Shared constructor

Dice.php

@@ -21,6 +21,11 @@ class Dice {
 	 */
 	private $instances = [];
 
+    /**
+     * @var Stores any instances marked as 'sharedConstructor' so create() can return the same instance
+     */
+	private $sharedConstructor = [];
+
 	/**
 	 * Add a rule $rule to the class $name
 	 * @param string $name The name of the class to add the rule for
@@ -61,6 +66,12 @@ public function create($name, array $args = [], array $share = []) {
 		// Is there a shared instance set? Return it. Better here than a closure for this, calling a closure is slower.
 		if (!empty($this->instances[$name])) return $this->instances[$name];
 
+        $rules = $this->getRule($name);
+        if (!empty($rules['sharedConstructor']) && isset($this->sharedConstructor[$name])) {
+            $snapshot = $this->snapshotArray($args);
+            if (!empty($this->sharedConstructor[$name][$snapshot])) return $this->sharedConstructor[$name][$snapshot]; 
+        }
+
 		// Create a closure for creating the object if there isn't one already
 		if (empty($this->cache[$name])) $this->cache[$name] = $this->getClosure($name, $this->getRule($name));
 
@@ -91,6 +102,18 @@ private function getClosure($name, array $rule) {
 			if ($constructor) $constructor->invokeArgs($this->instances[$name], $params($args, $share));
 			return $this->instances[$name];
 		};
+        else if (!empty($rule['sharedConstructor'])) $closure = function (array $args, array $share) use ($class, $name, $constructor, $params) {
+			//Shared instance: create the class without calling the constructor (and write to \$name and $name, see issue #68)
+            $snapshot = $this->snapshotArray($args);
+            if (!isset($this->sharedConstructor[$name])) {
+                $this->sharedConstructor[$name] = [];
+            }
+            $this->sharedConstructor[$name][$snapshot] = $this->sharedConstructor[ltrim($name, '\\')][$snapshot] = $class->newInstanceWithoutConstructor();
+
+			//Now call this constructor after constructing all the dependencies. This avoids problems with cyclic references (issue #7)
+			if ($constructor) $constructor->invokeArgs($this->sharedConstructor[$name][$snapshot], $params($args, $share));
+			return $this->sharedConstructor[$name][$snapshot];
+		};
 		else if ($params) $closure = function (array $args, array $share) use ($class, $params) {
 			// This class has depenencies, call the $params closure to generate them based on $args and $share
 			return new $class->name(...$params($args, $share));
@@ -184,4 +207,26 @@ private function getParams(\ReflectionMethod $method, array $rule) {
 			return $parameters;
 		};
 	}
+
+    /**
+     * Creates an unique hash for an array
+     * @param array $args
+     * @return string unique hash for an array
+     */
+    private function snapshotArray(array $args = [])
+    {
+        $res = "";
+        foreach ($args as $key => $arg) {
+            if (is_object($arg)) {
+                $res .= spl_object_hash($arg);
+            } elseif (is_array($arg)) {
+                $res .= $this->snapshotArray($arg);
+            } else {
+                $res .= $arg;
+            }
+            $res = $key . $res;
+        }
+        return $res;
+        #return md5($res);
+    }
 }

tests/ShareInstancesTest.php

@@ -86,4 +86,4 @@ public function testShareInstancesMultiple() {
 		$this->assertNotEquals($shareTest->share1->shared->uniq, $shareTest2->share2->shared->uniq);
 
