XML: hard depends on expat and delete libxml

[The libxml code path has been broken for at least 2.5 years, and Expat
is tiny, so there seems no point in supporting both. -smcv]

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=20253
Signed-off-by: Chengwei Yang <chengwei.yang@intel.com>
Reviewed-by: Simon McVittie <simon.mcvittie@collabora.co.uk>

7 files changed, 11 insertions, 409 deletions

diff --git a/README.cmake b/README.cmake
index 0c30ba66..9415a82d 100644
--- a/README.cmake
+++ b/README.cmake
@@ -141,9 +141,6 @@ DBUS_SYSTEM_BUS_DEFAULT_ADDRESS:STRING=unix:path=/var/run/dbus/system_bus_socket
 // Use atomic integer implementation for 486
 DBUS_USE_ATOMIC_INT_486:BOOL=OFF
 
-// Use expat (== ON) or libxml2 (==OFF)
-DBUS_USE_EXPAT:BOOL=ON
-
 win32 only:
 // enable win32 debug port for message output
 DBUS_USE_OUTPUT_DEBUG_STRING:BOOL=OFF
diff --git a/bus/Makefile.am b/bus/Makefile.am
index 6cbc09a6..74c62e74 100644
--- a/bus/Makefile.am
+++ b/bus/Makefile.am
@@ -42,12 +42,7 @@ agentdir=$(LAUNCHD_AGENT_DIR)
 agent_DATA=org.freedesktop.dbus-session.plist
 endif
 
-if DBUS_USE_LIBXML
-XML_SOURCES=config-loader-libxml.c
-endif
-if DBUS_USE_EXPAT
 XML_SOURCES=config-loader-expat.c
-endif
 
