summaryrefslogtreecommitdiffstats
path: root/unoxml/source/xpath/xpathapi.cxx
blob: f1968c20886006f369f3ff31a6568147e1be26be (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#include "xpathapi.hxx"

#include <stdarg.h>
#include <string.h>

#include <libxml/tree.h>
#include <libxml/xmlerror.h>
#include <libxml/xpath.h>
#include <libxml/xpathInternals.h>

#include <com/sun/star/xml/xpath/XPathException.hpp>

#include <rtl/ustrbuf.hxx>
#include <sal/log.hxx>

#include "xpathobject.hxx"

#include <node.hxx>
#include "../dom/document.hxx"

#include <comphelper/servicehelper.hxx>
#include <cppuhelper/supportsservice.hxx>

using namespace css::io;
using namespace css::uno;
using namespace css::xml::dom;
using namespace css::xml::xpath;

namespace XPath
{
    // ctor
    CXPathAPI::CXPathAPI(const Reference< XComponentContext >& rxContext)
        : m_xContext(rxContext)
    {
    }

    Sequence< OUString > SAL_CALL CXPathAPI::getSupportedServiceNames()
    {
        return { "com.sun.star.xml.xpath.XPathAPI" };
    }

    OUString SAL_CALL CXPathAPI::getImplementationName()
    {
        return "com.sun.star.comp.xml.xpath.XPathAPI";
    }

    sal_Bool SAL_CALL CXPathAPI::supportsService(const OUString& aServiceName)
    {
        return cppu::supportsService(this, aServiceName);
    }

    void SAL_CALL CXPathAPI::registerNS(
            const OUString& aPrefix,
            const OUString& aURI)
    {
        std::scoped_lock const g(m_Mutex);

        m_nsmap.emplace(aPrefix, aURI);
    }

    void SAL_CALL CXPathAPI::unregisterNS(
            const OUString& aPrefix,
            const OUString& aURI)
    {
        std::scoped_lock const g(m_Mutex);

        if ((m_nsmap.find(aPrefix))->second == aURI) {
            m_nsmap.erase(aPrefix);
        }
    }

    // register all namespaces stored in the namespace list for this object
    // with the current xpath evaluation context
    static void lcl_registerNamespaces(
            xmlXPathContextPtr ctx,
            const nsmap_t& nsmap)
    {
        OString oprefix, ouri;
        for (const auto& rEntry : nsmap)
        {
            oprefix = OUStringToOString(rEntry.first,  RTL_TEXTENCODING_UTF8);
            ouri    = OUStringToOString(rEntry.second, RTL_TEXTENCODING_UTF8);
            xmlChar const *p = reinterpret_cast<xmlChar const *>(oprefix.getStr());
            xmlChar const *u = reinterpret_cast<xmlChar const *>(ouri.getStr());
            (void)xmlXPathRegisterNs(ctx, p, u);
        }
    }

    // get all ns decls on a node (and parent nodes, if any)
    static void lcl_collectNamespaces(
            nsmap_t & rNamespaces, Reference< XNode > const& xNamespaceNode)
    {
        DOM::CNode *const pCNode(comphelper::getFromUnoTunnel<DOM::CNode>(xNamespaceNode));
        if (!pCNode) { throw RuntimeException(); }

        ::osl::MutexGuard const g(pCNode->GetOwnerDocument().GetMutex());

        xmlNodePtr pNode = pCNode->GetNodePtr();
        while (pNode != nullptr) {
            xmlNsPtr curDef = pNode->nsDef;
            while (curDef != nullptr) {
                const xmlChar* pHref = curDef->href;
                OUString aURI(reinterpret_cast<char const *>(pHref), strlen(reinterpret_cast<char const *>(pHref)), RTL_TEXTENCODING_UTF8);
                const xmlChar* pPre = curDef->prefix;
                OUString aPrefix(reinterpret_cast<char const *>(pPre), strlen(reinterpret_cast<char const *>(pPre)), RTL_TEXTENCODING_UTF8);
                // we could already have this prefix from a child node
                rNamespaces.emplace(aPrefix, aURI);
                curDef = curDef->next;
            }
            pNode = pNode->parent;
        }
    }

    static void lcl_collectRegisterNamespaces(
            CXPathAPI & rAPI, Reference< XNode > const& xNamespaceNode)
    {
        nsmap_t namespaces;
        lcl_collectNamespaces(namespaces, xNamespaceNode);
        for (const auto& rEntry : namespaces)
        {
            rAPI.registerNS(rEntry.first, rEntry.second);
        }
    }

