QXmlSchema internals: include/import/redefine schemas only once

According to the Schema standard, loading a schema needs only be done
once for each schema location. Currently, there was a problem with
indirect includes (and imports/redefines):

   a      In this scenario, schema a would only remember to have loaded
  / \     b, but not d, which resulted in an error when c was loading d
 b   c    again and the types in d were redefined.
 |   |
 d   d

Reviewed-by: Tobias Koenig <tokoe@kde.org>
Task-number: QTBUG-8394

2 files changed, 64 insertions, 6 deletions

diff --git a/src/xmlpatterns/schema/qxsdschemaparser.cpp b/src/xmlpatterns/schema/qxsdschemaparser.cpp
index 6ed28af..fd0b95c 100644
--- a/src/xmlpatterns/schema/qxsdschemaparser.cpp
+++ b/src/xmlpatterns/schema/qxsdschemaparser.cpp
@@ -264,16 +264,31 @@ XsdSchemaParser::XsdSchemaParser(const XsdSchemaContext::Ptr &context, const Xsd
     setupBuiltinTypeNames();
 }
 
+void XsdSchemaParser::addIncludedSchemas(const NamespaceSet &schemas)
+{
+    m_includedSchemas += schemas;
+}
+
 void XsdSchemaParser::setIncludedSchemas(const NamespaceSet &schemas)
 {
     m_includedSchemas = schemas;
 }
 
+void XsdSchemaParser::addImportedSchemas(const NamespaceSet &schemas)
+{
+    m_importedSchemas += schemas;
+}
+
 void XsdSchemaParser::setImportedSchemas(const NamespaceSet &schemas)
 {
     m_importedSchemas = schemas;
 }
 
+void XsdSchemaParser::addRedefinedSchemas(const NamespaceSet &schemas)
+{
+    m_redefinedSchemas += schemas;
+}
+
 void XsdSchemaParser::setRedefinedSchemas(const NamespaceSet &schemas)
 {
     m_redefinedSchemas = schemas;
@@ -297,6 +312,7 @@ void XsdSchemaParser::setDocumentURI(const QUrl &uri)
     // prevent to get included/imported/redefined twice
     m_includedSchemas.insert(uri);
     m_importedSchemas.insert(uri);
+    m_redefinedSchemas.insert(uri);
 }
 
 QUrl XsdSchemaParser::documentURI() const
@@ -594,8 +610,14 @@ void XsdSchemaParser::parseInclude()
             parser.setIncludedSchemas(m_includedSchemas);
             parser.setImportedSchemas(m_importedSchemas);
             parser.setRedefinedSchemas(m_redefinedSchemas);
-            if (!parser.parse(XsdSchemaParser::IncludeParser))
+            if (!parser.parse(XsdSchemaParser::IncludeParser)) {
                 return;
+            } else {
+                // add indirectly loaded schemas to the list of already loaded ones
+                addIncludedSchemas(parser.m_includedSchemas);
+                addImportedSchemas(parser.m_importedSchemas);
+                addRedefinedSchemas(parser.m_redefinedSchemas);
+            }
         }
     }
 
@@ -684,8 +706,14 @@ void XsdSchemaParser::parseImport()
                 parser.setIncludedSchemas(m_includedSchemas);
                 parser.setImportedSchemas(m_importedSchemas);
                 parser.setRedefinedSchemas(m_redefinedSchemas);
-                if (!parser.parse(XsdSchemaParser::ImportParser))
+                if (!parser.parse(XsdSchemaParser::ImportParser)) {
                     return;
+                } else {
+                    // add indirectly loaded schemas to the list of already loaded ones
+                    addIncludedSchemas(parser.m_includedSchemas);
+                    addImportedSchemas(parser.m_importedSchemas);
+                    addRedefinedSchemas(parser.m_redefinedSchemas);
+                }
             }
         }
     } else {
@@ -702,8 +730,14 @@ void XsdSchemaParser::parseImport()
                     parser.setIncludedSchemas(m_includedSchemas);
                     parser.setImportedSchemas(m_importedSchemas);
                     parser.setRedefinedSchemas(m_redefinedSchemas);
-                    if (!parser.parse(XsdSchemaParser::ImportParser))
+                    if (!parser.parse(XsdSchemaParser::ImportParser)) {
                         return;
+                    } else {
+                        // add indirectly loaded schemas to the list of already loaded ones
+                        addIncludedSchemas(parser.m_includedSchemas);
+                        addImportedSchemas(parser.m_importedSchemas);
+                        addRedefinedSchemas(parser.m_redefinedSchemas);
+                    }
                 }
             }
         } else {
@@ -839,8 +873,14 @@ void XsdSchemaParser::parseRedefine()
             parser.setIncludedSchemas(m_includedSchemas);
             parser.setImportedSchemas(m_importedSchemas);
             parser.setRedefinedSchemas(m_redefinedSchemas);
-            if (!parser.parse(XsdSchemaParser::RedefineParser))
+            if (!parser.parse(XsdSchemaParser::RedefineParser)) {
                 return;
+            } else {
+                // add indirectly loaded schemas to the list of already loaded ones
+                addIncludedSchemas(parser.m_includedSchemas);
+                addImportedSchemas(parser.m_importedSchemas);
+                addRedefinedSchemas(parser.m_redefinedSchemas);
+            }
 
             delete reply;
         }
diff --git a/src/xmlpatterns/schema/qxsdschemaparser_p.h b/src/xmlpatterns/schema/qxsdschemaparser_p.h
index ad5e9ce..80d44a5 100644
--- a/src/xmlpatterns/schema/qxsdschemaparser_p.h
+++ b/src/xmlpatterns/schema/qxsdschemaparser_p.h
@@ -120,20 +120,38 @@ namespace QPatternist
             typedef QSet<QUrl> NamespaceSet;
 
             /**
+             * Adds @p schemas to the list of already included schemas, so the parser
+             * can detect multiple includes of the same schema.
+             */
+            void addIncludedSchemas(const NamespaceSet &schemas);
+
+            /**
              * Sets which @p schemas have been included already, so the parser
-             * can detect circular includes.
+             * can detect multiple includes of the same schema.
              */
             void setIncludedSchemas(const NamespaceSet &schemas);
 
             /**
+             * Adds @p schemas to the list of already imported schemas, so the parser
+             * can detect multiple imports of the same schema.
+             */
+            void addImportedSchemas(const NamespaceSet &schemas);
+
+            /**
              * Sets which @p schemas have been imported already, so the parser
              * can detect circular imports.
              */
             void setImportedSchemas(const NamespaceSet &schemas);
 
             /**
+             * Adds @p schemas to the list of already redefined schemas, so the parser
+             * can detect multiple redefines of the same schema.
+             */
+            void addRedefinedSchemas(const NamespaceSet &schemas);
+
+            /**
              * Sets which @p schemas have been redefined already, so the parser
-             * can detect circular redefines.
+             * can detect multiple redefines of the same schema.
              */
             void setRedefinedSchemas(const NamespaceSet &schemas);