Refactor resolving of objects

m-holger
1 parent ce5b864c
Showing 9 changed files with 112 additions and 119 deletions
include/qpdf/QPDF.hh
include/qpdf/QPDFObjectHandle.hh
libqpdf/QPDF.cc
libqpdf/QPDFObject.cc
libqpdf/QPDFObjectHandle.cc
libqpdf/QPDF_Array.cc
libqpdf/QPDF_Unresolved.cc
libqpdf/qpdf/QPDFObject_private.hh
libqpdf/qpdf/QPDF_Unresolved.hh
@@ -792,12 +792,13 @@ class QPDF
     class Resolver
     {
         friend class QPDFObject;
+        friend class QPDF_Unresolved;
       private:
-        static void
-        resolve(QPDF* qpdf, QPDFObjGen const& og)
+        static QPDFObject*
+        resolved(QPDF* qpdf, QPDFObjGen og)
         {
-            qpdf->resolve(og);
+            return qpdf->resolve(og);
         }
     };
@@ -1056,7 +1057,7 @@ class QPDF
         QPDFObjGen exp_og,
         QPDFObjGen& og,
         bool skip_cache_if_in_xref);
-    void resolve(QPDFObjGen og);
+    QPDFObject* resolve(QPDFObjGen og);
     void resolveObjectsInStream(int obj_stream_number);
     void stopOnError(std::string const& message);
     QPDFObjectHandle reserveObjectIfNotExists(QPDFObjGen const& og);
@@ -1363,24 +1363,23 @@ class QPDFObjectHandle
     void writeJSON(int json_version, JSON::Writer& p, bool dereference_indirect = false);
   private:
-    QPDF_Array* asArray();
-    QPDF_Bool* asBool();
-    QPDF_Dictionary* asDictionary();
-    QPDF_InlineImage* asInlineImage();
-    QPDF_Integer* asInteger();
-    QPDF_Name* asName();
-    QPDF_Null* asNull();
-    QPDF_Operator* asOperator();
-    QPDF_Real* asReal();
-    QPDF_Reserved* asReserved();
-    QPDF_Stream* asStream();
+    QPDF_Array* asArray() const;
+    QPDF_Bool* asBool() const;
+    QPDF_Dictionary* asDictionary() const;
+    QPDF_InlineImage* asInlineImage() const;
+    QPDF_Integer* asInteger() const;
+    QPDF_Name* asName() const;
+    QPDF_Null* asNull() const;
+    QPDF_Operator* asOperator() const;
+    QPDF_Real* asReal() const;
+    QPDF_Reserved* asReserved() const;
+    QPDF_Stream* asStream() const;
     QPDF_Stream* asStreamWithAssert();
-    QPDF_String* asString();
+    QPDF_String* asString() const;
     void typeWarning(char const* expected_type, std::string const& warning);
     void objectWarning(std::string const& warning);
     void assertType(char const* type_name, bool istype);
-    inline bool dereference();
     void makeDirect(QPDFObjGen::set& visited, bool stop_at_streams);
     void disconnect();
     void setParsedOffset(qpdf_offset_t offset);
@@ -1728,11 +1728,11 @@ QPDF::readObjectAtOffset(
     return oh;
 }
-void
+QPDFObject*
 QPDF::resolve(QPDFObjGen og)
 {
     if (!isUnresolved(og)) {
-        return;
+        return m->obj_cache[og].object.get();
     }
     if (m->resolving.count(og)) {
@@ -1741,7 +1741,7 @@ QPDF::resolve(QPDFObjGen og)
         QTC::TC("qpdf", "QPDF recursion loop in resolve");
         warn(damagedPDF("", "loop detected resolving object " + og.unparse(' ')));
         updateCache(og, QPDF_Null::create(), -1, -1);
-        return;
+        return m->obj_cache[og].object.get();
     }
     ResolveRecorder rr(this, og);
@@ -1782,6 +1782,7 @@ QPDF::resolve(QPDFObjGen og)
     auto result(m->obj_cache[og].object);
     result->setDefaultDescription(this, og);
+    return result.get();
 }
 void
@@ -4,13 +4,6 @@
 #include <qpdf/QPDF_Destroyed.hh>
 void
-QPDFObject::doResolve()
-{
-    auto og = value->og;
-    QPDF::Resolver::resolve(value->qpdf, og);
-}
-
-void
 QPDFObject::destroy()
 {
