X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=include%2Fldap_cdefs.h;h=d759d6b11c121cc5fbeb34abce81bca5126bc818;hb=966cef8c9a3238efe0c482ad0ee08fd98944d112;hp=37c88b8cd0d43f8128ba617d3ef82f4a61826745;hpb=3b42f9ce2e9a9c21269a2858aaf96b47532b005a;p=openldap

diff --git a/include/ldap_cdefs.h b/include/ldap_cdefs.h
index 37c88b8cd0..d759d6b11c 100644
--- a/include/ldap_cdefs.h
+++ b/include/ldap_cdefs.h
@@ -1,12 +1,16 @@
 /* $OpenLDAP$ */
-/*
- * Copyright 1998-2000 The OpenLDAP Foundation, Redwood City, California, USA
+/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
+ * 
+ * Copyright 1998-2011 The OpenLDAP Foundation.
  * All rights reserved.
  *
- * Redistribution and use in source and binary forms are permitted only
- * as authorized by the OpenLDAP Public License.  A copy of this
- * license is available at http://www.OpenLDAP.org/license.html or
- * in file LICENSE in the top-level directory of the distribution.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted only as authorized by the OpenLDAP
+ * Public License.
+ *
+ * A copy of this license is available in file LICENSE in the
+ * top-level directory of the distribution or, alternatively, at
+ * <http://www.OpenLDAP.org/license.html>.
  */
 /* LDAP C Defines */
 
@@ -54,75 +58,191 @@
 #	define LDAP_GCCATTR(attrs)
 #endif
 
-
-/* Support for NT dynamic libraries. */
+/*
+ * Support for Windows DLLs.
+ *
+ * When external source code includes header files for dynamic libraries,
+ * the external source code is "importing" DLL symbols into its resulting
+ * object code. On Windows, symbols imported from DLLs must be explicitly
+ * indicated in header files with the __declspec(dllimport) directive.
+ * This is not totally necessary for functions because the compiler
+ * (gcc or MSVC) will generate stubs when this directive is absent.
+ * However, this is required for imported variables.
+ *
+ * The LDAP libraries, i.e. liblber and libldap, can be built as
+ * static or shared, based on configuration. Just about all other source
+ * code in OpenLDAP use these libraries. If the LDAP libraries
+ * are configured as shared, 'configure' defines the LDAP_LIBS_DYNAMIC
+ * macro. When other source files include LDAP library headers, the
+ * LDAP library symbols will automatically be marked as imported. When
+ * the actual LDAP libraries are being built, the symbols will not
+ * be marked as imported because the LBER_LIBRARY or LDAP_LIBRARY macros
+ * will be respectively defined.
+ *
+ * Any project outside of OpenLDAP with source code wanting to use
+ * LDAP dynamic libraries should explicitly define LDAP_LIBS_DYNAMIC.
+ * This will ensure that external source code appropriately marks symbols
+ * that will be imported.
+ *
+ * The slapd executable, itself, can be used as a dynamic library.
+ * For example, if a backend module is compiled as shared, it will
+ * import symbols from slapd. When this happens, the slapd symbols
+ * must be marked as imported in header files that the backend module
+ * includes. Remember that slapd links with various static libraries.
+ * If the LDAP libraries were configured as static, their object
+ * code is also part of the monolithic slapd executable. Thus, when
+ * a backend module imports symbols from slapd, it imports symbols from
+ * all of the static libraries in slapd as well. Thus, the SLAP_IMPORT
+ * macro, when defined, will appropriately mark symbols as imported.
+ * This macro should be used by shared backend modules as well as any
+ * other external source code that imports symbols from the slapd
+ * executable as if it were a DLL.
+ *
+ * Note that we don't actually have to worry about using the
+ * __declspec(dllexport) directive anywhere. This is because both
+ * MSVC and Mingw provide alternate (more effective) methods for exporting
+ * symbols out of binaries, i.e. the use of a DEF file.
+ *
+ * NOTE ABOUT BACKENDS: Backends can be configured as static or dynamic.
+ * When a backend is configured as dynamic, slapd will load the backend
+ * explicitly and populate function pointer structures by calling
+ * the backend's well-known initialization function. Because of this
+ * procedure, slapd never implicitly imports symbols from dynamic backends.
+ * This makes it unnecessary to tag various backend functions with the
+ * __declspec(dllimport) directive. This is because neither slapd nor
+ * any other external binary should ever be implicitly loading a backend
+ * dynamic module.
+ *
+ * Backends are supposed to be self-contained. However, it appears that
+ * back-meta DOES implicitly import symbols from back-ldap. This means
+ * that the __declspec(dllimport) directive should be marked on back-ldap
+ * functions (in its header files) if and only if we're compiling for
+ * windows AND back-ldap has been configured as dynamic AND back-meta
+ * is the client of back-ldap. When client is slapd, there is no effect
+ * since slapd does not implicitly import symbols.
+ *
+ * TODO(?): Currently, back-meta nor back-ldap is supported for Mingw32.
+ * Thus, there's no need to worry about this right now. This is something that
+ * may or may not have to be addressed in the future.
+ */
 
