WebCore::XMLDocumentParserScope does not restore xmlStructuredErrorCo…

…ntext properly

<https://bugs.webkit.org/show_bug.cgi?id=273665>
<rdar://127468626>

Reviewed by Alex Christensen.

Prior to this change, XMLDocumentParserScope would restore
xmlStructuredErrorContext using the saved value of
xmlGenericErrorContext.

The fix is to store the original value of xmlStructuredErrorContext in
its own instance variable so it can be restored separately.

If the structuredErrorContext parameter is not set when calling the
XMLDocumentParserScope() constructor, the value of genericErrorContext
is used for structuredErrorContext (as before).

API Test:
    TestWebKitAPI.XMLParsing.WebCoreRestoresLibxml2GenericAndStructuredErrorState

* Source/WebCore/xml/parser/XMLDocumentParserScope.cpp:
(WebCore::XMLDocumentParserScope::XMLDocumentParserScope):
- Add structuredErrorContext argument to constructor so that the
  single-argument constructor can pass in the correct value.
- Store xmlStructuredErrorContext in m_oldStructuredErrorContext.
- Set the structuredErrorContext using that argument, or fall back to
  genericErrorContext if structuredErrorContext is nullptr.
(WebCore::XMLDocumentParserScope::~XMLDocumentParserScope):
- Properly restore saved structuredErrorContext in
  m_oldStructuredErrorContext in the destructor.
* Source/WebCore/xml/parser/XMLDocumentParserScope.h:
(WebCore::XMLDocumentParserScope::XMLDocumentParserScope):
- Declare optional structuredErrorContext argument.
- Rename m_oldErrorContext to m_oldGenericErrorContext.
- Add m_oldStructuredErrorContext.

* Tools/TestWebKitAPI/Tests/WebCore/cocoa/XMLParsing.mm:
(TestWebKitAPI::TEST_F(XMLParsing, WebCoreRestoresLibxml2GenericAndStructuredErrorState)): Add.
- Add test for this change.

Canonical link: https://commits.webkit.org/278436@main

Source/WebCore/xml/parser/XMLDocumentParserScope.cpp

@@ -39,7 +39,7 @@ WeakPtr<CachedResourceLoader>& XMLDocumentParserScope::currentCachedResourceLoad
 
 #if ENABLE(XSLT)
 XMLDocumentParserScope::XMLDocumentParserScope(CachedResourceLoader* cachedResourceLoader)
-    : XMLDocumentParserScope(cachedResourceLoader, xmlGenericError, xmlStructuredError, xmlGenericErrorContext)
+    : XMLDocumentParserScope(cachedResourceLoader, xmlGenericError, xmlStructuredError, xmlGenericErrorContext, xmlStructuredErrorContext)
 {
 }
 #else
@@ -54,20 +54,21 @@ XMLDocumentParserScope::XMLDocumentParserScope(CachedResourceLoader* cachedResou
 #endif // ENABLE(XSLT)
 
 #if ENABLE(XSLT)
-XMLDocumentParserScope::XMLDocumentParserScope(CachedResourceLoader* cachedResourceLoader, xmlGenericErrorFunc genericErrorFunc, xmlStructuredErrorFunc structuredErrorFunc, void* errorContext)
+XMLDocumentParserScope::XMLDocumentParserScope(CachedResourceLoader* cachedResourceLoader, xmlGenericErrorFunc genericErrorFunc, xmlStructuredErrorFunc structuredErrorFunc, void* genericErrorContext, void* structuredErrorContext)
     : m_oldCachedResourceLoader(currentCachedResourceLoader())
     , m_oldGenericErrorFunc(xmlGenericError)
     , m_oldStructuredErrorFunc(xmlStructuredError)
-    , m_oldErrorContext(xmlGenericErrorContext)
+    , m_oldGenericErrorContext(xmlGenericErrorContext)
+    , m_oldStructuredErrorContext(xmlStructuredErrorContext)
 {
     initializeXMLParser();
     m_oldEntityLoader = xmlGetExternalEntityLoader();
     currentCachedResourceLoader() = cachedResourceLoader;
     xmlSetExternalEntityLoader(WebCore::externalEntityLoader);
     if (genericErrorFunc)
-        xmlSetGenericErrorFunc(errorContext, genericErrorFunc);
+        xmlSetGenericErrorFunc(genericErrorContext, genericErrorFunc);
     if (structuredErrorFunc)
-        xmlSetStructuredErrorFunc(errorContext, structuredErrorFunc);
+        xmlSetStructuredErrorFunc(structuredErrorContext ?: genericErrorContext, structuredErrorFunc);
 }
 #endif
 
