Configure and install CMake package configuration file to help find_package…

Configure and install CMake package configuration file to help find_package locate the gflags package.

CMakeLists.txt

 cmake_minimum_required(VERSION 2.8 FATAL_ERROR)
 
+# ----------------------------------------------------------------------------
+# includes
+set (CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+
+include (utils)
+
 # ----------------------------------------------------------------------------
 # package information
 set (PROJECT_NAME      "gflags")
@@ -11,6 +17,13 @@ set (PACKAGE_BUGREPORT "https://code.google.com/p/gflags/issues/")
 
 project (${PROJECT_NAME})
 
+version_numbers (
+  ${PACKAGE_VERSION}
+    PACKAGE_VERSION_MAJOR
+    PACKAGE_VERSION_MINOR
+    PACKAGE_VERSION_PATCH
+)
+
 # ----------------------------------------------------------------------------
 # configure options
 option (BUILD_SHARED_LIBS "Request build of shared libraries." OFF)
@@ -136,5 +149,38 @@ add_library (gflags ${GFLAGS_SRCS})
 
 # ----------------------------------------------------------------------------
 # installation
-install (TARGETS gflags DESTINATION lib)
-install (FILES ${PUBLIC_HDRS} DESTINATION include/${GFLAGS_NAMESPACE})
+if (WIN32)
+  set (LIBRARY_INSTALL_DIR Lib)
+  set (INCLUDE_INSTALL_DIR Include)
+  set (CONFIG_INSTALL_DIR  CMake)
+else ()
+  set (LIBRARY_INSTALL_DIR lib)
+  set (INCLUDE_INSTALL_DIR include)
+  set (CONFIG_INSTALL_DIR  cmake/${PACKAGE_NAME})
+endif ()
+
+install (TARGETS ${PACKAGE_NAME} DESTINATION ${LIBRARY_INSTALL_DIR} EXPORT gflags-lib)
+install (FILES   ${PUBLIC_HDRS}  DESTINATION ${INCLUDE_INSTALL_DIR}/${GFLAGS_NAMESPACE})
+
+file (RELATIVE_PATH INSTALL_PREFIX_REL2CONFIG_DIR "${CMAKE_INSTALL_PREFIX}" "${CMAKE_INSTALL_PREFIX}/${CONFIG_INSTALL_DIR}")
+configure_file (cmake/config.cmake.in  "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-config-install.cmake" @ONLY)
+configure_file (cmake/version.cmake.in "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-config-version.cmake" @ONLY)
+
+install (
+  FILES "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-config-install.cmake"
+  RENAME ${PACKAGE_NAME}-config.cmake
+  DESTINATION ${CONFIG_INSTALL_DIR}
+)
+
+install (
+  FILES "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-config-version.cmake"
+  DESTINATION ${CONFIG_INSTALL_DIR}
+)
+
+install (EXPORT gflags-lib DESTINATION ${CONFIG_INSTALL_DIR} FILE ${PACKAGE_NAME}-export.cmake)
+
+# ----------------------------------------------------------------------------
+# support direct use of build tree
+set (INSTALL_PREFIX_REL2CONFIG_DIR .)
+export (TARGETS gflags FILE "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-export.cmake")
+configure_file (cmake/config.cmake.in "${PROJECT_BINARY_DIR}/${PACKAGE_NAME}-config.cmake" @ONLY)

cmake/config.cmake.in

+## gflags CMake configuration file
+
+# library version information
+set (@PACKAGE_NAME@_VERSION_STRING "@PACKAGE_VERSION@")
+set (@PACKAGE_NAME@_VERSION_MAJOR  @PACKAGE_VERSION_MAJOR@)
+set (@PACKAGE_NAME@_VERSION_MINOR  @PACKAGE_VERSION_MINOR@)
+set (@PACKAGE_NAME@_VERSION_PATCH  @PACKAGE_VERSION_PATCH@)
+
+# import targets
+include ("${CMAKE_CURRENT_LIST_DIR}/@PACKAGE_NAME@-export.cmake")
+
+# installation prefix
+get_filename_component (CMAKE_CURRENT_LIST_DIR "${CMAKE_CURRENT_LIST_FILE}" PATH)
+get_filename_component (_INSTALL_PREFIX "${CMAKE_CURRENT_LIST_DIR}/@INSTALL_PREFIX_REL2CONFIG_DIR@" ABSOLUTE)
+
+# include directory
+set (@PACKAGE_NAME@_INCLUDE_DIR "${_INSTALL_PREFIX}/@INCLUDE_INSTALL_DIR@")
+
+# gflags library
+set (@PACKAGE_NAME@_LIBRARIES gflags)
+
+# unset private variables
+unset (_INSTALL_PREFIX)

cmake/utils.cmake

+## @file  utils.cmake
+#  @brief Utility CMake functions.
+
+# ----------------------------------------------------------------------------
+## @brief Extract version numbers from version string.
+#
+# @param [in]  VERSION Version string in the format "MAJOR[.MINOR[.PATCH]]".
+# @param [out] MAJOR   Major version number if given or 0.
+# @param [out] MINOR   Minor version number if given or 0.
+# @param [out] PATCH   Patch number if given or 0.
+#
+# @returns See @c [out] parameters.
+function (version_numbers VERSION MAJOR MINOR PATCH)
+  if (VERSION MATCHES "([0-9]+)(\\.[0-9]+)?(\\.[0-9]+)?(rc[1-9][0-9]*|[a-z]+)?")
+    if (CMAKE_MATCH_1)
+      set (VERSION_MAJOR ${CMAKE_MATCH_1})
+    else ()
+      set (VERSION_MAJOR 0)
+    endif ()
+    if (CMAKE_MATCH_2)
+      set (VERSION_MINOR ${CMAKE_MATCH_2})
+      string (REGEX REPLACE "^\\." "" VERSION_MINOR "${VERSION_MINOR}")
+    else ()
+      set (VERSION_MINOR 0)
+    endif ()
+    if (CMAKE_MATCH_3)
+      set (VERSION_PATCH ${CMAKE_MATCH_3})
+      string (REGEX REPLACE "^\\." "" VERSION_PATCH "${VERSION_PATCH}")
+    else ()
+      set (VERSION_PATCH 0)
+    endif ()
+  else ()
+    set (VERSION_MAJOR 0)
+    set (VERSION_MINOR 0)
+    set (VERSION_PATCH 0)
+  endif ()
+  set ("${MAJOR}" "${VERSION_MAJOR}" PARENT_SCOPE)
+  set ("${MINOR}" "${VERSION_MINOR}" PARENT_SCOPE)
+  set ("${PATCH}" "${VERSION_PATCH}" PARENT_SCOPE)
+endfunction ()

cmake/version.cmake.in

+## gflags CMake configuration version file
+
+# -----------------------------------------------------------------------------
+# library version
+set (PACKAGE_VERSION "@PACKAGE_VERSION@")
+
+# -----------------------------------------------------------------------------
+# check compatibility
+
+# Perform compatibility check here using the input CMake variables.
+# See example in http://www.cmake.org/Wiki/CMake_2.6_Notes.
+
+set (PACKAGE_VERSION_COMPATIBLE TRUE)
+set (PACKAGE_VERSION_UNSUITABLE FALSE)
+
+if ("${PACKAGE_FIND_VERSION_MAJOR}" EQUAL "@PACKAGE_VERSION_MAJOR@")
+  if ("${PACKAGE_FIND_VERSION_MINOR}" EQUAL "@PACKAGE_VERSION_MINOR@")
+    set (PACKAGE_VERSION_EXACT TRUE)
+  endif ()
+endif ()