[webview] Make optional based on presence of dependencies

src/modules/webview/CMakeLists.txt

@@ -1,53 +1,60 @@
-list( APPEND CALA_WEBVIEW_INCLUDE_DIRECTORIES
-    ${PROJECT_BINARY_DIR}/src/libcalamaresui
-)
-list( APPEND CALA_WEBVIEW_LINK_LIBRARIES
-    calamaresui
-)
+set( CALA_WEBVIEW_INCLUDE_DIRECTORIES ${PROJECT_BINARY_DIR}/src/libcalamaresui )
+set( CALA_WEBVIEW_LINK_LIBRARIES calamaresui )
 
 option( WEBVIEW_FORCE_WEBKIT "Always build webview with WebKit instead of WebEngine regardless of Qt version." OFF)
 
+set( _reason "" )
+
 message( STATUS "Found Qt version ${Qt5Core_VERSION}")
 if ( Qt5Core_VERSION VERSION_LESS 5.6 OR WEBVIEW_FORCE_WEBKIT )
     message( STATUS " .. using webkit")
-    find_package( Qt5 ${QT_VERSION} CONFIG REQUIRED WebKit WebKitWidgets )
-
-    list( APPEND CALA_WEBVIEW_INCLUDE_DIRECTORIES
-        ${QT_QTWEBKIT_INCLUDE_DIR}
-    )
-    list( APPEND CALA_WEBVIEW_LINK_LIBRARIES
-        Qt5::WebKit
-        Qt5::WebKitWidgets
-    )
-    set( WEBVIEW_WITH_WEBKIT 1 )
+    find_package( Qt5 ${QT_VERSION} CONFIG COMPONENTS WebKit WebKitWidgets )
+
+    if ( Qt5WebKit_FOUND AND Qt5WebKitWidgets_FOUND )
+        list( APPEND CALA_WEBVIEW_INCLUDE_DIRECTORIES
+            ${QT_QTWEBKIT_INCLUDE_DIR}
+        )
+        list( APPEND CALA_WEBVIEW_LINK_LIBRARIES
+            Qt5::WebKit
+            Qt5::WebKitWidgets
+        )
+        set( WEBVIEW_WITH_WEBKIT 1 )
+    else()
+        set( _reason "No suitable WebKit" )
+    endif()
 else()
     message( STATUS " .. using webengine")
-    find_package( Qt5 ${QT_VERSION} CONFIG REQUIRED WebEngine WebEngineWidgets )
-
-    list( APPEND CALA_WEBVIEW_INCLUDE_DIRECTORIES
-        ${QT_QTWEBENGINE_INCLUDE_DIR}
-    )
-    list( APPEND CALA_WEBVIEW_LINK_LIBRARIES
-        Qt5::WebEngine
-        Qt5::WebEngineWidgets
-    )
-    set( WEBVIEW_WITH_WEBENGINE 1 )
+    find_package( Qt5 ${QT_VERSION} CONFIG COMPONENTS WebEngine WebEngineWidgets )
+
+    if ( Qt5WebEngine_FOUND AND Qt5WebEngineWidgets_FOUND )
+        list( APPEND CALA_WEBVIEW_INCLUDE_DIRECTORIES
+            ${QT_QTWEBENGINE_INCLUDE_DIR}
+        )
+        list( APPEND CALA_WEBVIEW_LINK_LIBRARIES
+            Qt5::WebEngine
+            Qt5::WebEngineWidgets
+        )
+        set( WEBVIEW_WITH_WEBENGINE 1 )
+    else()
+        set( _reason "No suitable WebEngine" )
+    endif()
 endif()
 
-include_directories( ${CALA_WEBVIEW_INCLUDE_DIRECTORIES} )
-
-set( CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH}
-                       ${CMAKE_CURRENT_SOURCE_DIR}/CMakeModules )
+if ( NOT _reason )
+    include_directories( ${CALA_WEBVIEW_INCLUDE_DIRECTORIES} )
 
-configure_file( ${CMAKE_CURRENT_SOURCE_DIR}/WebViewConfig.h.in
-                ${CMAKE_CURRENT_BINARY_DIR}/WebViewConfig.h )
+    configure_file( ${CMAKE_CURRENT_SOURCE_DIR}/WebViewConfig.h.in
+                    ${CMAKE_CURRENT_BINARY_DIR}/WebViewConfig.h )
 
-calamares_add_plugin( webview
-    TYPE viewmodule
-    EXPORT_MACRO PLUGINDLLEXPORT_PRO
-    SOURCES
-        WebViewStep.cpp
-    LINK_PRIVATE_LIBRARIES
-        ${CALA_WEBVIEW_LINK_LIBRARIES}
-    SHARED_LIB
-)
+    calamares_add_plugin( webview
+        TYPE viewmodule
+        EXPORT_MACRO PLUGINDLLEXPORT_PRO
+        SOURCES
+            WebViewStep.cpp
+        LINK_PRIVATE_LIBRARIES
+            ${CALA_WEBVIEW_LINK_LIBRARIES}
+        SHARED_LIB
+    )
+else()
+    calamares_skip_module( "webview (${_reason})" )
+endif()