Show missing Phriction documents as red links, invisible documents with a lock

Summary: Ref T7691 (errata).  This shows links to Phriction documents in red if they're missing, and links to Phriction documents in grey with a lock icon if the user doesn't have the correct permissions to see the document.

Test Plan:
Tested a bunch of different configurations:

```
[[ ./../ ]] Back to Main Document
[[ ./../subdocument_2]] Mmmm more documents
[[ ./../invisible_document]] Mmmm more documents

[[ ./../ | Explicit Title ]] Back to Main Document
[[ ./../subdocument_2 | Explicit Title ]] Mmmm more documents
[[ ./../invisible_document | Explicit Title ]] Mmmm more documents

[[ ]] Absolute link
[[ subdocument_2 ]] Absolute link
[[ invisible_document ]] Absolute link

[[ | Explicit Title ]] Absolute link
[[ subdocument_2 | Explicit Title ]] Absolute link
[[ invisible_document | Explicit Title ]] Absolute link
```

Got the expected result:

{F1221106}

Reviewers: epriestley, chad, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin

Maniphest Tasks: T7691

Differential Revision: https://secure.phabricator.com/D15733

resources/celerity/map.php

@@ -88,7 +88,7 @@ return array(
     'rsrc/css/application/phortune/phortune-credit-card-form.css' => '8391eb02',
     'rsrc/css/application/phortune/phortune.css' => '9149f103',
     'rsrc/css/application/phrequent/phrequent.css' => 'ffc185ad',
-    'rsrc/css/application/phriction/phriction-document-css.css' => 'd1861e06',
+    'rsrc/css/application/phriction/phriction-document-css.css' => '55446c91',
     'rsrc/css/application/policy/policy-edit.css' => '815c66f7',
     'rsrc/css/application/policy/policy-transaction-detail.css' => '82100a43',
     'rsrc/css/application/policy/policy.css' => '957ea14c',
@@ -807,7 +807,7 @@ return array(
     'phortune-credit-card-form-css' => '8391eb02',
     'phortune-css' => '9149f103',
     'phrequent-css' => 'ffc185ad',
-    'phriction-document-css' => 'd1861e06',
+    'phriction-document-css' => '55446c91',
     'phui-action-panel-css' => '91c7b835',
     'phui-badge-view-css' => '3baef8db',
     'phui-big-info-view-css' => 'bd903741',

src/applications/phriction/markup/PhrictionRemarkupRule.php

@@ -2,6 +2,8 @@
 
 final class PhrictionRemarkupRule extends PhutilRemarkupRule {
 
+  const KEY_RULE_PHRICTION_LINK = 'phriction.link';
+
   public function getPriority() {
     return 175.0;
   }
@@ -48,37 +50,123 @@ final class PhrictionRemarkupRule extends PhutilRemarkupRule {
       }
     }
 
-    $name = trim(idx($matches, 2, $link));
+    $name = trim(idx($matches, 2, ''));
     if (empty($matches[2])) {
-      $name = explode('/', trim($name, '/'));
-      $name = end($name);
+      $name = null;
     }
 
-    $uri      = new PhutilURI($link);
-    $slug     = $uri->getPath();
-    $fragment = $uri->getFragment();
-    $slug     = PhabricatorSlug::normalize($slug);
-    $slug     = PhrictionDocument::getSlugURI($slug);
-    $href     = (string)id(new PhutilURI($slug))->setFragment($fragment);
+    // Link is now used for slug detection, so append a slash if one
+    // is needed.
+    $link = rtrim($link, '/').'/';
 
-    $text_mode = $this->getEngine()->isTextMode();
-    $mail_mode = $this->getEngine()->isHTMLMailMode();
+    $engine = $this->getEngine();
+    $token = $engine->storeText('x');
+    $metadata = $engine->getTextMetadata(
+      self::KEY_RULE_PHRICTION_LINK,
+      array());
+    $metadata[] = array(
+      'token' => $token,
+      'link' => $link,
+      'explicitName' => $name,
+    );
+    $engine->setTextMetadata(self::KEY_RULE_PHRICTION_LINK, $metadata);
 
