feat: support ninja build,reduced dependency

CMakeLists.txt

@@ -116,6 +116,18 @@ ELSE ()
     SET(LIB_SUFFIX "deps-debug")
 ENDIF ()
 
+IF(CMAKE_GENERATOR STREQUAL "Ninja")
+    MESSAGE(STATUS "Ninja generator is being used.")
+    SET (EXTERNAL_GENERATOR "-G Ninja")
+    SET (EXTERNAL_BUILD "ninja")
+elseif (CMAKE_GENERATOR STREQUAL "Unix Makefiles")
+    MESSAGE(STATUS "Unix Makefiles generator is being used.")
+    SET (EXTERNAL_GENERATOR "-GUnix Makefiles")
+    SET (EXTERNAL_BUILD "make")
+else ()
+    MESSAGE(FATAL_ERROR "only support Ninja or Unix Makefiles")
+ENDIF()
+
 SET_PROPERTY(DIRECTORY PROPERTY EP_BASE ${CMAKE_CURRENT_SOURCE_DIR}/${EP_BASE_SUFFIX})
 SET(CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake/modules/")
 SET(BUILD_SUPPORT_DIR ${PROJECT_SOURCE_DIR}/build_support)

cmake/braft.cmake

@@ -5,7 +5,7 @@
 
 INCLUDE(ExternalProject)
 
-SET(BRAFT_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_braft" CACHE PATH "Path to braft sources")
+SET(BRAFT_SOURCES_DIR "${LIB_SOURCE_DIR}/braft" CACHE PATH "Path to braft sources")
 SET(BRAFT_INSTALL_DIR ${LIB_INSTALL_PREFIX})
 SET(BRAFT_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "brpc include directory." FORCE)
 SET(BRAFT_LIBRARIES "${LIB_INSTALL_DIR}/libbraft.a" CACHE FILEPATH "brpc library." FORCE)
@@ -17,7 +17,7 @@ ELSE ()
 ENDIF ()
 
 ExternalProject_Add(
-        extern_braft
+        braft
         ${EXTERNAL_PROJECT_LOG_ARGS}
         DEPENDS brpc
         GIT_REPOSITORY "https://github.com/arana-db/braft.git"
@@ -51,11 +51,7 @@ ExternalProject_Add(
         -DPROTOBUF_PROTOC_EXECUTABLE=${PROTOBUF_PROTOC}
         -DOPENSSL_INCLUDE_DIR=${OPENSSL_INCLUDE_DIR}
         -DCMAKE_POSITION_INDEPENDENT_CODE=ON
-        BUILD_COMMAND make -j${CPU_CORE}
-        UPDATE_COMMAND ""
+        ${EXTERNAL_GENERATOR}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
+        BUILD_BYPRODUCTS ${BRAFT_LIBRARIES}
 )
-
-ADD_DEPENDENCIES(extern_braft brpc gflags)
-ADD_LIBRARY(braft STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET braft PROPERTY IMPORTED_LOCATION ${BRAFT_LIBRARIES})
-ADD_DEPENDENCIES(braft extern_braft)

cmake/brpc.cmake

@@ -3,7 +3,7 @@
 # LICENSE file in the root directory of this source tree. An additional grant
 # of patent rights can be found in the PATENTS file in the same directory.
 
