aboutsummaryrefslogtreecommitdiffstats
path: root/libqpdf/QPDFPageObjectHelper.cc
blob: 4d58da32b9c6253f18c7ec38270a20156634972b (plain) (blame)
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
#include <qpdf/QPDFPageObjectHelper.hh>
#include <qpdf/QTC.hh>
#include <qpdf/QPDF.hh>

QPDFPageObjectHelper::Members::~Members()
{
}

QPDFPageObjectHelper::Members::Members()
{
}

QPDFPageObjectHelper::QPDFPageObjectHelper(QPDFObjectHandle oh) :
    QPDFObjectHelper(oh)
{
}

QPDFObjectHandle
QPDFPageObjectHelper::getAttribute(std::string const& name,
                                   bool copy_if_shared)
{
    bool inheritable = ((name == "/MediaBox") || (name == "/CropBox") ||
                        (name == "/Resources") || (name == "/Rotate"));

    QPDFObjectHandle node = this->oh;
    QPDFObjectHandle result(node.getKey(name));
    std::set<QPDFObjGen> seen;
    bool inherited = false;
    while (inheritable && result.isNull() && node.hasKey("/Parent"))
    {
        seen.insert(node.getObjGen());
        node = node.getKey("/Parent");
        if (seen.count(node.getObjGen()))
        {
            break;
        }
        result = node.getKey(name);
        if (! result.isNull())
        {
            QTC::TC("qpdf", "QPDFPageObjectHelper non-trivial inheritance");
            inherited = true;
        }
    }
    if (copy_if_shared && (inherited || result.isIndirect()))
    {
        QTC::TC("qpdf", "QPDFPageObjectHelper copy shared attribute");
        result = result.shallowCopy();
        this->oh.replaceKey(name, result);
    }
    return result;
}


std::map<std::string, QPDFObjectHandle>
QPDFPageObjectHelper::getPageImages()
{
    return this->oh.getPageImages();
}

std::vector<QPDFAnnotationObjectHelper>
QPDFPageObjectHelper::getAnnotations(std::string const& only_subtype)
{
    std::vector<QPDFAnnotationObjectHelper> result;
    QPDFObjectHandle annots = this->oh.getKey("/Annots");
    if (annots.isArray())
    {
        size_t nannots = annots.getArrayNItems();
        for (size_t i = 0; i < nannots; ++i)
        {
            QPDFObjectHandle annot = annots.getArrayItem(i);
            if (only_subtype.empty() ||
                (annot.isDictionary() &&
                 annot.getKey("/Subtype").isName() &&
                 (only_subtype == annot.getKey("/Subtype").getName())))
            {
                result.push_back(QPDFAnnotationObjectHelper(annot));
            }
        }
    }
    return result;
}

std::vector<QPDFObjectHandle>
QPDFPageObjectHelper::getPageContents()
{
    return this->oh.getPageContents();
}

void
QPDFPageObjectHelper::addPageContents(QPDFObjectHandle contents, bool first)
{
    this->oh.addPageContents(contents, first);
}

void
QPDFPageObjectHelper::rotatePage(int angle, bool relative)
{
    this->oh.rotatePage(angle, relative);
}

void
QPDFPageObjectHelper::coalesceContentStreams()
{
    this->oh.coalesceContentStreams();
}

void
QPDFPageObjectHelper::parsePageContents(
    QPDFObjectHandle::ParserCallbacks* callbacks)
{
    this->oh.parsePageContents(callbacks);
}

void
QPDFPageObjectHelper::filterPageContents(
    QPDFObjectHandle::TokenFilter* filter,
    Pipeline* next)
{
    this->oh.filterPageContents(filter, next);
}

void
QPDFPageObjectHelper::pipePageContents(Pipeline* p)
{
    this->oh.pipePageContents(p);
}

void
QPDFPageObjectHelper::addContentTokenFilter(
    PointerHolder<QPDFObjectHandle::TokenFilter> token_filter)
{
    this->oh.addContentTokenFilter(token_filter);
}

class NameWatcher: public QPDFObjectHandle::TokenFilter
{
  public:
    NameWatcher() :
        saw_bad(false)
    {
    }
    virtual ~NameWatcher()
    {
    }
    virtual void handleToken(QPDFTokenizer::Token const&);
    std::set<std::string> names;
    bool saw_bad;
};

void
NameWatcher::handleToken(QPDFTokenizer::Token const& token)
{
    if (token.getType() == QPDFTokenizer::tt_name)
    {
        // Create a name object and get its name. This canonicalizes
        // the representation of the name
        this->names.insert(
            QPDFObjectHandle::newName(token.getValue()).getName());
    }
    else if (token.getType() == QPDFTokenizer::tt_bad)
    {
        saw_bad = true;
    }
    writeToken(token);
}

void
QPDFPageObjectHelper::removeUnreferencedResources()
{
    NameWatcher nw;
    try
    {
        filterPageContents(&nw);
    }
    catch (std::exception& e)
    {
        this->oh.warnIfPossible(
            std::string("Unable to parse content stream: ") + e.what() +
            "; not attempting to remove unreferenced objects from this page");
        return;
    }
    if (nw.saw_bad)
    {
        QTC::TC("qpdf", "QPDFPageObjectHelper bad token finding names");
        this->oh.warnIfPossible(
            "Bad token found while scanning content stream; "
            "not attempting to remove unreferenced objects from this page");
        return;
    }
    // Walk through /Font and /XObject dictionaries, removing any
    // resources that are not referenced. We must make copies of
    // resource dictionaries down into the dictionaries are mutating
    // to prevent mutating one dictionary from having the side effect
    // of mutating the one it was copied from.
    std::vector<std::string> to_filter;
    to_filter.push_back("/Font");
    to_filter.push_back("/XObject");
    QPDFObjectHandle resources = getAttribute("/Resources", true);
    for (std::vector<std::string>::iterator d_iter = to_filter.begin();
         d_iter != to_filter.end(); ++d_iter)
    {
        QPDFObjectHandle dict = resources.getKey(*d_iter);
        if (! dict.isDictionary())
        {
            continue;
        }
        dict = dict.shallowCopy();
        resources.replaceKey(*d_iter, dict);
        std::set<std::string> keys = dict.getKeys();
        for (std::set<std::string>::iterator k_iter = keys.begin();
             k_iter != keys.end(); ++k_iter)
        {
            if (! nw.names.count(*k_iter))
            {
                dict.removeKey(*k_iter);
            }
        }
    }
}

QPDFPageObjectHelper
QPDFPageObjectHelper::shallowCopyPage()
{
    QPDF* qpdf = this->oh.getOwningQPDF();
    if (! qpdf)
    {
        throw std::runtime_error(
            "QPDFPageObjectHelper::shallowCopyPage"
            " called with a direct objet");
    }
    QPDFObjectHandle new_page = this->oh.shallowCopy();
    return QPDFPageObjectHelper(qpdf->makeIndirectObject(new_page));
}