CMake: use copy_if_different to replace copy

Author: snnn

tensorflow/contrib/cmake/external/farmhash.cmake

@@ -19,7 +19,7 @@ if(WIN32)
       URL_HASH ${farmhash_HASH}
       DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
       BUILD_IN_SOURCE 1
-      PATCH_COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/patches/farmhash/CMakeLists.txt ${farmhash_BUILD}
+      PATCH_COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_SOURCE_DIR}/patches/farmhash/CMakeLists.txt ${farmhash_BUILD}
       INSTALL_DIR ${farmhash_INSTALL}
       CMAKE_CACHE_ARGS
           -DCMAKE_BUILD_TYPE:STRING=Release
@@ -53,5 +53,5 @@ add_custom_target(farmhash_copy_headers_to_destination
 
 foreach(header_file ${farmhash_HEADERS})
     add_custom_command(TARGET farmhash_copy_headers_to_destination PRE_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy ${header_file} ${farmhash_INCLUDE_DIR}/)
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${header_file} ${farmhash_INCLUDE_DIR}/)
 endforeach()

tensorflow/contrib/cmake/external/gemmlowp.cmake

@@ -11,5 +11,5 @@ ExternalProject_Add(gemmlowp
     URL_HASH ${gemmlowp_HASH}
     DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
     BUILD_IN_SOURCE 1
-    PATCH_COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/patches/gemmlowp/CMakeLists.txt ${gemmlowp_BUILD}
+    PATCH_COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_SOURCE_DIR}/patches/gemmlowp/CMakeLists.txt ${gemmlowp_BUILD}
     INSTALL_COMMAND "")

tensorflow/contrib/cmake/external/gif.cmake

@@ -19,7 +19,7 @@ if(WIN32)
       PREFIX gif
       URL ${gif_URL}
       URL_HASH ${gif_HASH}
-      PATCH_COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_SOURCE_DIR}/patches/gif/CMakeLists.txt ${gif_BUILD}
+      PATCH_COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_SOURCE_DIR}/patches/gif/CMakeLists.txt ${gif_BUILD}
       INSTALL_DIR ${gif_INSTALL}
       DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
       CMAKE_CACHE_ARGS
@@ -29,7 +29,7 @@ if(WIN32)
   )
 
   ExternalProject_Add_Step(gif copy_unistd
-      COMMAND ${CMAKE_COMMAND} -E copy
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different
           ${CMAKE_SOURCE_DIR}/patches/gif/unistd.h ${gif_BUILD}/lib/unistd.h
       DEPENDEES patch
       DEPENDERS build
@@ -67,5 +67,5 @@ add_custom_target(gif_copy_headers_to_destination
 
 foreach(header_file ${gif_HEADERS})
     add_custom_command(TARGET gif_copy_headers_to_destination PRE_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy ${header_file} ${gif_INCLUDE_DIR}/)
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${header_file} ${gif_INCLUDE_DIR}/)
 endforeach()

tensorflow/contrib/cmake/external/googletest.cmake

@@ -19,7 +19,7 @@ ExternalProject_Add(googletest
     GIT_TAG ${googletest_TAG}
     DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
     BUILD_IN_SOURCE 1
-    #PATCH_COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_SOURCE_DIR}/patches/grpc/CMakeLists.txt ${GRPC_BUILD}
+    #PATCH_COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_SOURCE_DIR}/patches/grpc/CMakeLists.txt ${GRPC_BUILD}
     INSTALL_COMMAND ""
     CMAKE_CACHE_ARGS
         -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE}

tensorflow/contrib/cmake/external/grpc.cmake

@@ -24,7 +24,7 @@ ExternalProject_Add(grpc
     GIT_TAG ${GRPC_TAG}
     DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
     BUILD_IN_SOURCE 1
-    PATCH_COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/patches/grpc/CMakeLists.txt ${GRPC_BUILD}
+    PATCH_COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_SOURCE_DIR}/patches/grpc/CMakeLists.txt ${GRPC_BUILD}
     INSTALL_COMMAND ""
     CMAKE_CACHE_ARGS
         -DCMAKE_BUILD_TYPE:STRING=Release

