Add a new exporter GvConvert to export a Graphviz script into another…

… format.

composer.json

@@ -19,6 +19,7 @@
         "php": ">=7.1"
     },
     "require-dev": {
+        "drupol/launcher": "^1.0",
         "drupol/php-conventions": "^1",
         "drupol/phpspec-annotation": "^1",
         "graphp/graphviz": "^0.2",

spec/drupol/phptree/Exporter/GvConvertSpec.php

@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace spec\drupol\phptree\Exporter;
+
+use drupol\phptree\Exporter\GvConvert;
+use drupol\phptree\Node\ValueNode;
+use PhpSpec\ObjectBehavior;
+
+class GvConvertSpec extends ObjectBehavior
+{
+    public function it_can_convert_a_tree_into_a_file()
+    {
+        $tree = new ValueNode('root');
+
+        $this
+            ->export($tree)
+            ->shouldBeString();
+    }
+
+    public function it_can_set_and_get_the_executable()
+    {
+        $this
+            ->getExecutable()
+            ->shouldBe('dot');
+
+        $this
+            ->setExecutable('foo')
+            ->shouldReturn($this);
+
+        $this
+            ->getExecutable()
+            ->shouldBe('foo');
+    }
+
+    public function it_can_set_and_get_the_format()
+    {
+        $this
+            ->getFormat()
+            ->shouldReturn('svg');
+
+        $this
+            ->setFormat('png')
+            ->shouldReturn($this);
+
+        $this
+            ->getFormat()
+            ->shouldReturn('png');
+    }
+    public function it_is_initializable()
+    {
+        $this->shouldHaveType(GvConvert::class);
+
+        $this
+            ->getExecutable()
+            ->shouldReturn('dot');
+    }
+}

src/Exporter/GvConvert.php

@@ -0,0 +1,146 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace drupol\phptree\Exporter;
+
+use drupol\phptree\Node\NodeInterface;
+
+/**
+ * Class GvConvert.
+ */
+class GvConvert extends Gv
+{
+    /**
+     * @var string
+     */
+    private $executable = 'dot';
+    /**
+     * @var string
+     */
+    private $format = 'svg';
+
+    /**
+     * GvDisplay constructor.
+     */
+    public function __construct()
+    {
+        if (0 === \stripos(PHP_OS, 'WIN')) {
+            $this->executable = 'dot.exe';
+        }
+    }
+
+    /**
+     * @param \drupol\phptree\Node\NodeInterface $node
+     *
+     * @throws \Exception
+     *
+     * @return string
+     */
+    public function export(NodeInterface $node): string
+    {
+        $path = $this->getTemporaryFile();
+
+        $this->writeToFile($path, parent::export($node));
+
+        \system($this->getConvertCommand($path));
+
+        return \sprintf('%s.%s', $path, $this->getFormat());
+    }
+
+    /**
+     * Get the executable to use.
+     *
+     * @return string
+     */
+    public function getExecutable(): string
+    {
+        return $this->executable;
+    }
+
+    /**
+     * @return string
+     */
+    public function getFormat(): string
+    {
+        return $this->format;
+    }
+
+    /**
+     * Change the executable to use.
+     *
+     * @param string $executable
+     *
+     * @return \drupol\phptree\Exporter\GvConvert
+     */
+    public function setExecutable(string $executable): GvConvert
+    {
+        $this->executable = $executable;
+
+        return $this;
+    }
+
+    /**
+     * @param string $format
+     *
+     * @return \drupol\phptree\Exporter\GvConvert
+     */
+    public function setFormat(string $format): GvConvert
+    {
+        $this->format = $format;
+
+        return $this;
+    }
+
+    /**
+     * @param string $path
+     *
+     * @return string
+     */
+    private function getConvertCommand(string $path): string
+    {
+        return \sprintf(
+            '%s -T%s %s -o %s.%s',
+            $this->getExecutable(),
+            $this->getFormat(),
+            $path,
+            $path,
+            $this->getFormat()
+        );
+    }
+
+    /**
+     * @throws \Exception
+     *
+     * @return string
+     */
+    private function getTemporaryFile(): string
+    {
+        $path = \tempnam(\sys_get_temp_dir(), 'graphviz');
+
+        if (false === $path) {
+            throw new \Exception('Unable to get temporary file name for graphviz script');
+        }
+
+        return $path;
+    }
+
+    /**
+     * @param string $path
+     * @param string $content
+     *
+     * @throws \Exception
+     *
+     * @return bool
+     */
+    private function writeToFile(string $path, string $content): bool
+    {
+        $ret = \file_put_contents($path, $content, LOCK_EX);
+
+        if (false === $ret) {
+            throw new \Exception('Unable to write graphviz script to temporary file');
+        }
+
+        return true;
+    }
+}