 /* LBER library */
-#if defined(LBER_DECL) && defined(_WIN32)
-#	define LBER_F(type)		extern __declspec(LBER_DECL) type
+#if defined(_WIN32) && \
+    ((defined(LDAP_LIBS_DYNAMIC) && !defined(LBER_LIBRARY)) || \
+     (!defined(LDAP_LIBS_DYNAMIC) && defined(SLAPD_IMPORT)))
+#	define LBER_F(type)		extern __declspec(dllimport) type
+#	define LBER_V(type)		extern __declspec(dllimport) type
 #else
-#	define LBER_F(type)		type
+#	define LBER_F(type)		extern type
+#	define LBER_V(type)		extern type
 #endif
 
 /* LDAP library */
-#if defined(LDAP_DECL) && defined(_WIN32)
-#	define LDAP_F(type)	extern __declspec(LDAP_DECL) type
+#if defined(_WIN32) && \
+    ((defined(LDAP_LIBS_DYNAMIC) && !defined(LDAP_LIBRARY)) || \
+     (!defined(LDAP_LIBS_DYNAMIC) && defined(SLAPD_IMPORT)))
+#	define LDAP_F(type)		extern __declspec(dllimport) type
+#	define LDAP_V(type)		extern __declspec(dllimport) type
 #else
-#	define LDAP_F(type)	extern type
-#endif
-
-/*
- * C library. Mingw32 links with the C run-time library by default,
- * so the explicit definition of CSTATIC will keep dllimport from
- * being defined.
- */
-#if (defined(__MINGW32__) && !defined(CSTATIC) || \
-     defined(_WIN32) && defined(_DLL))
-#	define LDAP_LIBC_F(type)	extern __declspec(dllimport) type
-#else
-#	define LDAP_LIBC_F(type)	extern type
+#	define LDAP_F(type)		extern type
+#	define LDAP_V(type)		extern type
 #endif
 
 /* AVL library */
-#if defined(LDAP_AVL_DECL) && defined(_WIN32)
-#	define LDAP_AVL_F(type)	extern __declspec(LDAP_AVL_DECL) type
-#else
-#	define LDAP_AVL_F(type)	extern type
-#endif
-
-/* LDBM library */
-#if defined(LDAP_LDBM_DECL) && defined(_WIN32)
-#	define LDAP_LDBM_F(type)	extern __declspec(LDAP_LDBM_DECL) type
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define LDAP_AVL_F(type)		extern __declspec(dllimport) type
+#	define LDAP_AVL_V(type)		extern __declspec(dllimport) type
 #else
-#	define LDAP_LDBM_F(type)	extern type
+#	define LDAP_AVL_F(type)		extern type
+#	define LDAP_AVL_V(type)		extern type
 #endif
 
 /* LDIF library */
-#if defined(LDAP_LDIF_DECL) && defined(_WIN32)
-#	define LDAP_LDIF_F(type)	extern __declspec(LDAP_LDIF_DECL) type
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define LDAP_LDIF_F(type)	extern __declspec(dllimport) type
+#	define LDAP_LDIF_V(type)	extern __declspec(dllimport) type
 #else
 #	define LDAP_LDIF_F(type)	extern type
+#	define LDAP_LDIF_V(type)	extern type
 #endif
 
