Implement multi-folder context option

lib/Database.php

@@ -1465,12 +1465,26 @@ class Database {
             // limit subscriptions to the listed folders
             $q->setWhere("coalesce(arsse_subscriptions.folder,0) in (select folder from folders)");
         }
+        if ($context->folders()) {
+            list($inClause, $inTypes, $inValues) = $this->generateIn($context->folders, "int");
+            // add a common table expression to list the folders and their children so that we select from the entire subtree
+            $q->setCTE("folders_multi(folder)", "SELECT id as folder from (select id from (select 0 as id union select id from arsse_folders where owner = ?) as f where id in ($inClause)) as folders_multi union select id from arsse_folders join folders_multi on coalesce(parent,0) = folder", ["str", $inTypes], [$user, $inValues]);
+            // limit subscriptions to the listed folders
+            $q->setWhere("coalesce(arsse_subscriptions.folder,0) in (select folder from folders_multi)");
+        }
         if ($context->not->folder()) {
             // add a common table expression to list the folder and its children so that we exclude from the entire subtree
             $q->setCTE("folders_excluded(folder)", "SELECT ? union select id from arsse_folders join folders_excluded on coalesce(parent,0) = folder", "int", $context->not->folder);
             // excluded any subscriptions in the listed folders
             $q->setWhereNot("coalesce(arsse_subscriptions.folder,0) in (select folder from folders_excluded)");
         }
+        if ($context->not->folders()) {
+            list($inClause, $inTypes, $inValues) = $this->generateIn($context->not->folders, "int");
+            // add a common table expression to list the folders and their children so that we select from the entire subtree
+            $q->setCTE("folders_multi_excluded(folder)", "SELECT id as folder from (select id from (select 0 as id union select id from arsse_folders where owner = ?) as f where id in ($inClause)) as folders_multi_excluded union select id from arsse_folders join folders_multi_excluded on coalesce(parent,0) = folder", ["str", $inTypes], [$user, $inValues]);
+            // limit subscriptions to the listed folders
+            $q->setWhereNot("coalesce(arsse_subscriptions.folder,0) in (select folder from folders_multi_excluded)");
+        }
         // handle text-matching context options
         $options = [
             "titleTerms"      => ["arsse_articles.title"],

tests/cases/Database/SeriesArticle.php

@@ -426,8 +426,10 @@ trait SeriesArticle {
             'Folder tree' => [(new Context)->folder(1), [5,6,7,8]],
             'Entire folder tree' => [(new Context)->folder(0), [1,2,3,4,5,6,7,8,19,20]],
             'Leaf folder' => [(new Context)->folder(6), [7,8]],
-            'Root folder only' => [(new Context)->folderShallow(0), [1,2,3,4]],
+            'Multiple folder trees' => [(new Context)->folders([1,5]), [5,6,7,8,19,20]],
+            'Multiple folder trees including root' => [(new Context)->folders([0,1,5]), [1,2,3,4,5,6,7,8,19,20]],
             'Shallow folder' => [(new Context)->folderShallow(1), [5,6]],
+            'Root folder only' => [(new Context)->folderShallow(0), [1,2,3,4]],
             'Multiple shallow folders' => [(new Context)->foldersShallow([1,6]), [5,6,7,8]],
             'Subscription' => [(new Context)->subscription(5), [19,20]],
             'Multiple subscriptions' => [(new Context)->subscriptions([4,5]), [7,8,19,20]],
@@ -508,6 +510,8 @@ trait SeriesArticle {
             'Excluding tag "Technology"' => [(new Context)->not->tagName("Technology"), [1,2,3,4,19,20]],
             'Excluding tag "Politics"' => [(new Context)->not->tagName("Politics"), [1,2,3,4,5,6]],
             'Excluding entire folder tree' => [(new Context)->not->folder(0), []],
+            'Excluding multiple folder trees' => [(new Context)->not->folders([1,5]), [1,2,3,4]],
+            'Excluding multiple folder trees including root' => [(new Context)->not->folders([0,1,5]), []],
         ];
     }