CMake: Update FindLibXml2.cmake

Change-Id: I55f77910be642535cba128900c2af40fa6824f04
Reviewed-on: https://code.wireshark.org/review/31874
Petri-Dish: João Valverde <j@v6e.pt>
Tested-by: Petri Dish Buildbot
Reviewed-by: João Valverde <j@v6e.pt>

4 files changed, 90 insertions, 71 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4f0ba19961..5cfe7b5265 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1097,12 +1097,6 @@ ws_find_package(SPANDSP ENABLE_SPANDSP HAVE_SPANDSP)
 ws_find_package(BCG729 ENABLE_BCG729 HAVE_BCG729)
 
 ws_find_package(LibXml2 ENABLE_LIBXML2 HAVE_LIBXML2)
-if(NOT LIBXML2_FOUND)
-	# The (official) FindLibXml2.cmake file sets this cache variable to a
-	# non-empty value, be sure to clear it when not found.
-	set(LIBXML2_LIBRARIES "")
-	set(LIBXML2_INCLUDE_DIR "")
-endif()
 
 # Capabilities
 ws_find_package(CAP ENABLE_CAP HAVE_LIBCAP)
diff --git a/cmake/modules/FindLibXml2.cmake b/cmake/modules/FindLibXml2.cmake
index 9677130b17..1f8becaea7 100644
--- a/cmake/modules/FindLibXml2.cmake
+++ b/cmake/modules/FindLibXml2.cmake
@@ -1,41 +1,54 @@
 # This code was copied from https://gitlab.kitware.com/cmake/cmake/raw/master/Modules/FindLibXml2.cmake
 # and modified to support Wireshark Windows 3rd party packages
 
-#.rst:
-# FindLibXml2
-# -----------
-#
-# Try to find the LibXml2 xml processing library
-#
-# Once done this will define
-#
-# ::
-#
-#   LIBXML2_FOUND - System has LibXml2
-#   LIBXML2_INCLUDE_DIR - The LibXml2 include directory
-#   LIBXML2_LIBRARIES - The libraries needed to use LibXml2
-#   LIBXML2_DEFINITIONS - Compiler switches required for using LibXml2
-#   LIBXML2_XMLLINT_EXECUTABLE - The XML checking tool xmllint coming with LibXml2
-#   LIBXML2_VERSION_STRING - the version of LibXml2 found (since CMake 2.8.8)
-#
-# :: Included for Wireshark build system
-#   LIBXML2_DLL_DIR      - (Windows) Path to the libxml2 DLL.
-#   LIBXML2_DLL          - (Windows) Name of the libxml2 DLL.
-
-
-#=============================================================================
-# Copyright 2006-2009 Kitware, Inc.
-# Copyright 2006 Alexander Neundorf <neundorf@kde.org>
-#
-# Distributed under the OSI-approved BSD License (the "License");
-# see accompanying file Copyright.txt for details.
-#
-# This software is distributed WITHOUT ANY WARRANTY; without even the
-# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
-# See the License for more information.
-#=============================================================================
-# (To distribute this file outside of CMake, substitute the full
-#  License text for the above reference.)
+# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+# file Copyright.txt or https://cmake.org/licensing for details.
+
+#[=======================================================================[.rst:
+FindLibXml2
+-----------
+
+Find the XML processing library (libxml2).
+
+IMPORTED Targets
+^^^^^^^^^^^^^^^^
+
+This module defines :prop_tgt:`IMPORTED` target ``LibXml2::LibXml2``, if
+libxml2 has been found.
+
+Result variables
+^^^^^^^^^^^^^^^^
+
+This module will set the following variables in your project:
+
+``LIBXML2_FOUND``
+  true if libxml2 headers and libraries were found
+``LIBXML2_INCLUDE_DIR``
+  the directory containing LibXml2 headers
+``LIBXML2_INCLUDE_DIRS``
+  list of the include directories needed to use LibXml2
+``LIBXML2_LIBRARIES``
+  LibXml2 libraries to be linked
+``LIBXML2_DEFINITIONS``
+  the compiler switches required for using LibXml2
+``LIBXML2_XMLLINT_EXECUTABLE``
+  path to the XML checking tool xmllint coming with LibXml2
+``LIBXML2_VERSION_STRING``
+  the version of LibXml2 found (since CMake 2.8.8)
+
+Cache variables
+^^^^^^^^^^^^^^^
+
+The following cache variables may also be set:
+
+``LIBXML2_INCLUDE_DIR``
+  the directory containing LibXml2 headers
+``LIBXML2_LIBRARY``
+  path to the LibXml2 library
+#]=======================================================================]
+
+include(FindWSWinLibs)
+FindWSWinLibs("libxml2-.*" LIBXML2_HINTS)
 
