From 79e119954c949754e2d9c243c084af1f9c9bc989 Mon Sep 17 00:00:00 2001
From: Nick Wellnhofer <wellnhofer@aevum.de>
Date: Mon, 15 Jul 2024 19:43:28 +0200
Subject: [PATCH] error: Make xmlLastError const

---
 error.c                   | 20 ++++++++++++--------
 globals.c                 | 31 +++++++++++++++++++++++++------
 include/libxml/xmlerror.h | 10 +++++++++-
 include/private/globals.h |  3 +++
 4 files changed, 49 insertions(+), 15 deletions(-)

diff --git a/error.c b/error.c
index e70c0d37..fc28bb69 100644
--- a/error.c
+++ b/error.c
@@ -17,6 +17,7 @@
 #include <libxml/xmlmemory.h>
 
 #include "private/error.h"
+#include "private/globals.h"
 #include "private/string.h"
 
 /************************************************************************
@@ -635,7 +636,7 @@ void
 xmlRaiseMemoryError(xmlStructuredErrorFunc schannel, xmlGenericErrorFunc channel,
                     void *data, int domain, xmlError *error)
 {
-    xmlError *lastError = &xmlLastError;
+    xmlError *lastError = xmlGetLastErrorInternal();
 
     xmlResetLastError();
     lastError->domain = domain;
@@ -694,7 +695,7 @@ xmlVRaiseError(xmlStructuredErrorFunc schannel,
 {
     xmlParserCtxtPtr ctxt = NULL;
     /* xmlLastError is a macro retrieving the per-thread global. */
-    xmlErrorPtr lastError = &xmlLastError;
+    xmlErrorPtr lastError = xmlGetLastErrorInternal();
     xmlErrorPtr to = lastError;
 
     if (code == XML_ERR_OK)
@@ -919,9 +920,11 @@ xmlParserValidityWarning(void *ctx, const char *msg ATTRIBUTE_UNUSED, ...)
 const xmlError *
 xmlGetLastError(void)
 {
-    if (xmlLastError.code == XML_ERR_OK)
-        return (NULL);
-    return (&xmlLastError);
+    const xmlError *error = xmlGetLastErrorInternal();
+
+    if (error->code == XML_ERR_OK)
+        return(NULL);
+    return(error);
 }
 
 /**
@@ -960,9 +963,10 @@ xmlResetError(xmlErrorPtr err)
 void
 xmlResetLastError(void)
 {
-    if (xmlLastError.code == XML_ERR_OK)
-        return;
-    xmlResetError(&xmlLastError);
+    xmlError *error = xmlGetLastErrorInternal();
+
+    if (error->code != XML_ERR_OK)
+        xmlResetError(error);
 }
 
 /**
diff --git a/globals.c b/globals.c
index 13daefec..1dfdfb56 100644
--- a/globals.c
+++ b/globals.c
@@ -79,6 +79,8 @@ struct _xmlGlobalState {
     unsigned localRngState[2];
 #endif
 
+    xmlError lastError;
+
 #define XML_OP XML_DECLARE_MEMBER
 XML_GLOBALS_ALLOC
 XML_GLOBALS_ERROR
@@ -679,7 +681,7 @@ xmlFreeGlobalState(void *state)
      * But the xmlError struct is fully public and widely used,
      * so changes are dangerous.
      */
-    xmlResetError(&(gs->gs_xmlLastError));
+    xmlResetError(&gs->lastError);
 #ifndef USE_TLS
     free(state);
 #endif
@@ -723,10 +725,10 @@ static void
 xmlInitGlobalState(xmlGlobalStatePtr gs) {
     xmlMutexLock(&xmlThrDefMutex);
 
-#ifdef LIBXML_THREAD_ENABLED
     gs->localRngState[0] = xmlGlobalRandom();
     gs->localRngState[1] = xmlGlobalRandom();
-#endif
+
+    memset(&gs->lastError, 0, sizeof(xmlError));
 
     gs->gs_xmlDoValidityCheckingDefaultValue =
          xmlDoValidityCheckingDefaultValueThrDef;
@@ -761,7 +763,6 @@ xmlInitGlobalState(xmlGlobalStatePtr gs) {
         xmlParserInputBufferCreateFilenameValueThrDef;
     gs->gs_xmlOutputBufferCreateFilenameValue =
         xmlOutputBufferCreateFilenameValueThrDef;
-    memset(&gs->gs_xmlLastError, 0, sizeof(xmlError));
 
     xmlMutexUnlock(&xmlThrDefMutex);
 
@@ -857,7 +858,14 @@ XML_GLOBALS_PARSER
 XML_GLOBALS_TREE
 #undef XML_OP
 
-#ifdef LIBXML_THREAD_ENABLED
+const xmlError *
+__xmlLastError(void) {
+    if (IS_MAIN_THREAD)
+        return(&xmlLastError);
+    else
+        return(&xmlGetThreadLocalStorage(0)->lastError);
+}
+
 /**
  * xmlGetLocalRngState:
  *
@@ -870,7 +878,6 @@ xmlGetLocalRngState(void) {
     else
         return(xmlGetThreadLocalStorage(0)->localRngState);
 }
-#endif
 
 /* For backward compatibility */
 
@@ -941,6 +948,18 @@ xmlCheckThreadLocalStorage(void) {
     return(0);
 }
 
+xmlError *
+xmlGetLastErrorInternal(void) {
+#ifdef LIBXML_THREAD_ENABLED
+    if (IS_MAIN_THREAD)
+        return(&xmlLastError);
+    else
+        return(&xmlGetThreadLocalStorage(0)->lastError);
+#else
+    return(&xmlLastError);
+#endif
+}
+
 /** DOC_DISABLE */
 
 /**
diff --git a/include/libxml/xmlerror.h b/include/libxml/xmlerror.h
index 36381bec..d847bfde 100644
--- a/include/libxml/xmlerror.h
+++ b/include/libxml/xmlerror.h
@@ -865,8 +865,16 @@ typedef void (*xmlGenericErrorFunc) (void *ctx,
 typedef void (*xmlStructuredErrorFunc) (void *userData, const xmlError *error);
 
 /** DOC_DISABLE */
+#if defined(LIBXML_THREAD_ENABLED)
+XML_DEPRECATED
+XMLPUBFUN const xmlError *
+__xmlLastError(void);
+#elif !defined(IN_LIBXML)
+XML_DEPRECATED
+XMLPUBVAR const xmlError xmlLastError;
+#endif
+
 #define XML_GLOBALS_ERROR \
-  XML_OP(xmlLastError, xmlError, XML_DEPRECATED) \
   XML_OP(xmlGenericError, xmlGenericErrorFunc, XML_NO_ATTR) \
   XML_OP(xmlGenericErrorContext, void *, XML_NO_ATTR) \
   XML_OP(xmlStructuredError, xmlStructuredErrorFunc, XML_NO_ATTR) \
diff --git a/include/private/globals.h b/include/private/globals.h
index 828b6d50..d111701e 100644
--- a/include/private/globals.h
+++ b/include/private/globals.h
@@ -6,6 +6,9 @@ xmlInitGlobalsInternal(void);
 XML_HIDDEN void
 xmlCleanupGlobalsInternal(void);
 
+XML_HIDDEN xmlError *
+xmlGetLastErrorInternal(void);
+
 #ifdef LIBXML_THREAD_ENABLED
 XML_HIDDEN unsigned *
 xmlGetLocalRngState(void);