CMake: Split QtBuild.cmake into smaller files

QtBuild.cmake is huge. Split it.

Move module, plugin, tools, executables and test related functions out
of QtBuild.cmake into separate files.
Do the same for many other things too.

An additional requirement is that all the new Helpers files only
define functions and macros.
No global variable definitions are allowed, nor execution of commands
with side effects.

Some notes:
qt_install_qml_files is removed because it's dead code.

Some functions still need to be figured out, because they are
interspersed and depend on various global state assignments.

Task-number: QTBUG-86035
Change-Id: I21d79ff02eef923c202eb1000422888727cb0e2c
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 84 insertions, 0 deletions

diff --git a/cmake/QtScopeFinalizerHelpers.cmake b/cmake/QtScopeFinalizerHelpers.cmake
new file mode 100644
index 0000000000..bd0775e059
--- /dev/null
+++ b/cmake/QtScopeFinalizerHelpers.cmake
@@ -0,0 +1,84 @@
+# Add a finalizer function for the current CMake list file.
+#
+# You may add up to nine arguments that are passed to the finalizer.
+# A finalizer that is registered with qt_add_list_file_finalizer(foo bar baz)
+# will be called with nine arguments: foo(bar baz IGNORE IGNORE IGNORE...),
+# because CMake's handling of empty list elements is a cruel joke.
+#
+# For CMake < 3.18 the function qt_watch_current_list_dir must know about the finalizer.
+function(qt_add_list_file_finalizer func)
+    set_property(GLOBAL APPEND
+        PROPERTY QT_LIST_FILE_FINALIZER_FILES "${CMAKE_CURRENT_LIST_FILE}")
+    set_property(GLOBAL APPEND
+        PROPERTY QT_LIST_FILE_FINALIZER_FUNCS ${func})
+    foreach(i RANGE 1 9)
+        set(arg "${ARGV${i}}")
+        if(i GREATER_EQUAL ARGC OR "${arg}" STREQUAL "")
+            set(arg "IGNORE")
+        endif()
+        set_property(GLOBAL APPEND
+            PROPERTY QT_LIST_FILE_FINALIZER_ARGV${i} "${arg}")
+    endforeach()
+endfunction()
+
+# Watcher function for the variable CMAKE_CURRENT_LIST_DIR.
+# This is the driver of the finalizer facility.
+function(qt_watch_current_list_dir variable access value current_list_file stack)
+    if(NOT access STREQUAL "MODIFIED_ACCESS")
+        # We are only interested in modifications of CMAKE_CURRENT_LIST_DIR.
+        return()
+    endif()
+    list(GET stack -1 stack_top)
+    if(stack_top STREQUAL current_list_file)
+        # If the top of the stack equals the current list file then
+        # we're entering a file. We're not interested in this case.
+        return()
+    endif()
+    get_property(files GLOBAL PROPERTY QT_LIST_FILE_FINALIZER_FILES)
+    if(NOT files)
+        return()
+    endif()
+    get_property(funcs GLOBAL PROPERTY QT_LIST_FILE_FINALIZER_FUNCS)
+    foreach(i RANGE 1 9)
+        get_property(args${i} GLOBAL PROPERTY QT_LIST_FILE_FINALIZER_ARGV${i})
+    endforeach()
+    list(LENGTH files n)
+    set(i 0)
+    while(i LESS n)
+        list(GET files ${i} file)
+        if(file STREQUAL stack_top)
+            list(GET funcs ${i} func)
+            foreach(k RANGE 1 9)
+                list(GET args${k} ${i} a${k})
+            endforeach()
+            # We've found a file we're looking for. Call the finalizer.
+            if(${CMAKE_VERSION} VERSION_LESS "3.18.0")
+                # Make finalizer known functions here:
+                if(func STREQUAL "qt_finalize_module")
+                    qt_finalize_module(${a1} ${a2} ${a3} ${a4} ${a5} ${a6} ${a7} ${a8} ${a9})
+                elseif(func STREQUAL "qt_finalize_plugin")
+                    qt_finalize_plugin(${a1} ${a2} ${a3} ${a4} ${a5} ${a6} ${a7} ${a8} ${a9})
+                elseif(func STREQUAL "qt_internal_finalize_app")
+                    qt_internal_finalize_app(${a1} ${a2} ${a3} ${a4} ${a5} ${a6} ${a7} ${a8} ${a9})
+                else()
+                    message(FATAL_ERROR "qt_watch_current_list_dir doesn't know about ${func}. Consider adding it.")
+                endif()
+            else()
+                cmake_language(CALL ${func} ${a1} ${a2} ${a3} ${a4} ${a5} ${a6} ${a7} ${a8} ${a9})
+            endif()
+            list(REMOVE_AT files ${i})
+            list(REMOVE_AT funcs ${i})
+            foreach(k RANGE 1 9)
+                list(REMOVE_AT args${k} ${i})
+            endforeach()
+            math(EXPR n "${n} - 1")
+        else()
+            math(EXPR i "${i} + 1")
+        endif()
+    endwhile()
+    set_property(GLOBAL PROPERTY QT_LIST_FILE_FINALIZER_FILES ${files})
+    set_property(GLOBAL PROPERTY QT_LIST_FILE_FINALIZER_FUNCS ${funcs})
+    foreach(i RANGE 1 9)
+        set_property(GLOBAL PROPERTY QT_LIST_FILE_FINALIZER_ARGV${i} "${args${i}}")
+    endforeach()
+endfunction()