Refactor using other packages (#3)

- Abandon Laravel 5.6 and 5.7
- Add dependencies
  - [mpyw/unclosure: Closure unwrapper especially suited for Laravel PDO.](https://github.com/mpyw/unclosure)
  - [mpyw/laravel-pdo-emulation-control: Temporarily enable/disable PDO prepared statement emulation](https://github.com/mpyw/laravel-pdo-emulation-control)
  - Remove `PdoDecorator` and introduce some new classes

Author: mpyw

.travis.yml

@@ -22,8 +22,6 @@ cache:
 env:
   - LARAVEL_VERSION=^6.0 TESTBENCH_VERSION=^4.0
   - LARAVEL_VERSION=5.8.* TESTBENCH_VERSION=3.8.*
-  - LARAVEL_VERSION=5.7.* TESTBENCH_VERSION=3.7.*
-  - LARAVEL_VERSION=5.6.* TESTBENCH_VERSION=3.6.*
 
 before_install:
   - sudo rm /usr/local/bin/docker-compose

README.md

@@ -5,7 +5,7 @@ A tiny extension of `MySqlConnection` that manages **session** system variables
 ## Requirements
 
 - PHP: ^7.1
-- Laravel: ^5.6 || ^6.0
+- Laravel: ^5.8 || ^6.0
 
 ## Installing
 

composer.json

@@ -23,8 +23,10 @@
     "require": {
         "php": "^7.1",
         "ext-pdo": "*",
-        "illuminate/support": "^5.6 || ^6.0 || ^7.0 || ^8.0",
-        "illuminate/database": "^5.6 || ^6.0 || ^7.0 || ^8.0"
+        "illuminate/support": "^5.8 || ^6.0 || ^7.0 || ^8.0",
+        "illuminate/database": "^5.8 || ^6.0 || ^7.0 || ^8.0",
+        "mpyw/unclosure": "^0.1.0",
+        "mpyw/laravel-pdo-emulation-control": "^0.1.0"
     },
     "require-dev": {
         "orchestra/testbench": "^4.0",

src/ManagesSystemVariables.php

@@ -41,9 +41,7 @@ public function setSystemVariable(string $key, $value, bool $memoizeForReconnect
      */
     public function setSystemVariables(array $values, bool $memoizeForReconnect = true)
     {
-        foreach (array_filter([&$this->pdo, &$this->readPdo]) as &$pdo) {
-            $pdo = PdoDecorator::withSystemVariables($pdo, $values);
-        }
+        (new SystemVariableAssigner($this->readPdo, $this->pdo))->assign($values);
 
         if (!$this->reconnector instanceof SystemVariableAwareReconnector) {
             $this->setReconnector(new SystemVariableAwareReconnector($this->reconnector));

src/PdoDecorator.php

@@ -0,0 +1,95 @@
+<?php
+
+namespace Mpyw\LaravelMySqlSystemVariableManager;
+
+use Closure;
+use Mpyw\LaravelPdoEmulationControl\EmulationController;
+use Mpyw\Unclosure\Value;
+use PDO;
+use Mpyw\LaravelMySqlSystemVariableManager\SystemVariableGrammar as Grammar;
+
+class SystemVariableAssigner
+{
+    /**
+     * @var \Closure[]|\PDO[]
+     */
+    protected $pdos;
+
+    /**
+     * SystemVariableAssigner constructor.
+     *
+     * @param null|\Closure|\PDO &...$pdos
+     */
+    public function __construct(&...$pdos)
+    {
+        $this->pdos = array_filter($pdos);
+    }
+
+    /**
+     * Set MySQL system variables for PDO.
+     *
+     * @param  array $values
+     * @return $this
+     */
+    public function assign(array $values)
+    {
+        return $values
+            ? $this->withEmulatedStatement(Grammar::assignmentStatement($values), $values)
+            : $this;
+    }
+
+    /**
+     * Configure PDO using query and parameters temporarily enabling PDO::ATTR_EMULATE_PREPARES.
+     *
+     * @param  string $query
+     * @param  array  $values
+     * @return $this
+     */
+    protected function withEmulatedStatement(string $query, array $values = [])
+    {
+        foreach ($this->pdos as &$pdo) {
+            $pdo = Value::withCallback(
+                $pdo,
+                Closure::fromCallable([$this, 'withEmulatedStatementFor']),
+                $query,
+                $values
+            );
+        }
+        unset($pdo);
+
+        return $this;
+    }
+
+    /**
+     * @param  PDO    $pdo
+     * @param  string $query
+     * @param  array  $values
+     * @return PDO
+     */
+    protected static function withEmulatedStatementFor(PDO $pdo, string $query, array $values): PDO
+    {
+        return (new EmulationController($pdo))->emulated(
+            Closure::fromCallable([static::class, 'withStatementFor']),
+            $pdo,
+            $query,
+            $values
+        );
+    }
+
+    /**
+     * @param  PDO    $pdo
+     * @param  string $query
+     * @param  array  $values
+     * @return PDO
+     */
+    protected static function withStatementFor(PDO $pdo, string $query, array $values): PDO
+    {
+        $statement = $pdo->prepare($query);
+        foreach (array_values($values) as $i => $value) {
+            $statement->bindValue($i + 1, $value, Grammar::paramTypeFor($value));
+        }
+        $statement->execute();
+
+        return $pdo;
+    }
+}

src/SystemVariableAssigner.php

@@ -0,0 +1,70 @@
+<?php
+
+namespace Mpyw\LaravelMySqlSystemVariableManager;
+
+use PDO;
+
+class SystemVariableGrammar
+{
+    /**
+     * @param  array  $values
+     * @return string
+     */
+    public static function assignmentStatement(array $values): string
+    {
+        return 'set session ' . implode(', ', static::assignmentExpressions($values));
+    }
+
+    /**
+     * @param  array    $values
+     * @return string[]
+     */
+    public static function assignmentExpressions(array $values): array
+    {
+        $expressions = [];
+        foreach ($values as $name => $value) {
+            $expressions[] = static::escapeIdentifier($name) . '=' . static::placeholderFor($value);
+        }
+        return $expressions;
+    }
+
+    /**
+     * @param  mixed $value
+     * @return int
+     */
+    public static function paramTypeFor($value): int
+    {
+        switch (gettype($value)) {
+            case 'integer':
+                return PDO::PARAM_INT;
+            case 'boolean':
+                return PDO::PARAM_BOOL;
+            case 'NULL':
+            default:
+                return PDO::PARAM_STR;
+        }
+    }
+
+    /**
+     * @param  mixed  $value
+     * @return string
+     */
+    public static function placeholderFor($value): string
+    {
+        switch (gettype($value)) {
+            case 'double':
+                return 'cast(? as decimal(65, 30))';
+            default:
+                return '?';
+        }
+    }
+
+    /**
+     * @param  string $identifier
+     * @return string
+     */
+    public static function escapeIdentifier(string $identifier): string
+    {
+        return '`' . str_replace('`', '``', $identifier) . '`';
+    }
+}