Fill meaningful message to parse error.

Author: jameslan

binding/exported-functions.txt

@@ -12,3 +12,4 @@ _xmlXPathFreeObject
 _xmlDocGetRootElement
 _xmlHasProp
 _xmlNodeGetContent
+_xmlGetLastError

src/index.mts

@@ -1,5 +1,10 @@
 import XmlDocument from './document.mjs';
-import { XmlParseError, xmlReadMemory } from './libxml2.mjs';
+import {
+    XmlErrorStruct,
+    xmlGetLastError,
+    XmlParseError,
+    xmlReadMemory,
+} from './libxml2.mjs';
 
 export {
     XmlNode,
@@ -17,8 +22,8 @@ export interface ParserOptions {
 export function parseXmlString(source: string /* , options?: ParserOptions */): XmlDocument {
     const docPtr = xmlReadMemory(source);
     if (!docPtr) {
-        // TODO: get error information from libxml2
-        throw new XmlParseError();
+        const err = xmlGetLastError();
+        throw new XmlParseError(XmlErrorStruct.message(err));
     }
     return new XmlDocument(docPtr);
 }

src/libxml2.mts

@@ -134,8 +134,14 @@ export module XmlNodeStruct {
 export class XmlAttrStruct extends XmlTreeCommonStruct {
 }
 
+export class XmlErrorStruct {
+    static message = getStringValueFunc(8);
+}
+
 export const xmlNewDoc = libxml2._xmlNewDoc;
 export const xmlXPathNewContext = libxml2._xmlXPathNewContext;
 export const xmlXPathFreeContext = libxml2._xmlXPathFreeContext;
 export const xmlXPathFreeObject = libxml2._xmlXPathFreeObject;
 export const xmlDocGetRootElement = libxml2._xmlDocGetRootElement;
+
+export const xmlGetLastError = libxml2._xmlGetLastError;

src/libxml2raw.d.ts

@@ -5,7 +5,7 @@ type XmlNodePtr = Pointer;
 type XmlAttrPtr = Pointer;
 type XmlXPathContextPtr = Pointer;
 type XmlXPathObjectPtr = Pointer;
-
+type XmlErrorPtr = Pointer;
 export class LibXml2 {
     HEAP32: Int32Array;
     getValue(ptr: Pointer, type: string): number;
@@ -34,6 +34,7 @@ export class LibXml2 {
     _xmlDocGetRootElement(doc: XmlDocPtr): XmlNodePtr;
     _xmlHasProp(node: XmlNodePtr, name: CString): XmlAttrPtr;
     _xmlNodeGetContent(node: XmlNodePtr): CString;
+    _xmlGetLastError(): XmlErrorPtr;
 }
 
 export default function moduleLoader(): Promise<LibXml2>;

test/parseXml.spec.mts

@@ -12,6 +12,9 @@ describe('parseXmlString', () => {
     });
 
     it('should throw exception on invalid xml string', () => {
-        expect(() => parseXmlString('<doc>')).to.throw(XmlParseError);
+        expect(() => parseXmlString('<doc>')).to.throw(
+            XmlParseError,
+            'Premature end of data in tag doc line 1\n',
+        );
     });
 });