Add support for XLIFF unit IDs

src/Extractors/Xliff.php

@@ -34,6 +34,9 @@ public static function fromString($string, Translations $translations, array $op
                     }
 
                     $translation = new Translation(null, (string) $segment->source);
+                    if (isset($unit['id'])) {
+                        $translation->addComment("XLIFF_UNIT_ID: $unit[id]");
+                    }
                     $translation->setTranslation(array_shift($targets));
                     $translation->setPluralTranslations($targets);
 

src/Generators/Xliff.php

@@ -2,11 +2,14 @@
 
 namespace Gettext\Generators;
 
+use Gettext\Translation;
 use Gettext\Translations;
 use DOMDocument;
 
 class Xliff extends Generator implements GeneratorInterface
 {
+    const UNIT_ID_REGEXP = '/^XLIFF_UNIT_ID: (.*)$/';
+
     /**
      * {@inheritdoc}
      */
@@ -34,8 +37,11 @@ public static function toString(Translations $translations, array $options = [])
         }
 
         foreach ($translations as $translation) {
+            //Find an XLIFF unit ID, if one is available; otherwise generate
+            $unitId = self::getUnitID($translation)?:md5($translation->getContext().$translation->getOriginal());
+
             $unit = $dom->createElement('unit');
-            $unit->setAttribute('id', md5($translation->getContext().$translation->getOriginal()));
+            $unit->setAttribute('id', $unitId);
 
             //Save comments as notes
             $notes = $dom->createElement('notes');
@@ -44,6 +50,11 @@ public static function toString(Translations $translations, array $options = [])
                 ->setAttribute('category', 'context');
 
             foreach ($translation->getComments() as $comment) {
+                //Skip XLIFF unit ID comments.
+                if (preg_match(self::UNIT_ID_REGEXP, $comment)) {
+                    continue;
+                }
+
                 $notes->appendChild(self::createTextNode($dom, 'note', $comment))
                     ->setAttribute('category', 'comment');
             }
@@ -91,4 +102,21 @@ private static function createTextNode(DOMDocument $dom, $name, $string)
 
         return $node;
     }
+
+    /**
+     * Gets the translation's unit ID, if one is available.
+     *
+     * @param Translation $translation
+     *
+     * @return string|null
+     */
+    public static function getUnitID(Translation $translation)
+    {
+        foreach ($translation->getComments() as $comment) {
+            if (preg_match(self::UNIT_ID_REGEXP, $comment, $matches)) {
+                return $matches[1];
+            }
+        }
+        return null;
+    }
 }

tests/AssetsTest.php

@@ -501,4 +501,25 @@ public function testPhpCode4()
         $this->runTestFormat('phpcode4/YamlDictionary', $countTranslations, $countTranslated);
     }
 
+    public function testXliff()
+    {
+        $translations = static::get('xliff/Xliff', 'Xliff');
+        $countTranslations = 2;
+        $countTranslated = 2;
+        $countHeaders = 9;
+
+        $this->assertCount($countTranslations, $translations);
+        $this->assertCount($countHeaders, $translations->getHeaders());
+        $this->assertEquals(2, $translations->countTranslated());
+
+        $translation1 = $translations->find(null, 'one file');
+        $this->assertEquals(\Gettext\Generators\Xliff::getUnitID($translation1), 'custom.unit.id');
+
+        $translation2 = $translations->find(null, 'one');
+        $this->assertEquals(\Gettext\Generators\Xliff::getUnitID($translation2), 'second.custom.unit.id');
+
+        $this->assertContent($translations, 'xliff/Po');
+
+        $this->runTestFormat('xliff/Po', $countTranslations, $countTranslated, $countHeaders);
+    }
 }

tests/assets/xliff/Po.po

@@ -0,0 +1,20 @@
+msgid ""
+msgstr ""
+"Content-Transfer-Encoding: 8bit\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Language: \n"
+"Language-Team: \n"
+"Last-Translator: \n"
+"MIME-Version: 1.0\n"
+"Plural-Forms: nplurals=3; plural=(n==1 ? 0 : n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2);\n"
+"Project-Id-Version: \n"
+"Report-Msgid-Bugs-To: \n"
+
+# XLIFF_UNIT_ID: custom.unit.id
+# Taken from http://www.gnu.org/savannah-checkouts/gnu/gettext/manual/html_node/Plural-forms.html
+msgid "one file"
+msgstr "1 plik"
+
+# XLIFF_UNIT_ID: second.custom.unit.id
+msgid "one"
+msgstr "1"

tests/assets/xliff/Xliff.xlf

@@ -0,0 +1,35 @@
+<?xml version="1.0" encoding="utf-8"?>
+<xliff xmlns="urn:oasis:names:tc:xliff:document:2.0" version="2.0" srcLang="" trgLang="">
+  <file id=".">
+    <notes>
+      <note id="Content-Transfer-Encoding">8bit</note>
+      <note id="Content-Type">text/plain; charset=UTF-8</note>
+      <note id="Language"></note>
+      <note id="Language-Team"></note>
+      <note id="Last-Translator"></note>
+      <note id="MIME-Version">1.0</note>
+      <note id="Plural-Forms"><![CDATA[nplurals=3; plural=(n==1 ? 0 : n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2);]]></note>
+      <note id="Project-Id-Version"></note>
+      <note id="Report-Msgid-Bugs-To"></note>
+    </notes>
+    <unit id="custom.unit.id">
+      <notes>
+        <note category="context"></note>
+        <note category="comment">Taken from http://www.gnu.org/savannah-checkouts/gnu/gettext/manual/html_node/Plural-forms.html</note>
+      </notes>
+      <segment>
+        <source>one file</source>
+        <target>1 plik</target>
+      </segment>
+    </unit>
+    <unit id="second.custom.unit.id">
+      <notes>
+        <note category="context"></note>
+      </notes>
+      <segment>
+        <source>one</source>
+        <target>1</target>
+      </segment>
+    </unit>
+  </file>
+</xliff>