feature #11404 [CssSelector] Add compare method to Specificity (barryvdh)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[CssSelector] Add compare method to Specificity

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #11400
| License       | MIT
| Doc PR        | -

TODO:
- [x] Add some tests

Add compare method to Specificity class, so we can compare the specificity without using the value, so it doesn't matter if the base isn't high enough (for example, 1,0,0 should be higher then 0,11,0. Currently with using values, this wouldn't be possible (100 vs 110).
As discussed in #11400, the getValue() isn't completely correct for every case, see the spec http://www.w3.org/TR/selectors/#specificity

Use case would, for example, be sorting an array of multiple properties.

Commits
-------

afbaf19 Add compare method to Specificity

src/Symfony/Component/CssSelector/Node/Specificity.php

@@ -75,4 +75,28 @@ class Specificity
     {
         return $this->a * self::A_FACTOR + $this->b * self::B_FACTOR + $this->c * self::C_FACTOR;
     }
+
+    /**
+     * Returns -1 if the object specificity is lower than the argument,
+     * 0 if they are equal, and 1 if the argument is lower
+     *
+     * @param Specificity $specificity
+     * @return int
+     */
+    public function compare(Specificity $specificity)
+    {
+        if ($this->a !== $specificity->a) {
+            return $this->a > $specificity->a ? 1 : -1;
+        }
+        
+        if ($this->b !== $specificity->b) {
+            return $this->b > $specificity->b ? 1 : -1;
+        }
+        
+        if ($this->c !== $specificity->c) {
+            return $this->c > $specificity->c ? 1 : -1;
+        }
+
+        return 0;
+    }
 }

src/Symfony/Component/CssSelector/Tests/Node/SpecificityTest.php

@@ -37,4 +37,26 @@ class SpecificityTest extends \PHPUnit_Framework_TestCase
             array(new Specificity(4, 3, 2), 432),
         );
     }
+
+    /** @dataProvider getCompareTestData */
+    public function testCompare(Specificity $a, Specificity $b, $result)
+    {
+        $this->assertEquals($result, $a->compare($b));
+    }
+
+    public function getCompareTestData()
+    {
+        return array(
+            array(new Specificity(0, 0, 0), new Specificity(0, 0, 0), 0),
+            array(new Specificity(0, 0, 1), new Specificity(0, 0, 1), 0),
+            array(new Specificity(0, 0, 2), new Specificity(0, 0, 1), 1),
+            array(new Specificity(0, 0, 2), new Specificity(0, 0, 3), -1),
+            array(new Specificity(0, 4, 0), new Specificity(0, 4, 0), 0),
+            array(new Specificity(0, 6, 0), new Specificity(0, 5, 11), 1),
+            array(new Specificity(0, 7, 0), new Specificity(0, 8, 0), -1),
+            array(new Specificity(9, 0, 0), new Specificity(9, 0, 0), 0),
+            array(new Specificity(11, 0, 0), new Specificity(10, 11, 0), 1),
+            array(new Specificity(12, 11, 0), new Specificity(13, 0, 0), -1),
+        );
+    }
 }