[libxml2] Rework validation context flags

[Nick Wellnhofer <nwellnhof src gnome org>]

commit d7cb33cf44aa688f24215c9cd398c1a26f0d25ff
Author: Nick Wellnhofer <wellnhofer aevum de>
Date:   Thu Jan 13 17:06:14 2022 +0100

    Rework validation context flags
    
    Use a bitmask instead of magic values to
    
    - keep track whether the validation context is part of a parser context
    - keep track whether xmlValidateDtdFinal was called
    
    This allows to add addtional flags later.
    
    Note that this deliberately changes the name of a public struct member,
    assuming that this was always private data never to be used by client
    code.

 HTMLparser.c           |  2 +-
 SAX2.c                 | 10 ++++++----
 include/libxml/valid.h | 14 +++++++-------
 parserInternals.c      |  2 +-
 valid.c                | 43 +++++++++++++++----------------------------
 5 files changed, 30 insertions(+), 41 deletions(-)
---
diff --git a/HTMLparser.c b/HTMLparser.c
index 3e8a1657..eb3a820a 100644
--- a/HTMLparser.c
+++ b/HTMLparser.c
@@ -5118,7 +5118,7 @@ htmlInitParserCtxt(htmlParserCtxtPtr ctxt)
     ctxt->linenumbers = xmlLineNumbersDefaultValue;
     ctxt->keepBlanks = xmlKeepBlanksDefaultValue;
     ctxt->html = 1;
-    ctxt->vctxt.finishDtd = XML_CTXT_FINISH_DTD_0;
+    ctxt->vctxt.flags = XML_VCTXT_USE_PCTXT;
     ctxt->vctxt.userData = ctxt;
     ctxt->vctxt.error = xmlParserValidityError;
     ctxt->vctxt.warning = xmlParserValidityWarning;
diff --git a/SAX2.c b/SAX2.c
index 03192465..edfb06f3 100644
--- a/SAX2.c
+++ b/SAX2.c
@@ -1747,7 +1747,8 @@ xmlSAX2StartElement(void *ctx, const xmlChar *fullname, const xmlChar **atts)
      * If it's the Document root, finish the DTD validation and
      * check the document root element for validity
      */
-    if ((ctxt->validate) && (ctxt->vctxt.finishDtd == XML_CTXT_FINISH_DTD_0)) {
+    if ((ctxt->validate) &&
+        ((ctxt->vctxt.flags & XML_VCTXT_DTD_VALIDATED) == 0)) {
        int chk;
 
        chk = xmlValidateDtdFinal(&ctxt->vctxt, ctxt->myDoc);
@@ -1756,7 +1757,7 @@ xmlSAX2StartElement(void *ctx, const xmlChar *fullname, const xmlChar **atts)
        if (chk < 0)
            ctxt->wellFormed = 0;
        ctxt->valid &= xmlValidateRoot(&ctxt->vctxt, ctxt->myDoc);
-       ctxt->vctxt.finishDtd = XML_CTXT_FINISH_DTD_1;
+       ctxt->vctxt.flags |= XML_VCTXT_DTD_VALIDATED;
     }
 #endif /* LIBXML_VALID_ENABLED */
 
@@ -2405,7 +2406,8 @@ xmlSAX2StartElementNs(void *ctx,
      * If it's the Document root, finish the DTD validation and
      * check the document root element for validity
      */
-    if ((ctxt->validate) && (ctxt->vctxt.finishDtd == XML_CTXT_FINISH_DTD_0)) {
+    if ((ctxt->validate) &&
+        ((ctxt->vctxt.flags & XML_VCTXT_DTD_VALIDATED) == 0)) {
        int chk;
 
        chk = xmlValidateDtdFinal(&ctxt->vctxt, ctxt->myDoc);
@@ -2414,7 +2416,7 @@ xmlSAX2StartElementNs(void *ctx,
        if (chk < 0)
            ctxt->wellFormed = 0;
        ctxt->valid &= xmlValidateRoot(&ctxt->vctxt, ctxt->myDoc);
-       ctxt->vctxt.finishDtd = XML_CTXT_FINISH_DTD_1;
+       ctxt->vctxt.flags |= XML_VCTXT_DTD_VALIDATED;
     }
 #endif /* LIBXML_VALID_ENABLED */
 }
diff --git a/include/libxml/valid.h b/include/libxml/valid.h
index 2bc7b380..15c9772c 100644
--- a/include/libxml/valid.h
+++ b/include/libxml/valid.h
@@ -60,17 +60,17 @@ typedef void (XMLCDECL *xmlValidityWarningFunc) (void *ctx,
 