     value = QPDF_Destroyed::getInstance();
@@ -240,79 +240,79 @@ QPDFObjectHandle::disconnect()
 qpdf_object_type_e
 QPDFObjectHandle::getTypeCode()
 {
-    return dereference() ? this->obj->getTypeCode() : ::ot_uninitialized;
+    return obj ? obj->getResolvedTypeCode() : ::ot_uninitialized;
 }
 char const*
 QPDFObjectHandle::getTypeName()
 {
-    return dereference() ? this->obj->getTypeName() : "uninitialized";
+    return obj ? obj->getTypeName() : "uninitialized";
 }
 QPDF_Array*
-QPDFObjectHandle::asArray()
+QPDFObjectHandle::asArray() const
 {
-    return dereference() ? obj->as<QPDF_Array>() : nullptr;
+    return obj ? obj->as<QPDF_Array>() : nullptr;
 }
 QPDF_Bool*
-QPDFObjectHandle::asBool()
+QPDFObjectHandle::asBool() const
 {
-    return dereference() ? obj->as<QPDF_Bool>() : nullptr;
+    return obj ? obj->as<QPDF_Bool>() : nullptr;
 }
 QPDF_Dictionary*
-QPDFObjectHandle::asDictionary()
+QPDFObjectHandle::asDictionary() const
 {
-    return dereference() ? obj->as<QPDF_Dictionary>() : nullptr;
+    return obj ? obj->as<QPDF_Dictionary>() : nullptr;
 }
 QPDF_InlineImage*
-QPDFObjectHandle::asInlineImage()
+QPDFObjectHandle::asInlineImage() const
 {
-    return dereference() ? obj->as<QPDF_InlineImage>() : nullptr;
+    return obj ? obj->as<QPDF_InlineImage>() : nullptr;
 }
 QPDF_Integer*
-QPDFObjectHandle::asInteger()
+QPDFObjectHandle::asInteger() const
 {
-    return dereference() ? obj->as<QPDF_Integer>() : nullptr;
+    return obj ? obj->as<QPDF_Integer>() : nullptr;
 }
 QPDF_Name*
-QPDFObjectHandle::asName()
+QPDFObjectHandle::asName() const
 {
-    return dereference() ? obj->as<QPDF_Name>() : nullptr;
+    return obj ? obj->as<QPDF_Name>() : nullptr;
 }
 QPDF_Null*
-QPDFObjectHandle::asNull()
+QPDFObjectHandle::asNull() const
 {
-    return dereference() ? obj->as<QPDF_Null>() : nullptr;
+    return obj ? obj->as<QPDF_Null>() : nullptr;
 }
 QPDF_Operator*
-QPDFObjectHandle::asOperator()
+QPDFObjectHandle::asOperator() const
 {
-    return dereference() ? obj->as<QPDF_Operator>() : nullptr;
+    return obj ? obj->as<QPDF_Operator>() : nullptr;
 }
 QPDF_Real*
-QPDFObjectHandle::asReal()
+QPDFObjectHandle::asReal() const
 {
-    return dereference() ? obj->as<QPDF_Real>() : nullptr;
+    return obj ? obj->as<QPDF_Real>() : nullptr;
 }
 QPDF_Reserved*
-QPDFObjectHandle::asReserved()
+QPDFObjectHandle::asReserved() const
 {
-    return dereference() ? obj->as<QPDF_Reserved>() : nullptr;
+    return obj ? obj->as<QPDF_Reserved>() : nullptr;
 }
 QPDF_Stream*
-QPDFObjectHandle::asStream()
+QPDFObjectHandle::asStream() const
 {
-    return dereference() ? obj->as<QPDF_Stream>() : nullptr;
+    return obj ? obj->as<QPDF_Stream>() : nullptr;
 }
 QPDF_Stream*
@@ -324,21 +324,21 @@ QPDFObjectHandle::asStreamWithAssert()
 }
 QPDF_String*
-QPDFObjectHandle::asString()
+QPDFObjectHandle::asString() const
 {
-    return dereference() ? obj->as<QPDF_String>() : nullptr;
+    return obj ? obj->as<QPDF_String>() : nullptr;
 }
 bool
 QPDFObjectHandle::isDestroyed()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_destroyed);
+    return obj && obj->getResolvedTypeCode() == ::ot_destroyed;
 }
 bool
 QPDFObjectHandle::isBool()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_boolean);
+    return obj && obj->getResolvedTypeCode() == ::ot_boolean;
 }
 bool
@@ -346,25 +346,25 @@ QPDFObjectHandle::isDirectNull() const
 {
     // Don't call dereference() -- this is a const method, and we know
     // objid == 0, so there's nothing to resolve.
