build: add option to build without Qt WebEngine

This patch allows building the project without Qt WebEngine, by
disabling (for the time being) the features that depend on it:
the emoji picker, link previews, and media file previews in the
chatview.

Co-authored-by: Andreas Traczyk <andreas.traczyk@savoirfairelinux.com>
Co-authored-by: Amin Bandali <amin.bandali@savoirfairelinux.com>
Change-Id: I74751b0cc6f22c61a6fd7281ca3207e0fdbb2212

CMakeLists.txt

@@ -42,12 +42,22 @@ set(QT_MODULES
     Concurrent
     Core
     Core5Compat
-    WebEngineCore
-    WebEngineQuick
-    WebChannel
-    WebEngineWidgets
     Multimedia
 )
+
+if(NOT DEFINED WITH_WEBENGINE)
+    set(WITH_WEBENGINE true)
+endif()
+
+if(WITH_WEBENGINE)
+    list(APPEND QT_MODULES
+        WebEngineCore
+        WebEngineQuick
+        WebChannel
+        WebEngineWidgets
+    )
+endif()
+
 find_package(Qt6 COMPONENTS ${QT_MODULES} REQUIRED)
 foreach(MODULE ${QT_MODULES})
   list(APPEND QT_LIBS "Qt::${MODULE}")
@@ -57,8 +67,23 @@ set(SRC_DIR ${PROJECT_SOURCE_DIR}/src)
 set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} ${Qt5Widgets_EXECUTABLE_COMPILE_FLAGS})
 set(CMAKE_INSTALL_RPATH_USE_LINK_PATH true)
 
+if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.12.0")
+    include(FindPython3)
+    find_package (Python3 COMPONENTS Interpreter)
+    set(PYTHON_EXEC ${Python3_EXECUTABLE})
+else()
+    include(FindPythonInterp)
+    set(PYTHON_EXEC ${PYTHON_EXECUTABLE})
+endif()
+
 set(QML_RESOURCES ${PROJECT_SOURCE_DIR}/resources.qrc)
-set(QML_RESOURCES_QML ${PROJECT_SOURCE_DIR}/qml.qrc)
+if(WITH_WEBENGINE)
+    set(QML_RESOURCES_QML ${PROJECT_SOURCE_DIR}/qml.qrc)
+else()
+    execute_process(COMMAND ${PYTHON_EXEC} ${CMAKE_CURRENT_SOURCE_DIR}/scripts/gen-qrc-without-webengine.py
+        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
+    set(QML_RESOURCES_QML ${PROJECT_SOURCE_DIR}/qml_without_webengine.qrc)
+endif()
 
 if (APPLE)
     include(FetchContent)
@@ -78,14 +103,6 @@ file(GLOB_RECURSE
     RES_FILES CONFIGURE_DEPENDS
     ${PROJECT_SOURCE_DIR}/resources/*
 )
-if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.12.0")
-    include(FindPython3)
-    find_package (Python3 COMPONENTS Interpreter)
-    set(PYTHON_EXEC ${Python3_EXECUTABLE})
-else()
-    include(FindPythonInterp)
-    set(PYTHON_EXEC ${PYTHON_EXECUTABLE})
-endif()
 execute_process(
     COMMAND ${PYTHON_EXEC} ${PROJECT_SOURCE_DIR}/gen-resources.py
     WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
@@ -137,7 +154,6 @@ set(COMMON_SOURCES
     ${SRC_DIR}/currentconversation.cpp
     ${SRC_DIR}/currentaccount.cpp
     ${SRC_DIR}/videodevices.cpp
-    ${SRC_DIR}/previewengine.cpp
     ${SRC_DIR}/videoprovider.cpp
     ${SRC_DIR}/callparticipantsmodel.cpp
 )
@@ -194,11 +210,19 @@ set(COMMON_HEADERS
     ${SRC_DIR}/currentconversation.h
     ${SRC_DIR}/currentaccount.h
     ${SRC_DIR}/videodevices.h
-    ${SRC_DIR}/previewengine.h
     ${SRC_DIR}/videoprovider.h
     ${SRC_DIR}/callparticipantsmodel.h
 )
 
+if(WITH_WEBENGINE)
+    list(APPEND COMMON_SOURCES
+                ${SRC_DIR}/previewengine.cpp)
+    add_definitions(-DWITH_WEBENGINE)
+else()
+    list(APPEND COMMON_SOURCES
+                ${SRC_DIR}/nowebengine/previewengine.cpp)
+endif()
+
 # For libavutil/avframe.
 set(LIBJAMI_CONTRIB_DIR "${PROJECT_SOURCE_DIR}/../daemon/contrib")
 find_path(AVUTIL_INCLUDE_DIR libavutil/avutil.h