 # use pkg-config to get the directories and then use these values
 # in the find_path() and find_library() calls
@@ -43,27 +56,31 @@ find_package(PkgConfig QUIET)
 PKG_CHECK_MODULES(PC_LIBXML QUIET libxml-2.0)
 set(LIBXML2_DEFINITIONS ${PC_LIBXML_CFLAGS_OTHER})
 
-INCLUDE(FindWSWinLibs)
-FindWSWinLibs("libxml2-.*" "LIBXML2_HINTS")
-
 find_path(LIBXML2_INCLUDE_DIR NAMES libxml/xpath.h
    HINTS
    ${PC_LIBXML_INCLUDEDIR}
    ${PC_LIBXML_INCLUDE_DIRS}
-   "${LIBXML2_HINTS}/include"
+   ${LIBXML2_HINTS}/include
    PATH_SUFFIXES libxml2
    )
 
-find_library(LIBXML2_LIBRARIES NAMES xml2 libxml2 libxml2-2
+# CMake 3.9 and below used 'LIBXML2_LIBRARIES' as the name of
+# the cache entry storing the find_library result.  Use the
+# value if it was set by the project or user.
+if(DEFINED LIBXML2_LIBRARIES AND NOT DEFINED LIBXML2_LIBRARY)
+  set(LIBXML2_LIBRARY ${LIBXML2_LIBRARIES})
+endif()
+
+find_library(LIBXML2_LIBRARY NAMES xml2 libxml2 libxml2-2
    HINTS
    ${PC_LIBXML_LIBDIR}
    ${PC_LIBXML_LIBRARY_DIRS}
-   "${LIBXML2_HINTS}/lib"
+   ${LIBXML2_HINTS}/lib
    )
 
 find_program(LIBXML2_XMLLINT_EXECUTABLE xmllint
    HINTS
-   "${LIBXML2_HINTS}/bin"
+   ${LIBXML2_HINTS}/bin
    )
 # for backwards compat. with KDE 4.0.x:
 set(XMLLINT_EXECUTABLE "${LIBXML2_XMLLINT_EXECUTABLE}")
@@ -79,31 +96,20 @@ elseif(LIBXML2_INCLUDE_DIR AND EXISTS "${LIBXML2_INCLUDE_DIR}/libxml/xmlversion.
     unset(libxml2_version_str)
 endif()
 
+set(LIBXML2_INCLUDE_DIRS ${LIBXML2_INCLUDE_DIR} ${PC_LIBXML_INCLUDE_DIRS})
+set(LIBXML2_LIBRARIES ${LIBXML2_LIBRARY})
+
 include(FindPackageHandleStandardArgs)
 FIND_PACKAGE_HANDLE_STANDARD_ARGS(LibXml2
-                                  REQUIRED_VARS LIBXML2_LIBRARIES LIBXML2_INCLUDE_DIR
+                                  REQUIRED_VARS LIBXML2_LIBRARY LIBXML2_INCLUDE_DIR
                                   VERSION_VAR LIBXML2_VERSION_STRING)
 
