HDFS-16604. Install gtest via FetchContent_Declare in CMake (#4374)

Reviewed-by: Inigo Goiri <inigoiri@apache.org>
Signed-off-by: Akira Ajisaka <aajisaka@apache.org>

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/CMakeLists-gtest.txt.in

@@ -1,33 +0,0 @@
-#
-# Licensed to the Apache Software Foundation (ASF) under one
-# or more contributor license agreements.  See the NOTICE file
-# distributed with this work for additional information
-# regarding copyright ownership.  The ASF licenses this file
-# to you under the Apache License, Version 2.0 (the
-# "License"); you may not use this file except in compliance
-# with the License.  You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
-
-project(googletest-download NONE)
-
-include(ExternalProject)
-ExternalProject_Add(googletest
-  GIT_REPOSITORY    https://github.com/google/googletest.git
-  GIT_TAG           release-1.10.0
-  SOURCE_DIR        "${CMAKE_CURRENT_BINARY_DIR}/googletest-src"
-  BINARY_DIR        "${CMAKE_CURRENT_BINARY_DIR}/googletest-build"
-  CONFIGURE_COMMAND ""
-  BUILD_COMMAND     ""
-  INSTALL_COMMAND   ""
-  TEST_COMMAND      ""
-)

hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/CMakeLists.txt

@@ -52,31 +52,20 @@ find_package(Threads)
 
 include(CheckCXXSourceCompiles)
 include(CheckSymbolExists)
-
-# Download and build gtest
-configure_file(CMakeLists-gtest.txt.in googletest-download/CMakeLists.txt)
-execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
-  RESULT_VARIABLE result
-  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download)
-if(result)
-  message(FATAL_ERROR "CMake step for googletest failed: ${result}")
-endif()
-execute_process(COMMAND ${CMAKE_COMMAND} --build .
-  RESULT_VARIABLE result
-  WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/googletest-download)
-if(result)
-  message(FATAL_ERROR "Build step for googletest failed: ${result}")
-endif()
-
-# Prevent overriding the parent project's compiler/linker
-# settings on Windows
+include(FetchContent)
+
+# Install googletest
+# As per the approach documented in the GoogleTest repo -
+# https://github.com/google/googletest/blob/e649993a402d96afe25fbf3413749adf0f2947f6/googletest/README.md#incorporating-into-an-existing-cmake-project
+FetchContent_Declare(
+  googletest
+  URL https://github.com/google/googletest/archive/703bd9caab50b139428cea1aaff9974ebee5742e.zip
+)
+# The commit SHA 703bd9caab50b139428cea1aaff9974ebee5742e in the URL above corresponds to the
+# tag release-1.10.0 in the googletest repository.
+# For Windows: Prevent overriding the parent project's compiler/linker settings
 set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
-
-# Add googletest directly to our build. This defines
-# the gtest and gtest_main targets.
-add_subdirectory(${CMAKE_CURRENT_BINARY_DIR}/googletest-src
-                 ${CMAKE_CURRENT_BINARY_DIR}/googletest-build
-                 EXCLUDE_FROM_ALL)
+FetchContent_MakeAvailable(googletest)
 
 # Check if thread_local is supported
 unset (THREAD_LOCAL_SUPPORTED CACHE)