From 7eab385bb326ee0d8f6144592477ae0178daf526 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Sat, 21 Jan 2023 11:18:51 -0500
Subject: [PATCH] add CMake option to skip automatic download of large
 potential files

---
 cmake/CMakeLists.txt            |  2 ++
 cmake/Modules/LAMMPSUtils.cmake | 40 +++++++++++++++++----------------
 2 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 0223750ace..767bbbfe34 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -566,6 +566,8 @@ RegisterStyles(${LAMMPS_SOURCE_DIR})
 ########################################################
 # Fetch missing external files and archives for packages
 ########################################################
+option(DOWNLOAD_POTENTIALS "Automatically download large potential files" ON)
+mark_as_advanced(DOWNLOAD_POTENTIALS)
 foreach(PKG ${STANDARD_PACKAGES} ${EXTRA_PACKAGES} ${SUFFIX_PACKAGES})
   if(PKG_${PKG})
     FetchPotentials(${LAMMPS_SOURCE_DIR}/${PKG} ${LAMMPS_POTENTIALS_DIR})
diff --git a/cmake/Modules/LAMMPSUtils.cmake b/cmake/Modules/LAMMPSUtils.cmake
index 9602379403..d42f91f10e 100644
--- a/cmake/Modules/LAMMPSUtils.cmake
+++ b/cmake/Modules/LAMMPSUtils.cmake
@@ -118,25 +118,27 @@ endfunction(GenerateBinaryHeader)
 
 # fetch missing potential files
 function(FetchPotentials pkgfolder potfolder)
-  if(EXISTS "${pkgfolder}/potentials.txt")
-    file(STRINGS "${pkgfolder}/potentials.txt" linelist REGEX "^[^#].")
-    foreach(line ${linelist})
-      string(FIND ${line} " " blank)
-      math(EXPR plusone "${blank}+1")
-      string(SUBSTRING ${line} 0 ${blank} pot)
-      string(SUBSTRING ${line} ${plusone} -1 sum)
-      if(EXISTS "${LAMMPS_POTENTIALS_DIR}/${pot}")
-        file(MD5 "${LAMMPS_POTENTIALS_DIR}/${pot}" oldsum)
-      endif()
-      if(NOT sum STREQUAL oldsum)
-        message(STATUS "Downloading external potential ${pot} from ${LAMMPS_POTENTIALS_URL}")
-        string(MD5 TMP_EXT "${CMAKE_BINARY_DIR}")
-        file(DOWNLOAD "${LAMMPS_POTENTIALS_URL}/${pot}.${sum}" "${CMAKE_BINARY_DIR}/${pot}.${TMP_EXT}"
-          EXPECTED_HASH MD5=${sum} SHOW_PROGRESS)
-        file(COPY "${CMAKE_BINARY_DIR}/${pot}.${TMP_EXT}" DESTINATION "${LAMMPS_POTENTIALS_DIR}")
-        file(RENAME "${LAMMPS_POTENTIALS_DIR}/${pot}.${TMP_EXT}" "${LAMMPS_POTENTIALS_DIR}/${pot}")
-      endif()
-    endforeach()
+  if(DOWNLOAD_POTENTIALS)
+    if(EXISTS "${pkgfolder}/potentials.txt")
+      file(STRINGS "${pkgfolder}/potentials.txt" linelist REGEX "^[^#].")
+      foreach(line ${linelist})
+        string(FIND ${line} " " blank)
+        math(EXPR plusone "${blank}+1")
+        string(SUBSTRING ${line} 0 ${blank} pot)
+        string(SUBSTRING ${line} ${plusone} -1 sum)
+        if(EXISTS "${LAMMPS_POTENTIALS_DIR}/${pot}")
+          file(MD5 "${LAMMPS_POTENTIALS_DIR}/${pot}" oldsum)
+        endif()
+        if(NOT sum STREQUAL oldsum)
+          message(STATUS "Downloading external potential ${pot} from ${LAMMPS_POTENTIALS_URL}")
+          string(RANDOM LENGTH 10 TMP_EXT)
+          file(DOWNLOAD "${LAMMPS_POTENTIALS_URL}/${pot}.${sum}" "${CMAKE_BINARY_DIR}/${pot}.${TMP_EXT}"
+            EXPECTED_HASH MD5=${sum} SHOW_PROGRESS)
+          file(COPY "${CMAKE_BINARY_DIR}/${pot}.${TMP_EXT}" DESTINATION "${LAMMPS_POTENTIALS_DIR}")
+          file(RENAME "${LAMMPS_POTENTIALS_DIR}/${pot}.${TMP_EXT}" "${LAMMPS_POTENTIALS_DIR}/${pot}")
+        endif()
+      endforeach()
+    endif()
   endif()
 endfunction(FetchPotentials)