    // register function and variable lookup functions with the current
    // xpath evaluation context
    static void lcl_registerExtensions(
            xmlXPathContextPtr ctx,
            const extensions_t& extensions)
    {
        for (const auto& rExtensionRef : extensions)
        {
            Libxml2ExtensionHandle aHandle = rExtensionRef->getLibxml2ExtensionHandle();
            if ( aHandle.functionLookupFunction != 0 )
            {
                xmlXPathRegisterFuncLookup(ctx,
                    reinterpret_cast<xmlXPathFuncLookupFunc>(
                        sal::static_int_cast<sal_IntPtr>(aHandle.functionLookupFunction)),
                    reinterpret_cast<void*>(
                        sal::static_int_cast<sal_IntPtr>(aHandle.functionData)));
            }
            if ( aHandle.variableLookupFunction != 0 )
            {
                xmlXPathRegisterVariableLookup(ctx,
                    reinterpret_cast<xmlXPathVariableLookupFunc>(
                        sal::static_int_cast<sal_IntPtr>(aHandle.variableLookupFunction)),
                    reinterpret_cast<void*>(
                        sal::static_int_cast<sal_IntPtr>(aHandle.variableData)));
            }
        }
    }

    /**
     * Use an XPath string to select a nodelist.
     */
    Reference< XNodeList > SAL_CALL CXPathAPI::selectNodeList(
            const Reference< XNode >& contextNode,
            const OUString& expr)
    {
        Reference< XXPathObject > xobj = eval(contextNode, expr);
        return xobj->getNodeList();
    }

    /**
     * same as selectNodeList but registers all name space declarations found on namespaceNode
     */
    Reference< XNodeList > SAL_CALL CXPathAPI::selectNodeListNS(
            const Reference< XNode >&  contextNode,
            const OUString& expr,
            const Reference< XNode >&  namespaceNode)
    {
        lcl_collectRegisterNamespaces(*this, namespaceNode);
        return selectNodeList(contextNode, expr);
    }

    /**
     * Same as selectNodeList but returns the first node (if any)
     */
    Reference< XNode > SAL_CALL CXPathAPI::selectSingleNode(
            const Reference< XNode >& contextNode,
            const OUString& expr)
    {
        Reference< XNodeList > aList = selectNodeList(contextNode, expr);
        Reference< XNode > aNode = aList->item(0);
        return aNode;
    }

    /**
     * Same as selectSingleNode but registers all namespaces declared on
     * namespaceNode
     */
    Reference< XNode > SAL_CALL CXPathAPI::selectSingleNodeNS(
            const Reference< XNode >& contextNode,
            const OUString& expr,
            const Reference< XNode >&  namespaceNode )
    {
        lcl_collectRegisterNamespaces(*this, namespaceNode);
        return selectSingleNode(contextNode, expr);
    }

    static OUString make_error_message(xmlErrorPtr pError)
    {
        OUStringBuffer buf;
        if (pError) {
            if (pError->message) {
                buf.appendAscii(pError->message);
            }
            int line = pError->line;
            if (line) {
                buf.append("Line: ");
                buf.append(static_cast<sal_Int32>(line));
                buf.append("\n");
            }
            int column = pError->int2;
            if (column) {
                buf.append("Column: ");
                buf.append(static_cast<sal_Int32>(column));
                buf.append("\n");
            }
        } else {
            buf.append("no error argument!");
        }
        OUString msg = buf.makeStringAndClear();
        return msg;
    }

    extern "C" {

#if defined __GNUC__
        __attribute__ ((format (printf, 2, 3)))
#endif
        static void generic_error_func(void *, const char *format, ...)
        {
            char str[1000];
            va_list args;

            va_start(args, format);
#ifdef _WIN32
#define vsnprintf _vsnprintf
#endif
            vsnprintf(str, sizeof(str), format, args);
            va_end(args);

            SAL_WARN("unoxml", "libxml2 error: " << str);
        }

        static void structured_error_func(void *, xmlErrorPtr error)
        {
            SAL_WARN("unoxml", "libxml2 error: " << make_error_message(error));
        }

    } // extern "C"

    /**
     * evaluates an XPath string. relative XPath expressions are evaluated relative to
     * the context Node
     */
    Reference< XXPathObject > SAL_CALL CXPathAPI::eval(
            Reference< XNode > const& xContextNode,
            const OUString& expr)
    {
        if (!xContextNode.is()) { throw RuntimeException(); }

        nsmap_t nsmap;
        extensions_t extensions;