-SET(BRPC_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_brpc" CACHE PATH "Path to brpc sources")
+SET(BRPC_SOURCES_DIR "${LIB_SOURCE_DIR}/brpc" CACHE PATH "Path to brpc sources")
 SET(BRPC_INSTALL_DIR ${LIB_INSTALL_PREFIX})
 SET(BRPC_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "brpc include directory." FORCE)
 SET(BRPC_LIBRARIES "${LIB_INSTALL_DIR}/libbrpc.a" CACHE FILEPATH "brpc library." FORCE)
@@ -14,7 +14,7 @@ SET(CMAKE_FIND_LIBRARY_SUFFIXES ${LIB_INSTALL_PREFIX})
 SET(CMAKE_CPP_FLAGS "${CMAKE_CXX_FLAGS} -Wno-deprecated-declarations")
 # If minimal .a is need, you can set  WITH_DEBUG_SYMBOLS=OFF
 ExternalProject_Add(
-        extern_brpc
+        brpc
         ${EXTERNAL_PROJECT_LOG_ARGS}
         DEPENDS ssl crypto zlib protobuf leveldb gflags
         URL https://github.com/apache/brpc/archive/refs/tags/1.8.0.tar.gz
@@ -54,10 +54,7 @@ ExternalProject_Add(
         -DPROJECT_BINARY_DIR=${LIB_INSTALL_PREFIX}
         -DWITH_GLOG=OFF
         -DDOWNLOAD_GTEST=OFF
-        BUILD_COMMAND make -j${CPU_CORE}
-        UPDATE_COMMAND ""
+        ${EXTERNAL_GENERATOR}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
+        BUILD_BYPRODUCTS ${BRPC_LIBRARIES}
 )
-ADD_DEPENDENCIES(extern_brpc ssl crypto zlib protobuf leveldb gflags)
-ADD_LIBRARY(brpc STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET brpc PROPERTY IMPORTED_LOCATION ${BRPC_LIBRARIES})
-ADD_DEPENDENCIES(brpc extern_brpc)

cmake/fmt.cmake

@@ -10,12 +10,12 @@ ELSE ()
     SET(LIB_FMT libfmt.a)
 ENDIF ()
 
-SET(FMT_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_fmt" CACHE PATH "Path to fmt sources")
+SET(FMT_SOURCES_DIR "${LIB_SOURCE_DIR}/fmt" CACHE PATH "Path to fmt sources")
 SET(FMT_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "fmt include directory." FORCE)
 SET(FMT_LIBRARIES "${LIB_INSTALL_DIR}/${LIB_FMT}" CACHE FILEPATH "fmt library directory." FORCE)
 
 ExternalProject_Add(
-        extern_fmt
+        fmt
         URL https://github.com/fmtlib/fmt/archive/10.1.1.zip
         URL_HASH SHA256=3c2e73019178ad72b0614a3124f25de454b9ca3a1afe81d5447b8d3cbdb6d322
         DOWNLOAD_NO_PROGRESS 1
@@ -33,11 +33,8 @@ ExternalProject_Add(
         -DFMT_DOC=FALSE
         -DFMT_TEST=FALSE
         -DSHARED_LIBS=FALSE
-        BUILD_COMMAND make -j${CPU_CORE}
+        ${EXTERNAL_GENERATOR}
+        BUILD_BYPRODUCTS ${FMT_LIBRARIES}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
         UPDATE_COMMAND ""
 )
-
-
-ADD_LIBRARY(fmt STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET fmt PROPERTY IMPORTED_LOCATION ${FMT_LIBRARIES})
-ADD_DEPENDENCIES(fmt extern_fmt)

cmake/gflags.cmake

@@ -9,22 +9,21 @@ ELSE ()
     SET(LIB_GFLAGS libgflags.a)
 ENDIF ()
 
-SET(GFLAGS_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_gflags" CACHE PATH "Path to gflags sources")
+SET(GFLAGS_SOURCES_DIR "${LIB_SOURCE_DIR}/gflags" CACHE PATH "Path to gflags sources")
 SET(GFLAGS_INCLUDE_DIR ${LIB_INCLUDE_DIR} CACHE PATH "gflags include directory." FORCE)
 SET(GFLAGS_LIBRARIES ${LIB_INSTALL_DIR}/${LIB_GFLAGS} CACHE FILEPATH "gflags library." FORCE)
 SET(GFLAGS_LIBRARY ${LIB_INSTALL_DIR}/${LIB_GFLAGS} CACHE FILEPATH "gflags library." FORCE)
 
