[[ LCB ]] Add constant formalism for binary module format versioning.

runrevmark · runrevmark · commit 0ae0416d633b · 2015-03-10T09:42:39.000Z
diff --git a/libscript/src/script-builder.cpp b/libscript/src/script-builder.cpp
@@ -148,8 +148,8 @@ bool MCScriptEndModule(MCScriptModuleBuilderRef self, MCStreamRef p_stream)
         byte_t t_header[4];
         t_header[0] = 'L';
         t_header[1] = 'C';
-        t_header[2] = 0;
-        t_header[3] = 0;
+        t_header[2] = ((kMCScriptCurrentModuleVersion & 0xFF) >> 0);
+        t_header[3] = ((kMCScriptCurrentModuleVersion & 0xFF) >> 8);
         
         t_success = MCStreamWrite(p_stream, t_header, 4) &&
                     MCScriptWriteRawModule(p_stream, &self -> module);
diff --git a/libscript/src/script-module.cpp b/libscript/src/script-module.cpp
@@ -427,8 +427,8 @@ bool MCScriptCreateModuleFromStream(MCStreamRef stream, MCScriptModuleRef& r_mod
     
     if (t_header[0] != 'L' ||
         t_header[1] != 'C' ||
-        t_header[2] != 0x00 ||
-        t_header[3] != 0x00)
+        t_header[2] != (kMCScriptCurrentModuleVersion & 0xFF) ||
+        t_header[3] != ((kMCScriptCurrentModuleVersion >> 8) & 0xFF))
         return false;
     
     MCScriptModule *t_module;
diff --git a/libscript/src/script-private.h b/libscript/src/script-private.h
@@ -565,6 +565,18 @@ bool MCScriptBytecodeIterate(byte_t*& x_bytecode, byte_t *p_bytecode_limit, MCSc
 //   byte       version[1]
 //   <pickle of module struct>
 
+// The module version will be incremented for every public release of the libscript
+// which occurs in which the module binary format changes.
+//
+// We will only aim to support module formats which have been released as final and
+// stable.
+//
+// The following constants keep track of, and should be updated to reflect the meaning
+// of each module version.
+
+#define kMCScriptModuleVersion_8_0_0_DP_1 0
+#define kMCScriptCurrentModuleVersion kMCScriptModuleVersion_8_0_0_DP_1
+
 ////////////////////////////////////////////////////////////////////////////////
 
 #endif
