OpenSystemsDevelopment / qpdf

Commit b89b1d772db935ed36b8abe8a21ee6468ada3d23

Authored by Jay Berkenbilt
1 parent 93de6eaf

Fix memory leak in pdf-invert-images 

A class can't have a PointerHolder to itself since PointerHolder
doesn't have the concept of weak references.
Inline Side-by-side
Showing 1 changed file with 13 additions and 16 deletions
examples/pdf-invert-images.cc
  View file @b89b1d7
... ... @@ -40,12 +40,12 @@ class ImageInverter: public QPDFObjectHandle::StreamDataProvider
40 40 virtual void provideStreamData(int objid, int generation,
41 41 Pipeline* pipeline) override;
42 42  
43   - void setSelfPh(PointerHolder<QPDFObjectHandle::StreamDataProvider>);
44   - void registerImage(QPDFObjectHandle image);
  43 + void registerImage(
  44 + QPDFObjectHandle image,
  45 + PointerHolder<QPDFObjectHandle::StreamDataProvider> self);
45 46  
46 47 private:
47 48 QPDF other;
48   - PointerHolder<QPDFObjectHandle::StreamDataProvider> self_ph;
49 49 // Map og in original to copied image
50 50 std::map<QPDFObjGen, QPDFObjectHandle> copied_images;
51 51 };
... ... @@ -56,18 +56,18 @@ ImageInverter::ImageInverter()
56 56 }
57 57  
58 58 void
59   -ImageInverter::setSelfPh(PointerHolder<QPDFObjectHandle::StreamDataProvider> p)
  59 +ImageInverter::registerImage(
  60 + QPDFObjectHandle image,
  61 + PointerHolder<QPDFObjectHandle::StreamDataProvider> self)
60 62 {
61 63 // replaceStreamData requires a pointer holder to the stream data
62 64 // provider, but there's no way for us to generate one ourselves,
63   - // so we have to have it handed to us.
64   - this->self_ph = p;
65   -}
66   -
  65 + // so we have to have it handed to us. Don't be tempted to have
  66 + // the class contain a PointerHolder to itself as a member. Doing
  67 + // this will prevent the class from ever being deleted since the
  68 + // reference count will never drop to zero (and PointerHolder
  69 + // doesn't have weak references).
67 70  
68   -void
69   -ImageInverter::registerImage(QPDFObjectHandle image)
70   -{
71 71 QPDFObjGen og(image.getObjGen());
72 72 // Store information about the images based on the object and
73 73 // generation number. Recall that a single image object may be
... ... @@ -88,7 +88,7 @@ ImageInverter::registerImage(QPDFObjectHandle image)
88 88 // filterable in the input QPDF object, so we don't have to deal
89 89 // with it explicitly here. We could explicitly use /DCTDecode and
90 90 // write through a DCT filter if we wanted.
91   - image.replaceStreamData(this->self_ph,
  91 + image.replaceStreamData(self,
92 92 QPDFObjectHandle::newNull(),
93 93 QPDFObjectHandle::newNull());
94 94 }
... ... @@ -149,9 +149,6 @@ int main(int argc, char* argv[])
149 149  
150 150 ImageInverter* inv = new ImageInverter;
151 151 PointerHolder<QPDFObjectHandle::StreamDataProvider> p = inv;
152   - // We need to give ImageInverter the pointer holder that it
153   - // needs to pass to replaceStreamData.
154   - inv->setSelfPh(p);
155 152  
156 153 // For each page...
157 154 std::vector<QPDFPageObjectHelper> pages =
... ... @@ -186,7 +183,7 @@ int main(int argc, char* argv[])
186 183 (color_space.getName() == "/DeviceGray") &&
187 184 (bits_per_component.getIntValue() == 8))
188 185 {
189   - inv->registerImage(image);
  186 + inv->registerImage(image, p);
190 187 }
191 188 }
192 189 }
... ...