 if DBUS_BUS_ENABLE_KQUEUE
 DIR_WATCH_SOURCE=dir-watch-kqueue.c
diff --git a/bus/config-loader-libxml.c b/bus/config-loader-libxml.c
deleted file mode 100644
index c73a1815..00000000
--- a/bus/config-loader-libxml.c
+++ /dev/null
@@ -1,324 +0,0 @@
-/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
-/* config-loader-libxml.c  libxml2 XML loader
- *
- * Copyright (C) 2003 Red Hat, Inc.
- *
- * Licensed under the Academic Free License version 2.1
- * 
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- * 
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
- *
- */
-
-#include <config.h>
-#include "config-parser.h"
-#include <dbus/dbus-internals.h>
-#include <libxml/xmlreader.h>
-#include <libxml/parser.h>
-#include <libxml/globals.h>
-#include <libxml/xmlmemory.h>
-#ifdef HAVE_ERRNO_H
-#include <errno.h>
-#endif
-#include <string.h>
-
-/* About the error handling: 
- *  - setup a "structured" error handler that catches structural
- *    errors and some oom errors 
- *  - assume that a libxml function returning an error code means
- *    out-of-memory
- */
-#define _DBUS_MAYBE_SET_OOM(e) (dbus_error_is_set(e) ? (void)0 : _DBUS_SET_OOM(e))
-
-
-static dbus_bool_t
-xml_text_start_element (BusConfigParser   *parser,
-			xmlTextReader     *reader,
-			DBusError         *error)
-{
-  const char *name;
-  int n_attributes;
-  const char **attribute_names, **attribute_values;
-  dbus_bool_t ret;
-  int i, status, is_empty;
-
-  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
-
-  ret = FALSE;
-  attribute_names = NULL;
-  attribute_values = NULL;
-
-  name = xmlTextReaderConstName (reader);
-  n_attributes = xmlTextReaderAttributeCount (reader);
-  is_empty = xmlTextReaderIsEmptyElement (reader);
-
-  if (name == NULL || n_attributes < 0 || is_empty == -1)
-    {
-      _DBUS_MAYBE_SET_OOM (error);
-      goto out;
-    }
-
-  attribute_names = dbus_new0 (const char *, n_attributes + 1);
-  attribute_values = dbus_new0 (const char *, n_attributes + 1);
-  if (attribute_names == NULL || attribute_values == NULL)
-    {
-      _DBUS_SET_OOM (error);
-      goto out;
-    }
-  i = 0;
-  while ((status = xmlTextReaderMoveToNextAttribute (reader)) == 1)
-    {
-      _dbus_assert (i < n_attributes);
-      attribute_names[i] = xmlTextReaderConstName (reader);
-      attribute_values[i] = xmlTextReaderConstValue (reader);
-      if (attribute_names[i] == NULL || attribute_values[i] == NULL)
-	{ 
-          _DBUS_MAYBE_SET_OOM (error);
-	  goto out;
-	}
-      i++;
-    }
-  if (status == -1)
-    {
-      _DBUS_MAYBE_SET_OOM (error);
-      goto out;
-    }
-  _dbus_assert (i == n_attributes);
-
-  ret = bus_config_parser_start_element (parser, name,
-					 attribute_names, attribute_values,
-					 error);
-  if (ret && is_empty == 1)
-    ret = bus_config_parser_end_element (parser, name, error);
-
- out:
-  dbus_free (attribute_names);
-  dbus_free (attribute_values);
-
-  return ret;
-}
-
-static void xml_shut_up (void *ctx, const char *msg, ...)
-{
-    return;
-}
-
-static void
-xml_text_reader_error (void *arg, xmlErrorPtr xml_error)
-{
-  DBusError *error = arg;
-
-#if 0
-  _dbus_verbose ("XML_ERROR level=%d, domain=%d, code=%d, msg=%s\n",
-                 xml_error->level, xml_error->domain,
-                 xml_error->code, xml_error->message);
-#endif
-
-  if (!dbus_error_is_set (error))
-    {
-      if (xml_error->code == XML_ERR_NO_MEMORY)
-        _DBUS_SET_OOM (error);
-      else if (xml_error->level == XML_ERR_ERROR ||
-               xml_error->level == XML_ERR_FATAL)
-        dbus_set_error (error, DBUS_ERROR_FAILED,
-                        "Error loading config file: '%s'",
-                        xml_error->message);
-    }
-}
-
-
-BusConfigParser*
-bus_config_load (const DBusString      *file,
-                 dbus_bool_t            is_toplevel,
-                 const BusConfigParser *parent,
-                 DBusError             *error)
-
-{
-  xmlTextReader *reader;
-  BusConfigParser *parser;
-  DBusString dirname, data;
-  DBusError tmp_error;
-  int ret;
-  
-  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
-  
-  parser = NULL;
-  reader = NULL;
-
-  if (!_dbus_string_init (&dirname))
-    {
-      _DBUS_SET_OOM (error);
-      return NULL;
-    }
-
-  if (!_dbus_string_init (&data))
-    {
-      _DBUS_SET_OOM (error);
