Replace Nested Conditional with Guard Clauses

1 files changed, 142 insertions, 140 deletions

diff --git a/lib/random.php b/lib/random.php
index d88f06a..aa3fe96 100644
--- a/lib/random.php
+++ b/lib/random.php
@@ -44,171 +44,173 @@ if (!defined('PHP_VERSION_ID')) {
 /**
  * PHP 7.0.0 and newer have these functions natively.
  */
-if (PHP_VERSION_ID < 70000) {
-    if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
-        define('RANDOM_COMPAT_READ_BUFFER', 8);
-    }
+if (PHP_VERSION_ID >= 70000) {
+    return;
+}
 
-    $RandomCompatDIR = dirname(__FILE__);
+if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
+    define('RANDOM_COMPAT_READ_BUFFER', 8);
+}
 
-    require_once $RandomCompatDIR.'/byte_safe_strings.php';
-    require_once $RandomCompatDIR.'/cast_to_int.php';
-    require_once $RandomCompatDIR.'/error_polyfill.php';
+$RandomCompatDIR = dirname(__FILE__);
 
-    if (!is_callable('random_bytes')) {
-        /**
-         * PHP 5.2.0 - 5.6.x way to implement random_bytes()
-         *
-         * We use conditional statements here to define the function in accordance
-         * to the operating environment. It's a micro-optimization.
-         *
-         * In order of preference:
-         *   1. Use libsodium if available.
-         *   2. fread() /dev/urandom if available (never on Windows)
-         *   3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
-         *   4. COM('CAPICOM.Utilities.1')->GetRandom()
-         *
-         * See RATIONALE.md for our reasoning behind this particular order
-         */
-        if (extension_loaded('libsodium')) {
-            // See random_bytes_libsodium.php
-            if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) {
-                require_once $RandomCompatDIR.'/random_bytes_libsodium.php';
-            } elseif (method_exists('Sodium', 'randombytes_buf')) {
-                require_once $RandomCompatDIR.'/random_bytes_libsodium_legacy.php';
-            }
+require_once $RandomCompatDIR.'/byte_safe_strings.php';
+require_once $RandomCompatDIR.'/cast_to_int.php';
+require_once $RandomCompatDIR.'/error_polyfill.php';
+
+if (!is_callable('random_bytes')) {
+    /**
+     * PHP 5.2.0 - 5.6.x way to implement random_bytes()
+     *
+     * We use conditional statements here to define the function in accordance
+     * to the operating environment. It's a micro-optimization.
+     *
+     * In order of preference:
+     *   1. Use libsodium if available.
+     *   2. fread() /dev/urandom if available (never on Windows)
+     *   3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
+     *   4. COM('CAPICOM.Utilities.1')->GetRandom()
+     *
+     * See RATIONALE.md for our reasoning behind this particular order
+     */
+    if (extension_loaded('libsodium')) {
+        // See random_bytes_libsodium.php
+        if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) {
+            require_once $RandomCompatDIR.'/random_bytes_libsodium.php';
+        } elseif (method_exists('Sodium', 'randombytes_buf')) {
+            require_once $RandomCompatDIR.'/random_bytes_libsodium_legacy.php';
         }
+    }
 
-        /**
-         * Reading directly from /dev/urandom:
-         */
-        if (DIRECTORY_SEPARATOR === '/') {
-            // DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast
-            // way to exclude Windows.
-            $RandomCompatUrandom = true;
-            $RandomCompat_basedir = ini_get('open_basedir');
-
-            if (!empty($RandomCompat_basedir)) {
-                $RandomCompat_open_basedir = explode(
-                    PATH_SEPARATOR,
-                    strtolower($RandomCompat_basedir)
-                );
-                $RandomCompatUrandom = (array() !== array_intersect(
-                    array('/dev', '/dev/', '/dev/urandom'),
-                    $RandomCompat_open_basedir
-                ));
-                $RandomCompat_open_basedir = null;
-            }
+    /**
+     * Reading directly from /dev/urandom:
+     */
+    if (DIRECTORY_SEPARATOR === '/') {
+        // DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast
+        // way to exclude Windows.
+        $RandomCompatUrandom = true;
+        $RandomCompat_basedir = ini_get('open_basedir');
 
-            if (
-                !is_callable('random_bytes')
-                &&
-                $RandomCompatUrandom
-                &&
-                @is_readable('/dev/urandom')
-            ) {
-                // Error suppression on is_readable() in case of an open_basedir
-                // or safe_mode failure. All we care about is whether or not we
-                // can read it at this point. If the PHP environment is going to
-                // panic over trying to see if the file can be read in the first
-                // place, that is not helpful to us here.
-
-                // See random_bytes_dev_urandom.php
-                require_once $RandomCompatDIR.'/random_bytes_dev_urandom.php';
-            }
-            // Unset variables after use
-            $RandomCompat_basedir = null;
-        } else {
-            $RandomCompatUrandom = false;
+        if (!empty($RandomCompat_basedir)) {
+            $RandomCompat_open_basedir = explode(
+                PATH_SEPARATOR,
+                strtolower($RandomCompat_basedir)
+            );
+            $RandomCompatUrandom = (array() !== array_intersect(
+                array('/dev', '/dev/', '/dev/urandom'),
+                $RandomCompat_open_basedir
+            ));
+            $RandomCompat_open_basedir = null;
         }
 