tensorflow/contrib/cmake/external/highwayhash.cmake

@@ -28,7 +28,7 @@ ExternalProject_Add(highwayhash
     GIT_TAG ${highwayhash_TAG}
     DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
     BUILD_IN_SOURCE 1
-    PATCH_COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/patches/highwayhash/CMakeLists.txt ${highwayhash_BUILD}
+    PATCH_COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_SOURCE_DIR}/patches/highwayhash/CMakeLists.txt ${highwayhash_BUILD}
     INSTALL_DIR ${highwayhash_INSTALL}
     CMAKE_CACHE_ARGS
         -DCMAKE_BUILD_TYPE:STRING=Release

tensorflow/contrib/cmake/external/jpeg.cmake

@@ -32,7 +32,7 @@ if (WIN32)
         PREFIX jpeg
         URL ${jpeg_URL}
         URL_HASH ${jpeg_HASH}
-        PATCH_COMMAND ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_SOURCE_DIR}/patches/jpeg/CMakeLists.txt ${jpeg_BUILD}
+        PATCH_COMMAND ${CMAKE_COMMAND} -E copy_if_different ${CMAKE_CURRENT_SOURCE_DIR}/patches/jpeg/CMakeLists.txt ${jpeg_BUILD}
         INSTALL_DIR ${jpeg_INSTALL}
         DOWNLOAD_DIR "${DOWNLOAD_LOCATION}"
         CMAKE_CACHE_ARGS
@@ -42,7 +42,7 @@ if (WIN32)
     )
 
     ExternalProject_Add_Step(jpeg copy_jconfig
-        COMMAND ${CMAKE_COMMAND} -E copy
+        COMMAND ${CMAKE_COMMAND} -E copy_if_different
             ${jpeg_BUILD}/jconfig.vc ${jpeg_BUILD}/jconfig.h
         DEPENDEES patch
         DEPENDERS build
@@ -76,5 +76,5 @@ add_custom_target(jpeg_copy_headers_to_destination
 
 foreach(header_file ${jpeg_HEADERS})
     add_custom_command(TARGET jpeg_copy_headers_to_destination PRE_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy ${header_file} ${jpeg_INCLUDE_DIR})
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${header_file} ${jpeg_INCLUDE_DIR})
 endforeach()

tensorflow/contrib/cmake/external/png.cmake

@@ -42,5 +42,5 @@ add_custom_target(png_copy_headers_to_destination
 
 foreach(header_file ${png_HEADERS})
   add_custom_command(TARGET png_copy_headers_to_destination PRE_BUILD
-      COMMAND ${CMAKE_COMMAND} -E copy ${header_file} ${png_INCLUDE_DIR}/)
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different ${header_file} ${png_INCLUDE_DIR}/)
 endforeach()

tensorflow/contrib/cmake/external/tensorboard.cmake

@@ -20,7 +20,7 @@ function(tb_new_http_archive)
   foreach(src_file ${_TB_FILES})
     add_custom_command(
       TARGET tensorboard_copy_dependencies PRE_BUILD
-      COMMAND ${CMAKE_COMMAND} -E copy ${src_dir}/${src_file} ${dst_dir}/${src_file}
+      COMMAND ${CMAKE_COMMAND} -E copy_if_different ${src_dir}/${src_file} ${dst_dir}/${src_file}
     )
   endforeach()
 
@@ -37,7 +37,7 @@ function(tb_http_file)
 
   add_custom_command(
     TARGET tensorboard_copy_dependencies PRE_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy ${src_dir}/${src_file} ${dst_dir}/${src_file}
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${src_dir}/${src_file} ${dst_dir}/${src_file}
   )
 
   add_custom_target(${_TB_NAME} DEPENDS ${src_dir}/${src_file})

tensorflow/contrib/cmake/external/zlib.cmake

@@ -42,5 +42,5 @@ add_custom_target(zlib_copy_headers_to_destination
 
 foreach(header_file ${ZLIB_HEADERS})
     add_custom_command(TARGET zlib_copy_headers_to_destination PRE_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy ${header_file} ${zlib_INCLUDE_DIR})
+    COMMAND ${CMAKE_COMMAND} -E copy_if_different ${header_file} ${zlib_INCLUDE_DIR})
 endforeach()