        {
            std::scoped_lock const g(m_Mutex);
            nsmap = m_nsmap;
            extensions = m_extensions;
        }

        // get the node and document
        ::rtl::Reference<DOM::CDocument> const pCDoc(
                dynamic_cast<DOM::CDocument*>( comphelper::getFromUnoTunnel<DOM::CNode>(
                        xContextNode->getOwnerDocument())));
        if (!pCDoc.is()) { throw RuntimeException(); }

        DOM::CNode *const pCNode = comphelper::getFromUnoTunnel<DOM::CNode>(xContextNode);
        if (!pCNode) { throw RuntimeException(); }

        ::osl::MutexGuard const g(pCDoc->GetMutex()); // lock the document!

        xmlNodePtr const pNode = pCNode->GetNodePtr();
        if (!pNode) { throw RuntimeException(); }
        xmlDocPtr pDoc = pNode->doc;

        /* NB: workaround for #i87252#:
           libxml < 2.6.17 considers it an error if the context
           node is the empty document (i.e. its xpathCtx->doc has no
           children). libxml 2.6.17 does not consider it an error.
           Unfortunately, old libxml prints an error message to stderr,
           which (afaik) cannot be turned off in this case, so we handle it.
        */
        if (!pDoc->children) {
            throw XPathException();
        }

        /* Create xpath evaluation context */
        std::shared_ptr<xmlXPathContext> const xpathCtx(
                xmlXPathNewContext(pDoc), xmlXPathFreeContext);
        if (xpathCtx == nullptr) { throw XPathException(); }

        // set context node
        xpathCtx->node = pNode;
        // error handling
        xpathCtx->error = structured_error_func;
        xmlSetGenericErrorFunc(nullptr, generic_error_func);

        // register namespaces and extension
        lcl_registerNamespaces(xpathCtx.get(), nsmap);
        lcl_registerExtensions(xpathCtx.get(), extensions);

        /* run the query */
        OString o1 = OUStringToOString(expr, RTL_TEXTENCODING_UTF8);
        xmlChar const *pStr = reinterpret_cast<xmlChar const *>(o1.getStr());
        std::shared_ptr<xmlXPathObject> const xpathObj(
                xmlXPathEval(pStr, xpathCtx.get()), xmlXPathFreeObject);
        xmlSetGenericErrorFunc(nullptr, nullptr);
        if (nullptr == xpathObj) {
            // OSL_ENSURE(xpathCtx->lastError == NULL, xpathCtx->lastError->message);
            throw XPathException();
        }
        Reference<XXPathObject> const xObj(
                new CXPathObject(pCDoc, pCDoc->GetMutex(), xpathObj));
        return xObj;
    }

    /**
     * same as eval but registers all namespace declarations found on namespaceNode
     */
    Reference< XXPathObject > SAL_CALL CXPathAPI::evalNS(
            const Reference< XNode >& contextNode,
            const OUString& expr,
            const Reference< XNode >& namespaceNode)
    {
        lcl_collectRegisterNamespaces(*this, namespaceNode);
        return eval(contextNode, expr);
    }

    /**
     * uses the service manager to create an instance of the service denoted by aName.
     * If the returned object implements the XXPathExtension interface, it is added to the list
     * of extensions that are used when evaluating XPath strings with this XPathAPI instance
     */
    void SAL_CALL CXPathAPI::registerExtension(
            const OUString& aName)
    {
        std::scoped_lock const g(m_Mutex);

        // get extension from service manager
        Reference< XXPathExtension > const xExtension(
                m_xContext->getServiceManager()->createInstanceWithContext(aName, m_xContext), UNO_QUERY_THROW);
        m_extensions.push_back(xExtension);
    }

    /**
     * registers the given extension instance to be used by XPath evaluations performed through this
     * XPathAPI instance
     */
    void SAL_CALL CXPathAPI::registerExtensionInstance(
            Reference< XXPathExtension> const& xExtension)
    {
        if (!xExtension.is()) {
            throw RuntimeException();
        }
        std::scoped_lock const g(m_Mutex);
        m_extensions.push_back( xExtension );
    }
}

extern "C" SAL_DLLPUBLIC_EXPORT css::uno::XInterface*
unoxml_CXPathAPI_get_implementation(
    css::uno::XComponentContext* context , css::uno::Sequence<css::uno::Any> const&)
{
    return cppu::acquire(new XPath::CXPathAPI(context));
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab: */