-      _dbus_string_free (&dirname);
-      return NULL;
-    }
-
-  if (is_toplevel)
-    {
-      /* xmlMemSetup only fails if one of the functions is NULL */
-      xmlMemSetup (dbus_free,
-                   dbus_malloc,
-                   dbus_realloc,
-                   _dbus_strdup);
-      xmlInitParser ();
-      xmlSetGenericErrorFunc (NULL, xml_shut_up);
-    }
-
-  if (!_dbus_string_get_dirname (file, &dirname))
-    {
-      _DBUS_SET_OOM (error);
-      goto failed;
-    }
-  
-  parser = bus_config_parser_new (&dirname, is_toplevel, parent);
-  if (parser == NULL)
-    {
-      _DBUS_SET_OOM (error);
-      goto failed;
-    }
-  
-  if (!_dbus_file_get_contents (&data, file, error))
-    goto failed;
-
-  reader = xmlReaderForMemory (_dbus_string_get_const_data (&data), 
-                               _dbus_string_get_length (&data),
-			       NULL, NULL, 0);
-  if (reader == NULL)
-    {
-      _DBUS_SET_OOM (error);
-      goto failed;
-    }
-
-  xmlTextReaderSetParserProp (reader, XML_PARSER_SUBST_ENTITIES, 1);
-
-  dbus_error_init (&tmp_error);
-  xmlTextReaderSetStructuredErrorHandler (reader, xml_text_reader_error, &tmp_error);
-
-  while ((ret = xmlTextReaderRead (reader)) == 1)
-    {
-      int type;
-      
-      if (dbus_error_is_set (&tmp_error))
-        goto reader_out;
-
-      type = xmlTextReaderNodeType (reader);
-      if (type == -1)
-        {
-          _DBUS_MAYBE_SET_OOM (&tmp_error);
-          goto reader_out;
-        }
-
-      switch ((xmlReaderTypes) type) {
-      case XML_READER_TYPE_ELEMENT:
-	xml_text_start_element (parser, reader, &tmp_error);
-	break;
-
-      case XML_READER_TYPE_TEXT:
-      case XML_READER_TYPE_CDATA:
-	{
-	  DBusString content;
-	  const char *value;
-	  value = xmlTextReaderConstValue (reader);
-	  if (value != NULL)
-	    {
-	      _dbus_string_init_const (&content, value);
-	      bus_config_parser_content (parser, &content, &tmp_error);
-	    }
-          else
-            _DBUS_MAYBE_SET_OOM (&tmp_error);
-	  break;
-	}
-
-      case XML_READER_TYPE_DOCUMENT_TYPE:
-	{
-	  const char *name;
-	  name = xmlTextReaderConstName (reader);
-	  if (name != NULL)
-	    bus_config_parser_check_doctype (parser, name, &tmp_error);
-          else
-            _DBUS_MAYBE_SET_OOM (&tmp_error);
-	  break;
-	}
-
-      case XML_READER_TYPE_END_ELEMENT:
-	{
-	  const char *name;
-	  name = xmlTextReaderConstName (reader);
-	  if (name != NULL)
-	    bus_config_parser_end_element (parser, name, &tmp_error);
-          else
-            _DBUS_MAYBE_SET_OOM (&tmp_error);
-	  break;
-	}
-
-      case XML_READER_TYPE_DOCUMENT:
-      case XML_READER_TYPE_DOCUMENT_FRAGMENT:
-      case XML_READER_TYPE_PROCESSING_INSTRUCTION:
-      case XML_READER_TYPE_COMMENT:
-      case XML_READER_TYPE_ENTITY:
-      case XML_READER_TYPE_NOTATION:
-      case XML_READER_TYPE_WHITESPACE:
-      case XML_READER_TYPE_SIGNIFICANT_WHITESPACE:
-      case XML_READER_TYPE_END_ENTITY:
-      case XML_READER_TYPE_XML_DECLARATION:
-	/* nothing to do, just read on */
-	break;
-
-      case XML_READER_TYPE_NONE:
-      case XML_READER_TYPE_ATTRIBUTE:
-      case XML_READER_TYPE_ENTITY_REFERENCE:
-	_dbus_assert_not_reached ("unexpected nodes in XML");
-      }
-
-      if (dbus_error_is_set (&tmp_error))
-        goto reader_out;
-    }
-
-  if (ret == -1)
-    _DBUS_MAYBE_SET_OOM (&tmp_error);
-
- reader_out:
-  xmlFreeTextReader (reader);
-  reader = NULL;
-  if (dbus_error_is_set (&tmp_error))
-    {
-      dbus_move_error (&tmp_error, error);
-      goto failed;
-    }
-  
-  if (!bus_config_parser_finished (parser, error))
-    goto failed;
-  _dbus_string_free (&dirname);
-  _dbus_string_free (&data);
-  if (is_toplevel)
-    xmlCleanupParser();
-  _DBUS_ASSERT_ERROR_IS_CLEAR (error);
-  return parser;
-  
- failed:
-  _DBUS_ASSERT_ERROR_IS_SET (error);
-  _dbus_string_free (&dirname);
-  _dbus_string_free (&data);
-  if (is_toplevel)
-    xmlCleanupParser();
-  if (parser)
-    bus_config_parser_unref (parser);
-  _dbus_assert (reader == NULL); /* must go to reader_out first */
-  return NULL;
-}
diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 9c1ef2ec..ed1df562 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -89,8 +89,6 @@ if (WIN32)
     addExplorerWrapper(${CMAKE_PROJECT_NAME})
 endif (WIN32)
 