-    return (isInitialized() && (getObjectID() == 0) && (obj->getTypeCode() == ::ot_null));
+    return (obj && getObjectID() == 0 && obj->getTypeCode() == ::ot_null);
 }
 bool
 QPDFObjectHandle::isNull()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_null);
+    return obj && obj->getResolvedTypeCode() == ::ot_null;
 }
 bool
 QPDFObjectHandle::isInteger()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_integer);
+    return obj && obj->getResolvedTypeCode() == ::ot_integer;
 }
 bool
 QPDFObjectHandle::isReal()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_real);
+    return obj && obj->getResolvedTypeCode() == ::ot_real;
 }
 bool
@@ -401,49 +401,49 @@ QPDFObjectHandle::getValueAsNumber(double&amp; value)
 bool
 QPDFObjectHandle::isName()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_name);
+    return obj && obj->getResolvedTypeCode() == ::ot_name;
 }
 bool
 QPDFObjectHandle::isString()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_string);
+    return obj && obj->getResolvedTypeCode() == ::ot_string;
 }
 bool
 QPDFObjectHandle::isOperator()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_operator);
+    return obj && obj->getResolvedTypeCode() == ::ot_operator;
 }
 bool
 QPDFObjectHandle::isInlineImage()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_inlineimage);
+    return obj && obj->getResolvedTypeCode() == ::ot_inlineimage;
 }
 bool
 QPDFObjectHandle::isArray()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_array);
+    return obj && obj->getResolvedTypeCode() == ::ot_array;
 }
 bool
 QPDFObjectHandle::isDictionary()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_dictionary);
+    return obj && obj->getResolvedTypeCode() == ::ot_dictionary;
 }
 bool
 QPDFObjectHandle::isStream()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_stream);
+    return obj && obj->getResolvedTypeCode() == ::ot_stream;
 }
 bool
 QPDFObjectHandle::isReserved()
 {
-    return dereference() && (obj->getTypeCode() == ::ot_reserved);
+    return obj && obj->getResolvedTypeCode() == ::ot_reserved;
 }
 bool
@@ -1586,7 +1586,7 @@ QPDFObjectHandle::unparse()
 std::string
 QPDFObjectHandle::unparseResolved()
 {
-    if (!dereference()) {
+    if (!obj) {
         throw std::logic_error("attempted to dereference an uninitialized QPDFObjectHandle");
     }
     return obj->unparse();
@@ -1615,7 +1615,7 @@ QPDFObjectHandle::getJSON(int json_version, bool dereference_indirect)
 {
     if ((!dereference_indirect) && isIndirect()) {
         return JSON::makeString(unparse());
-    } else if (!dereference()) {
+    } else if (!obj) {
         throw std::logic_error("attempted to dereference an uninitialized QPDFObjectHandle");
     } else {
         Pl_Buffer p{"json"};
@@ -1631,7 +1631,7 @@ QPDFObjectHandle::writeJSON(int json_version, JSON::Writer&amp; p, bool dereference_
 {
     if (!dereference_indirect && isIndirect()) {
         p << "\"" << getObjGen().unparse(' ') << " R\"";
-    } else if (!dereference()) {
+    } else if (!obj) {
         throw std::logic_error("attempted to dereference an uninitialized QPDFObjectHandle");
     } else {