-# SET(GFLAGS_INCLUDE_PATH "${LIB_INCLUDE_DIR}/gflags" CACHE PATH "gflags include directory." FORCE)
-
 ExternalProject_Add(
-        extern_gflags
+        gflags
         URL https://github.com/gflags/gflags/archive/v2.2.2.zip
         URL_HASH SHA256=19713a36c9f32b33df59d1c79b4958434cb005b5b47dc5400a7a4b078111d9b5
         DOWNLOAD_NO_PROGRESS 1
         DOWNLOAD_DIR "${CMAKE_CURRENT_SOURCE_DIR}/download"
         DOWNLOAD_NAME "gflags-2.2.2.zip"
         SOURCE_DIR ${GFLAGS_SOURCES_DIR}
         CMAKE_ARGS
+        ${EXTERNAL_GENERATOR}
         ${EXTERNAL_PROJECT_C}
         ${EXTERNAL_PROJECT_CXX}
         ${EXTERNAL_PROJECT_CXX_FLAGS}
@@ -39,10 +38,7 @@ ExternalProject_Add(
         -DGFLAGS_NAMESPACE=gflags
         -DGFLAGS_BUILD_TESTING=OFF
         -DCMAKE_INSTALL_PREFIX=${LIB_INSTALL_PREFIX}
-        BUILD_COMMAND make -j${CPU_CORE}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
         UPDATE_COMMAND ""
+        BUILD_BYPRODUCTS ${GFLAGS_LIBRARY}
 )
-
-ADD_LIBRARY(gflags STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET gflags PROPERTY IMPORTED_LOCATION ${GFLAGS_LIBRARIES})
-ADD_DEPENDENCIES(gflags extern_gflags)

cmake/gtest.cmake

@@ -3,31 +3,27 @@
 # LICENSE file in the root directory of this source tree. An additional grant
 # of patent rights can be found in the PATENTS file in the same directory.
 
-SET(GTEST_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_gtest" CACHE PATH "Path to gtest sources")
+SET(GTEST_SOURCES_DIR "${LIB_SOURCE_DIR}/gtest" CACHE PATH "Path to gtest sources")
 SET(GTEST_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "gtest include directory." FORCE)
 SET(GTEST_LIBRARIES "${LIB_INSTALL_DIR}/libgtest.a" CACHE FILEPATH "gtest lib directory." FORCE)
 SET(GTEST_MAIN_LIBRARIES "${LIB_INSTALL_DIR}/libgtest_main.a" CACHE FILEPATH "gtest main include directory." FORCE)
 SET(GMOCK_LIBRARIES "${LIB_INSTALL_DIR}/libgmock.a" CACHE FILEPATH "gmock directory." FORCE)
 
 ExternalProject_Add(
-        extern_gtest
+        gtest
         GIT_REPOSITORY https://github.com/google/googletest.git
         GIT_TAG v1.14.0
         GIT_SHALLOW true
         SOURCE_DIR ${GTEST_SOURCES_DIR}
         CMAKE_ARGS
+        ${EXTERNAL_GENERATOR}
         -DCMAKE_INSTALL_PREFIX=${LIB_INSTALL_PREFIX}
         -DCMAKE_INSTALL_LIBDIR=${CMAKE_INSTALL_LIBDIR}
         -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
         ${EXTERNAL_PROJECT_C}
         ${EXTERNAL_PROJECT_CXX}
         ${EXTERNAL_PROJECT_CXX_FLAGS}
         ${EXTERNAL_PROJECT_CXX_LINK_FLAGS}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
+        BUILD_BYPRODUCTS ${GTEST_LIBRARIES}
 )
-
-ADD_DEPENDENCIES(extern_gtest snappy gflags zlib)
-ADD_LIBRARY(gtest STATIC IMPORTED GLOBAL)
-ADD_LIBRARY(gtest_main STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET gtest PROPERTY IMPORTED_LOCATION ${GTEST_LIBRARIES})
-SET_PROPERTY(TARGET gtest_main PROPERTY IMPORTED_LOCATION ${GTEST_MAIN_LIBRARIES})
-ADD_DEPENDENCIES(gtest extern_gtest)

cmake/leveldb.cmake

@@ -3,13 +3,13 @@
 # LICENSE file in the root directory of this source tree. An additional grant
 # of patent rights can be found in the PATENTS file in the same directory.
 
