First pass of features

includes/db.php

@@ -1,23 +1,65 @@
 <?php
 
-function readJsonFile($filename) {
-    $filepath = __DIR__ . '/../data/' . $filename;
+function getDataDirectory(): string {
+    return __DIR__ . '/../data';
+}
+
+function getDataFilePath(string $filename): string {
+    return getDataDirectory() . '/' . $filename;
+}
+
+function ensureDataDirectory(): void {
+    $dataDir = getDataDirectory();
+    if (!is_dir($dataDir)) {
+        mkdir($dataDir, 0755, true);
+    }
+}
+
+function readJsonFile(string $filename) {
+    $filepath = getDataFilePath($filename);
     if (!file_exists($filepath)) {
         return [];
     }
-    $content = file_get_contents($filepath);
-    return json_decode($content, true) ?? [];
-}
-
-function writeJsonFile($filename, $data) {
-    $filepath = __DIR__ . '/../data/' . $filename;
-    $json = json_encode($data, JSON_PRETTY_PRINT);
-    return file_put_contents($filepath, $json);
-}
-
-function ensureDataDirectory() {
-    $dataDir = __DIR__ . '/../data';
-    if (!file_exists($dataDir)) {
-        mkdir($dataDir, 0755, true);
+    $fp = fopen($filepath, 'rb');
+    if ($fp === false) {
+        return [];
     }
-} 
+    if (!flock($fp, LOCK_SH)) {
+        fclose($fp);
+        return [];
+    }
+    $content = stream_get_contents($fp);
+    flock($fp, LOCK_UN);
+    fclose($fp);
+    if ($content === false || $content === '') {
+        return [];
+    }
+    $decoded = json_decode($content, true);
+    return $decoded ?? [];
+}
+
+function writeJsonFile(string $filename, $data): bool {
+    ensureDataDirectory();
+    $filepath = getDataFilePath($filename);
+    $fp = fopen($filepath, 'c+');
+    if ($fp === false) {
+        return false;
+    }
+    if (!flock($fp, LOCK_EX)) {
+        fclose($fp);
+        return false;
+    }
+    $json = json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);
+    if ($json === false) {
+        flock($fp, LOCK_UN);
+        fclose($fp);
+        return false;
+    }
+    ftruncate($fp, 0);
+    rewind($fp);
+    $written = fwrite($fp, $json);
+    fflush($fp);
+    flock($fp, LOCK_UN);
+    fclose($fp);
+    return $written !== false;
+}