-    if ($this->getEngine()->getState('toc')) {
-      $text = $name;
-    } else if ($text_mode || $mail_mode) {
-      return PhabricatorEnv::getProductionURI($href);
-    } else {
-      $text = $this->newTag(
-        'a',
-        array(
-          'href'  => $href,
-          'class' => 'phriction-link',
-        ),
-        $name);
+    return $token;
+  }
+
+  public function didMarkupText() {
+    $engine = $this->getEngine();
+    $metadata = $engine->getTextMetadata(
+      self::KEY_RULE_PHRICTION_LINK,
+      array());
+
+    if (!$metadata) {
+      return;
     }
 
-    return $this->getEngine()->storeText($text);
+    $slugs = ipull($metadata, 'link');
+
+    // We have to make two queries here to distinguish between
+    // documents the user can't see, and documents that don't
+    // exist.
+    $visible_documents = id(new PhrictionDocumentQuery())
+      ->setViewer($engine->getConfig('viewer'))
+      ->withSlugs($slugs)
+      ->needContent(true)
+      ->execute();
+    $existant_documents = id(new PhrictionDocumentQuery())
+      ->setViewer(PhabricatorUser::getOmnipotentUser())
+      ->withSlugs($slugs)
+      ->execute();
+
+    $visible_documents = mpull($visible_documents, null, 'getSlug');
+    $existant_documents = mpull($existant_documents, null, 'getSlug');
+
+    foreach ($metadata as $spec) {
+      $link = $spec['link'];
+      $name = $spec['explicitName'];
+      $class = 'phriction-link';
+
+      if (idx($existant_documents, $link) === null) {
+        // The target document doesn't exist.
+        if ($name === null) {
+          $name = explode('/', trim($link, '/'));
+          $name = end($name);
+        }
+        $class = 'phriction-link-missing';
+      } else if (idx($visible_documents, $link) === null) {
+        // The document exists, but the user can't see it.
+        if ($name === null) {
+          $name = explode('/', trim($link, '/'));
+          $name = end($name);
+        }
+        $class = 'phriction-link-lock';
+      } else {
+        if ($name === null) {
+          // Use the title of the document if no name is set.
+          $name = $visible_documents[$link]
+            ->getContent()
+            ->getTitle();
+        }
+      }
+
+      $uri      = new PhutilURI($link);
+      $slug     = $uri->getPath();
+      $fragment = $uri->getFragment();
+      $slug     = PhabricatorSlug::normalize($slug);
+      $slug     = PhrictionDocument::getSlugURI($slug);
+      $href     = (string)id(new PhutilURI($slug))->setFragment($fragment);
+
+      $text_mode = $this->getEngine()->isTextMode();
+      $mail_mode = $this->getEngine()->isHTMLMailMode();
+
+      if ($this->getEngine()->getState('toc')) {
+        $text = $name;
+      } else if ($text_mode || $mail_mode) {
+        return PhabricatorEnv::getProductionURI($href);
+      } else {
+        if ($class === 'phriction-link-lock') {
+          $name = array(
+            $this->newTag(
+              'i',
+              array(
+                'class' => 'phui-icon-view phui-font-fa fa-lock',
+              ),
+              ''),
+            ' ',
+            $name,
+          );
+        }
+        $text = $this->newTag(
+          'a',
+          array(
+            'href'  => $href,
+            'class' => $class,
+          ),
+          $name);
+        $this->getEngine()->overwriteStoredText($spec['token'], $text);
+      }
+    }
   }
 
 }

webroot/rsrc/css/application/phriction/phriction-document-css.css

@@ -36,3 +36,13 @@
 .phui-document-content .phriction-link {
   font-weight: bold;
 }
+
+.phui-document-content .phriction-link-missing {
+  font-weight: bold;
+  color: {$red};
+}
+
+.phui-document-content .phriction-link-lock {
+  font-weight: bold;
+  color: {$greytext};
+}