 /* LUNICODE library */
-#if defined(LDAP_LUNICODE_DECL) && defined(_WIN32)
-#	define LDAP_LUNICODE_F(type)	extern __declspec(LDAP_LUNICODE_DECL) type
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define LDAP_LUNICODE_F(type)	extern __declspec(dllimport) type
+#	define LDAP_LUNICODE_V(type)	extern __declspec(dllimport) type
 #else
 #	define LDAP_LUNICODE_F(type)	extern type
+#	define LDAP_LUNICODE_V(type)	extern type
 #endif
 
 /* LUTIL library */
-#if defined(LDAP_LUTIL_DECL) && defined(_WIN32)
-#	define LDAP_LUTIL_F(type)	extern __declspec(LDAP_LUTIL_DECL) type
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define LDAP_LUTIL_F(type)	extern __declspec(dllimport) type
+#	define LDAP_LUTIL_V(type)	extern __declspec(dllimport) type
 #else
 #	define LDAP_LUTIL_F(type)	extern type
+#	define LDAP_LUTIL_V(type)	extern type
+#endif
+
+/* REWRITE library */
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define LDAP_REWRITE_F(type)	extern __declspec(dllimport) type
+#	define LDAP_REWRITE_V(type)	extern __declspec(dllimport) type
+#else
+#	define LDAP_REWRITE_F(type)	extern type
+#	define LDAP_REWRITE_V(type)	extern type
 #endif
 
-/* SLAPD (as a module exporting symbols) */
-#if defined(LDAP_SLAPD_DECL) && defined(_WIN32)
-#	define LDAP_SLAPD_F(type)	extern __declspec(LDAP_SLAPD_DECL) type
+/* SLAPD (as a dynamic library exporting symbols) */
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define LDAP_SLAPD_F(type)	extern __declspec(dllimport) type
+#	define LDAP_SLAPD_V(type)	extern __declspec(dllimport) type
 #else
 #	define LDAP_SLAPD_F(type)	extern type
+#	define LDAP_SLAPD_V(type)	extern type
+#endif
+
+/* SLAPD (as a dynamic library exporting symbols) */
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define LDAP_SLAPI_F(type)	extern __declspec(dllimport) type
+#	define LDAP_SLAPI_V(type)	extern __declspec(dllimport) type
+#else
+#	define LDAP_SLAPI_F(type)	extern type
+#	define LDAP_SLAPI_V(type)	extern type
+#endif
+
+/* SLAPD (as a dynamic library exporting symbols) */
+#if defined(_WIN32) && defined(SLAPD_IMPORT)
+#	define SLAPI_F(type)		extern __declspec(dllimport) type
+#	define SLAPI_V(type)		extern __declspec(dllimport) type
+#else
+#	define SLAPI_F(type)		extern type
+#	define SLAPI_V(type)		extern type
+#endif
+
+/*
+ * C library. Mingw32 links with the dynamic C run-time library by default,
+ * so the explicit definition of CSTATIC will keep dllimport from
+ * being defined, if desired.
+ *
+ * MSVC defines the _DLL macro when the compiler is invoked with /MD or /MDd,
+ * which means the resulting object code will be linked with the dynamic
+ * C run-time library.
+ *
+ * Technically, it shouldn't be necessary to redefine any functions that
+ * the headers for the C library should already contain. Nevertheless, this
+ * is here as a safe-guard.
+ *
+ * TODO: Determine if these macros ever get expanded for Windows. If not,
+ * the declspec expansion can probably be removed.
+ */
+#if (defined(__MINGW32__) && !defined(CSTATIC)) || \
+    (defined(_MSC_VER) && defined(_DLL))
+#	define LDAP_LIBC_F(type)	extern __declspec(dllimport) type
+#	define LDAP_LIBC_V(type)	extern __declspec(dllimport) type
+#else
+#	define LDAP_LIBC_F(type)	extern type
+#	define LDAP_LIBC_V(type)	extern type
 #endif
 
 #endif /* _LDAP_CDEFS_H */