Implement extracted getEmailLogo method

apps/theming/lib/Capabilities.php

@@ -82,7 +82,7 @@ public function getCapabilities() {
 				'color-element-bright' => $this->util->elementColor($color),
 				'color-element-dark' => $this->util->elementColor($color, false),
 				'logo' => $this->url->getAbsoluteURL($this->theming->getLogo()),
-				'emailLogo' => $this->url->getAbsoluteURL($this->theming->getLogo(false, true)),
+				'emailLogo' => $this->url->getAbsoluteURL($this->theming->getEmailLogo()),
 				'background' => $backgroundLogo === 'backgroundColor' || ($backgroundLogo === '' && $this->theming->getColorPrimary() !== '#0082c9') ?
 					$this->theming->getColorPrimary() :
 					$this->url->getAbsoluteURL($this->theming->getBackground()),

apps/theming/lib/ThemingDefaults.php

@@ -256,6 +256,40 @@ public function getLogo($useSvg = true): string {
 		return $this->urlGenerator->linkToRoute('theming.Theming.getImage', [ 'key' => 'logo', 'useSvg' => $useSvg, 'v' => $cacheBusterCounter ]);
 	}
 
+	/**
+	 * Themed email logo url
+	 *
+	 * @return string
+	 */
+	public function getEmailLogo(): string {
+		$logoKey = 'emailLogo';
+		$emailLogo = $this->config->getAppValue('theming', $logoKey . 'Mime', '');
+		$cacheBusterCounter = $this->config->getAppValue('theming', 'cachebuster', '0');
+
+		// short cut to avoid setting up the filesystem just to check if the logo is there
+		//
+		// explanation: if an SVG is requested and the app config value for logoMime is set then the logo is there.
+		// otherwise we need to check it and maybe also generate a PNG from the SVG (that's done in getImage() which
+		// needs to be called then)
+		if ($emailLogo !== false) {
+			$logoExists = true;
+		} else {
+			try {
+				$this->imageManager->getImage($logoKey, false);
+				$logoExists = true;
+			} catch (\Exception $e) {
+				$logoExists = false;
+			}
+		}
+
+		if (!$emailLogo || !$logoExists) {
+			$emailLogo = $this->urlGenerator->imagePath('core', 'logo/logo.png');
+			return $emailLogo . '?v=' . $cacheBusterCounter;
+		}
+
+		return $this->urlGenerator->linkToRoute('theming.Theming.getImage', [ 'key' => $logoKey, 'useSvg' => false, 'v' => $cacheBusterCounter ]);
+	}
+
 	/**
 	 * Themed background image url
 	 *

apps/theming/tests/ThemingDefaultsTest.php

@@ -649,7 +649,7 @@ public function testGetEmailLogoCustom() {
 			->method('linkToRoute')
 			->with('theming.Theming.getImage')
 			->willReturn('custom-email-logo?v=0');
-		$this->assertEquals('custom-email-logo' . '?v=0', $this->template->getLogo(false, true));
+		$this->assertEquals('custom-email-logo' . '?v=0', $this->template->getEmailLogo());
 	}
 
 	public function testGetScssVariablesCached() {

lib/private/Mail/EMailTemplate.php

@@ -380,7 +380,7 @@ public function addHeader() {
 		}
 		$this->headerAdded = true;
 
-		$logoUrl = $this->urlGenerator->getAbsoluteURL($this->themingDefaults->getLogo(false, true));
+		$logoUrl = $this->urlGenerator->getAbsoluteURL($this->themingDefaults->getEmailLogo());
 		$this->htmlBody .= vsprintf($this->header, [$this->themingDefaults->getColorPrimary(), $logoUrl, $this->themingDefaults->getName()]);
 	}
 

lib/private/legacy/OC_Defaults.php

@@ -324,6 +324,20 @@ public function getLogo($useSvg = true) {
 		return $logo . '?v=' . hash('sha1', implode('.', \OCP\Util::getVersion()));
 	}
 
+	/**
+	 * Themed email logo url
+	 *
+	 * @return string
+	 */
+	public function getEmailLogo() {
+		if ($this->themeExist('getEmailLogo')) {
+			return $this->theme->getEmailLogo();
+		}
+
+		$logo = \OC::$server->getURLGenerator()->imagePath('core', 'logo/logo.png');
+		return $logo . '?v=' . hash('sha1', implode('.', \OCP\Util::getVersion()));
+	}
+
 	public function getTextColorPrimary() {
 		if ($this->themeExist('getTextColorPrimary')) {
 			return $this->theme->getTextColorPrimary();

lib/public/Defaults.php

@@ -180,8 +180,18 @@ public function getiTunesAppId(): string {
 	 * @return string
 	 * @since 12.0.0
 	 */
-	public function getLogo(bool $useSvg = true, $emailLogo = false): string {
-		return $this->defaults->getLogo($useSvg, $emailLogo);
+	public function getLogo(bool $useSvg = true): string {
+		return $this->defaults->getLogo($useSvg);
+	}
+
+	/**
+	 * Themed email logo url
+	 *
+	 * @return string
+	 * @since 12.0.0
+	 */
+	public function getEmailLogo(): string {
+		return $this->defaults->getEmailLogo();
 	}
 
 	/**