 #ifdef IN_LIBXML
 /**
- * XML_CTXT_FINISH_DTD_0:
+ * XML_VCTXT_DTD_VALIDATED:
  *
- * Special value for finishDtd field when embedded in an xmlParserCtxt
+ * Set after xmlValidateDtdFinal was called.
  */
-#define XML_CTXT_FINISH_DTD_0 0xabcd1234
+#define XML_VCTXT_DTD_VALIDATED (1u << 0)
 /**
- * XML_CTXT_FINISH_DTD_1:
+ * XML_VCTXT_USE_PCTXT:
  *
- * Special value for finishDtd field when embedded in an xmlParserCtxt
+ * Set if the validation context is part of a parser context.
  */
-#define XML_CTXT_FINISH_DTD_1 0xabcd1235
+#define XML_VCTXT_USE_PCTXT (1u << 1)
 #endif
 
 /*
@@ -90,7 +90,7 @@ struct _xmlValidCtxt {
     int                nodeMax;       /* Max depth of the parsing stack */
     xmlNodePtr        *nodeTab;       /* array of nodes */
 
-    unsigned int     finishDtd;       /* finished validating the Dtd ? */
+    unsigned int         flags;       /* internal flags */
     xmlDocPtr              doc;       /* the document */
     int                  valid;       /* temporary validity check result */
 
diff --git a/parserInternals.c b/parserInternals.c
index c5c0b16d..cf5ad369 100644
--- a/parserInternals.c
+++ b/parserInternals.c
@@ -1733,7 +1733,7 @@ xmlInitParserCtxt(xmlParserCtxtPtr ctxt)
        ctxt->options |= XML_PARSE_NOBLANKS;
     }
 
