Refactoring for libusb detection

cmake/modules/FindLibUSB.cmake

@@ -6,139 +6,132 @@
 #  LIBUSB_LIBRARY - The libraries needed to use libusb
 #  LIBUSB_DEFINITIONS - Compiler switches required for using libusb
 
-
-if (CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")      # FreeBSD
-    FIND_PATH(LIBUSB_INCLUDE_DIR NAMES libusb.h
-  	HINTS
-	  /usr/include
-	  )
-else ()                                        # other OS
-	  FIND_PATH(LIBUSB_INCLUDE_DIR NAMES libusb.h
-	  HINTS
-	  /usr
-	  /usr/local
-	  /opt
-	  PATH_SUFFIXES libusb-1.0
-	  )
-endif()
-
-
-# macOS
-if (APPLE)
-	  set(LIBUSB_NAME libusb-1.0.a)
-elseif(MSYS OR MINGW)
-	  set(LIBUSB_NAME usb-1.0)
-elseif(MSVC)
-	  set(LIBUSB_NAME libusb-1.0.lib)
-elseif(CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
-	  set(LIBUSB_NAME usb)
-else()
-	  set(LIBUSB_NAME usb-1.0)
-endif()
-
-if (MSYS OR MINGW)
-	  if (CMAKE_SIZEOF_VOID_P EQUAL 8)
-	  	  find_library(
-				    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-		        HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MinGW64/static)
-	  else ()
-		    find_library(
-				    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-			      HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MinGW32/static)
-	  endif ()
-elseif (MSVC)
-	  if (CMAKE_SIZEOF_VOID_P EQUAL 8)
-	    	find_library(
-				    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-            HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MS64/dll)
-	  else ()
-		    find_library(
-				    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-			      HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MS32/dll)
-	  endif ()
-else()
-  	find_library(LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-  	HINTS
-  	/usr
-	  /usr/local
-	  /opt)
+if (NOT (CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")) # all OS apart from FreeBSD
+    FIND_PATH(
+        LIBUSB_INCLUDE_DIR NAMES libusb.h
+        HINTS /usr /usr/local /opt
+        PATH_SUFFIXES libusb-1.0
+        )
 endif ()
 
+if (APPLE)                                      # macOS
+    set(LIBUSB_NAME libusb-1.0.a)
+    find_library(
+        LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
+        HINTS /usr /usr/local /opt
+        )
+
+elseif (MINGW OR MSYS)                          # Windows with MinGW or MSYS
+    set(LIBUSB_NAME usb-1.0)
+
+    if (CMAKE_SIZEOF_VOID_P EQUAL 8)            # 64-bit
+        find_library(
+            LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
+            HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MinGW64/static
+            NO_DEFAULT_PATH
+            NO_CMAKE_FIND_ROOT_PATH
+            )
+    else ()                                     # 32-bit
+        find_library(
+            LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
+            HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MinGW32/static
+            NO_DEFAULT_PATH
+            NO_CMAKE_FIND_ROOT_PATH
+            )
+    endif ()
+
+elseif (MSVC)                                   # Windows with MSVC
+    set(LIBUSB_NAME libusb-1.0.lib)
+    if (CMAKE_SIZEOF_VOID_P EQUAL 8)            # 64-bit
+        find_library(
+            LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
+            HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MS64/dll
+            NO_DEFAULT_PATH
+            NO_CMAKE_FIND_ROOT_PATH
+            )
+    else ()                                     # 32-bit
+        find_library(
+            LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
+            HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MS32/dll
+            NO_DEFAULT_PATH
+            NO_CMAKE_FIND_ROOT_PATH
+            )
+    endif ()
+
+elseif (CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")   # FreeBSD
+    # libusb is integrated into FreeBSD
+    FIND_PATH(
+        LIBUSB_INCLUDE_DIR NAMES libusb.h
+        HINTS /usr/include
+        )
+
+    set(LIBUSB_NAME usb)
+    find_library(
+        LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
+        HINTS /usr /usr/local /opt
+        )
+
+else ()                                          # all other OS
+    set(LIBUSB_NAME usb-1.0)
+    find_library(
+        LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
+        HINTS /usr /usr/local /opt
+        )
+endif()
+
 include(FindPackageHandleStandardArgs)
 FIND_PACKAGE_HANDLE_STANDARD_ARGS(Libusb DEFAULT_MSG LIBUSB_LIBRARY LIBUSB_INCLUDE_DIR)
-
 mark_as_advanced(LIBUSB_INCLUDE_DIR LIBUSB_LIBRARY)
 
-if(NOT LIBUSB_FOUND)
-    if(WIN32 OR MSVC OR MINGW OR MSYS)
-        find_package(7Zip REQUIRED)
+if (NOT LIBUSB_FOUND)
+    if (WIN32 OR MINGW OR MSYS OR MSVC)         # Windows
 
-        set(LIBUSB_WIN_VERSION 1.0.23)
+        # Preparations for installing libusb library
+        find_package(7Zip REQUIRED)
+        set(LIBUSB_WIN_VERSION 1.0.23)           # set libusb version to 1.0.23 (latest as of Apr 2020)
         set(LIBUSB_WIN_ARCHIVE libusb-${LIBUSB_WIN_VERSION}.7z)
         set(LIBUSB_WIN_ARCHIVE_PATH ${CMAKE_BINARY_DIR}/${LIBUSB_WIN_ARCHIVE})
         set(LIBUSB_WIN_OUTPUT_FOLDER ${CMAKE_BINARY_DIR}/3rdparty/libusb-${LIBUSB_WIN_VERSION})
 
