Merge pull request #747 from m-holger/new_stream

Add optional parameter allow_nullptr to QPDFObjectHandle::getOwningQPDF

Merge pull request #747 from m-holger/new_stream
Add optional parameter allow_nullptr to QPDFObjectHandle::getOwningQPDF
Jay Berkenbilt · GitHub
2 parents 2b01a79e c53d54b1
Showing 7 changed files with 58 additions and 63 deletions
include/qpdf/QPDFObjectHandle.hh
libqpdf/QPDF.cc
libqpdf/QPDFFormFieldObjectHelper.cc
libqpdf/QPDFJob.cc
libqpdf/QPDFObjectHandle.cc
libqpdf/QPDFPageObjectHelper.cc
libqpdf/QPDF_pages.cc
@@ -957,9 +957,11 @@ class QPDFObjectHandle
         std::set<std::string>* resource_names = nullptr);
     // Return the QPDF object that owns an indirect object.  Returns
-    // null for a direct object.
+    // null for a direct object if allow_nullptr is set to true or
+    // throws a runtime error otherwise.
     QPDF_DLL
-    QPDF* getOwningQPDF();
+    inline QPDF*
+    getOwningQPDF(bool allow_nullptr = true, std::string const& error_msg = "");
     // Create a shallow copy of an object as a direct object, but do not
     // traverse across indirect object boundaries. That means that,
@@ -1876,4 +1878,17 @@ QPDFObjectHandle::isInitialized() const
     return initialized;
 }
+// Indirect object accessors
+inline QPDF*
+QPDFObjectHandle::getOwningQPDF(
+    bool allow_nullptr, std::string const& error_msg)
+{
+    // Will be null for direct objects
+    if (!allow_nullptr && (this->qpdf == nullptr)) {
+        throw std::runtime_error(
+            error_msg == "" ? "attempt to use a null qpdf object" : error_msg);
+    }
+    return this->qpdf;
+}
+
 #endif // QPDFOBJECTHANDLE_HH
@@ -2266,7 +2266,7 @@ QPDF::copyForeignObject(QPDFObjectHandle foreign)
         throw std::logic_error(
             "QPDF::copyForeign called with direct object handle");
     }
-    QPDF* other = foreign.getOwningQPDF();
+    QPDF* other = foreign.getOwningQPDF(false);
     if (other == this) {
         QTC::TC("qpdf", "QPDF copyForeign not foreign");
         throw std::logic_error(
@@ -2456,11 +2456,9 @@ QPDF::copyStreamData(QPDFObjectHandle result, QPDFObjectHandle foreign)
     QPDFObjGen local_og(result.getObjGen());
     // Copy information from the foreign stream so we can pipe its
     // data later without keeping the original QPDF object around.