-SET(LEVELDB_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_leveldb" CACHE PATH "Path to leveldb sources")
+SET(LEVELDB_SOURCES_DIR "${LIB_SOURCE_DIR}/leveldb" CACHE PATH "Path to leveldb sources")
 SET(LEVELDB_INCLUDE_DIR "${LIB_INCLUDE_DIR}/leveldb" CACHE PATH "leveldb include directory." FORCE)
 SET(LEVELDB_LIBRARIES "${LIB_INSTALL_DIR}/libleveldb.a" CACHE FILEPATH "leveldb include directory." FORCE)
 SET(LEVELDB_INSTALL_LIBDIR "${LIB_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR}")
 
 ExternalProject_Add(
-        extern_leveldb
+        leveldb
         ${EXTERNAL_PROJECT_LOG_ARGS}
         DEPENDS snappy
         GIT_REPOSITORY "https://github.com/google/leveldb.git"
@@ -31,11 +31,8 @@ ExternalProject_Add(
         -DLEVELDB_BUILD_TESTS=OFF
         -DLEVELDB_BUILD_BENCHMARKS=OFF
         -DCMAKE_BUILD_TYPE=${THIRD_PARTY_BUILD_TYPE}
-        BUILD_COMMAND make -j${CPU_CORE}
+        ${EXTERNAL_GENERATOR}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
         UPDATE_COMMAND ""
+        BUILD_BYPRODUCTS ${LEVELDB_LIBRARIES}
 )
-
-ADD_DEPENDENCIES(extern_leveldb snappy)
-ADD_LIBRARY(leveldb STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET leveldb PROPERTY IMPORTED_LOCATION ${LEVELDB_LIBRARIES})
-ADD_DEPENDENCIES(leveldb extern_leveldb)

cmake/lz4.cmake

@@ -3,12 +3,12 @@
 # LICENSE file in the root directory of this source tree. An additional grant
 # of patent rights can be found in the PATENTS file in the same directory.
 
-SET(LZ4_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_lz4" CACHE PATH "Path to lz4 sources")
+SET(LZ4_SOURCES_DIR "${LIB_SOURCE_DIR}/lz4" CACHE PATH "Path to lz4 sources")
 SET(LZ4_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "lz4 include directory." FORCE)
 SET(LZ4_LIBRARIES "${LIB_INSTALL_DIR}/liblz4.a" CACHE FILEPATH "lz4 include directory." FORCE)
 
 ExternalProject_Add(
-        extern_lz4
+        lz4
         URL https://github.com/lz4/lz4/archive/refs/tags/v1.9.4.tar.gz
         URL_HASH SHA256=0b0e3aa07c8c063ddf40b082bdf7e37a1562bda40a0ff5272957f3e987e0e54b
         DOWNLOAD_DIR "${CMAKE_CURRENT_SOURCE_DIR}/download"
@@ -28,10 +28,8 @@ ExternalProject_Add(
         -DBUILD_TESTING=OFF
         -DBUILD_STATIC_LIBS=ON
         -DBUILD_SHARED_LIBS=OFF
-        BUILD_COMMAND make -j${CPU_CORE}
+        ${EXTERNAL_GENERATOR}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
         UPDATE_COMMAND ""
+        BUILD_BYPRODUCTS ${LZ4_LIBRARIES}
 )
-
-ADD_LIBRARY(lz4 STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET lz4 PROPERTY IMPORTED_LOCATION ${LZ4_LIBRARIES})
-ADD_DEPENDENCIES(lz4 extern_lz4)

cmake/openssl.cmake

@@ -3,9 +3,12 @@
 # LICENSE file in the root directory of this source tree. An additional grant
 # of patent rights can be found in the PATENTS file in the same directory.
 