@@ -76,8 +77,8 @@ XMLDocumentParserScope::~XMLDocumentParserScope()
     currentCachedResourceLoader() = m_oldCachedResourceLoader;
     xmlSetExternalEntityLoader(m_oldEntityLoader);
 #if ENABLE(XSLT)
-    xmlSetGenericErrorFunc(m_oldErrorContext, m_oldGenericErrorFunc);
-    xmlSetStructuredErrorFunc(m_oldErrorContext, m_oldStructuredErrorFunc);
+    xmlSetGenericErrorFunc(m_oldGenericErrorContext, m_oldGenericErrorFunc);
+    xmlSetStructuredErrorFunc(m_oldStructuredErrorContext, m_oldStructuredErrorFunc);
 #endif
 }
 

Source/WebCore/xml/parser/XMLDocumentParserScope.h

@@ -47,7 +47,7 @@ class XMLDocumentParserScope {
     static WeakPtr<CachedResourceLoader>& currentCachedResourceLoader();
 
 #if ENABLE(XSLT)
-    XMLDocumentParserScope(CachedResourceLoader*, xmlGenericErrorFunc, xmlStructuredErrorFunc = nullptr, void* errorContext = nullptr);
+    XMLDocumentParserScope(CachedResourceLoader*, xmlGenericErrorFunc, xmlStructuredErrorFunc = nullptr, void* genericErrorContext = nullptr, void* structuredErrorContext = nullptr);
 #endif
 
 private:
@@ -57,7 +57,8 @@ class XMLDocumentParserScope {
 #if ENABLE(XSLT)
     xmlGenericErrorFunc m_oldGenericErrorFunc { nullptr };
     xmlStructuredErrorFunc m_oldStructuredErrorFunc { nullptr };
-    void* m_oldErrorContext { nullptr };
+    void* m_oldGenericErrorContext { nullptr };
+    void* m_oldStructuredErrorContext { nullptr };
 #endif
 };
 

Tools/TestWebKitAPI/Tests/WebCore/cocoa/XMLParsing.mm

@@ -50,6 +50,38 @@ void SetUp() final
     }
 };
 
+TEST_F(XMLParsing, WebCoreRestoresLibxml2GenericAndStructuredErrorState)
+{
+    void* origGenericErrorContext = xmlGenericErrorContext;
+    void* origStructuredErrorContext = xmlStructuredErrorContext;
+    xmlGenericErrorFunc origGenericErrorFunc = xmlGenericError;
+    xmlStructuredErrorFunc origStructuredErrorFunc = xmlStructuredError;
+
+    void* testGenericErrorContext = reinterpret_cast<void*>(0xaaaaaaaa);
+    void* testStructuredErrorContext = reinterpret_cast<void*>(0xbbbbbbbb);
+    xmlGenericErrorFunc testGenericErrorFunc = reinterpret_cast<xmlGenericErrorFunc>(0xcccccccc);
+    xmlStructuredErrorFunc testStructuredErrorFunc = reinterpret_cast<xmlStructuredErrorFunc>(0xdddddddd);
+
+    // Set test values.
+    xmlSetGenericErrorFunc(testGenericErrorContext, testGenericErrorFunc);
+    xmlSetStructuredErrorFunc(testStructuredErrorContext, testStructuredErrorFunc);
+
+    // Parse XHTML in WebKit.
+    String chunk = "<x/>"_s;
+    auto result = WebCoreTestSupport::testDocumentFragmentParseXML(chunk, WebCore::DefaultParserContentPolicy);
+    EXPECT_TRUE(result);
+
+    // Verify test values are restored.
+    EXPECT_EQ(testGenericErrorContext, xmlGenericErrorContext);
+    EXPECT_EQ(testStructuredErrorContext, xmlStructuredErrorContext);
+    EXPECT_EQ(testGenericErrorFunc, xmlGenericError);
+    EXPECT_EQ(testStructuredErrorFunc, xmlStructuredError);
+
+    // Restore original values.
+    xmlSetGenericErrorFunc(origGenericErrorContext, origGenericErrorFunc);
+    xmlSetStructuredErrorFunc(origStructuredErrorContext, origStructuredErrorFunc);
+}
+
 TEST_F(XMLParsing, WebCoreDoesNotBreakLibxml2)
 {
     xmlExternalEntityLoader origEntityLoader = xmlGetExternalEntityLoader();