From 2bc67082714e618c48e55d4d93bbca2bb9a958b4 Mon Sep 17 00:00:00 2001
From: Daniel Wendt <daniel.wendt@linux.com>
Date: Tue, 13 Mar 2018 11:25:16 +0100
Subject: [PATCH] Enable "unused result" warning for MSVC Compiler (Visual
 Studio >= 2012, MSVC 11.0)

After researching the Internet, the annotation should be used in
declaration and implementation. After own tests with the MSVC 2012
compiler it is sufficient to use the annotation only in the
declaration to get a compiler warning, as with the GCC compiler.
So the annotation is not necessary in the C implementation.

Bug:https://bugs.freedesktop.org/show_bug.cgi?id=105460
---
 README.cmake          |  4 ++++
 cmake/CMakeLists.txt  |  7 +++++++
 dbus/dbus-internals.h |  5 +++--
 dbus/dbus-macros.h    | 23 +++++++++++++++++------
 dbus/dbus-sysdeps.h   |  4 +++-
 dbus/dbus-userdb.h    |  4 ++--
 test/test-utils.h     |  8 ++++----
 7 files changed, 40 insertions(+), 15 deletions(-)

diff --git a/README.cmake b/README.cmake
index 6d5621f..2fe33dc 100644
--- a/README.cmake
+++ b/README.cmake
@@ -165,6 +165,10 @@ x11 only:
 // Build with X11 auto launch support
 DBUS_BUILD_X11:BOOL=ON
 
+MSVC only (Visual Studio >= 2012):
+// Enable code analyzing for MSVC compiler: /analyze
+DBUS_MSVC_ANALYZE:BOOL=OFF
+
 
 Note: The above mentioned options could be extracted after 
 configuring from the output of running "<maketool> help-options" 
diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 6349adb..56dc1f4 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -176,6 +176,7 @@ if(MSVC)
     ADD_DEFINITIONS(-D_CRT_SECURE_NO_DEPRECATE -D_CRT_NONSTDC_NO_DEPRECATE)
     SET(CMAKE_C_FLAGS_DEBUG   "${CMAKE_C_FLAGS_DEBUG}   /FIconfig.h")
     SET(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} /FIconfig.h")
+    option (DBUS_MSVC_ANALYZE "Enable code analyzing for MSVC compiler: /analyze" OFF)
 endif()
 
 #
@@ -218,6 +219,9 @@ if(MSVC)
     # 4114 same type qualifier used more than once
     # 4133 'type' : incompatible types - from 'type1' to 'type2'
     set(WARNINGS_ERRORS "4002 4003 4013 4028 4031 4047 4114 4133")
+    if(DBUS_MSVC_ANALYZE AND MSVC_VERSION GREATER 1600)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /analyze")
+    endif()
 else()
     set(WARNINGS "sign-compare")
     set(WARNINGS_DISABLED "")
@@ -594,6 +598,9 @@ message("        Docbook Generator:        ${DOCBOOK_GENERATOR_NAME}           "
 
 
 message("        gcc coverage profiling:   ${DBUS_GCOV_ENABLED}                ")
+if(MSVC)
+message("        MSVC code analyze mode:   ${DBUS_MSVC_ANALYZE}                ")
+endif()
 message("        Building unit tests:      ${DBUS_BUILD_TESTS}                 ")
 message("        Building with GLib:       ${DBUS_WITH_GLIB}                   ")
 message("        Building verbose mode:    ${DBUS_ENABLE_VERBOSE_MODE}         ")
diff --git a/dbus/dbus-internals.h b/dbus/dbus-internals.h
index 57a67d0..ae9ab62 100644
--- a/dbus/dbus-internals.h
+++ b/dbus/dbus-internals.h
@@ -366,7 +366,8 @@ typedef enum
   _DBUS_N_GLOBAL_LOCKS
 } DBusGlobalLock;
 
-dbus_bool_t _dbus_lock   (DBusGlobalLock lock) _DBUS_GNUC_WARN_UNUSED_RESULT;
+_DBUS_WARN_UNUSED_RESULT
+dbus_bool_t _dbus_lock   (DBusGlobalLock lock);
 void        _dbus_unlock (DBusGlobalLock lock);
 
 #define _DBUS_LOCK_NAME(name)           _DBUS_LOCK_##name
@@ -399,7 +400,7 @@ union DBusGUID
   char as_bytes[DBUS_UUID_LENGTH_BYTES];                /**< guid as 16 single-byte values */
 };
 
-DBUS_PRIVATE_EXPORT _DBUS_GNUC_WARN_UNUSED_RESULT
+DBUS_PRIVATE_EXPORT _DBUS_WARN_UNUSED_RESULT
 dbus_bool_t _dbus_generate_uuid  (DBusGUID         *uuid,
                                   DBusError        *error);
 DBUS_PRIVATE_EXPORT
diff --git a/dbus/dbus-macros.h b/dbus/dbus-macros.h
index 2c8956e..bf3a0b0 100644
--- a/dbus/dbus-macros.h
+++ b/dbus/dbus-macros.h
@@ -92,10 +92,24 @@
 #define DBUS_ALLOC_SIZE2(x,y)
 #endif
 
