Use ECMGenerateExportHeader to manage deprecated API better

Summary:
Allows
* projects linking to KItemModels to hide deprecated API up to a
  given version or silence deprecation warnings after a given version,
  using
  * -DKITEMMODELS_DISABLE_DEPRECATED_BEFORE_AND_AT
  * -DKITEMMODELS_NO_DEPRECATED
  * -DKITEMMODELS_DEPRECATED_WARNINGS_SINCE
  * -DKITEMMODELS_NO_DEPRECATED_WARNINGS

  or
  * -DKF_DISABLE_DEPRECATED_BEFORE_AND_AT
  * -DKF_NO_DEPRECATED
  * -DKF_DEPRECATED_WARNINGS_SINCE
  * -DKF_NO_DEPRECATED_WARNINGS
* to build KItemModels optionally with deprecated API excluded from
  the build, using "EXCLUDE_DEPRECATED_BEFORE_AND_AT" cmake argument.

Test Plan:
Builds with EXCLUDE_DEPRECATED_BEFORE_AND_AT set to 0, 4.8.0,
CURRENT.

Reviewers: #frameworks, dfaure, mlaurent

Reviewed By: mlaurent

Subscribers: kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D24600

CMakeLists.txt

@@ -19,13 +19,13 @@ include(ECMQtDeclareLoggingCategory)
 set(REQUIRED_QT_VERSION 5.11.0)
 find_package(Qt5Core ${REQUIRED_QT_VERSION} REQUIRED NO_MODULE)
 
-
-include(GenerateExportHeader)
-
+include(ECMGenerateExportHeader)
 include(ECMSetupVersion)
 include(ECMGenerateHeaders)
 include(ECMAddQch)
 
+set(EXCLUDE_DEPRECATED_BEFORE_AND_AT 0 CACHE STRING "Control the range of deprecated API excluded from the build [default=0].")
+
 option(BUILD_QCH "Build API documentation in QCH format (for e.g. Qt Assistant, Qt Creator & KDevelop)" OFF)
 add_feature_info(QCH ${BUILD_QCH} "API documentation in QCH format (for e.g. Qt Assistant, Qt Creator & KDevelop)")
 

src/CMakeLists.txt

@@ -15,8 +15,20 @@ set(kitemmodels_SRCS
 ecm_qt_declare_logging_category(kitemmodels_SRCS HEADER kitemmodels_debug.h IDENTIFIER KITEMMODELS_LOG CATEGORY_NAME kf5.kitemmodels)
 
 add_library(KF5ItemModels ${kitemmodels_SRCS})
-generate_export_header(KF5ItemModels BASE_NAME KItemModels)
 add_library(KF5::ItemModels ALIAS KF5ItemModels)
+ecm_generate_export_header(KF5ItemModels
+    BASE_NAME KItemModels
+    # GROUP_BASE_NAME KF <- enable once all of KF modules use ecm_generate_export_header
+    VERSION ${KF5_VERSION}
+    DEPRECATED_BASE_VERSION 0
+    DEPRECATION_VERSIONS 4.8
+    EXCLUDE_DEPRECATED_BEFORE_AND_AT ${EXCLUDE_DEPRECATED_BEFORE_AND_AT}
+)
+# reminder trigger to apply KITEMMODELS_ENABLE_DEPRECATED_SINCE & friends to KConcatenateRowsProxyModel when the time is there
+if (REQUIRED_QT_VERSION VERSION_GREATER 5.12.0)
+    message(WARNING "With Qt 5.13 as min dep, mark KConcatenateRowsProxyModel as deprecated to the compiler & remove this warning")
+endif()
+
 
 target_include_directories(KF5ItemModels INTERFACE "$<INSTALL_INTERFACE:${KDE_INSTALL_INCLUDEDIR_KF5}/KItemModels>")
 

src/kdescendantsproxymodel.cpp

@@ -208,10 +208,12 @@ KDescendantsProxyModel::~KDescendantsProxyModel()
     delete d_ptr;
 }
 
+#if KITEMMODELS_BUILD_DEPRECATED_SINCE(4, 8)
 void KDescendantsProxyModel::setRootIndex(const QModelIndex &index)
 {
     Q_UNUSED(index)
 }
+#endif
 
 QModelIndexList KDescendantsProxyModel::match(const QModelIndex &start, int role, const QVariant &value, int hits, Qt::MatchFlags flags) const
 {

src/kdescendantsproxymodel.h

@@ -104,12 +104,15 @@ public:
      */
     void setSourceModel(QAbstractItemModel *model) override;
 
+#if KITEMMODELS_ENABLE_DEPRECATED_SINCE(4, 8)
     /**
-     * @deprecated
+     * @deprecated Since 4.8
      *
      * This method does nothing.
      */
+    KITEMMODELS_DEPRECATED_VERSION(4, 8, "Method is a no-op.")
     void setRootIndex(const QModelIndex &index);
+#endif
 
     /**
      * Set whether to show ancestor data in the model. If @p display is true, then