1/* libs/graphics/ports/SkXMLParser_expat.cpp
2**
3** Copyright 2006, The Android Open Source Project
4**
5** Licensed under the Apache License, Version 2.0 (the "License");
6** you may not use this file except in compliance with the License.
7** You may obtain a copy of the License at
8**
9**     http://www.apache.org/licenses/LICENSE-2.0
10**
11** Unless required by applicable law or agreed to in writing, software
12** distributed under the License is distributed on an "AS IS" BASIS,
13** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14** See the License for the specific language governing permissions and
15** limitations under the License.
16*/
17
18#include "SkXMLParser.h"
19#include "SkChunkAlloc.h"
20#include "SkString.h"
21#include "SkStream.h"
22
23#include "expat.h"
24
25static inline char* dupstr(SkChunkAlloc& chunk, const char src[], size_t len)
26{
27    SkASSERT(src);
28    char*   dst = (char*)chunk.alloc(len + 1, SkChunkAlloc::kThrow_AllocFailType);
29
30    memcpy(dst, src, len);
31    dst[len] = 0;
32    return dst;
33}
34
35static inline int count_pairs(const char** p)
36{
37    const char** start = p;
38    while (*p)
39    {
40        SkASSERT(p[1] != NULL);
41        p += 2;
42    }
43    return (p - start) >> 1;
44}
45
46struct Data {
47    Data() : fAlloc(2048), fState(NORMAL) {}
48
49    XML_Parser              fParser;
50    SkXMLPullParser::Curr*  fCurr;
51    SkChunkAlloc            fAlloc;
52
53    enum State {
54        NORMAL,
55        MISSED_START_TAG,
56        RETURN_END_TAG
57    };
58    State fState;
59    const char* fEndTag;    // if state is RETURN_END_TAG
60};
61
62static void XMLCALL start_proc(void *data, const char *el, const char **attr)
63{
64    Data*                   p = (Data*)data;
65    SkXMLPullParser::Curr*  c = p->fCurr;
66    SkChunkAlloc&           alloc = p->fAlloc;
67
68    c->fName = dupstr(alloc, el, strlen(el));
69
70    int n = count_pairs(attr);
71    SkXMLPullParser::AttrInfo* info = (SkXMLPullParser::AttrInfo*)alloc.alloc(n * sizeof(SkXMLPullParser::AttrInfo),
72                                                                              SkChunkAlloc::kThrow_AllocFailType);
73    c->fAttrInfoCount = n;
74    c->fAttrInfos = info;
75
76    for (int i = 0; i < n; i++)
77    {
78        info[i].fName = dupstr(alloc, attr[0], strlen(attr[0]));
79        info[i].fValue = dupstr(alloc, attr[1], strlen(attr[1]));
80        attr += 2;
81    }
82
83    c->fEventType = SkXMLPullParser::START_TAG;
84    XML_StopParser(p->fParser, true);
85}
86
87static void XMLCALL end_proc(void *data, const char *el)
88{
89    Data*                   p = (Data*)data;
90    SkXMLPullParser::Curr*  c = p->fCurr;
91
92    if (c->fEventType == SkXMLPullParser::START_TAG)
93    {
94        /*  if we get here, we were called with a start_tag immediately
95            followed by this end_tag. The caller will only see the end_tag,
96            so we set a flag to notify them of the missed start_tag
97        */
98        p->fState = Data::MISSED_START_TAG;
99
100        SkASSERT(c->fName != NULL);
101        SkASSERT(strcmp(c->fName, el) == 0);
102    }
103    else
104        c->fName = dupstr(p->fAlloc, el, strlen(el));
105
106    c->fEventType = SkXMLPullParser::END_TAG;
107    XML_StopParser(p->fParser, true);
108}
109
110#include <ctype.h>
111
112static bool isws(const char s[])
113{
114    for (; *s; s++)
115        if (!isspace(*s))
116            return false;
117    return true;
118}
119
120static void XMLCALL text_proc(void* data, const char* text, int len)
121{
122    Data*                   p = (Data*)data;
123    SkXMLPullParser::Curr*  c = p->fCurr;
124
125    c->fName = dupstr(p->fAlloc, text, len);
126    c->fIsWhitespace = isws(c->fName);
127
128    c->fEventType = SkXMLPullParser::TEXT;
129    XML_StopParser(p->fParser, true);
130}
131
132//////////////////////////////////////////////////////////////////////////
133
134struct SkXMLPullParser::Impl {
135    Data    fData;
136    void*   fBuffer;
137    size_t  fBufferLen;
138};
139
140static void reportError(XML_Parser parser)
141{
142    XML_Error code = XML_GetErrorCode(parser);
143    int lineNumber = XML_GetCurrentLineNumber(parser);
144    const char* msg = XML_ErrorString(code);
145
146    printf("-------- XML error [%d] on line %d, %s\n", code, lineNumber, msg);
147}
148
149bool SkXMLPullParser::onInit()
150{
151    fImpl = new Impl;
152
153    XML_Parser p = XML_ParserCreate(NULL);
154    SkASSERT(p);
155
156    fImpl->fData.fParser = p;
157    fImpl->fData.fCurr = &fCurr;
158
159    XML_SetElementHandler(p, start_proc, end_proc);
160    XML_SetCharacterDataHandler(p, text_proc);
161    XML_SetUserData(p, &fImpl->fData);
162
163    size_t len = fStream->read(NULL, 0);
164    fImpl->fBufferLen = len;
165    fImpl->fBuffer = sk_malloc_throw(len);
166    fStream->rewind();
167    size_t  len2 = fStream->read(fImpl->fBuffer, len);
168    return len2 == len;
169}
170
171void SkXMLPullParser::onExit()
172{
173    sk_free(fImpl->fBuffer);
174    XML_ParserFree(fImpl->fData.fParser);
175    delete fImpl;
176    fImpl = NULL;
177}
178
179SkXMLPullParser::EventType SkXMLPullParser::onNextToken()
180{
181    if (Data::RETURN_END_TAG == fImpl->fData.fState)
182    {
183        fImpl->fData.fState = Data::NORMAL;
184        fCurr.fName = fImpl->fData.fEndTag; // restore name from (below) save
185        return SkXMLPullParser::END_TAG;
186    }
187
188    fImpl->fData.fAlloc.reuse();
189
190    XML_Parser p = fImpl->fData.fParser;
191    XML_Status status;
192
193    status = XML_ResumeParser(p);
194
195CHECK_STATUS:
196    switch (status) {
197    case XML_STATUS_OK:
198        return SkXMLPullParser::END_DOCUMENT;
199
200    case XML_STATUS_ERROR:
201        if (XML_GetErrorCode(p) != XML_ERROR_NOT_SUSPENDED)
202        {
203            reportError(p);
204            return SkXMLPullParser::ERROR;
205        }
206        status = XML_Parse(p, (const char*)fImpl->fBuffer, fImpl->fBufferLen, true);
207        goto CHECK_STATUS;
208
209    case XML_STATUS_SUSPENDED:
210        if (Data::MISSED_START_TAG == fImpl->fData.fState)
211        {
212            // return a start_tag, and clear the flag so we return end_tag next
213            SkASSERT(SkXMLPullParser::END_TAG == fCurr.fEventType);
214            fImpl->fData.fState = Data::RETURN_END_TAG;
215            fImpl->fData.fEndTag = fCurr.fName;  // save this pointer
216            return SkXMLPullParser::START_TAG;
217        }
218        break;
219    }
220    return fCurr.fEventType;
221}
222
223