-        /**
-         * mcrypt_create_iv()
-         *
-         * We only want to use mcypt_create_iv() if:
-         *
-         * - random_bytes() hasn't already been defined
-         * - PHP >= 5.3.7
-         * - the mcrypt extensions is loaded
-         * - One of these two conditions is true:
-         *   - We're on Windows (DIRECTORY_SEPARATOR !== '/')
-         *   - We're not on Windows and /dev/urandom is readabale
-         *     (i.e. we're not in a chroot jail)
-         * - Special case:
-         *   - If we're not on Windows, but the PHP version is between
-         *     5.6.10 and 5.6.12, we don't want to use mcrypt. It will
-         *     hang indefinitely. This is bad.
-         */
         if (
             !is_callable('random_bytes')
             &&
-            PHP_VERSION_ID >= 50307
+            $RandomCompatUrandom
             &&
-            extension_loaded('mcrypt')
+            @is_readable('/dev/urandom')
         ) {
-            // Prevent this code from hanging indefinitely on non-Windows;
-            // see https://bugs.php.net/bug.php?id=69833
-            if (
-                DIRECTORY_SEPARATOR !== '/' || 
-                (PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
-            ) {
-                // See random_bytes_mcrypt.php
-                require_once $RandomCompatDIR.'/random_bytes_mcrypt.php';
-            }
+            // Error suppression on is_readable() in case of an open_basedir
+            // or safe_mode failure. All we care about is whether or not we
+            // can read it at this point. If the PHP environment is going to
+            // panic over trying to see if the file can be read in the first
+            // place, that is not helpful to us here.
+
+            // See random_bytes_dev_urandom.php
+            require_once $RandomCompatDIR.'/random_bytes_dev_urandom.php';
         }
-        $RandomCompatUrandom = null;
+        // Unset variables after use
+        $RandomCompat_basedir = null;
+    } else {
+        $RandomCompatUrandom = false;
+    }
 
-        /**
-         * This is a Windows-specific fallback, for when the mcrypt extension
-         * isn't loaded.
-         */
+    /**
+     * mcrypt_create_iv()
+     *
+     * We only want to use mcypt_create_iv() if:
+     *
+     * - random_bytes() hasn't already been defined
+     * - PHP >= 5.3.7
+     * - the mcrypt extensions is loaded
+     * - One of these two conditions is true:
+     *   - We're on Windows (DIRECTORY_SEPARATOR !== '/')
+     *   - We're not on Windows and /dev/urandom is readabale
+     *     (i.e. we're not in a chroot jail)
+     * - Special case:
+     *   - If we're not on Windows, but the PHP version is between
+     *     5.6.10 and 5.6.12, we don't want to use mcrypt. It will
+     *     hang indefinitely. This is bad.
+     */
+    if (
+        !is_callable('random_bytes')
+        &&
+        PHP_VERSION_ID >= 50307
+        &&
+        extension_loaded('mcrypt')
+    ) {
+        // Prevent this code from hanging indefinitely on non-Windows;
+        // see https://bugs.php.net/bug.php?id=69833
         if (
-            !is_callable('random_bytes')
-            &&
-            extension_loaded('com_dotnet')
-            &&
-            class_exists('COM')
+            DIRECTORY_SEPARATOR !== '/' || 
+            (PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
         ) {
-            $RandomCompat_disabled_classes = preg_split(
-                '#\s*,\s*#',
-                strtolower(ini_get('disable_classes'))
-            );
+            // See random_bytes_mcrypt.php
+            require_once $RandomCompatDIR.'/random_bytes_mcrypt.php';
+        }
+    }
+    $RandomCompatUrandom = null;
 
-            if (!in_array('com', $RandomCompat_disabled_classes)) {
-                try {
-                    $RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');
-                    if (method_exists($RandomCompatCOMtest, 'GetRandom')) {
-                        // See random_bytes_com_dotnet.php
-                        require_once $RandomCompatDIR.'/random_bytes_com_dotnet.php';
-                    }
-                } catch (com_exception $e) {
-                    // Don't try to use it.
+    /**
+     * This is a Windows-specific fallback, for when the mcrypt extension
+     * isn't loaded.
+     */
+    if (
+        !is_callable('random_bytes')
+        &&
+        extension_loaded('com_dotnet')
+        &&
+        class_exists('COM')
+    ) {
+        $RandomCompat_disabled_classes = preg_split(
+            '#\s*,\s*#',
+            strtolower(ini_get('disable_classes'))
+        );
+
+        if (!in_array('com', $RandomCompat_disabled_classes)) {
+            try {
+                $RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');
+                if (method_exists($RandomCompatCOMtest, 'GetRandom')) {
+                    // See random_bytes_com_dotnet.php
+                    require_once $RandomCompatDIR.'/random_bytes_com_dotnet.php';
                 }
+            } catch (com_exception $e) {
+                // Don't try to use it.
             }
-            $RandomCompat_disabled_classes = null;
-            $RandomCompatCOMtest = null;
         }
+        $RandomCompat_disabled_classes = null;
+        $RandomCompatCOMtest = null;
+    }
 
+    /**
+     * throw new Exception
+     */
+    if (!is_callable('random_bytes')) {
         /**
-         * throw new Exception
+         * We don't have any more options, so let's throw an exception right now
+         * and hope the developer won't let it fail silently.
          */
-        if (!is_callable('random_bytes')) {
-            /**
-             * We don't have any more options, so let's throw an exception right now
-             * and hope the developer won't let it fail silently.
-             */
-            function random_bytes($length)
-            {
-                throw new Exception(
-                    'There is no suitable CSPRNG installed on your system'
-                );
-            }
+        function random_bytes($length)
+        {
+            throw new Exception(
+                'There is no suitable CSPRNG installed on your system'
+            );
         }
     }
+}
 
-    if (!is_callable('random_int')) {
-        require_once $RandomCompatDIR.'/random_int.php';
-    }
-
-    $RandomCompatDIR = null;
+if (!is_callable('random_int')) {
+    require_once $RandomCompatDIR.'/random_int.php';
 }
+
+$RandomCompatDIR = null;