HunterInit.cmake : download gate to CMAKE_BINARY_DIR / check status / check signature

package/hunter/.gitignore

@@ -1 +0,0 @@
-HunterGate.cmake

package/hunter/HunterInit.cmake

@@ -1,13 +1,31 @@
-if(NOT EXISTS ${CMAKE_CURRENT_LIST_DIR}/HunterGate.cmake)
+set(hunter_gate_file ${CMAKE_BINARY_DIR}/HunterGate.cmake)
+if(NOT EXISTS ${hunter_gate_file})
+  set(url https://raw.githubusercontent.com/hunter-packages/gate/c4e5b3e4d1c97fb46ae86af7f59baac95f7f1cf0/cmake/HunterGate.cmake)
+  message("hunter_gate_file=${hunter_gate_file}")
+  set(expected_sha256 "9952fdeb6909855c7802938914d45dffa5e1b87252d4b4a6e9d54421dffe649f")
   file(
-    DOWNLOAD
-    https://raw.githubusercontent.com/hunter-packages/gate/c4e5b3e4d1c97fb46ae86af7f59baac95f7f1cf0/cmake/HunterGate.cmake
-    ${CMAKE_CURRENT_LIST_DIR}//HunterGate.cmake
+    DOWNLOAD ${url}
+    ${hunter_gate_file}
+    STATUS status
   )
+  list(GET status 0 status_code)
+  list(GET status 1 status_string)
+  if(status_code EQUAL 0)
+    file(SHA256 ${hunter_gate_file} computed_sha256)
+    if (NOT ${computed_sha256} STREQUAL ${expected_sha256})
+      message(FATAL_ERROR "HunterInit.cmake ; error downloading ${url} -> bad signature !")
+    endif()
+  else()
+    message(FATAL_ERROR "HunterInit.cmake : error downloading ${url}
+      status : ${status_code}
+      status_string : ${status_string}
+      ")
+  endif()
 endif()
 
+
 # FIXME : will need to replace this url with the main hunter url !
-include("${CMAKE_CURRENT_LIST_DIR}/HunterGate.cmake")
+include("${CMAKE_BINARY_DIR}/HunterGate.cmake")
 HunterGate(
   URL "https://github.com/pthom/hunter/archive/hunter_magnum_rc4.tar.gz"
   SHA1 "31554df9e988f27f4daa9f4df9529d75007500bf"