Detect bash instead of relying on MSVC detection. (simdjson#894)

lemire · web-flow · commit d2c9ea8a9a05 · 2020-05-20T12:13:14.000-04:00
diff --git a/singleheader/CMakeLists.txt b/singleheader/CMakeLists.txt
@@ -1,8 +1,7 @@
 #
 # Amalgamation
 #
-# We should check whether bash is available here and avoid failures on systems where
-# bash is unavailable.
+
 set(SINGLEHEADER_FILES
   ${CMAKE_CURRENT_BINARY_DIR}/simdjson.cpp
   ${CMAKE_CURRENT_BINARY_DIR}/simdjson.h
@@ -17,32 +16,16 @@ set(SINGLEHEADER_REPO_FILES
 )
 set_source_files_properties(${SINGLEHEADER_FILES} PROPERTIES GENERATED TRUE)
 
-if (MSVC)
-  # MSVC doesn't have bash, so we use existing amalgamated files instead of generating them ...
-  # (Do not do this if the source and destination are the same!)
-  if (NOT (${CMAKE_CURRENT_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_BINARY_DIR}))
-    add_custom_command(
-      OUTPUT ${SINGLEHEADER_FILES}
-      COMMAND ${CMAKE_COMMAND} -E copy
-        ${SINGLEHEADER_REPO_FILES}
-        ${CMAKE_CURRENT_BINARY_DIR}
-      DEPENDS ${SINGLEHEADER_REPO_FILES}
-    )
-  endif()
-
-else(MSVC)
+find_program(BASH bash)
 
-  ##
-  # Important! The script amalgamate.sh is not generally executable. It
-  # assumes that bash is at /bin/bash which may not be true.
-  ###
+if (BASH)
   add_custom_command(
     OUTPUT ${SINGLEHEADER_FILES}
     COMMAND ${CMAKE_COMMAND} -E env
       AMALGAMATE_SOURCE_PATH=${PROJECT_SOURCE_DIR}/src
       AMALGAMATE_INPUT_PATH=${PROJECT_SOURCE_DIR}/include
       AMALGAMATE_OUTPUT_PATH=${CMAKE_CURRENT_BINARY_DIR}
-      bash ${CMAKE_CURRENT_SOURCE_DIR}/amalgamate.sh
+      ${BASH} ${CMAKE_CURRENT_SOURCE_DIR}/amalgamate.sh
       #
       # This is the best way I could find to make amalgamation trigger whenever source files or
       # header files change: since the "simdjson" library has to get rebuilt when that happens, we
@@ -72,7 +55,22 @@ else(MSVC)
   # "make amalgamate" to generate the header files directly and update the original source
   #
   add_custom_target(amalgamate DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/simdjson.cpp ${CMAKE_CURRENT_SOURCE_DIR}/simdjson.h ${CMAKE_CURRENT_SOURCE_DIR}/amalgamate_demo.cpp ${CMAKE_CURRENT_SOURCE_DIR}/README.md)
-endif(MSVC)
+
+else(BASH)
+
+  # We do not have bash, so we use existing amalgamated files instead of generating them ...
+  # (Do not do this if the source and destination are the same!)
+  if (NOT (${CMAKE_CURRENT_SOURCE_DIR} STREQUAL ${CMAKE_CURRENT_BINARY_DIR}))
+    add_custom_command(
+      OUTPUT ${SINGLEHEADER_FILES}
+      COMMAND ${CMAKE_COMMAND} -E copy
+        ${SINGLEHEADER_REPO_FILES}
+        ${CMAKE_CURRENT_BINARY_DIR}
+      DEPENDS ${SINGLEHEADER_REPO_FILES}
+    )
+  endif()
+
+endif(BASH)
 
 
 #
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
@@ -58,15 +58,17 @@ add_cpp_test(jsoncheck LABELS acceptance per_implementation)
 add_cpp_test(parse_many_test LABELS acceptance per_implementation)
 add_cpp_test(pointercheck LABELS acceptance per_implementation)
 add_cpp_test(extracting_values_example LABELS acceptance per_implementation)
+find_program(BASH bash) 
+
 
 # Script tests
-if (NOT MSVC) # Can't run .sh on windows
+if (BASH AND (NOT MSVC)) # The scripts are not robust enough to run under Windows even if bash is available
   #
   # json2json test
   #
   add_test(
     NAME testjson2json
-    COMMAND bash ${CMAKE_CURRENT_SOURCE_DIR}/testjson2json.sh
+    COMMAND ${BASH} ${CMAKE_CURRENT_SOURCE_DIR}/testjson2json.sh
     WORKING_DIRECTORY $<TARGET_FILE_DIR:minify>
   )
   set_property(TEST testjson2json APPEND PROPERTY DEPENDS minify json2json)
@@ -79,14 +81,11 @@ if (NOT MSVC) # Can't run .sh on windows
     add_executable(allparserscheckfile allparserscheckfile.cpp)
     target_link_libraries(allparserscheckfile competition-all)
 
-    add_test(issue150 bash ${CMAKE_CURRENT_SOURCE_DIR}/issue150.sh)
+    add_test(issue150 ${BASH} ${CMAKE_CURRENT_SOURCE_DIR}/issue150.sh)
     set_property(TEST issue150 APPEND PROPERTY DEPENDS allparserscheckfile)
     set_property(TEST issue150 APPEND PROPERTY LABELS per_implementation)
   endif()
-endif()
 
-# This should really test whether bash is available.
-if (NOT MSVC)
   #
   # json2json tool test: check that json2json can parse twitter.json
   #