-    ctxt->vctxt.finishDtd = XML_CTXT_FINISH_DTD_0;
+    ctxt->vctxt.flags = XML_VCTXT_USE_PCTXT;
     ctxt->vctxt.userData = ctxt;
     ctxt->vctxt.error = xmlParserValidityError;
     ctxt->vctxt.warning = xmlParserValidityWarning;
diff --git a/valid.c b/valid.c
index 8e596f1d..5cd1e676 100644
--- a/valid.c
+++ b/valid.c
@@ -64,10 +64,9 @@ xmlVErrMemory(xmlValidCtxtPtr ctxt, const char *extra)
     if (ctxt != NULL) {
         channel = ctxt->error;
         data = ctxt->userData;
-       /* Use the special values to detect if it is part of a parsing
+       /* Look up flag to detect if it is part of a parsing
           context */
-       if ((ctxt->finishDtd == XML_CTXT_FINISH_DTD_0) ||
-           (ctxt->finishDtd == XML_CTXT_FINISH_DTD_1)) {
+       if (ctxt->flags & XML_VCTXT_USE_PCTXT) {
            long delta = (char *) ctxt - (char *) ctxt->userData;
            if ((delta > 0) && (delta < 250))
                pctxt = ctxt->userData;
@@ -104,10 +103,9 @@ xmlErrValid(xmlValidCtxtPtr ctxt, xmlParserErrors error,
     if (ctxt != NULL) {
         channel = ctxt->error;
         data = ctxt->userData;
-       /* Use the special values to detect if it is part of a parsing
+       /* Look up flag to detect if it is part of a parsing
           context */
-       if ((ctxt->finishDtd == XML_CTXT_FINISH_DTD_0) ||
-           (ctxt->finishDtd == XML_CTXT_FINISH_DTD_1)) {
+       if (ctxt->flags & XML_VCTXT_USE_PCTXT) {
            long delta = (char *) ctxt - (char *) ctxt->userData;
            if ((delta > 0) && (delta < 250))
                pctxt = ctxt->userData;
@@ -151,10 +149,9 @@ xmlErrValidNode(xmlValidCtxtPtr ctxt,
     if (ctxt != NULL) {
         channel = ctxt->error;
         data = ctxt->userData;
-       /* Use the special values to detect if it is part of a parsing
+       /* Look up flag to detect if it is part of a parsing
           context */
-       if ((ctxt->finishDtd == XML_CTXT_FINISH_DTD_0) ||
-           (ctxt->finishDtd == XML_CTXT_FINISH_DTD_1)) {
+       if (ctxt->flags & XML_VCTXT_USE_PCTXT) {
            long delta = (char *) ctxt - (char *) ctxt->userData;
            if ((delta > 0) && (delta < 250))
                pctxt = ctxt->userData;
@@ -194,10 +191,9 @@ xmlErrValidNodeNr(xmlValidCtxtPtr ctxt,
     if (ctxt != NULL) {
         channel = ctxt->error;
         data = ctxt->userData;
-       /* Use the special values to detect if it is part of a parsing
+       /* Look up flag to detect if it is part of a parsing
           context */
-       if ((ctxt->finishDtd == XML_CTXT_FINISH_DTD_0) ||
-           (ctxt->finishDtd == XML_CTXT_FINISH_DTD_1)) {
+       if (ctxt->flags & XML_VCTXT_USE_PCTXT) {
            long delta = (char *) ctxt - (char *) ctxt->userData;
            if ((delta > 0) && (delta < 250))
                pctxt = ctxt->userData;
@@ -235,10 +231,9 @@ xmlErrValidWarning(xmlValidCtxtPtr ctxt,
     if (ctxt != NULL) {
         channel = ctxt->warning;
         data = ctxt->userData;
-       /* Use the special values to detect if it is part of a parsing
+       /* Look up flag to detect if it is part of a parsing
           context */
-       if ((ctxt->finishDtd == XML_CTXT_FINISH_DTD_0) ||
-           (ctxt->finishDtd == XML_CTXT_FINISH_DTD_1)) {
+       if (ctxt->flags & XML_VCTXT_USE_PCTXT) {
            long delta = (char *) ctxt - (char *) ctxt->userData;
            if ((delta > 0) && (delta < 250))
                pctxt = ctxt->userData;
@@ -1642,9 +1637,7 @@ xmlAddElementDecl(xmlValidCtxtPtr ctxt,
      * and flag it by setting a special parent value
      * so the parser doesn't unallocate it.
      */
-    if ((ctxt != NULL) &&
-        ((ctxt->finishDtd == XML_CTXT_FINISH_DTD_0) ||
-         (ctxt->finishDtd == XML_CTXT_FINISH_DTD_1))) {
+    if ((ctxt != NULL) && (ctxt->flags & XML_VCTXT_USE_PCTXT)) {
        ret->content = content;
        if (content != NULL)
            content->parent = (xmlElementContentPtr) 1;
@@ -2642,13 +2635,7 @@ xmlIsStreaming(xmlValidCtxtPtr ctxt) {
 
     if (ctxt == NULL)
         return(0);
-    /*
-     * These magic values are also abused to detect whether we're validating
-     * while parsing a document. In this case, userData points to the parser
-     * context.
-     */
-    if ((ctxt->finishDtd != XML_CTXT_FINISH_DTD_0) &&
-        (ctxt->finishDtd != XML_CTXT_FINISH_DTD_1))
+    if ((ctxt->flags & XML_VCTXT_USE_PCTXT) == 0)
         return(0);
     pctxt = ctxt->userData;
     return(pctxt->parseMode == XML_PARSE_READER);
@@ -6677,8 +6664,8 @@ xmlValidateDocumentFinal(xmlValidCtxtPtr ctxt, xmlDocPtr doc) {
     }
 
     /* trick to get correct line id report */
-    save = ctxt->finishDtd;
-    ctxt->finishDtd = 0;
+    save = ctxt->flags;
+    ctxt->flags &= ~XML_VCTXT_USE_PCTXT;
 
     /*
      * Check all the NOTATION/NOTATIONS attributes
@@ -6694,7 +6681,7 @@ xmlValidateDocumentFinal(xmlValidCtxtPtr ctxt, xmlDocPtr doc) {
     ctxt->valid = 1;
     xmlHashScan(table, xmlValidateCheckRefCallback, ctxt);
 
-    ctxt->finishDtd = save;
+    ctxt->flags = save;
     return(ctxt->valid);
 }