From f9717e35cab505cfca95e708b53336bd7bf78f56 Mon Sep 17 00:00:00 2001
From: danieldg <danieldg@e03df62e-2008-0410-955e-edbf42e46eb7>
Date: Tue, 6 Oct 2009 16:50:48 +0000
Subject: [PATCH] Take advantage of link errors to check API_VERSION at module
 load time

git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@11805 e03df62e-2008-0410-955e-edbf42e46eb7
---
 include/modules.h | 26 ++++++++++++++------------
 src/modules.cpp   | 25 +++++++++----------------
 2 files changed, 23 insertions(+), 28 deletions(-)

diff --git a/include/modules.h b/include/modules.h
index ca345dbc1..d59bdf05b 100644
--- a/include/modules.h
+++ b/include/modules.h
@@ -104,8 +104,8 @@ struct ModResult {
 	}
 };
 
-/** If you change the module API, change this value. */
-#define API_VERSION 13000
+/** If you change the module API in any way, increment this value. */
+#define API_VERSION 131
 
 class ServerConfig;
 
@@ -226,13 +226,14 @@ do { \
 #define IS_AWAY(x) (!x->awaymsg.empty())
 
 /** Holds a module's Version information.
- *  The four members (set by the constructor only) indicate details as to the version number
- *  of a module. A class of type Version is returned by the GetVersion method of the Module class.
- *  The flags and API values represent the module flags and API version of the module.
- *  The API version of a module must match the API version of the core exactly for the module to
- *  load successfully.
+ * The members (set by the constructor only) indicate details as to the version number
+ * of a module. A class of type Version is returned by the GetVersion method of the Module class.
+ *
+ * The core provides only one implementation of the template, causing a run-time linking
+ * error when attempting to load a module compiled against a different API_VERSION.
  */
-class CoreExport Version : public classbase
+template<int api>
+class CoreExport VersionBase : public classbase
 {
  public:
 	/** Module description
@@ -242,16 +243,17 @@ class CoreExport Version : public classbase
 	 */
 	const std::string version;
 
-	/** Flags and API version
+	/** Flags
 	 */
-	const int Flags, API;
+	const int Flags;
 
 	/** Initialize version class
 	 */
-	Version(const std::string &desc, int flags,
-		int api_ver = API_VERSION, const std::string& src_rev = VERSION " r" REVISION);
+	VersionBase(const std::string &desc, int flags = VF_NONE, int dummy = 0, const std::string& src_rev = VERSION " r" REVISION);
 };
 
+typedef VersionBase<API_VERSION> Version;
+
 /** The ModuleMessage class is the base class of Request and Event
  * This class is used to represent a basic data structure which is passed
  * between modules for safe inter-module communications.
diff --git a/src/modules.cpp b/src/modules.cpp
index f7904d07b..36a885ea9 100644
--- a/src/modules.cpp
+++ b/src/modules.cpp
@@ -27,9 +27,12 @@
 
 
 // version is a simple class for holding a modules version number
-Version::Version(const std::string &modv, int flags, int api_ver, const std::string& rev)
-: description(modv), version(rev), Flags(flags), API(api_ver)
+template<>
+VersionBase<API_VERSION>::VersionBase(const std::string &modv, int flags, int api_ver, const std::string& rev)
+: description(modv), version(rev), Flags(flags)
 {
+	if (api_ver != API_VERSION)
+		abort();
 }
 
 Request::Request(char* anydata, Module* src, Module* dst)
@@ -439,19 +442,7 @@ bool ModuleManager::Load(const char* filename)
 			newmod->ModuleDLLFactory = newhandle;
 			Version v = newmod->GetVersion();
 
-			if (v.API != API_VERSION)
-			{
-				DetachAll(newmod);
-				delete newmod;
-				delete newhandle;
-				LastModuleError = "Unable to load " + filename_str + ": Incorrect module API version: " + ConvToStr(v.API) + " (our version: " + ConvToStr(API_VERSION) + ")";
-				ServerInstance->Logs->Log("MODULE", DEFAULT, LastModuleError);
-				return false;
-			}
-			else
-			{
-				ServerInstance->Logs->Log("MODULE", DEFAULT,"New module introduced: %s (API version %d, Module version %s)%s", filename, v.API, v.version.c_str(), (!(v.Flags & VF_VENDOR) ? " [3rd Party]" : " [Vendor]"));
-			}
+			ServerInstance->Logs->Log("MODULE", DEFAULT,"New module introduced: %s (Module version %s)%s", filename, v.version.c_str(), (!(v.Flags & VF_VENDOR) ? " [3rd Party]" : " [Vendor]"));
 
 			Modules[filename_str] = newmod;
 		}
@@ -463,7 +454,9 @@ bool ModuleManager::Load(const char* filename)
 			return false;
 		}
 	}
-	/** XXX: Is there anything we can do about this mess? -- Brain */
+	/** XXX: Is there anything we can do about this mess? -- Brain
+	 * Yeah, don't use exceptions without RAII. -- Daniel
+	 */
 	catch (LoadModuleException& modexcept)
 	{
 		DetachAll(newmod);
-- 
2.39.5