-    QPDF* foreign_stream_qpdf = foreign.getOwningQPDF();
-    if (!foreign_stream_qpdf) {
-        throw std::logic_error("unable to retrieve owning qpdf"
-                               " from foreign stream");
-    }
+    QPDF* foreign_stream_qpdf = foreign.getOwningQPDF(
+        false, "unable to retrieve owning qpdf from foreign stream");
+
     QPDF_Stream* stream = dynamic_cast<QPDF_Stream*>(
         QPDFObjectHandle::ObjAccessor::getObject(foreign).get());
     if (!stream) {
@@ -362,13 +362,11 @@ QPDFFormFieldObjectHelper::setV(QPDFObjectHandle value, bool need_appearances)
         setFieldAttribute("/V", value);
     }
     if (need_appearances) {
-        QPDF* qpdf = this->oh.getOwningQPDF();
-        if (!qpdf) {
-            throw std::logic_error(
-                "QPDFFormFieldObjectHelper::setV called with"
-                " need_appearances = true on an object that is"
-                " not associated with an owning QPDF");
-        }
+        QPDF* qpdf = this->oh.getOwningQPDF(
+            false,
+            "QPDFFormFieldObjectHelper::setV called with need_appearances = "
+            "true on an object that is not associated with an owning QPDF");
+
         QPDFAcroFormDocumentHelper(*qpdf).setNeedAppearances(true);
     }
 }
@@ -883,7 +881,7 @@ QPDFFormFieldObjectHelper::generateTextAppearance(
         if (found_font_in_dr && resources.isDictionary()) {
             QTC::TC("qpdf", "QPDFFormFieldObjectHelper get font from /DR");
             if (resources.isIndirect()) {
-                resources = resources.getOwningQPDF()->makeIndirectObject(
+                resources = resources.getOwningQPDF(false)->makeIndirectObject(
                     resources.shallowCopy());
                 AS.getDict().replaceKey("/Resources", resources);
             }
@@ -2161,7 +2161,7 @@ QPDFJob::doUnderOverlayForPage(
     std::map<unsigned long long, std::shared_ptr<QPDFAcroFormDocumentHelper>>
         afdh;
     auto make_afdh = [&](QPDFPageObjectHelper& ph) {
-        QPDF* q = ph.getObjectHandle().getOwningQPDF();
+        QPDF* q = ph.getObjectHandle().getOwningQPDF(false);
         return get_afdh_for_qpdf(afdh, q);
     };
     auto dest_afdh = make_afdh(dest_page);
@@ -2597,7 +2597,7 @@ static QPDFObjectHandle
 added_page(QPDF& pdf, QPDFObjectHandle page)
 {
     QPDFObjectHandle result = page;
-    if (page.getOwningQPDF() != &pdf) {
+    if (page.getOwningQPDF(false) != &pdf) {
         // Calling copyForeignObject on an object we already copied
         // will give us the already existing copy.
         result = pdf.copyForeignObject(page);
@@ -1207,14 +1207,6 @@ QPDFObjectHandle::getUniqueResourceName(
                            " QPDFObjectHandle::getUniqueResourceName");
 }
-// Indirect object accessors
-QPDF*
-QPDFObjectHandle::getOwningQPDF()
-{
-    // Will be null for direct objects
-    return this->qpdf;
-}
-
 // Dictionary mutators
 void
@@ -1634,16 +1626,15 @@ QPDFObjectHandle::coalesceContentStreams()
         // files may have pages that are invalid in other ways.
         return;
     }
-    QPDF* qpdf = getOwningQPDF();
-    if (qpdf == nullptr) {
-        // Should not be possible for a page object to not have an
-        // owning PDF unless it was manually constructed in some
-        // incorrect way. However, it can happen in a PDF file whose
-        // page structure is direct, which is against spec but still
-        // possible to hand construct, as in fuzz issue 27393.
-        throw std::runtime_error("coalesceContentStreams called on object"
-                                 " with no associated PDF file");
-    }
+    // Should not be possible for a page object to not have an
+    // owning PDF unless it was manually constructed in some
+    // incorrect way. However, it can happen in a PDF file whose
+    // page structure is direct, which is against spec but still
+    // possible to hand construct, as in fuzz issue 27393.
