1 files changed, 130 insertions, 0 deletions
diff --git a/common/app/helpers.php b/common/app/helpers.php
new file mode 100644
index 0000000..e943252
--- /dev/null
+++ b/common/app/helpers.php
@@ -0,0 +1,130 @@
+<?php
+
+/**
+ * Register polyfills for old PHP versions.
+ * 
+ * This way, the real function will only be called if it
+ * is available, and we won't force the use of our own 
+ * implementation.
+ */
+function register_polyfills()
+{
+    if (!function_exists('hash_equals')) {
+        function hash_equals($known_string, $user_string) {
+            call_user_func_array('_hash_equals', func_get_args());
+        }
+    }
+
+    if (!function_exists('random_bytes')) {
+        // If this function does not exist, it will be exposed
+        // automatically by paragonie/random_compat.
+    }
+}
+
+register_polyfills();
+
+/**
+ * Path to the _custom_ directory.
+ *
+ * @param  string $file Append this filename to the returned path.
+ * @return string
+ */
+function custom_path($file = '')
+{
+    return __DIR__.'/../custom' . (!empty($file) ? '/'.$file : '');
+}
+
+/**
+ * Path to the _views_ directory.
+ *
+ * @param  string $file Append this filename to the returned path.
+ * @return string
+ */
+function views_path($file = '')
+{
+    return custom_path('views/' . $file);
+}
+
+/**
+ * Path to the _admin_ directory.
+ *
+ * @param  string $file Append this filename to the returned path.
+ * @return string
+ */
+function admin_path($file = '')
+{
+    return __DIR__.'/../admin' . (!empty($file) ? '/'.$file : '');
+}
+
+/**
+ * Is moonmoon installed?
+ *
+ * @return bool
+ */
+function is_installed()
+{
+    return file_exists(custom_path('config.yml')) && file_exists(custom_path('people.opml'));
+}
+
+/**
+ * Shortcut to Simplel10n::getString().
+ *
+ * @param  string $str
+ * @param  string $comment
+ * @return string
+ */
+function _g($str, $comment='')
+{
+    return Simplel10n::getString($str, $comment);
+}
+
+/**
+ * Reset the moonmoon instance.
+ */
+function removeCustomFiles()
+{
+    $toRemove = [
+        custom_path('config.yml'),
+        custom_path('people.opml'),
+        custom_path('people.opml.bak'),
+        custom_path('cache')
+    ];
+
+    foreach ($toRemove as $path) {
+        if (file_exists($path)) {
+            unlink($path);
+        }
+    }
+}
+
+/**
+ * Compare two strings in a constant-time manner.
+ *
+ * It returns `true` if both strings are exactly the same
+ * (same size and same value).
+ *
+ * @param  string $known_string
+ * @param  string $user_string
+ * @return bool
+ */
+function _hash_equals($known_string = '', $user_string = '')
+{
+    // In our case, it's not problematic if `$known_string`'s 
+    // size leaks, we will only compare password hashes and 
+    // CSRF tokens—their size is already somehow public.
+    if (!is_string($known_string) || !is_string($user_string) 
+         || strlen($known_string) !== strlen($user_string)) {
+        return false;
+    }
+
+    $ret = 0;    
+
+    // Do not stop the comparison when a difference is found,
+    // always completely compare them.
+    for ($i = 0; $i < strlen($known_string); $i++) {
+        $ret |=  (ord($known_string[$i]) ^ ord($user_string[$i]));
+    }   
+
+    return !$ret;
+}
+