-# Included for Wireshark build system. If libxml2 was found, include direct
-# paths to the DLLs for windows
-if(WIN32)
-  if(LIBXML2_FOUND)
-    set ( LIBXML2_DLL_DIR "${LIBXML2_HINTS}/bin"
-      CACHE PATH "Path to Libxml2 DLL"
-    )
-    file( GLOB _libxml2_dll RELATIVE "${LIBXML2_DLL_DIR}"
-      "${LIBXML2_DLL_DIR}/libxml2-*.dll"
-    )
-    set ( LIBXML2_DLL ${_libxml2_dll}
-      # We're storing filenames only. Should we use STRING instead?
-      CACHE FILEPATH "Libxml2 DLL file name"
-    )
-    mark_as_advanced( LIBXML2_DLL_DIR LIBXML2_DLL )
-  else()
-    set( LIBXML2_LIBRARIES )
-    set( LIBXML2_DLL_DIR )
-    set( LIBXML2_DLL )
-  endif()
+mark_as_advanced(LIBXML2_INCLUDE_DIR LIBXML2_LIBRARY LIBXML2_XMLLINT_EXECUTABLE)
+
+if(LibXml2_FOUND AND NOT TARGET LibXml2::LibXml2)
+   add_library(LibXml2::LibXml2 UNKNOWN IMPORTED)
+   set_target_properties(LibXml2::LibXml2 PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${LIBXML2_INCLUDE_DIRS}")
+   set_property(TARGET LibXml2::LibXml2 APPEND PROPERTY IMPORTED_LOCATION "${LIBXML2_LIBRARY}")
 endif()
 
-mark_as_advanced(LIBXML2_INCLUDE_DIR LIBXML2_LIBRARIES LIBXML2_XMLLINT_EXECUTABLE)
+AddWSWinDLL(LibXml2 LIBXML2_HINTS "libxml2-*")
diff --git a/cmake/modules/FindWSWinLibs.cmake b/cmake/modules/FindWSWinLibs.cmake
index 75568d49d8..088a020810 100644
--- a/cmake/modules/FindWSWinLibs.cmake
+++ b/cmake/modules/FindWSWinLibs.cmake
@@ -41,3 +41,22 @@ function( FindWSWinLibs _WS_LIB_SEARCH_PATH _LIB_HINT_VAR )
     endforeach()
   endif()
 endfunction()
+
+function(AddWSWinDLL _PKG_NAME _PKG_HINTS _DLL_GLOB)
+  if(WIN32 AND ${_PKG_NAME}_FOUND)
+    string(TOUPPER ${_PKG_NAME} _PKG_VAR)
+    set ( ${_PKG_VAR}_DLL_DIR "${${_PKG_HINTS}}/bin"
+      CACHE PATH "Path to ${_PKG_NAME} DLL"
+    )
+    file( GLOB _pkg_dll RELATIVE "${${_PKG_VAR}_DLL_DIR}"
+      "${${_PKG_VAR}_DLL_DIR}/${_DLL_GLOB}.dll"
+    )
+    set ( ${_PKG_VAR}_DLL ${_pkg_dll}
+      CACHE STRING "${_PKG_NAME} DLL file name"
+    )
+    mark_as_advanced( ${_PKG_VAR}_DLL_DIR ${_PKG_VAR}_DLL )
+  else()
+    set( ${_PKG_VAR}_DLL_DIR )
+    set( ${_PKG_VAR}_DLL )
+  endif()
+endfunction()
diff --git a/epan/CMakeLists.txt b/epan/CMakeLists.txt
index 2135d84153..651a8d2711 100644
--- a/epan/CMakeLists.txt
+++ b/epan/CMakeLists.txt
@@ -29,7 +29,7 @@ include_directories(
 		${SMI_INCLUDE_DIRS}
 		${SNAPPY_INCLUDE_DIRS}
 		${ZLIB_INCLUDE_DIRS}
-		${LIBXML2_INCLUDE_DIR}
+		${LIBXML2_INCLUDE_DIRS}
 )
 
 add_definitions(