7 @@ class DiffusionBrowseFileController extends DiffusionController {
 
 
   private static function buildDisplayRows($text_list, $rev_list, $blame_dict,
-    $needs_blame, DiffusionRequest $drequest) {
+    $needs_blame, DiffusionRequest $drequest, $file_query, $selected) {
     $last_rev = null;
     $color = null;
     $rows = array();
@@ -208,6 +223,8 @@ class DiffusionBrowseFileController extends DiffusionController {
         $rev = $rev_list[$k];
         if ($last_rev == $rev) {
           $blame_info =
+            ($file_query->getSupportsBlameOnBlame() ?
+              '<th style="background: '.$color.'; width: 2em;"></th>' : '').
             '<th style="background: '.$color.'; width: 9em;"></th>'.
             '<th style="background: '.$color.'"></th>';
         } else {
@@ -220,8 +237,25 @@ class DiffusionBrowseFileController extends DiffusionController {
             $drequest,
             substr($rev, 0, 7));
 
+          if (!$file_query->getSupportsBlameOnBlame()) {
+            $prev_link = '';
+          } else {
+            $prev_rev = $file_query->getPrevRev($rev);
+            $path = $drequest->getPath();
+            $prev_link = self::renderBrowse(
+              $drequest,
+              $path,
+              "\xC2\xAB",
+              $prev_rev,
+              $n,
+              $selected);
+            $prev_link = '<th style="background: ' . $color .
+              '; width: 2em;">' . $prev_link . '</th>';
+          }
+
           $author_link = $blame_dict[$rev]['author'];
           $blame_info =
+            $prev_link .
             '<th style="background: '.$color.
               '; width: 9em;">'.$revision_link.'</th>'.
             '<th style="background: '.$color.
@@ -278,17 +312,41 @@ class DiffusionBrowseFileController extends DiffusionController {
   }
 
 
-  /**
-   * Returns a content-type corrsponding to an image file extension
-   *
-   * @param string $path File path
-   * @return mixed A content-type string or NULL if path doesn't end with a
-   *               recognized image extension
-   */
-  public function getImageType($path) {
-    $ext = pathinfo($path);
-    $ext = $ext['extension'];
-    return idx($this->imageTypes, $ext);
+  private static function renderBrowse(
+    DiffusionRequest $drequest,
+    $path,
+    $name = null,
+    $rev = null,
+    $line = null,
+    $view = null) {
+
+    $callsign = $drequest->getCallsign();
+
+    if ($name === null) {
+      $name = $path;
+    }
+
+    $at = null;
+    if ($rev) {
+      $at = ';'.$rev;
+    }
+
+    if ($view) {
+      $view = '?view='.$view;
+    }
+
+    if ($line) {
+      $line = '$'.$line;
+    }
+
+    return phutil_render_tag(
+      'a',
+      array(
+        'href' => "/diffusion/{$callsign}/browse/{$path}{$at}{$line}{$view}",
+      ),
+      $name
+    );
   }
 
+
 }

src/applications/diffusion/query/filecontent/base/DiffusionFileContentQuery.php

@@ -50,6 +50,16 @@ abstract class DiffusionFileContentQuery {
     return $query;
   }
 
+  public function getSupportsBlameOnBlame() {
+    return false;
+  }
+
+  public function getPrevRev($rev) {
+    // TODO: support git once the 'parent' info of a commit is saved
+    // to the database.
+    throw new Exception("Unsupported VCS!");
+  }
+
   final protected function getRequest() {
     return $this->request;
   }

src/applications/diffusion/query/filecontent/svn/DiffusionSvnFileContentQuery.php

@@ -18,6 +18,14 @@
 
 final class DiffusionSvnFileContentQuery extends DiffusionFileContentQuery {
 
+  public function getSupportsBlameOnBlame() {
+    return true;
+  }
+
+  public function getPrevRev($rev) {
+    return max($rev - 1, 0);
+  }
+
   protected function executeQuery() {
     $drequest = $this->getRequest();