intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 325 insertions, 0 deletions

diff --git a/library/cpp/xml/document/xml-textreader.h b/library/cpp/xml/document/xml-textreader.h
new file mode 100644
index 0000000000..ab4c329d26
--- /dev/null
+++ b/library/cpp/xml/document/xml-textreader.h
@@ -0,0 +1,325 @@
+#pragma once
+
+#include "xml-document.h"
+#include "xml-options.h"
+
+#include <contrib/libs/libxml/include/libxml/xmlreader.h>
+
+#include <library/cpp/string_utils/ztstrbuf/ztstrbuf.h>
+
+#include <util/generic/noncopyable.h>
+#include <util/generic/ptr.h>
+#include <util/generic/strbuf.h>
+#include <util/generic/string.h>
+#include <functional>
+#include <util/stream/input.h>
+#include <util/stream/str.h>
+
+namespace NXml {
+    /**
+     * TextReader Parser
+     *
+     * API of the XML streaming API based on C# interfaces.
+     * Provides fast, non-cached, forward-only access to XML data.
+     *
+     * Like the SAX parser, the TextReader parser is suitable for sequential
+     * parsing, but instead of implementing handlers for specific parts of the
+     * document, it allows you to detect the current node type, process the node
+     * accordingly, and skip forward in the document as much as necessary.
+     *
+     * Unlike the DOM parser, you may not move backwards in the XML document.
+     * And unlike the SAX parser, you must not waste time processing nodes that do not
+     * interest you.
+     *
+     * All methods are on the single parser instance, but their result depends on the current context.
+     * For instance, use Read() to move to the next node, and MoveToElement() to navigate to child nodes.
+     * These methods will return false when no more nodes are available. Then use
+     * methods such as GetName() and GetValue() to examine the elements and their attributes.
+     *
+     * This wrapper is inspired by TextReader from libxml++.
+     */
+
+    class TTextReader: private TNonCopyable {
+    public:
+        // strongly-typed alias for enum from xmlreader.h
+        enum class ENodeType : int {
+            // clang-format off
+            Attribute             = XML_READER_TYPE_ATTRIBUTE,
+            CDATA                 = XML_READER_TYPE_CDATA,
+            Comment               = XML_READER_TYPE_COMMENT,
+            Document              = XML_READER_TYPE_DOCUMENT,
+            DocumentFragment      = XML_READER_TYPE_DOCUMENT_FRAGMENT,
+            DocumentType          = XML_READER_TYPE_DOCUMENT_TYPE,
+            Element               = XML_READER_TYPE_ELEMENT,
+            EndElement            = XML_READER_TYPE_END_ELEMENT,
+            EndEntity             = XML_READER_TYPE_END_ENTITY,
+            Entity                = XML_READER_TYPE_ENTITY,
+            EntityReference       = XML_READER_TYPE_ENTITY_REFERENCE,
+            None                  = XML_READER_TYPE_NONE,
+            Notation              = XML_READER_TYPE_NOTATION,
+            ProcessingInstruction = XML_READER_TYPE_PROCESSING_INSTRUCTION,
+            SignificantWhitespace = XML_READER_TYPE_SIGNIFICANT_WHITESPACE,
+            Text                  = XML_READER_TYPE_TEXT,
+            Whitespace            = XML_READER_TYPE_WHITESPACE,
+            XmlDeclaration        = XML_READER_TYPE_XML_DECLARATION,
+            // clang-format on
+        };
+
+        enum class EReadState : int {
+            // clang-format off
+            Closed      = XML_TEXTREADER_MODE_CLOSED,
+            EndOfFile   = XML_TEXTREADER_MODE_EOF,
+            Error       = XML_TEXTREADER_MODE_ERROR,
+            Initial     = XML_TEXTREADER_MODE_INITIAL,
+            Interactive = XML_TEXTREADER_MODE_INTERACTIVE,
+            Reading     = XML_TEXTREADER_MODE_READING,
+            // clang-format on
+        };
+
+    public:
+        TTextReader(IInputStream& stream, const TOptions& options = TOptions());
+        ~TTextReader();
+
+        /**
+         * Moves the position of the current instance to the next node in the stream, exposing its properties.
