From 1f71ef4300812edbdbf84ff0eafbb774528dcc06 Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@audacityteam.org>
Date: Sat, 20 Jun 2020 10:21:27 -0400
Subject: [PATCH] New interface library target wxBase restricts view of
 wxWidgets...

... It will be used as a target link library of some lower level Audacity
libraries, to be separated from the executable.

These libraries will have link time dependency only on the wxBase subset of
non-monolithic wxWidgets builds.

More, they are restricted to use only a proper subset of wxBase functionality:
they are prevented, at compile time, not only from using any graphical user
interface, but also from using the main event loop or global application object
-- though these things are also in wxBase.

They may still use things like strings, files, threads, atomics, and other
utilities that may have modern C++ standard library equivalents.

It would be preferable to use those, but it is not a priority to make those
rewrites.
---
 cmake-proxies/wxWidgets/CMakeLists.txt | 39 ++++++++++++++++++++++----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/cmake-proxies/wxWidgets/CMakeLists.txt b/cmake-proxies/wxWidgets/CMakeLists.txt
index ac0b827a7..47b6bd0ee 100644
--- a/cmake-proxies/wxWidgets/CMakeLists.txt
+++ b/cmake-proxies/wxWidgets/CMakeLists.txt
@@ -1,5 +1,6 @@
 
 add_library( ${TARGET} INTERFACE )
+add_library( wxBase INTERFACE )
 add_library( ${symbol} ALIAS ${TARGET} )
 
 def_vars()
@@ -248,11 +249,39 @@ if( NOT ours )
    )
 endif()
 
-target_include_directories( ${TARGET} INTERFACE ${INCLUDES} )
-target_compile_definitions( ${TARGET} INTERFACE ${DEFINES} )
-target_compile_options( ${TARGET} INTERFACE ${COPTS} )
-target_link_directories( ${TARGET} INTERFACE ${LINKDIRS} )
-target_link_libraries( ${TARGET} INTERFACE ${LIBRARIES} )
+foreach( target "${TARGET}" wxBase )
+   target_include_directories( ${target} INTERFACE ${INCLUDES} )
+   target_compile_definitions( ${target} INTERFACE ${DEFINES} )
+   target_compile_options( ${target} INTERFACE ${COPTS} )
+   target_link_directories( ${target} INTERFACE ${LINKDIRS} )
+   target_link_libraries( ${target} INTERFACE ${LIBRARIES} )
+endforeach()
+
+# wxBase exposes only the GUI-less subset of full wxWidgets
+# Also prohibit use of some other headers by pre-defining their include guards
+# wxUSE_GUI=0 doesn't exclude all of wxCore dependency, and the application
+# object and event loops are in wxBase, but we want to exclude their use too
+target_compile_definitions( wxBase INTERFACE
+   "wxUSE_GUI=0"
+ 
+   # Don't use app.h
+   _WX_APP_H_BASE_
+
+   # Don't use evtloop.h
+   _WX_EVTLOOP_H_
+
+   # Don't use image.h
+   _WX_IMAGE_H
+
+   # Don't use colour.h
+   _WX_COLOUR_H_BASE_
+
+   # Don't use brush.h
+   _WX_BRUSH_H_BASE_
+
+   # Don't use pen.h
+   _WX_PEN_H_BASE_
+)
 
 install( TARGETS ${TARGET} DESTINATION ${_LIBDIR} )