Check download status and fail build if download fails (#510)

Also check SHA256 hashsum of downloaded files.

cmake/Modules/GetLuaJIT.cmake

@@ -17,6 +17,7 @@ if(TERRA_LUA STREQUAL "luajit")
   set(LUAJIT_VERSION_PATCH 0)
   set(LUAJIT_VERSION_EXTRA -beta3)
   set(LUAJIT_COMMIT "50936d784474747b4569d988767f1b5bab8bb6d0")
+  set(LUAJIT_HASH_SHA256 "4d44e4709130b031c1c2c81cf5c102dfce877bf454409dabba03249e18870e66")
   if(NOT LUAJIT_VERSION_COMMIT STREQUAL "")
     set(LUAJIT_URL_PREFIX "https://github.com/LuaJIT/LuaJIT/archive/")
   else()
@@ -30,6 +31,7 @@ elseif(TERRA_LUA STREQUAL "moonjit")
   set(LUAJIT_VERSION_PATCH 0)
   set(LUAJIT_VERSION_EXTRA -dev)
   set(LUAJIT_COMMIT "eb7168839138591e0d2a1751122966603a8b87c8")
+  set(LUAJIT_HASH_SHA256 "6086a84b9666233808dd8b19b9085ce7f68419e26cc266c6511eb96f8d7a5ce2")
   set(LUAJIT_URL_PREFIX "https://github.com/moonjit/moonjit/archive/")
 else()
   message(FATAL_ERROR "TERRA_LUA must be one of 'luajit', 'moonjit'")
@@ -76,7 +78,17 @@ string(CONCAT
   "${CMAKE_SHARED_LIBRARY_SUFFIX}"
 )
 
-file(DOWNLOAD "${LUAJIT_URL}" "${LUAJIT_TAR}")
+option(TERRA_SKIP_LUA_DOWNLOAD "do not download LuaJIT (used in Nix build because Nix pre-downloads LuaJIT)" OFF)
+if(NOT TERRA_SKIP_LUA_DOWNLOAD)
+  file(DOWNLOAD "${LUAJIT_URL}" "${LUAJIT_TAR}"
+    EXPECTED_HASH SHA256=${LUAJIT_HASH_SHA256}
+    STATUS LUAJIT_TAR_STATUS)
+  list(GET LUAJIT_TAR_STATUS 0 LUAJIT_TAR_STATUS_CODE)
+  if(NOT LUAJIT_TAR_STATUS_CODE EQUAL 0)
+    list(GET LUAJIT_TAR_STATUS 1 LUAJIT_TAR_STATUS_MESSAGE)
+    message(FATAL_ERROR "Failed to download LuaJIT release ${LUAJIT_URL}: ${LUAJIT_TAR_STATUS_MESSAGE}")
+  endif()
+endif()
 
 execute_process(
   COMMAND "${CMAKE_COMMAND}" -E tar xzf "${LUAJIT_TAR}"
@@ -293,4 +305,5 @@ mark_as_advanced(
   LUAJIT_OBJECT_DIR
   LUAJIT_LIBRARY
   LUAJIT_EXECUTABLE
+  TERRA_SKIP_LUA_DOWNLOAD
 )

default.nix

@@ -54,6 +54,7 @@ in stdenv.mkDerivation rec {
     "-DHAS_TERRA_VERSION=0"
     "-DTERRA_VERSION=${version}"
     "-DTERRA_LUA=luajit"
+    "-DTERRA_SKIP_LUA_DOWNLOAD=ON"
     "-DCLANG_RESOURCE_DIR=${llvmMerged}/lib/clang/${clangVersion}"
   ] ++ lib.optional enableCUDA "-DTERRA_ENABLE_CUDA=ON";
 
@@ -65,9 +66,6 @@ in stdenv.mkDerivation rec {
   patches = [ ./nix/cflags.patch ];
 
   postPatch = ''
-    sed -i '/file(DOWNLOAD "''${LUAJIT_URL}" "''${LUAJIT_TAR}")/d' \
-      cmake/Modules/GetLuaJIT.cmake
-
     substituteInPlace src/terralib.lua \
       --subst-var-by NIX_LIBC_INCLUDE ${lib.getDev stdenv.cc.libc}/include
   '';