+         * @return true if the node was read successfully, false if there are no more nodes to read
+         */
+        bool Read();
+
+        /**
+         * Reads the contents of the current node, including child nodes and markup.
+         * @return A string containing the XML content, or an empty string
+         *         if the current node is neither an element nor attribute, or has no child nodes
+         */
+        TString ReadInnerXml() const;
+
+        /**
+         * Reads the current node and its contents, including child nodes and markup.
+         * @return A string containing the XML content, or an empty string
+         *         if the current node is neither an element nor attribute
+         */
+        TString ReadOuterXml() const;
+
+        /**
+         * Reads the contents of an element or a text node as a string.
+         * @return A string containing the contents of the Element or Text node,
+         *         or an empty string if the reader is positioned on any other type of node
+         */
+        TString ReadString() const;
+
+        /**
+         * Parses an attribute value into one or more Text and EntityReference nodes.
+         * @return A bool where true indicates the attribute value was parsed,
+         *         and false indicates the reader was not positioned on an attribute node
+         *         or all the attribute values have been read
+         */
+        bool ReadAttributeValue() const;
+
+        /**
+         * Gets the number of attributes on the current node.
+         * @return The number of attributes on the current node, or zero if the current node
+         *         does not support attributes
+         */
+        int GetAttributeCount() const;
+
+        /**
+         * Gets the base Uniform Resource Identifier (URI) of the current node.
+         * @return The base URI of the current node or an empty string if not available
+         */
+        TStringBuf GetBaseUri() const;
+
+        /**
+         * Gets the depth of the current node in the XML document.
+         * @return The depth of the current node in the XML document
+         */
+        int GetDepth() const;
+
+        /**
+         * Gets a value indicating whether the current node has any attributes.
+         * @return true if the current has attributes, false otherwise
+         */
+        bool HasAttributes() const;
+
+        /**
+         * Whether the node can have a text value.
+         * @return true if the current node can have an associated text value, false otherwise
+         */
+        bool HasValue() const;
+
+        /**
+         * Whether an Attribute node was generated from the default value defined in the DTD or schema.
+         * @return true if defaulted, false otherwise
+         */
+        bool IsDefault() const;
+
+        /**
+         * Check if the current node is empty.
+         * @return true if empty, false otherwise
+         */
+        bool IsEmptyElement() const;
+
+        /**
+         * The local name of the node.
+         * @return the local name or empty string if not available
+         */
+        TStringBuf GetLocalName() const;
+
+        /**
+         * The qualified name of the node, equal to Prefix:LocalName.
+         * @return the name or empty string if not available
+         */
+        TStringBuf GetName() const;
+
+        /**
+         * The URI defining the namespace associated with the node.
+         * @return the namespace URI or empty string if not available
+         */
+        TStringBuf GetNamespaceUri() const;
+
+        /**
+         * Get the node type of the current node.
+         * @return the ENodeType of the current node
+         */
+        ENodeType GetNodeType() const;
+
+        /**
+         * Get the namespace prefix associated with the current node.
+         * @return the namespace prefix, or an empty string if not available
+         */
+        TStringBuf GetPrefix() const;
+
+        /**
+         * Get the quotation mark character used to enclose the value of an attribute.
+         * @return " or '
+         */
+        char GetQuoteChar() const;
+
+        /**
+         * Provides the text value of the node if present.
+         * @return the string or empty if not available
+         */
+        TStringBuf GetValue() const;
+
+        /**
+         * Gets the read state of the reader.
+         * @return the state value
+         */
+        EReadState GetReadState() const;
+
+        /**
+         * This method releases any resources allocated by the current instance
+         * changes the state to Closed and close any underlying input.