+    QPDF* qpdf = getOwningQPDF(
+        false,
+        "coalesceContentStreams called on object  with no associated PDF file");
+
     QPDFObjectHandle new_contents = newStream(qpdf);
     this->replaceKey("/Contents", new_contents);
@@ -432,7 +432,8 @@ QPDFPageObjectHelper::externalizeInlineImages(size_t min_size, bool shallow)
                 this->oh.replaceKey(
                     "/Contents",
                     QPDFObjectHandle::newStream(
-                        this->oh.getOwningQPDF(), b.getBufferSharedPointer()));
+                        this->oh.getOwningQPDF(false),
+                        b.getBufferSharedPointer()));
             }
         }
     } else {
@@ -683,11 +684,10 @@ QPDFPageObjectHelper::removeUnreferencedResources()
 QPDFPageObjectHelper
 QPDFPageObjectHelper::shallowCopyPage()
 {
-    QPDF* qpdf = this->oh.getOwningQPDF();
-    if (!qpdf) {
-        throw std::runtime_error("QPDFPageObjectHelper::shallowCopyPage"
-                                 " called with a direct object");
-    }
+    QPDF* qpdf = this->oh.getOwningQPDF(
+        false,
+        "QPDFPageObjectHelper::shallowCopyPage called with a direct object");
+
     QPDFObjectHandle new_page = this->oh.shallowCopy();
     return QPDFPageObjectHelper(qpdf->makeIndirectObject(new_page));
 }
@@ -743,11 +743,10 @@ QPDFPageObjectHelper::getMatrixForTransformations(bool invert)
 QPDFObjectHandle
 QPDFPageObjectHelper::getFormXObjectForPage(bool handle_transformations)
 {
-    QPDF* qpdf = this->oh.getOwningQPDF();
-    if (!qpdf) {
-        throw std::runtime_error("QPDFPageObjectHelper::getFormXObjectForPage"
-                                 " called with a direct object");
-    }
+    QPDF* qpdf = this->oh.getOwningQPDF(
+        false,
+        "QPDFPageObjectHelper::getFormXObjectForPage called with a direct "
+        "object");
     QPDFObjectHandle result = QPDFObjectHandle::newStream(qpdf);
     QPDFObjectHandle newdict = result.getDict();
     newdict.replaceKey("/Type", QPDFObjectHandle::newName("/XObject"));
@@ -917,11 +916,9 @@ QPDFPageObjectHelper::placeFormXObject(
 void
 QPDFPageObjectHelper::flattenRotation(QPDFAcroFormDocumentHelper* afdh)
 {
-    QPDF* qpdf = this->oh.getOwningQPDF();
-    if (!qpdf) {
-        throw std::runtime_error("QPDFPageObjectHelper::flattenRotation"
-                                 " called with a direct object");
-    }
+    QPDF* qpdf = this->oh.getOwningQPDF(
+        false,
+        "QPDFPageObjectHelper::flattenRotation called with a direct object");
     auto rotate_oh = this->oh.getKey("/Rotate");
     int rotate = 0;
@@ -1066,16 +1063,12 @@ QPDFPageObjectHelper::copyAnnotations(
         return;
     }
-    QPDF* from_qpdf = from_page.getObjectHandle().getOwningQPDF();
-    if (!from_qpdf) {
-        throw std::runtime_error("QPDFPageObjectHelper::copyAnnotations:"
-                                 " from page is a direct object");
-    }
-    QPDF* this_qpdf = this->oh.getOwningQPDF();
-    if (!this_qpdf) {
-        throw std::runtime_error("QPDFPageObjectHelper::copyAnnotations:"
-                                 " this page is a direct object");
-    }
+    QPDF* from_qpdf = from_page.getObjectHandle().getOwningQPDF(
+        false,
+        "QPDFPageObjectHelper::copyAnnotations: from page is a direct object");
+    QPDF* this_qpdf = this->oh.getOwningQPDF(
+        false,
+        "QPDFPageObjectHelper::copyAnnotations: this page is a direct object");
     std::vector<QPDFObjectHandle> new_annots;
     std::vector<QPDFObjectHandle> new_fields;
@@ -234,7 +234,7 @@ QPDF::insertPage(QPDFObjectHandle newpage, int pos)
         newpage = makeIndirectObject(newpage);
     } else if (newpage.getOwningQPDF() != this) {
         QTC::TC("qpdf", "QPDF insert foreign page");
-        newpage.getOwningQPDF()->pushInheritedAttributesToPage();
+        newpage.getOwningQPDF(false)->pushInheritedAttributesToPage();
         newpage = copyForeignObject(newpage);
     } else {
         QTC::TC("qpdf", "QPDF insert indirect page");