-        if(EXISTS ${LIBUSB_WIN_ARCHIVE_PATH})
+        # Get libusb package
+        if (EXISTS ${LIBUSB_WIN_ARCHIVE_PATH})   # ... should the package be already there (for whatever reason)
             message(STATUS "libusb archive already in build folder")
-        else()
+        else ()                                  # ... download the package (1.0.23 as of Apr 2020)
             message(STATUS "downloading libusb ${LIBUSB_WIN_VERSION}")
             file(DOWNLOAD
                 https://sourceforge.net/projects/libusb/files/libusb-1.0/libusb-${LIBUSB_WIN_VERSION}/libusb-${LIBUSB_WIN_VERSION}.7z/download
-                ${LIBUSB_WIN_ARCHIVE_PATH}
-                EXPECTED_MD5 cf3d38d2ff053ef343d10c0b8b0950c2
-            )
-        endif()
+                ${LIBUSB_WIN_ARCHIVE_PATH} EXPECTED_MD5 cf3d38d2ff053ef343d10c0b8b0950c2
+                )
+        endif ()
+
         file(MAKE_DIRECTORY ${LIBUSB_WIN_OUTPUT_FOLDER})
 
-        if(${ZIP_EXECUTABLE} MATCHES "p7zip")
-            #execute_process(COMMAND ${ZIP_EXECUTABLE} -d --keep -f ${LIBUSB_WIN_ARCHIVE_PATH} WORKING_DIRECTORY ${LIBUSB_WIN_OUTPUT_FOLDER})
-            execute_process(COMMAND ${ZIP_EXECUTABLE} -d ${LIBUSB_WIN_ARCHIVE_PATH} WORKING_DIRECTORY ${LIBUSB_WIN_OUTPUT_FOLDER})
-        else()
-            execute_process(COMMAND ${ZIP_EXECUTABLE} x -y ${LIBUSB_WIN_ARCHIVE_PATH} -o${LIBUSB_WIN_OUTPUT_FOLDER})
-        endif()
-
-        FIND_PATH(LIBUSB_INCLUDE_DIR NAMES libusb.h
-        HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/include
-        PATH_SUFFIXES libusb-1.0
-        NO_DEFAULT_PATH
-        NO_CMAKE_FIND_ROOT_PATH
-        )
-
-        if (MSYS OR MINGW)
-            if (CMAKE_SIZEOF_VOID_P EQUAL 8)
-                find_library(
-								    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-                    HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MinGW64/static
-                    NO_DEFAULT_PATH
-                    NO_CMAKE_FIND_ROOT_PATH
-                    )
-            else ()
-                find_library(
-								    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-                    HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MinGW32/static
-                    NO_DEFAULT_PATH
-                    NO_CMAKE_FIND_ROOT_PATH
-                    )
-            endif ()
-        elseif(MSVC)
-            if (CMAKE_SIZEOF_VOID_P EQUAL 8)
-                find_library(
-								    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-                    HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MS64/dll
-                    NO_DEFAULT_PATH
-                    NO_CMAKE_FIND_ROOT_PATH
-                    )
-            else ()
-                find_library(
-								    LIBUSB_LIBRARY NAMES ${LIBUSB_NAME}
-                    HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/MS32/dll
-                    NO_DEFAULT_PATH
-                    NO_CMAKE_FIND_ROOT_PATH
-                    )
-            endif ()
+        # Extract libusb package
+        if (${ZIP_EXECUTABLE} MATCHES "p7zip")
+            execute_process(
+                COMMAND ${ZIP_EXECUTABLE} -d ${LIBUSB_WIN_ARCHIVE_PATH}
+                WORKING_DIRECTORY ${LIBUSB_WIN_OUTPUT_FOLDER}
+                )
+        else ()
+            execute_process(
+                COMMAND ${ZIP_EXECUTABLE} x -y ${LIBUSB_WIN_ARCHIVE_PATH} -o ${LIBUSB_WIN_OUTPUT_FOLDER}
+                )
         endif ()
+
+        # Find path to libusb library
+        FIND_PATH(
+            LIBUSB_INCLUDE_DIR NAMES libusb.h
+            HINTS ${LIBUSB_WIN_OUTPUT_FOLDER}/include
+            PATH_SUFFIXES libusb-1.0
+            NO_DEFAULT_PATH
+            NO_CMAKE_FIND_ROOT_PATH
+            )
+
         FIND_PACKAGE_HANDLE_STANDARD_ARGS(Libusb DEFAULT_MSG LIBUSB_LIBRARY LIBUSB_INCLUDE_DIR)
-    endif()
-else()
-    message(STATUS "found USB")
-endif()
+        message(STATUS "installed libusb library")
+    else ()                                      # all other OS
+        message(FATAL_ERROR "libusb library not found on your system! Compilation terminated.")
+    endif ()
+else (NOT LIBUSB_FOUND)
+    message(STATUS "found libusb library")
+endif ()