+         */
+        void Close();
+
+        /**
+         * Provides the value of the attribute with the specified index relative to the containing element.
+         * @param number the zero-based index of the attribute relative to the containing element
+         */
+        TString GetAttribute(int number) const;
+
+        /**
+         * Provides the value of the attribute with the specified qualified name.
+         * @param name the qualified name of the attribute
+         */
+        TString GetAttribute(TZtStringBuf name) const;
+
+        /**
+         * Provides the value of the specified attribute.
+         * @param localName the local name of the attribute
+         * @param nsUri the namespace URI of the attribute
+         */
+        TString GetAttribute(TZtStringBuf localName, TZtStringBuf nsUri) const;
+
+        /**
+         * Resolves a namespace prefix in the scope of the current element.
+         * @param prefix the prefix whose namespace URI is to be resolved. To return the default namespace, specify empty string.
+         * @return a string containing the namespace URI to which the prefix maps.
+         */
+        TString LookupNamespace(TZtStringBuf prefix) const;
+
+        /**
+         * Moves the position of the current instance to the attribute with the specified index relative to the containing element.
+         * @param number the zero-based index of the attribute relative to the containing element
+         * @return true in case of success, false if not found
+         */
+        bool MoveToAttribute(int number);
+
+        /**
+         * Moves the position of the current instance to the attribute with the specified qualified name.
+         * @param name the qualified name of the attribute
+         * @return true in case of success, false if not found
+         */
+        bool MoveToAttribute(TZtStringBuf name);
+
+        /**
+         * Moves the position of the current instance to the attribute with the specified local name and namespace URI.
+         * @param localName the local name of the attribute
+         * @param nsUri the namespace URI of the attribute
+         * @return true in case of success, false if not found
+         */
+        bool MoveToAttribute(TZtStringBuf localName, TZtStringBuf nsUri);
+
+        /**
+         * Moves the position of the current instance to the first attribute associated with the current node.
+         * @return true in case of success, false if not found
+         */
+        bool MoveToFirstAttribute();
+
+        /**
+         * Moves the position of the current instance to the next attribute associated with the current node.
+         * @return true in case of success, false if not found
+         */
+        bool MoveToNextAttribute();
+
+        /**
+         * Moves the position of the current instance to the node that contains the current Attribute node.
+         * @return true in case of success, false if not found
+         */
+        bool MoveToElement();
+
+        /**
+         * Reads the contents of the current node and the full subtree. It then makes the subtree available until the next Read() call.
+         */
+        TConstNode Expand() const;
+
+        /**
+         * Skip to the node following the current one in document order while avoiding the subtree if any.
+         * @return true if the node was read successfully, false if there is no more nodes to read
+         */
+        bool Next();
+
+        /**
+         * Retrieve the validity status from the parser context.
+         */
+        bool IsValid() const;
+
+    private:
+        static int ReadFromInputStreamCallback(void* context, char* buffer, int len);
+        static void OnLibxmlError(void* arg, const char* msg, xmlParserSeverities severity, xmlTextReaderLocatorPtr locator);
+
+        void SetupErrorHandler();
+        TStringStream& LogError() const;
+        void CheckForExceptions() const;
+        void ThrowException() const;
+
+        // helpers that check return codes of C functions from libxml
+        bool BoolResult(int value) const;
+        int IntResult(int value) const;
+        char CharResult(int value) const;
+        TStringBuf ConstStringResult(const xmlChar* value) const;
+        TStringBuf ConstStringOrEmptyResult(const xmlChar* value) const;
+        TString TempStringResult(TCharPtr value) const;
+        TString TempStringOrEmptyResult(TCharPtr value) const;
+
+    private:
+        IInputStream& Stream;
+
+        mutable bool IsError;
+        mutable TStringStream ErrorBuffer;
+
+        struct TDeleter;
+        THolder<xmlTextReader, TDeleter> Impl;
+    };
+
+}