From 6a5bd7f0dacd96b66c294919fa5859ca12224d5f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Peter=20K=C3=BCmmel?= <syntheticpp@gmx.net>
Date: Fri, 25 Apr 2014 18:24:56 +0200
Subject: [PATCH 1/2] Qt4: write moc parameter file only when content has
 changed

---
 Modules/Qt4Macros.cmake | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Modules/Qt4Macros.cmake b/Modules/Qt4Macros.cmake
index b1b12d68b..8c4daac6b 100644
--- a/Modules/Qt4Macros.cmake
+++ b/Modules/Qt4Macros.cmake
@@ -135,7 +135,9 @@ function (QT4_CREATE_MOC_COMMAND infile outfile moc_flags moc_options moc_target
     set(targetincludes)
     set(targetdefines)
   else()
-    file(WRITE ${_moc_parameters_file} "${_moc_parameters}\n")
+    set(CMAKE_CONFIGURABLE_FILE_CONTENT "${_moc_parameters}")
+    configure_file("${CMAKE_ROOT}/Modules/CMakeConfigurableFile.in"
+                   "${_moc_parameters_file}" @ONLY)
   endif()
 
   set(_moc_extra_parameters_file @${_moc_parameters_file})

From 17c31b8bd4aa56d924b94cf41b9c4a6a90d23264 Mon Sep 17 00:00:00 2001
From: Stephen Kelly <steveire@gmail.com>
Date: Wed, 30 Apr 2014 08:35:51 +0200
Subject: [PATCH 2/2] Qt4: Extend the Qt4Targets test to cover dir and target
 moc parameters.

---
 Tests/Qt4Targets/CMakeLists.txt               | 61 ++++++++++++-------
 .../Qt4Targets/IncrementalMoc/CMakeLists.txt  | 12 +++-
 2 files changed, 48 insertions(+), 25 deletions(-)

diff --git a/Tests/Qt4Targets/CMakeLists.txt b/Tests/Qt4Targets/CMakeLists.txt
index 74300845a..ae0a02bb6 100644
--- a/Tests/Qt4Targets/CMakeLists.txt
+++ b/Tests/Qt4Targets/CMakeLists.txt
@@ -37,29 +37,44 @@ set_property(TARGET Qt4WrapMacroTest PROPERTY AUTOMOC OFF)
 target_include_directories(Qt4WrapMacroTest PRIVATE "${CMAKE_CURRENT_SOURCE_DIR}/interface")
 target_link_libraries(Qt4WrapMacroTest Qt4::QtGui)
 
-set(timeformat "%Y%j%H%M%S")
-try_compile(RESULT
-  "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild"
-  "${CMAKE_CURRENT_SOURCE_DIR}/IncrementalMoc"
-  IncrementalMoc
-  CMAKE_FLAGS -DADD_DEF=0 "-DQT_QMAKE_EXECUTABLE:FILEPATH=${QT_QMAKE_EXECUTABLE}")
-file(TIMESTAMP "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild/moc_foo.cpp" tsvar_before "${timeformat}")
-if (NOT tsvar_before)
-  message(SEND_ERROR "Unable to read timestamp from moc file from first build!")
-endif()
+macro(test_incremental def)
+  set(timeformat "%Y%j%H%M%S")
+  try_compile(RESULT
+    "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild_${def}"
+    "${CMAKE_CURRENT_SOURCE_DIR}/IncrementalMoc"
+    IncrementalMoc
+    CMAKE_FLAGS -D${def}=0 "-DQT_QMAKE_EXECUTABLE:FILEPATH=${QT_QMAKE_EXECUTABLE}"
+    OUTPUT_VARIABLE output
+    )
+  file(TIMESTAMP "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild_${def}/moc_foo.cpp" tsvar_before "${timeformat}")
+  if (NOT tsvar_before)
+    message(SEND_ERROR
+      "Unable to read timestamp from moc file from first build with -D${def}!\n"
+      "try_compile output:\n${output}"
+      )
+  endif()
 
-execute_process(COMMAND "${CMAKE_COMMAND}" -E sleep 2) # Ensure that the timestamp will change.
+  execute_process(COMMAND "${CMAKE_COMMAND}" -E sleep 2) # Ensure that the timestamp will change.
 
-try_compile(RESULT
-  "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild"
-  "${CMAKE_CURRENT_SOURCE_DIR}/IncrementalMoc"
-  IncrementalMoc
-  CMAKE_FLAGS -DADD_DEF=1 "-DQT_QMAKE_EXECUTABLE:FILEPATH=${QT_QMAKE_EXECUTABLE}")
-file(TIMESTAMP "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild/moc_foo.cpp" tsvar_after "${timeformat}")
-if (NOT tsvar_after)
-  message(SEND_ERROR "Unable to read timestamp from moc file from second build!")
-endif()
+  try_compile(RESULT
+    "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild_${def}"
+    "${CMAKE_CURRENT_SOURCE_DIR}/IncrementalMoc"
+    IncrementalMoc
+    CMAKE_FLAGS -D${def}=1 "-DQT_QMAKE_EXECUTABLE:FILEPATH=${QT_QMAKE_EXECUTABLE}"
+    OUTPUT_VARIABLE output
+    )
+  file(TIMESTAMP "${CMAKE_CURRENT_BINARY_DIR}/IncrementalMocBuild_${def}/moc_foo.cpp" tsvar_after "${timeformat}")
+  if (NOT tsvar_after)
+    message(SEND_ERROR
+      "Unable to read timestamp from moc file from second build!\n"
+      "try_compile output:\n${output}"
+      )
+  endif()
 
-if (NOT tsvar_after GREATER tsvar_before)
-  message(SEND_ERROR "Rebuild did not re-create moc file. Before: ${tsvar_before}. After: ${tsvar_after}")
-endif()
+  if (NOT tsvar_after GREATER tsvar_before)
+    message(SEND_ERROR "Rebuild did not re-create moc file with -D${def}. Before: ${tsvar_before}. After: ${tsvar_after}")
+  endif()
+endmacro()
+
+test_incremental(ADD_TARGET_DEF)
+test_incremental(ADD_DIR_DEF)
diff --git a/Tests/Qt4Targets/IncrementalMoc/CMakeLists.txt b/Tests/Qt4Targets/IncrementalMoc/CMakeLists.txt
index 4ba0ceddf..65e2b64bf 100644
--- a/Tests/Qt4Targets/IncrementalMoc/CMakeLists.txt
+++ b/Tests/Qt4Targets/IncrementalMoc/CMakeLists.txt
@@ -4,10 +4,18 @@ project(IncrementalMoc)
 
 find_package(Qt4 REQUIRED)
 
-qt4_generate_moc(foo.h moc_foo.cpp)
+if (ADD_TARGET_DEF)
+  set(target_args TARGET testlib)
+endif()
+
+if (ADD_DIR_DEF)
+  add_definitions(-DNEW_DEF)
+endif()
+
+qt4_generate_moc(foo.h moc_foo.cpp ${target_args})
 
 add_library(testlib foo.cpp moc_foo.cpp)
 target_link_libraries(testlib Qt4::QtCore)
-if (ADD_DEF)
+if (ADD_TARGET_DEF)
   target_compile_definitions(testlib PRIVATE NEW_DEF)
 endif()