-option (DBUS_USE_EXPAT "Use expat (== ON) or libxml2 (==OFF)" ON)
-
 if(NOT WIN32)
 	option (DBUS_ENABLE_ABSTRACT_SOCKETS "enable support for abstract sockets" ON)
 	set (CMAKE_THREAD_PREFER_PTHREAD ON)
@@ -104,11 +102,7 @@ option (DBUS_ENABLE_STATS "enable bus daemon usage statistics" OFF)
 
 option (DBUS_ENABLE_STATS "enable bus daemon usage statistics" OFF)
 
-if (DBUS_USE_EXPAT)
-    find_package(EXPAT)
-else ()
-    find_package(LibXml2)
-endif ()
+find_package(EXPAT)
 find_package(X11)
 
 # analogous to AC_USE_SYSTEM_EXTENSIONS in configure.ac
@@ -309,16 +303,9 @@ if(NOT LIBXML2_FOUND AND NOT EXPAT_FOUND)
     message(FATAL "Neither expat nor libxml2 found!")
 endif(NOT LIBXML2_FOUND AND NOT EXPAT_FOUND)
 
-if(DBUS_USE_EXPAT)
-    SET(XML_LIB "Expat")
-    SET(XML_LIBRARY     ${EXPAT_LIBRARIES})
-    SET(XML_INCLUDE_DIR ${EXPAT_INCLUDE_DIR})
-else(DBUS_USE_EXPAT)
-    SET(XML_LIB "LibXML2")
-    SET(XML_LIBRARY     ${LIBXML2_LIBRARIES})
-    SET(XML_INCLUDE_DIR ${LIBXML2_INCLUDE_DIR})
-endif(DBUS_USE_EXPAT)
-
+SET(XML_LIB "Expat")
+SET(XML_LIBRARY     ${EXPAT_LIBRARIES})
+SET(XML_INCLUDE_DIR ${EXPAT_INCLUDE_DIR})
 
 #AC_ARG_WITH(init-scripts, AS_HELP_STRING([--with-init-scripts=[redhat]],[Style of init scripts to install]))
 #AC_ARG_WITH(session-socket-dir, AS_HELP_STRING([--with-session-socket-dir=[dirname]],[Where to put sockets for the per-login-session message bus]))
diff --git a/cmake/bus/CMakeLists.txt b/cmake/bus/CMakeLists.txt
index 2657605e..f2ea55eb 100644
--- a/cmake/bus/CMakeLists.txt
+++ b/cmake/bus/CMakeLists.txt
@@ -29,11 +29,7 @@ FOREACH(FILE ${FILES})
 	configure_file(${FILE} ${TARGET} )
 ENDFOREACH(FILE)
 
-if(DBUS_USE_EXPAT)
-    SET (XML_SOURCES ${BUS_DIR}/config-loader-expat.c)
-else(DBUS_USE_EXPAT)
-    SET (XML_SOURCES ${BUS_DIR}/config-loader-libxml.c)
-endif (DBUS_USE_EXPAT)
+SET (XML_SOURCES ${BUS_DIR}/config-loader-expat.c)
 
 # after next cvs update
 #set (DIR_WATCH_SOURCE ${BUS_DIR}/dir-watch-default.c)
diff --git a/cmake/modules/CPackInstallConfig.cmake b/cmake/modules/CPackInstallConfig.cmake
index f8073a25..74b66898 100644
--- a/cmake/modules/CPackInstallConfig.cmake
+++ b/cmake/modules/CPackInstallConfig.cmake
@@ -1,14 +1,7 @@
 
 if (DBUS_INSTALL_SYSTEM_LIBS)
 	if (MINGW)
-		if (DBUS_USE_EXPAT)
-			# expat
-			install_files(/bin FILES ${LIBEXPAT_LIBRARIES})	
-		else (DBUS_USE_EXPAT)
-			# xml2
-			install_files(/bin FILES ${LIBXML2_LIBRARIES})	
-			install_files(/bin FILES ${LIBICONV_LIBRARIES})	
-		endif (DBUS_USE_EXPAT)
+		install_files(/bin FILES ${LIBEXPAT_LIBRARIES})
 	else (MINGW)
 		INCLUDE(InstallRequiredSystemLibraries)
 	endif (MINGW)
diff --git a/configure.ac b/configure.ac
index 008d0d52..f6335f7d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -158,7 +158,6 @@ AC_ARG_ENABLE(userdb-cache, AS_HELP_STRING([--enable-userdb-cache],[build with u
 AC_ARG_ENABLE(launchd, AS_HELP_STRING([--enable-launchd],[build with launchd auto-launch support]),enable_launchd=$enableval,enable_launchd=auto)
 AC_ARG_ENABLE(systemd, AS_HELP_STRING([--enable-systemd],[build with systemd at_console support]),enable_systemd=$enableval,enable_systemd=auto)
 
