qpdf-test-compare.cc
7.3 KB
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
#include <qpdf/Pl_StdioFile.hh>
#include <qpdf/QPDF.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QUtil.hh>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
static char const* whoami = nullptr;
void
usage()
{
std::cerr << "Usage: " << whoami << " actual expected" << std::endl
<< R"(Where "actual" is the actual output and "expected" is the expected)"
<< std::endl
<< "output of a test, compare the two PDF files. The files are considered"
<< std::endl
<< "to match if all their objects are identical except that, if a stream is"
<< std::endl
<< "compressed with FlateDecode, the uncompressed data must match." << std::endl
<< std::endl
<< "If the files match, the output is the expected file. Otherwise, it is"
<< std::endl
<< "the actual file. Read comments in the test suite for rationale." << std::endl;
exit(2);
}
void
cleanEncryption(QPDF& q)
{
auto enc = q.getTrailer().getKey("/Encrypt");
if (!enc.isDictionary()) {
return;
}
enc.removeKey("/O");
enc.removeKey("/OE");
enc.removeKey("/U");
enc.removeKey("/UE");
enc.removeKey("/Perms");
}
std::string
compareObjects(std::string const& label, QPDFObjectHandle act, QPDFObjectHandle exp)
{
if (act.getTypeCode() != exp.getTypeCode()) {
QTC::TC("compare", "objects with different type");
return label + ": different types";
}
if (act.isStream()) {
auto act_dict = act.getDict();
auto exp_dict = exp.getDict();
act_dict.removeKey("/Length");
exp_dict.removeKey("/Length");
if (act_dict.unparse() != exp_dict.unparse()) {
QTC::TC("compare", "different stream dictionaries");
return label + ": stream dictionaries differ";
}
if (act_dict.getKey("/Type").isNameAndEquals("/XRef")) {
QTC::TC("compare", "ignore data for xref stream");
return "";
}
auto act_filters = act_dict.getKey("/Filter");
bool uncompress = false;
if (act_filters.isName()) {
act_filters = act_filters.wrapInArray();
}
if (act_filters.isArray()) {
for (auto& filter: act_filters.aitems()) {
if (filter.isNameAndEquals("/FlateDecode")) {
uncompress = true;
break;
}
}
}
std::shared_ptr<Buffer> act_data;
std::shared_ptr<Buffer> exp_data;
if (uncompress) {
QTC::TC("compare", "uncompressing");
act_data = act.getStreamData();
exp_data = exp.getStreamData();
} else {
QTC::TC("compare", "not uncompressing");
act_data = act.getRawStreamData();
exp_data = exp.getRawStreamData();
}
if (act_data->getSize() != exp_data->getSize()) {
QTC::TC("compare", "differing data size", uncompress ? 0 : 1);
return label + ": stream data size differs";
}
auto act_buf = act_data->getBuffer();
auto exp_buf = exp_data->getBuffer();
if (memcmp(act_buf, exp_buf, act_data->getSize()) != 0) {
QTC::TC("compare", "different data", uncompress ? 0 : 1);
return label + ": stream data differs";
}
} else if (act.unparseResolved() != exp.unparseResolved()) {
QTC::TC("compare", "different non-stream");
return label + ": object contents differ";
}
return "";
}
std::string
compare(char const* actual_filename, char const* expected_filename)
{
QPDF actual;
actual.processFile(actual_filename);
QPDF expected;
expected.processFile(expected_filename);
// The motivation behind this program is to compare files in a way that allows for
// differences in the exact bytes of zlib compression. If all zlib implementations produced
// exactly the same output, we would just be able to use straight comparison, but since they
// don't, we use this. As such, we are enforcing a standard of "sameness" that goes beyond
// showing semantic equivalence. The only difference we are allowing is compressed data.
auto act_trailer = actual.getTrailer();
auto exp_trailer = expected.getTrailer();
act_trailer.removeKey("/Length");
exp_trailer.removeKey("/Length");
auto trailer_diff = compareObjects("trailer", act_trailer, exp_trailer);
if (!trailer_diff.empty()) {
QTC::TC("compare", "different trailer");
return trailer_diff;
}
cleanEncryption(actual);
cleanEncryption(expected);
auto actual_objects = actual.getAllObjects();
auto expected_objects = expected.getAllObjects();
if (actual_objects.size() != expected_objects.size()) {
// Not exercised in the test suite since the trailers will differ in this case.
return "different number of objects";
}
for (size_t i = 0; i < actual_objects.size(); ++i) {
auto act = actual_objects[i];
auto exp = expected_objects[i];
auto act_og = act.getObjGen();
auto exp_og = exp.getObjGen();
if (act_og != exp_og) {
// not reproduced in the test suite
return "different object IDs";
}
auto ret = compareObjects(act_og.unparse(), act, exp);
if (!ret.empty()) {
return ret;
}
}
return "";
}
int
main(int argc, char* argv[])
{
if ((whoami = strrchr(argv[0], '/')) == nullptr) {
whoami = argv[0];
} else {
++whoami;
}
if ((argc == 2) && (strcmp(argv[1], "--version") == 0)) {
std::cout << whoami << " from qpdf version " << QPDF::QPDFVersion() << std::endl;
exit(0);
}
if (argc != 3) {
usage();
}
bool show_why = QUtil::get_env("QPDF_COMPARE_WHY");
try {
char const* to_output;
auto actual = argv[1];
auto expected = argv[2];
auto difference = compare(actual, expected);
if (difference.empty()) {
// The files are identical; write the expected file. This way, tests can be written
// that compare the output of this program to the expected file.
to_output = expected;
} else {
if (show_why) {
std::cerr << difference << std::endl;
exit(2);
}
// The files differ; write the actual file. If it is determined that the actual file
// is correct because of changes that result in intended differences, this enables
// the output of this program to replace the expected file in the test suite.
to_output = actual;
}
auto f = QUtil::safe_fopen(to_output, "rb");
QUtil::FileCloser fc(f);
QUtil::binary_stdout();
auto out = std::make_unique<Pl_StdioFile>("stdout", stdout);
unsigned char buf[2048];
bool done = false;
while (!done) {
size_t len = fread(buf, 1, sizeof(buf), f);
if (len <= 0) {
done = true;
} else {
out->write(buf, len);
}
}
if (!difference.empty()) {
exit(2);
}
} catch (std::exception& e) {
std::cerr << whoami << ": " << e.what() << std::endl;
exit(2);
}
return 0;
}