Wayland: Use viewporter (#836)

cmake/FindWayland.cmake

@@ -1,14 +1,137 @@
-find_package(PkgConfig)
+# SPDX-FileCopyrightText: 2014 Alex Merry <alex.merry@kde.org>
+# SPDX-FileCopyrightText: 2014 Martin Gräßlin <mgraesslin@kde.org>
+#
+# SPDX-License-Identifier: BSD-3-Clause
 
-pkg_search_module(WAYLAND_CLIENT IMPORTED_TARGET wayland-client)
+#[=======================================================================[.rst:
+FindWayland
+-----------
 
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(Wayland
-    REQUIRED_VARS
-        WAYLAND_CLIENT_LIBRARIES
-    VERSION_VAR WAYLAND_CLIENT_VERSION
+Try to find Wayland.
+
+This is a component-based find module, which makes use of the COMPONENTS
+and OPTIONAL_COMPONENTS arguments to find_module.  The following components
+are available::
+
+  Client  Server  Cursor  Egl
+
+If no components are specified, this module will act as though all components
+were passed to OPTIONAL_COMPONENTS.
+
+This module will define the following variables, independently of the
+components searched for or found:
+
+``Wayland_FOUND``
+    TRUE if (the requested version of) Wayland is available
+``Wayland_VERSION``
+    Found Wayland version
+``Wayland_TARGETS``
+    A list of all targets imported by this module (note that there may be more
+    than the components that were requested)
+``Wayland_LIBRARIES``
+    This can be passed to target_link_libraries() instead of the imported
+    targets
+``Wayland_INCLUDE_DIRS``
+    This should be passed to target_include_directories() if the targets are
+    not used for linking
+``Wayland_DEFINITIONS``
+    This should be passed to target_compile_options() if the targets are not
+    used for linking
+``Wayland_DATADIR``
+    The core wayland protocols data directory
+    Since 5.73.0
+
+For each searched-for components, ``Wayland_<component>_FOUND`` will be set to
+TRUE if the corresponding Wayland library was found, and FALSE otherwise.  If
+``Wayland_<component>_FOUND`` is TRUE, the imported target
+``Wayland::<component>`` will be defined.  This module will also attempt to
+determine ``Wayland_*_VERSION`` variables for each imported target, although
+``Wayland_VERSION`` should normally be sufficient.
+
+In general we recommend using the imported targets, as they are easier to use
+and provide more control.  Bear in mind, however, that if any target is in the
+link interface of an exported library, it must be made available by the
+package config file.
+
+Since pre-1.0.0.
+#]=======================================================================]
+
+include(${CMAKE_CURRENT_LIST_DIR}/ECMFindModuleHelpersStub.cmake)
+
+ecm_find_package_version_check(Wayland)
+
+set(Wayland_known_components
+    Client
+    Server
+    Cursor
+    Egl
+)
+foreach(_comp ${Wayland_known_components})
+    string(TOLOWER "${_comp}" _lc_comp)
+    set(Wayland_${_comp}_component_deps)
+    set(Wayland_${_comp}_pkg_config "wayland-${_lc_comp}")
+    set(Wayland_${_comp}_lib "wayland-${_lc_comp}")
+    set(Wayland_${_comp}_header "wayland-${_lc_comp}.h")
+endforeach()
+set(Wayland_Egl_component_deps Client)
+
+ecm_find_package_parse_components(Wayland
+    RESULT_VAR Wayland_components
+    KNOWN_COMPONENTS ${Wayland_known_components}
+)
+ecm_find_package_handle_library_components(Wayland
+    COMPONENTS ${Wayland_components}
 )
 
-if (Wayland_FOUND)
-    add_library(Wayland::client ALIAS PkgConfig::WAYLAND_CLIENT)
+# If pkg-config didn't provide us with version information,
+# try to extract it from wayland-version.h
+# (Note that the version from wayland-egl.pc will probably be
+# the Mesa version, rather than the Wayland version, but that
+# version will be ignored as we always find wayland-client.pc
+# first).
+if(NOT Wayland_VERSION)
+    find_file(Wayland_VERSION_HEADER
+        NAMES wayland-version.h
+        HINTS ${Wayland_INCLUDE_DIRS}
+    )
+    mark_as_advanced(Wayland_VERSION_HEADER)
+    if(Wayland_VERSION_HEADER)
+        file(READ ${Wayland_VERSION_HEADER} _wayland_version_header_contents)
+        string(REGEX REPLACE
+            "^.*[ \t]+WAYLAND_VERSION[ \t]+\"([0-9.]*)\".*$"
+            "\\1"
+            Wayland_VERSION
+            "${_wayland_version_header_contents}"
+        )
+        unset(_wayland_version_header_contents)
+    endif()
 endif()
+
+find_package_handle_standard_args(Wayland
+    FOUND_VAR
+        Wayland_FOUND
+    REQUIRED_VARS
+        Wayland_LIBRARIES
+    VERSION_VAR
+        Wayland_VERSION
+    HANDLE_COMPONENTS
+)
+
+pkg_get_variable(Wayland_DATADIR wayland-scanner pkgdatadir)
+if (CMAKE_CROSSCOMPILING AND (NOT EXISTS "${Wayland_DATADIR}/wayland.xml"))
+    # PKG_CONFIG_SYSROOT_DIR only applies to -I and -L flags, so pkg-config
+    # does not prepend CMAKE_SYSROOT when cross-compiling unless you pass
+    # --define-prefix explicitly. Therefore we have to  manually do prepend
+    # it here when cross-compiling.
+    # See https://gitlab.kitware.com/cmake/cmake/-/issues/16647#note_844761
+    set(Wayland_DATADIR ${CMAKE_SYSROOT}${Wayland_DATADIR})
+endif()
+if (NOT EXISTS "${Wayland_DATADIR}/wayland.xml")
+    message(WARNING "Could not find wayland.xml in ${Wayland_DATADIR}")
+endif()
+
+include(FeatureSummary)
+set_package_properties(Wayland PROPERTIES
+    URL "https://wayland.freedesktop.org/"
+    DESCRIPTION "C library implementation of the Wayland protocol: a protocol for a compositor to talk to its clients"
+)