-AC_ARG_WITH(xml, AS_HELP_STRING([--with-xml=[libxml/expat]],[XML library to use (libxml may be named libxml2 on some systems)]))
 AC_ARG_WITH(init-scripts, AS_HELP_STRING([--with-init-scripts=[redhat]],[Style of init scripts to install]))
 AC_ARG_WITH(session-socket-dir, AS_HELP_STRING([--with-session-socket-dir=[dirname]],[Where to put sockets for the per-login-session message bus]))
 AC_ARG_WITH(test-socket-dir, AS_HELP_STRING([--with-test-socket-dir=[dirname]],[Where to put sockets for make check]))
@@ -910,49 +909,13 @@ PKG_PROG_PKG_CONFIG
 
 #### Sort out XML library
 
-# see what we have
 AC_CHECK_LIB(expat, XML_ParserCreate_MM,
-             [ AC_CHECK_HEADERS(expat.h, have_expat=true, have_expat=false) ],
-             have_expat=false)
-
-# see what we want to use
-dbus_use_libxml=false
-dbus_use_expat=false
-if test x$with_xml = xexpat; then
-        if ! $have_expat ; then
-           AC_MSG_ERROR([Explicitly requested expat but expat not found])
-        fi
-        dbus_use_expat=true
-elif test x$with_xml = xlibxml; then
-        PKG_CHECK_MODULES(LIBXML, libxml-2.0 >= 2.6.0, have_libxml=true, have_libxml=false)
-        if ! $have_libxml ; then
-           AC_MSG_ERROR([Explicitly requested libxml but libxml not found])
-        fi
-        dbus_use_libxml=true
-else
-        ### expat is the default because libxml can't currently survive
-        ### our brutal OOM-handling unit test setup.
-        ### http://bugzilla.gnome.org/show_bug.cgi?id=109368
-        if test x$have_expat = xfalse; then
-                AC_MSG_ERROR([Could not find expat.h, check config.log for failed attempts])
-        fi
-	### By default, only use Expat since it's tested and known to work.  If you're a
-	### general-purpose OS vendor, please don't enable libxml.  For embedded use
-	### if your OS is built around libxml, that's another case.
-	dbus_use_expat=true
-fi
+             [ AC_CHECK_HEADERS(expat.h, [],
+                                [AC_MSG_ERROR([Could not find expat.h, check config.log for failed attempts])]) ],
+             [ AC_MSG_ERROR([Explicitly requested expat but expat not found]) ])
 
-AM_CONDITIONAL(DBUS_USE_EXPAT, $dbus_use_expat)
-AM_CONDITIONAL(DBUS_USE_LIBXML, $dbus_use_libxml)
-
-if $dbus_use_expat; then
-   XML_LIBS=-lexpat
-   XML_CFLAGS=
-fi
-if $dbus_use_libxml; then
-   XML_LIBS=$LIBXML_LIBS
-   XML_CFLAGS=$LIBXML_CFLAGS
-fi
+XML_LIBS=-lexpat
+XML_CFLAGS=
 AC_SUBST([XML_CFLAGS])
 AC_SUBST([XML_LIBS])
 
@@ -1899,7 +1862,6 @@ echo "
         Building XML docs:        ${enable_xml_docs}
         Building cache support:   ${enable_userdb_cache}
         Building launchd support: ${have_launchd}
-        Using XML parser:         ${with_xml}
         Init scripts style:       ${with_init_scripts}
         Abstract socket names:    ${ac_cv_have_abstract_sockets}
         System bus socket:        ${DBUS_SYSTEM_SOCKET}
@@ -1937,10 +1899,6 @@ fi
 if test x$enable_checks = xno; then
         echo "NOTE: building without checks for arguments passed to public API makes it harder to debug apps using D-Bus, but will slightly decrease D-Bus library size and _very_ slightly improve performance."
 fi
-if test x$dbus_use_libxml = xtrue; then
-        echo
-	echo "WARNING: You have chosen to use libxml as your xml parser however this code path is not maintained by the D-Bus developers and if it breaks you get to keep the pieces.  If you have selected this option in err please reconfigure with expat (e.g. --with-xml=expat)."
-fi
 
 if test "x$DBUS_HAVE_INT64" = x0; then
   AC_MSG_WARN([You have disabled 64-bit integers via --without-64-bit.