From cbc5bb70d02cd7a7f48605a1a3d3693c7e88d7be Mon Sep 17 00:00:00 2001
From: Molkobain <lajarige.guillaume@free.fr>
Date: Sun, 25 Apr 2021 14:00:07 +0200
Subject: [PATCH] Performance: Change theme signature check to be done only
 when necessary at runtime in a production environment

---
 application/themehandler.class.inc.php | 56 ++++++++++++++++++++++++--
 core/config.class.inc.php              |  8 ++++
 2 files changed, 60 insertions(+), 4 deletions(-)

diff --git a/application/themehandler.class.inc.php b/application/themehandler.class.inc.php
index ef3c4d24e..a168fdfb3 100644
--- a/application/themehandler.class.inc.php
+++ b/application/themehandler.class.inc.php
@@ -174,6 +174,29 @@ class ThemeHandler
 		return static::GetCompiledThemesFolderAbsolutePath().$sThemeId.'/';
 	}
 
+	/**
+	 * @param string $sThemeId
+	 *
+	 * @return string Absolute path of the compiled file for the $sThemeId theme (Note: It doesn't mean that the theme is actually compiled)
+	 * @since 3.0.0
+	 */
+	public static function GetCompiledThemeFileAbsolutePath(string $sThemeId): string
+	{
+		return static::GetCompiledThemeFolderAbsolutePath($sThemeId).'main.css';
+	}
+
+	/**
+	 * @param string $sThemeId
+	 *
+	 * @return string Absolute URL of the compiled file for the $sThemeId theme (Note: It doesn't mean that the theme is actually compiled)
+	 * @throws \Exception
+	 * @since 3.0.0
+	 */
+	public static function GetCompiledThemeFileAbsoluteUrl(string $sThemeId): string
+	{
+		return utils::GetAbsoluteUrlModulesRoot().'branding/themes/'.$sThemeId.'/main.css';
+	}
+
 	/**
 	 * Return the absolute URL for the current theme CSS file
 	 *
@@ -186,7 +209,9 @@ class ThemeHandler
 			// Try to compile theme defined in the configuration
 			// Note: In maintenance mode we should stick to the app theme (also we don't have access to many PHP classes, including the user preferences)
 			$sThemeId = SetupUtils::IsInMaintenanceMode() ? static::GetApplicationThemeId() : static::GetCurrentUserThemeId();
-			static::CompileTheme($sThemeId);
+			if (static::ShouldThemeSignatureCheckBeForced($sThemeId)) {
+				static::CompileTheme($sThemeId);
+			}
 		}
 		catch (CoreException $oCompileException) {
 			// Fallback on our default theme (should always be compilable) in case the previous theme doesn't exists
@@ -199,11 +224,34 @@ class ThemeHandler
 				SetupUtils::builddir($sDefaultThemeDirPath);
 			}
 
-			static::CompileTheme($sThemeId, false, "", $aDefaultTheme['parameters']);
+			if (static::ShouldThemeSignatureCheckBeForced($sThemeId)) {
+				static::CompileTheme($sThemeId, false, "", $aDefaultTheme['parameters']);
+			}
 		}
 
-		// Return absolute url to theme compiled css
-		return utils::GetAbsoluteUrlModulesRoot().'branding/themes/'.$sThemeId.'/main.css';
+		return static::GetCompiledThemeFileAbsoluteUrl($sThemeId);
+	}
+
+	/**
+	 * @param string $sThemeId
+	 *
+	 * @return bool True if the $sThemeId signature check -and possibly the compilation- should be forced (dev. environment, missing compiled file, ...)
+	 */
+	protected static function ShouldThemeSignatureCheckBeForced(string $sThemeId): bool
+	{
+		if (utils::IsDevelopmentEnvironment()) {
+			return true;
+		}
+
+		if (false === file_exists(static::GetCompiledThemeFileAbsolutePath($sThemeId))) {
+			return true;
+		}
+
+		if (true === utils::GetConfig()->Get('theme.force_signature_check_at_runtime')) {
+			return true;
+		}
+
+		return false;
 	}
 
 	/**
diff --git a/core/config.class.inc.php b/core/config.class.inc.php
index 4806e5800..5da4a3660 100644
--- a/core/config.class.inc.php
+++ b/core/config.class.inc.php
@@ -1407,6 +1407,14 @@ class Config
 			'source_of_value' => '',
 			'show_in_conf_sample' => false,
 		],
+		'theme.force_signature_check_at_runtime' => [
+			'type' => 'bool',
+			'description' => 'If true, checking that the current theme signature matches the compiled file -to recompile it if necessary- will be done for each page. This can slow the application, only use it if you are experiencing issues while customizing a theme.)',
+			'default' => false,
+			'value' => false,
+			'source_of_value' => '',
+			'show_in_conf_sample' => false,
+		],
 	];
 
 	public function IsProperty($sPropCode)