-SET(OPENSSL_SOURCE_DIR "${LIB_SOURCE_DIR}/extern_openssl" CACHE PATH "Path to OpenSSL sources")
+SET(OPENSSL_SOURCE_DIR "${LIB_SOURCE_DIR}/openssl" CACHE PATH "Path to OpenSSL sources")
 SET(OPENSSL_INSTALL_DIR "${LIB_INSTALL_PREFIX}")
 SET(OPENSSL_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "Openssl include directory." FORCE)
+SET(OPENSSL_LIB "lib")
+SET(OPENSSL_SSL_LIBRARY "${OPENSSL_INSTALL_DIR}/${OPENSSL_LIB}/libssl.a")
+SET(OPENSSL_CRYPTO_LIBRARY "${OPENSSL_INSTALL_DIR}/${OPENSSL_LIB}/libcrypto.a")
 
 FILE(MAKE_DIRECTORY ${OPENSSL_INCLUDE_DIR})
 
@@ -40,20 +43,15 @@ ExternalProject_Add(
         INSTALL_COMMAND make install_sw
         INSTALL_DIR ${OPENSSL_INSTALL_DIR}
         UPDATE_COMMAND ""
+        BUILD_BYPRODUCTS ${OPENSSL_SSL_LIBRARY} ${OPENSSL_CRYPTO_LIBRARY}
 )
 
-SET(OPENSSL_LIB "lib")
 ADD_LIBRARY(ssl STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET ssl PROPERTY IMPORTED_LOCATION ${OPENSSL_INSTALL_DIR}/${OPENSSL_LIB}/libssl.a)
+SET_PROPERTY(TARGET ssl PROPERTY IMPORTED_LOCATION ${OPENSSL_SSL_LIBRARY})
 SET_PROPERTY(TARGET ssl PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${OPENSSL_INCLUDE_DIR})
 ADD_DEPENDENCIES(ssl OpenSSL)
-SET(OPENSSL_SSL_LIBRARY ${OPENSSL_INSTALL_DIR}/${OPENSSL_LIB}/libssl.a)
-list(APPEND LIBS ssl)
 
 ADD_LIBRARY(crypto STATIC IMPORTED GLOBAL)
 SET_PROPERTY(TARGET crypto PROPERTY IMPORTED_LOCATION ${OPENSSL_INSTALL_DIR}/${OPENSSL_LIB}/libcrypto.a)
 SET_PROPERTY(TARGET crypto PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${OPENSSL_INCLUDE_DIR})
 ADD_DEPENDENCIES(crypto OpenSSL)
-SET(OPENSSL_CRYPTO_LIBRARY ${OPENSSL_INSTALL_DIR}/${OPENSSL_LIB}/libcrypto.a)
-
-SET(OPENSSL_INCLUDE_DIR ${LIB_INCLUDE_DIR})

cmake/protobuf.cmake

@@ -13,14 +13,14 @@ ELSE ()
     SET(LIB_PROTOC "libprotoc.a")
 ENDIF ()
 
-SET(PROTOBUF_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_protobuf" CACHE PATH "Path to protobuf sources")
+SET(PROTOBUF_SOURCES_DIR "${LIB_SOURCE_DIR}/protobuf" CACHE PATH "Path to protobuf sources")
 SET(PROTOBUF_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "protobuf include directory." FORCE)
 SET(PROTOBUF_LIBRARY "${LIB_INSTALL_DIR}/${LIB_PROTOBUF}" CACHE FILEPATH "protobuf install directory." FORCE)
 SET(PROTOC_LIBRARY "${LIB_INSTALL_DIR}/${LIB_PROTOC}" CACHE FILEPATH "protoc install directory." FORCE)
 SET(PROTOBUF_PROTOC "${LIB_INSTALL_PREFIX}/bin/protoc")
 
 ExternalProject_Add(
-        extern_protobuf
+        protobuf
         UPDATE_COMMAND ""
         LOG_CONFIGURE 1
         LOG_BUILD 1
@@ -45,9 +45,7 @@ ExternalProject_Add(
         -DBUILD_SHARED_LIBS=OFF
         -Dprotobuf_BUILD_TESTS=OFF
         -Dprotobuf_BUILD_LIBPROTOC=ON
-        BUILD_COMMAND make -j${CPU_CORE}
+        ${EXTERNAL_GENERATOR}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
+        BUILD_BYPRODUCTS ${LIB_PROTOBUF}
 )
-
-ADD_LIBRARY(protobuf STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET protobuf PROPERTY IMPORTED_LOCATION ${PROTOBUF_LIBRARY})
-ADD_DEPENDENCIES(protobuf extern_protobuf)

cmake/rocksdb.cmake

@@ -3,12 +3,12 @@
 # LICENSE file in the root directory of this source tree. An additional grant
 # of patent rights can be found in the PATENTS file in the same directory.
 
