From 46448263469b5b803948e3461bb77b82fe94da7e Mon Sep 17 00:00:00 2001
From: Guy Sartorelli <guy.sartorelli@silverstripe.com>
Date: Thu, 4 Apr 2024 17:19:14 +1300
Subject: [PATCH] NEW File converter API

---
 src/Conversion/FileConverter.php              |  23 +++
 src/Conversion/InterventionImageConverter.php | 164 ++++++++++++++++++
 2 files changed, 187 insertions(+)
 create mode 100644 src/Conversion/FileConverter.php
 create mode 100644 src/Conversion/InterventionImageConverter.php

diff --git a/src/Conversion/FileConverter.php b/src/Conversion/FileConverter.php
new file mode 100644
index 00000000..ed9c1287
--- /dev/null
+++ b/src/Conversion/FileConverter.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace SilverStripe\Assets\Conversion;
+
+use SilverStripe\Assets\Storage\DBFile;
+
+interface FileConverter
+{
+    /**
+     * Checks whether this converter supports a conversion from one file type to another.
+     *
+     * @param DBFile|string $from A DBFile instance or specific file extension
+     * @param array $options Any options defined for this converter which should apply to the conversion
+     */
+    public function supportsConversion(DBFile|string $from, string $toExtension, array $options = []): bool;
+
+    /**
+     * Converts the given DBFile instance to another file type.
+     *
+     * @param array $options Any options defined for this converter which should apply to the conversion
+     */
+    public function convert(DBFile $original, string $toExtension, array $options = []): DBFile;
+}
diff --git a/src/Conversion/InterventionImageConverter.php b/src/Conversion/InterventionImageConverter.php
new file mode 100644
index 00000000..c19c7074
--- /dev/null
+++ b/src/Conversion/InterventionImageConverter.php
@@ -0,0 +1,164 @@
+<?php
+
+namespace SilverStripe\Assets\Conversion;
+
+use SilverStripe\Assets\Image_Backend;
+use SilverStripe\Assets\InterventionBackend;
+use SilverStripe\Assets\Storage\AssetStore;
+use SilverStripe\Assets\Storage\DBFile;
+use SilverStripe\Core\Injector\Injector;
+
+/**
+ * Image converter powered by the Intervention Image library, assuming you haven't swapped out the ImageBackend implementation.
+ */
+class InterventionImageConverter implements FileConverter
+{
+    public function supportsConversion(DBFile|string $from, string $toExtension, array $options = []): bool
+    {
+        // If backend is not InterventionBackend, return false
+        // GD and Imagick support different things so be dynamic between those
+        if ($from instanceof DBFile) {
+            $backend = $from->getImageBackend();
+            $from = $from->getExtension() ?: $from->getMimeType();
+        } else {
+            $backend = Injector::inst()->get(Image_Backend::class);
+        }
+        // This converter requires intervention image
+        if (!is_a($backend, InterventionBackend::class)) {
+            return false;
+        }
+        /** @var InterventionBackend $backend */
+        $driver = $backend->getImageManager()->config['driver'] ?? null;
+        return $this->supportedByIntervention($from, $toExtension, $driver);
+    }
+
+    public function convert(DBFile $original, string $toExtension, array $options = []): DBFile
+    {
+        // TODO allow swapping quality
+        // TODO find any other options intervention supports
+        return $original->manipulateExtension(
+            $toExtension,
+            function (AssetStore $store, string $filename, string $hash, string $variant) use ($original) {
+                $backend = $original->getImageBackend();
+                $config = ['conflict' => AssetStore::CONFLICT_USE_EXISTING];
+                $tuple = $backend->writeToStore($store, $filename, $hash, $variant, $config);
+                return [$tuple, $backend];
+            }
+        );
+    }
+
+    private function supportedByIntervention(string $from, string $to, string $driver): bool
+    {
+        // If the driver is somehow not GD or Imagick, we have no way to know what it might support
+        if ($driver !== 'gd' && $driver !== 'imagick') {
+            return false;
+        }
+
+        foreach ([$from, $to] as $format) {
+            // This follows the logic in intervention's AbstractEncoder::process() method
+            // and the various methods in the Encoder classes for GD and Imagick
+            switch (strtolower($format)) {
+                case 'gif':
+                case 'image/gif':
+                    // always supported
+                    break;
+                case 'png':
+                case 'image/png':
+                case 'image/x-png':
+                    // always supported
+                    break;
+                case 'jpg':
+                case 'jpeg':
+                case 'jfif':
+                case 'image/jp2':
+                case 'image/jpg':
+                case 'image/jpeg':
+                case 'image/pjpeg':
+                case 'image/jfif':
+                    // always supported
+                    break;
+                case 'tif':
+                case 'tiff':
+                case 'image/tiff':
+                case 'image/tif':
+                case 'image/x-tif':
+                case 'image/x-tiff':
+                    if ($driver === 'gd') {
+                        false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'bmp':
+                case 'ms-bmp':
+                case 'x-bitmap':
+                case 'x-bmp':
+                case 'x-ms-bmp':
+                case 'x-win-bitmap':
+                case 'x-windows-bmp':
+                case 'x-xbitmap':
+                case 'image/ms-bmp':
+                case 'image/x-bitmap':
+                case 'image/x-bmp':
+                case 'image/x-ms-bmp':
+                case 'image/x-win-bitmap':
+                case 'image/x-windows-bmp':
+                case 'image/x-xbitmap':
+                    if ($driver === 'gd' && !function_exists('imagebmp')) {
+                        return false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'ico':
+                case 'image/x-ico':
+                case 'image/x-icon':
+                case 'image/vnd.microsoft.icon':
+                    if ($driver === 'gd') {
+                        return false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'psd':
+                case 'image/vnd.adobe.photoshop':
+                    if ($driver === 'gd') {
+                        return false;
+                    }
+                    // always supported by imagick
+                    break;
+                case 'webp':
+                case 'image/webp':
+                case 'image/x-webp':
+                    if ($driver === 'gd' && !function_exists('imagewebp')) {
+                        return false;
+                    }
+                    if ($driver === 'imagick' && !\Imagick::queryFormats('WEBP')) {
+                        return false;
+                    }
+                    break;
+                case 'avif':
+                case 'image/avif':
+                    if ($driver === 'gd' && !function_exists('imageavif')) {
+                        return false;
+                    }
+                    if ($driver === 'imagick' && !\Imagick::queryFormats('AVIF')) {
+                        return false;
+                    }
+                    break;
+                case 'heic':
+                case 'image/heic':
+                case 'image/heif':
+                    if ($driver === 'gd') {
+                        return false;
+                    }
+                    if ($driver === 'imagick' && !\Imagick::queryFormats('HEIC')) {
+                        return false;
+                    }
+                    break;
+                default:
+                    // Anything else is not supported
+                    return false;
+            }
+        }
+        // If we get here both formats are in the explicit list above and are supported
+        return true;
+    }
+}