-#if    (__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
-#define _DBUS_GNUC_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
+/** @def _DBUS_WARN_UNUSED_RESULT
+ *
+ * An attribute for functions whose result must be checked by the caller.
+ *
+ * This macro is used in function declarations. Unlike gcc-specific
+ * attributes, to avoid compilation failure with MSVC it must appear
+ * somewhere before the function name in the declaration. Our preferred
+ * coding style is to place it before the return type, for example:
+ *
+ * DBUS_PRIVATE_EXPORT _DBUS_WARN_UNUSED_RESULT
+ * dbus_bool_t _dbus_user_database_lock_system (void);
+ */
+#if     defined(_MSC_VER) && (_MSC_VER >= 1700)
+#define _DBUS_WARN_UNUSED_RESULT _Must_inspect_result_
+#elif    (__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
+#define _DBUS_WARN_UNUSED_RESULT __attribute__((warn_unused_result))
 #else
-#define _DBUS_GNUC_WARN_UNUSED_RESULT
+#define _DBUS_WARN_UNUSED_RESULT
 #endif
 
 /** @def _DBUS_GNUC_PRINTF
@@ -104,9 +118,6 @@
 /** @def _DBUS_GNUC_NORETURN
  * used to tell gcc about functions that never return, such as _dbus_abort()
  */
-/** @def _DBUS_GNUC_WARN_UNUSED_RESULT
- * used to tell gcc about functions whose result must be used
- */
 
 /* Normally docs are in .c files, but there isn't a .c file for this. */
 /**
diff --git a/dbus/dbus-sysdeps.h b/dbus/dbus-sysdeps.h
index b3c73b6..093f448 100644
--- a/dbus/dbus-sysdeps.h
+++ b/dbus/dbus-sysdeps.h
@@ -135,6 +135,7 @@ typedef struct { SOCKET sock; } DBusSocket;
 static inline SOCKET
 _dbus_socket_printable (DBusSocket s) { return s.sock; }
 
+_DBUS_WARN_UNUSED_RESULT
 static inline dbus_bool_t
 _dbus_socket_is_valid (DBusSocket s) { return s.sock != INVALID_SOCKET; }
 
@@ -153,6 +154,7 @@ typedef struct { int fd; } DBusSocket;
 static inline int
 _dbus_socket_printable (DBusSocket s) { return s.fd; }
 
+_DBUS_WARN_UNUSED_RESULT
 static inline dbus_bool_t
 _dbus_socket_is_valid (DBusSocket s) { return s.fd >= 0; }
 
@@ -462,7 +464,7 @@ const char* _dbus_get_tmpdir      (void);
 /**
  * Random numbers 
  */
-_DBUS_GNUC_WARN_UNUSED_RESULT
+_DBUS_WARN_UNUSED_RESULT
 dbus_bool_t _dbus_generate_random_bytes_buffer (char       *buffer,
                                                 int         n_bytes,
                                                 DBusError  *error);
diff --git a/dbus/dbus-userdb.h b/dbus/dbus-userdb.h
index 53fc90b..ac1497d 100644
--- a/dbus/dbus-userdb.h
+++ b/dbus/dbus-userdb.h
@@ -93,8 +93,8 @@ void           _dbus_group_info_free_allocated  (DBusGroupInfo    *info);
 
 DBUS_PRIVATE_EXPORT
 DBusUserDatabase* _dbus_user_database_get_system    (void);
-DBUS_PRIVATE_EXPORT
-dbus_bool_t       _dbus_user_database_lock_system   (void) _DBUS_GNUC_WARN_UNUSED_RESULT;
+DBUS_PRIVATE_EXPORT _DBUS_WARN_UNUSED_RESULT
+dbus_bool_t       _dbus_user_database_lock_system   (void);
 DBUS_PRIVATE_EXPORT
 void              _dbus_user_database_unlock_system (void);
 void              _dbus_user_database_flush_system  (void);
diff --git a/test/test-utils.h b/test/test-utils.h
index 860ee21..14ea365 100644
--- a/test/test-utils.h
+++ b/test/test-utils.h
@@ -10,16 +10,16 @@
 #include <dbus/dbus-internals.h>
 typedef DBusLoop TestMainContext;
 
-_DBUS_GNUC_WARN_UNUSED_RESULT
+_DBUS_WARN_UNUSED_RESULT
 TestMainContext *test_main_context_get            (void);
-_DBUS_GNUC_WARN_UNUSED_RESULT
+_DBUS_WARN_UNUSED_RESULT
 TestMainContext *test_main_context_try_get        (void);
 TestMainContext *test_main_context_ref            (TestMainContext *ctx);
 void             test_main_context_unref          (TestMainContext *ctx);
 void             test_main_context_iterate        (TestMainContext *ctx,
                                                    dbus_bool_t      may_block);
 
-_DBUS_GNUC_WARN_UNUSED_RESULT
+_DBUS_WARN_UNUSED_RESULT
 dbus_bool_t test_connection_try_setup             (TestMainContext *ctx,
                                                    DBusConnection *connection);
 void        test_connection_setup                 (TestMainContext *ctx,
@@ -27,7 +27,7 @@ void        test_connection_setup                 (TestMainContext *ctx,
 void        test_connection_shutdown              (TestMainContext *ctx,
                                                    DBusConnection *connection);
 
-_DBUS_GNUC_WARN_UNUSED_RESULT
+_DBUS_WARN_UNUSED_RESULT
 dbus_bool_t test_server_try_setup                 (TestMainContext *ctx,
                                                    DBusServer    *server);
 void        test_server_setup                     (TestMainContext *ctx,
-- 
2.7.0.windows.1