-SET(ROCKSDB_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_rocksdb" CACHE PATH "Path to RocksDB sources")
+SET(ROCKSDB_SOURCES_DIR "${LIB_SOURCE_DIR}/rocksdb" CACHE PATH "Path to RocksDB sources")
 SET(ROCKSDB_INCLUDE_DIR "${LIB_INCLUDE_DIR}" CACHE PATH "rocksdb include directory." FORCE)
 SET(ROCKSDB_LIBRARIES "${LIB_INSTALL_DIR}/librocksdb.a" CACHE FILEPATH "rocksdb include directory." FORCE)
 
 ExternalProject_Add(
-        extern_rocksdb
+        rocksdb
         ${EXTERNAL_PROJECT_LOG_ARGS}
         DEPENDS gflags snappy zlib lz4 zstd
         GIT_REPOSITORY https://github.com/facebook/rocksdb.git
@@ -41,11 +41,8 @@ ExternalProject_Add(
         -DWITH_ZSTD=ON
         -DWITH_GFLAGS=ON
         -DUSE_RTTI=ON
-        BUILD_COMMAND make -j${CPU_CORE}
+        ${EXTERNAL_GENERATOR}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
         UPDATE_COMMAND ""
+        BUILD_BYPRODUCTS ${ROCKSDB_LIBRARIES}
 )
-
-ADD_DEPENDENCIES(extern_rocksdb snappy gflags zlib lz4)
-ADD_LIBRARY(rocksdb STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET rocksdb PROPERTY IMPORTED_LOCATION ${ROCKSDB_LIBRARIES})
-ADD_DEPENDENCIES(rocksdb extern_rocksdb)

cmake/snappy.cmake

@@ -3,12 +3,12 @@
 # LICENSE file in the root directory of this source tree. An additional grant
 # of patent rights can be found in the PATENTS file in the same directory.
 
-SET(Snappy_SOURCES_DIR "${LIB_SOURCE_DIR}/extern_snappy" CACHE PATH "Path to snappy sources")
+SET(Snappy_SOURCES_DIR "${LIB_SOURCE_DIR}/snappy" CACHE PATH "Path to snappy sources")
 SET(Snappy_INCLUDE_DIRS "${LIB_INCLUDE_DIR}" CACHE PATH "Snappy include directory." FORCE)
 SET(Snappy_LIBRARIES "${LIB_INSTALL_DIR}/libsnappy.a" CACHE FILEPATH "Snappy install directory." FORCE)
 
 ExternalProject_Add(
-        extern_snappy
+        snappy
         ${EXTERNAL_PROJECT_LOG_ARGS}
         GIT_REPOSITORY "https://github.com/google/snappy.git"
         GIT_TAG "1.2.1"
@@ -26,9 +26,7 @@ ExternalProject_Add(
         -DSNAPPY_BUILD_BENCHMARKS=OFF
         -DBUILD_STATIC_LIBS=ON
         -DBUILD_SHARED_LIBS=OFF
-        UPDATE_COMMAND ""
+        ${EXTERNAL_GENERATOR}
+        BUILD_COMMAND ${EXTERNAL_BUILD} -j${CPU_CORE}
+        BUILD_BYPRODUCTS ${Snappy_LIBRARIES}
 )
-
-ADD_LIBRARY(snappy STATIC IMPORTED GLOBAL)
-SET_PROPERTY(TARGET snappy PROPERTY IMPORTED_LOCATION ${Snappy_LIBRARIES})
-ADD_DEPENDENCIES(snappy extern_snappy)