 	}
-}
+}

tests/SharedConstructorTest.php

@@ -0,0 +1,96 @@
+<?php
+class SharedConstructorTest extends DiceTest
+{
+    public function testSharedConstructor()
+    {
+        $rule = [];
+        $rule['sharedConstructor'] = ['true'];
+        $this->dice->addRule('Test\SharedConstructor\Greeter', $rule);
+
+        $greeter = $this->dice->create('Test\SharedConstructor\Greeter');
+        $actual = $greeter->greet("John Doe");
+        $expected = "Hi, John Doe!";
+        $this->assertEquals($expected, $actual);
+        $actual = $greeter->greet("John Doe");
+        $expected = "From cache: Hi, John Doe!";
+        $this->assertEquals($expected, $actual);
+
+        $greeter2 = $this->dice->create('Test\SharedConstructor\Greeter');
+        $actual = $greeter2->greet("John Doe");
+        $expected = "From cache: Hi, John Doe!";
+        $this->assertEquals($expected, $actual);
+        $this->assertSame($greeter, $greeter2);
+    }
+
+    public function testSharedConstructorComplex()
+    {
+        $sharedConstructor = ['sharedConstructor' => true];
+        $singleton = ['shared' => true];
+        $this->dice->addRule('Test\SharedConstructor\BarBazShared', $sharedConstructor);
+        $this->dice->addRule('Test\SharedConstructor\BarBaz', $sharedConstructor);
+        $this->dice->addRule('Test\SharedConstructor\Baz', $singleton);
+
+        $bar = $this->dice->create('Test\SharedConstructor\Bar', ['I am bar']);
+        $baz = $this->dice->create('Test\SharedConstructor\Baz', ['I am baz']);
+        $barBaz = $this->dice->create('Test\SharedConstructor\BarBaz', [$bar, $baz]);
+        $strongWrapper = function ($str) {
+            return "<strong>$str</strong>";
+        };
+        $bWrapper = function ($str) {
+            return "<b>$str</b>";
+        };
+        $barBazShared = $this->dice->create(
+            'Test\SharedConstructor\BarBazShared',
+            [$barBaz, $strongWrapper]
+        );
+        $barBazShared2 = $this->dice->create(
+            'Test\SharedConstructor\BarBazShared',
+            [$barBaz, $strongWrapper]
+        );
+
+        $this->assertEquals($barBazShared->id, $barBazShared2->id);
+
+        # Bar is not shared, so Dice will create new instance
+        # Despite that the argument to Bar is the same
+        $anotherBar = $this->dice->create(
+            'Test\SharedConstructor\Bar',
+            ['I am bar']
+        );
+        $anotherBarBaz = $this->dice->create(
+            'Test\SharedConstructor\BarBaz',
+            [$anotherBar, $baz]
+        );
+        $barBazShared3 = $this->dice->create(
+            'Test\SharedConstructor\BarBazShared',
+            [$anotherBarBaz, $strongWrapper]
+        );
+        $this->assertFalse($barBazShared3->id == $barBazShared->id);
+        $this->assertFalse($barBazShared3->id == $barBazShared2->id);
+
+        $this->assertEquals($barBazShared3->getBarBazWrapped(), $barBazShared->getBarBazWrapped());
+        $this->assertEquals($barBazShared3->getBarBazWrapped(), $barBazShared2->getBarBazWrapped());
+
+        # Baz is the same always even if we pass different param to the constructor
+        $sameBaz = $this->dice->create(
+            'Test\SharedConstructor\Baz',
+            ['I am another baz']
+        );
+        $sameBarBaz = $this->dice->create(
+            'Test\SharedConstructor\BarBaz',
+            [$bar, $sameBaz]
+        );
+        $barBazShared4 = $this->dice->create(
+            'Test\SharedConstructor\BarBazShared',
+            [$sameBarBaz, $strongWrapper]
+        );
+        $this->assertEquals($barBazShared4->id, $barBazShared->id);
+
+        # test change closure
+        $barBazShared5 = $this->dice->create(
+            'Test\SharedConstructor\BarBazShared',
+            [$sameBarBaz, $bWrapper]
+        );
+        $this->assertFalse($barBazShared5->id == $barBazShared->id);
+        $this->assertFalse($barBazShared5->id == $barBazShared4->id);
+    }
+}

tests/TestData/SharedConstructor.php

@@ -0,0 +1,109 @@
+<?php
+# First test-case. We are interested in getting data from cache if we created an object twice
+# with same constructor params using Dice
+
+namespace Test\SharedConstructor;
+
+class Greeter
+{
+    protected $greeting;
+
+    protected $cache = array();
+
+    public function __construct($greeting = "Hi")
+    {
+        $this->greeting = $greeting;
+    }
+
+    public function greet($name)
+    {
+        if (!empty($this->cache[$name])) {
+            return "From cache: " . $this->cache[$name];
+        }
+        $this->cache[$name] = sprintf("%s, %s!", $this->greeting, $name);
+        return $this->cache[$name];
+    }
+}
+
+# Second test case. We are interested in more complex sharedConstructor usage.
+# Namely, we want constructor to receive objects and closures so we can test
+# arguments are hashed correctly
+class BarBazShared
+{
+    private $barBaz;
+    private $clo;
+    public $id;
+
+    public function __construct(BarBaz $barBaz, \Closure $clo)
+    {
+        $this->barBaz = $barBaz;
+        $this->clo = $clo;
+        $this->id = microtime(); // should stay the same if instance is the same
+    }
+
+    public function getUid()
+    {
+    }
+
+    public function getBarBazWrapped()
+    {
+        $clo = $this->clo;
+        return $clo(sprintf(
+            "Bar: %s, baz: %s",
+            $this->barBaz->getBar()->value(),
+            $this->barBaz->getBaz()->value()
+        ));
+    }
+}
+
+class BarBaz
+{
+    private $bar;
+    private $baz;
+
+    public function __construct(Bar $bar, Baz $baz)
+    {
+        $this->bar = $bar;
+        $this->baz = $baz;
+    }
+
+    public function getBar()
+    {
+        return $this->bar;
+    }
+
+    public function getBaz()
+    {
+        return $this->baz;
+    }
+}
+
+class Bar
+{
+    private $bar;
+
+    public function __construct($bar)
+    {
+        $this->bar = $bar;
+    }
+
+    public function value()
+    {
+        return $this->bar;
+    }
+}
+
+class Baz
+{
+    private $baz;
+
+    public function __construct($baz)
+    {
+        $this->baz = $baz;
+    }
+
+    public function value()
+    {
+        return $this->baz;
+    }
+}