Stop using internal struct fields for libxml2 2.14

Author: jeroen

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: xml2
 Title: Parse XML
-Version: 1.3.9000
+Version: 1.4.0
 Authors@R: c(
     person("Hadley", "Wickham", role = "aut"),
     person("Jim", "Hester", role = "aut"),

NEWS.md

@@ -4,6 +4,8 @@
 
 * Workaround for xQuartz/Cocoa on MacOS hitting our global error handler.
 
+* Avoid accessing some struct internals disallowed in libxml2 2.14
+
 # xml2 1.3.8
 
 * Replace new "non-api" call IS_S4_OBJECT with Rf_isS4

src/xml2_doc.cpp

@@ -291,11 +291,14 @@ extern "C" SEXP  doc_url(SEXP doc_sxp) {
 extern "C" SEXP  doc_new(SEXP version_sxp, SEXP encoding_sxp) {
 
   const char* encoding = CHAR(STRING_ELT(encoding_sxp, 0));
+  const xmlCharEncoding enc = xmlParseCharEncoding(encoding);
+  if(enc < 0){
+    Rf_error("Requested unsupported encoding '%s'", encoding);
+  }
 
   BEGIN_CPP
   XPtrDoc x(xmlNewDoc(asXmlChar(version_sxp)));
-  xmlCharEncodingHandlerPtr p = xmlFindCharEncodingHandler(encoding);
-  x->encoding = xmlStrdup(reinterpret_cast<const xmlChar *>(p->name));
+  x->encoding = xmlStrdup(reinterpret_cast<const xmlChar *>(xmlGetCharEncodingName(enc)));
   return SEXP(x);
   END_CPP
 }

src/xml2_output.cpp

@@ -161,7 +161,7 @@ extern "C" SEXP doc_write_character(SEXP doc_sxp, SEXP encoding_sxp, SEXP option
     Rf_error("Error writing to buffer");
   }
   SEXP out = PROTECT(Rf_allocVector(STRSXP, 1));
-  SET_STRING_ELT(out, 0, Xml2String(buffer->content).asRString());
+  SET_STRING_ELT(out, 0, Xml2String(xmlBufferContent(buffer)).asRString());
 
   xmlFree(buffer);
 
@@ -235,7 +235,7 @@ extern "C" SEXP node_write_character(SEXP node_sxp, SEXP encoding_sxp, SEXP opti
     xmlFree(buffer);
     Rf_error("Error writing to buffer");
   }
-  SEXP out = PROTECT(Rf_ScalarString(Xml2String(buffer->content).asRString()));
+  SEXP out = PROTECT(Rf_ScalarString(Xml2String(xmlBufferContent(buffer)).asRString()));
   xmlFree(buffer);
 
   UNPROTECT(1);