Use ExternalProject machinery to fetch/update third party

buildconfig/CMake/Bootstrap.cmake

@@ -5,29 +5,49 @@ if( MSVC )
   # Git LFS does not work properly with <= 1.9
   find_package ( Git 1.9.5 REQUIRED )
   find_package ( GitLFS REQUIRED)
-
+
+  # Use ExternalProject functionality as it already knows how to do clone/update
+  include ( ExternalProject )
   set( EXTERNAL_ROOT ${PROJECT_SOURCE_DIR}/external )
   set( THIRD_PARTY_GIT_URL "https://github.com/mantidproject/thirdparty-msvc2015.git" )
-  set( THIRD_PARTY_GIT_SHA1 master )
-  set( THIRD_PARTY_DIR ${EXTERNAL_ROOT}/thirdparty-msvc2015 )
+  set ( THIRD_PARTY_GIT_SHA1 master )
+  set ( THIRD_PARTY_DIR ${EXTERNAL_ROOT}/src/ThirdParty )
+  # Generates a script to do the clone/update in tmp
+  set ( _project_name ThirdParty )
+  ExternalProject_Add( ${_project_name}
+    PREFIX ${EXTERNAL_ROOT}
+    GIT_REPOSITORY ${THIRD_PARTY_GIT_URL}
+    GIT_TAG ${THIRD_PARTY_GIT_SHA1}
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND ""
+    INSTALL_COMMAND ""
+    TEST_COMMAND ""
+  )
+  set_property ( TARGET ${_project_name} PROPERTY EXCLUDE_FROM_ALL )
 
-  if( NOT IS_DIRECTORY ${THIRD_PARTY_DIR} )
-    message ( STATUS "Third party directory not found. Pulling down libraries for MSVC" )
-    execute_process( COMMAND "${GIT_EXECUTABLE}" clone ${THIRD_PARTY_GIT_URL} ${THIRD_PARTY_DIR}
-                     WORKING_DIRECTORY ${EXTERNAL_ROOT} )
-    execute_process( COMMAND "${GIT_EXECUTABLE}" checkout ${THIRD_PARTY_GIT_SHA1}
-                     WORKING_DIRECTORY ${THIRD_PARTY_DIR} )
-  else()
-    message ( STATUS "Found existing ${THIRD_PARTY_DIR}. Updating to ${THIRD_PARTY_GIT_SHA1}" )
-    execute_process( COMMAND "${GIT_EXECUTABLE}" checkout ${THIRD_PARTY_GIT_SHA1}
-                     WORKING_DIRECTORY ${THIRD_PARTY_DIR} )
-    execute_process( COMMAND "${GIT_EXECUTABLE}" pull --rebase origin master
-                     WORKING_DIRECTORY ${THIRD_PARTY_DIR} )
-  endif()
+  # Do fetch/update now as we need the dependencies to configure
+  set ( _tmp_dir ${EXTERNAL_ROOT}/tmp )
+  if ( NOT EXISTS ${THIRD_PARTY_DIR}/.git )
+    message ( STATUS "Fetching third party dependencies" )
+    execute_process ( COMMAND ${CMAKE_COMMAND} ARGS -P ${_tmp_dir}/${_project_name}-gitclone.cmake
+                      COMMENT 
+                      RESULT_VARIABLE error_code )
+    if ( error_code )
+      message(FATAL_ERROR "Failed to clone repository: 'THIRD_PARTY_GIT_URL'")
+    endif ()
+  else ()
+    message ( STATUS "Updating third party dependencies" )
+    execute_process ( COMMAND ${CMAKE_COMMAND} ARGS -P ${_tmp_dir}/${_project_name}-gitupdate.cmake
+                      RESULT_VARIABLE error_code )
+    if ( error_code )
+      message(FATAL_ERROR "Failed to update repository: 'THIRD_PARTY_GIT_URL'")
+    endif ()
+  endif ()
+  unset ( _tmp_dir )
 
-  # Print out where we think we are looking for 3rd party stuff
+  # Print out where we are looking for 3rd party stuff
   set ( THIRD_PARTY_BIN "${THIRD_PARTY_DIR}/bin;${THIRD_PARTY_DIR}/lib/qt4/bin;${THIRD_PARTY_DIR}/lib/python2.7" )
-  message ( STATUS "Thirdparty dependencies are in ${THIRD_PARTY_DIR}. " )
+  message ( STATUS "Third party dependencies are in ${THIRD_PARTY_DIR}" )
   # Add to the path so that cmake can configure correctly without the user having to do it
   set ( ENV{PATH} "${THIRD_PARTY_BIN};$ENV{PATH}" )
 
@@ -39,6 +59,7 @@ if( MSVC )
   set ( BOOST_LIBRARYDIR "${CMAKE_LIBRARY_PATH}" )
   set ( Boost_NO_SYSTEM_PATHS TRUE )
 
+  # Configure MSVC
   include ( MSVCSetup )
 else()
   find_package ( Git )

external/.gitignore

@@ -1 +1,2 @@
-thirdparty-msvc2015
+src/*
+tmp/*