Add aggregated facts to the Facts application

Summary:
Some facts are aggregations of other facts. For example, we may compute how many times each macro is used in each object as a "raw fact":

  Dnnn uses macro "psyduck" 6 times.

But we want to present this data in aggregate form, e.g. "order macros by popularity". We can do this at runtime and it probably won't be too awful a query, but we can also aggregate it cheaply:

  Macro "psyduck" is used 3920 times across all objects.

...and then do a query like "select macros ordered by usage".

"Aggregate" facts support facts like this. The aggregate facts I've implemented are:

  - Count of all objects.
  - Count of objects of type X.
  - Last time facts were updated.

These clearly fit the "aggregate" facts template well. I'm not 100% sure macros do. We can use this table to answer a question like "What are the most popular macros, ordered by use?" We can also use it to answer a question like "What are the most popular macros in the last 6 months?", if we build a specific fact for that. But we can't use it to answer a question like "What are the most popular macros between times X and Y?". Maybe that's important; maybe not.

This seems like a good fit for at least some types of facts.

I'll de-magic the keys a bit in the next diff.

Test Plan: Ran the engines and got some aggregated facts about other facts.

Reviewers: vrana, btrahan

Reviewed By: vrana

CC: aran

Maniphest Tasks: T1562

Differential Revision: https://secure.phabricator.com/D3089

src/applications/fact/controller/PhabricatorFactController.php

@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+abstract class PhabricatorFactController extends PhabricatorController {
+
+  public function buildStandardPageResponse($view, array $data) {
+    $page = $this->buildStandardPageView();
+
+    $page->setBaseURI('/fact/');
+    $page->setTitle(idx($data, 'title'));
+
+    $page->setGlyph("\xCE\xA3");
+    $page->appendChild($view);
+
+    $response = new AphrontWebpageResponse();
+    return $response->setContent($page->render());
+  }
+
+}

src/applications/fact/controller/PhabricatorFactHomeController.php

@@ -0,0 +1,59 @@
+<?php
+
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+final class PhabricatorFactHomeController extends PhabricatorFactController {
+
+  public function processRequest() {
+
+    $facts = id(new PhabricatorFactAggregate())->loadAllWhere(
+      'factType LIKE %> OR factType = %s',
+      '+N:',
+      'updated');
+
+    $rows = array();
+    foreach ($facts as $fact) {
+      $rows[] = array(
+        phutil_escape_html($fact->getFactType()),
+        (int)$fact->getValueX(),
+      );
+    }
+
+    $table = new AphrontTableView($rows);
+    $table->setHeaders(
+      array(
+        'Fact',
+        'Value',
+      ));
+    $table->setColumnClasses(
+      array(
+        'wide',
+        'n',
+      ));
+
+    $panel = new AphrontPanelView();
+    $panel->setHeader('Facts!');
+    $panel->appendChild($table);
+
+    return $this->buildStandardPageResponse(
+      $panel,
+      array(
+        'title' => 'Facts!',
+      ));
+  }
+
+}