Merge b5565aa into 710ac0a

Author: will-lauer

CMakeLists.txt

@@ -142,6 +142,7 @@ configure_package_config_file(
     cmake/DataSketchesConfig.cmake.in
     "${CMAKE_CURRENT_BINARY_DIR}/DataSketchesConfig.cmake"
     INSTALL_DESTINATION lib/DataSketches/cmake
+    PATH_VARS CMAKE_INSTALL_INCLUDEDIR
 )
 install(EXPORT ${PROJECT_NAME} DESTINATION lib/DataSketches/cmake)
 install(FILES "${CMAKE_CURRENT_BINARY_DIR}/DataSketchesConfigVersion.cmake"

README.md

@@ -25,18 +25,18 @@ Installing the latest cmake on OSX: brew install cmake
 Building and running unit tests using cmake for OSX and Linux:
 
 ```
-	$ cmake -S . -B build/Release -DCMAKE_BUILD_TYPE=Release
-	$ cmake --build build/Release -t test
+    $ cmake -S . -B build/Release -DCMAKE_BUILD_TYPE=Release
+    $ cmake --build build/Release -t test
 ```
 
 Building and running unit tests using cmake for Windows from the command line:
 
 ```
-	$ cd build
-	$ cmake ..
-	$ cd ..
-	$ cmake --build build --config Release
-	$ cmake --build build --config Release --target RUN_TESTS
+    $ cd build
+    $ cmake ..
+    $ cd ..
+    $ cmake --build build --config Release
+    $ cmake --build build --config Release --target RUN_TESTS
 ```
 
 To install a local distribution (OSX and Linux), use the following command. The
@@ -46,8 +46,8 @@ the installation will be in /tmp/install/DataSketches (/tmp/install/DataSketches
 /tmp/install/DataSketches/lib, etc)
 
 ```
-	$ cmake -S . -B build/Release -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/install/DataSketches
-	$ cmake --build build/Release -t install
+    $ cmake -S . -B build/Release -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/tmp/install/DataSketches
+    $ cmake --build build/Release -t install
 ```
 
 To generate an installable package using cmake's built in cpack packaging tool,
@@ -56,44 +56,54 @@ variable (semi-colon separated list). Cmake usually supports packaging types suc
 DEB, STGZ, TGZ, TZ, ZIP, etc.
 
 ```
-	$ cmake3 -S . -B build/Release -DCMAKE_BUILD_TYPE=Release -DCPACK_GENERATOR="RPM;STGZ;TGZ" 
-	$ cmake3 --build build/Release -t package
+    $ cmake3 -S . -B build/Release -DCMAKE_BUILD_TYPE=Release -DCPACK_GENERATOR="RPM;STGZ;TGZ" 
+    $ cmake3 --build build/Release -t package
 ```
 
 The DataSketches project can be included in other projects' CMakeLists.txt files in one of two ways.
 If DataSketches has been installed on the host (using an RPM, DEB, "make install" into /usr/local, or some 
 way, then CMake's `find_package` command can be used like this:
 
 ```
-	find_package(DataSketches 3.2 REQUIRED)
-	target_link_library(my_dependent_target PUBLIC ${DATASKETCHES_LIB})
+    find_package(DataSketches 3.2 REQUIRED)
+    target_link_library(my_dependent_target PUBLIC ${DATASKETCHES_LIB})
 ```
 
+When used with find_package, DataSketches exports several variables, including
+
+   - `DATASKETCHES_VERSION`: The version number of the datasketches package that was imported.
+   - `DATASKETCHES_INCLUDE_DIR`: The directory that should be added to access DataSketches include files.
+   Because cmake automatically includes the interface directories for included target libraries when
+   using `target_link_library`, under normal circumstances there will be no need to include this directly.
+   - `DATASKETCHES_LIB`: The name of the DataSketches target to include as a dependency. Projects pulling
+   in DataSketches should reference this with `target_link_library` in order to set up all the correct dependencies 
+   and include paths.
+
 If you don't have DataSketches installed locally, dependent projects can pull it directly
 from GitHub using CMake's `ExternalProject` module. The code would look something like this:
 
 ```
-	cmake_policy(SET CMP0097 NEW)
-	include(ExternalProject)
-	ExternalProject_Add(datasketches
-	    GIT_REPOSITORY https://github.com/apache/datasketches-cpp.git
-	    GIT_TAG 3.2.0
-	    GIT_SHALLOW true
-	    GIT_SUBMODULES ""
-	    INSTALL_DIR /tmp/datasketches-prefix
-	   	CMAKE_ARGS -DBUILD_TESTS=OFF -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE} -DCMAKE_INSTALL_PREFIX=/tmp/datasketches-prefix
-
-		# Override the install command to add DESTDIR
-		# This is necessary to work around an oddity in the RPM (but not other) package
-		# generation, as CMake otherwise picks up the Datasketch files when building
-		# an RPM for a dependent package. (RPM scans the directory for files in addition to installing
-		# those files referenced in an "install" rule in the cmake file)
-	    INSTALL_COMMAND env DESTDIR= ${CMAKE_COMMAND} --build . --target install
-	)
-	ExternalProject_Get_property(datasketches INSTALL_DIR)
-	set(datasketches_INSTALL_DIR ${INSTALL_DIR})
-	message("Source dir of datasketches = ${datasketches_INSTALL_DIR}")
-	target_include_directories(my_dependent_target 
-								PRIVATE ${datasketches_INSTALL_DIR}/include/DataSketches)
-	add_dependencies(my_dependent_target datasketches)
+    cmake_policy(SET CMP0097 NEW)
+    include(ExternalProject)
+    ExternalProject_Add(datasketches
+        GIT_REPOSITORY https://github.com/apache/datasketches-cpp.git
+        GIT_TAG 3.2.0
+        GIT_SHALLOW true
+        GIT_SUBMODULES ""
+        INSTALL_DIR /tmp/datasketches-prefix
+           CMAKE_ARGS -DBUILD_TESTS=OFF -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE} -DCMAKE_INSTALL_PREFIX=/tmp/datasketches-prefix
+
+        # Override the install command to add DESTDIR
+        # This is necessary to work around an oddity in the RPM (but not other) package
+        # generation, as CMake otherwise picks up the Datasketch files when building
+        # an RPM for a dependent package. (RPM scans the directory for files in addition to installing
+        # those files referenced in an "install" rule in the cmake file)
+        INSTALL_COMMAND env DESTDIR= ${CMAKE_COMMAND} --build . --target install
+    )
+    ExternalProject_Get_property(datasketches INSTALL_DIR)
+    set(datasketches_INSTALL_DIR ${INSTALL_DIR})
+    message("Source dir of datasketches = ${datasketches_INSTALL_DIR}")
+    target_include_directories(my_dependent_target 
+                                PRIVATE ${datasketches_INSTALL_DIR}/include/DataSketches)
+    add_dependencies(my_dependent_target datasketches)
 ```

cmake/DataSketchesConfig.cmake.in

@@ -1,7 +1,10 @@
+set(DATASKETCHES_VERSION "@PROJECT_VERSION@")
+
 @PACKAGE_INIT@
 
 include("${CMAKE_CURRENT_LIST_DIR}/DataSketches.cmake")
 
+set_and_check(DATASKETCHES_INCLUDE_DIR "@PACKAGE_CMAKE_INSTALL_INCLUDEDIR@/DataSketches")
 set(DATASKETCHES_LIB "datasketches")
 
 check_required_components("@PROJECT_NAME@")