         obj->writeJSON(json_version, p);
@@ -1874,11 +1874,7 @@ QPDFObjectHandle::parse(
 qpdf_offset_t
 QPDFObjectHandle::getParsedOffset()
 {
-    if (dereference()) {
-        return this->obj->getParsedOffset();
-    } else {
-        return -1;
-    }
+    return obj ? obj->getParsedOffset() : -1;
 }
 QPDFObjectHandle
@@ -2055,9 +2051,7 @@ QPDFObjectHandle::newReserved(QPDF* qpdf)
 void
 QPDFObjectHandle::setObjectDescription(QPDF* owning_qpdf, std::string const& object_description)
 {
-    // This is called during parsing on newly created direct objects, so we can't call dereference()
-    // here.
-    if (isInitialized() && obj.get()) {
+    if (obj) {
         auto descr = std::make_shared<QPDFValue::Description>(object_description);
         obj->setDescription(owning_qpdf, descr);
     }
@@ -2066,13 +2060,13 @@ QPDFObjectHandle::setObjectDescription(QPDF* owning_qpdf, std::string const&amp; obj
 bool
 QPDFObjectHandle::hasObjectDescription()
 {
-    return dereference() && obj.get() && obj->hasDescription();
+    return obj && obj->hasDescription();
 }
 QPDFObjectHandle
 QPDFObjectHandle::shallowCopy()
 {
-    if (!dereference()) {
+    if (!obj) {
         throw std::logic_error("operation attempted on uninitialized QPDFObjectHandle");
     }
     return {obj->copy()};
@@ -2081,7 +2075,7 @@ QPDFObjectHandle::shallowCopy()
 QPDFObjectHandle
 QPDFObjectHandle::unsafeShallowCopy()
 {
-    if (!dereference()) {
+    if (!obj) {
         throw std::logic_error("operation attempted on uninitialized QPDFObjectHandle");
     }
     return {obj->copy(true)};
@@ -2172,10 +2166,10 @@ QPDFObjectHandle::typeWarning(char const* expected_type, std::string const&amp; warn
     std::string description;
     // Type checks above guarantee that the object has been dereferenced. Nevertheless, dereference
     // throws exceptions in the test suite
-    if (!dereference()) {
+    if (!obj) {
         throw std::logic_error("attempted to dereference an uninitialized QPDFObjectHandle");
     }
-    this->obj->getDescription(context, description);
+    obj->getDescription(context, description);
     // Null context handled by warn
     warn(
         context,
@@ -2193,7 +2187,7 @@ QPDFObjectHandle::warnIfPossible(std::string const&amp; warning)
 {
     QPDF* context = nullptr;
     std::string description;
-    if (dereference() && obj->getDescription(context, description)) {
+    if (obj && obj->getDescription(context, description)) {
         warn(context, QPDFExc(qpdf_e_damaged_pdf, "", description, 0, warning));
     } else {
         *QPDFLogger::defaultLogger()->getError() << warning << "\n";
@@ -2205,8 +2199,8 @@ QPDFObjectHandle::objectWarning(std::string const&amp; warning)
 {
     QPDF* context = nullptr;
     std::string description;
-    // Type checks above guarantee that the object has been dereferenced.
-    this->obj->getDescription(context, description);
+    // Type checks above guarantee that the object is initialized.
+    obj->getDescription(context, description);
     // Null context handled by warn
     warn(context, QPDFExc(qpdf_e_object, "", description, 0, warning));
 }
@@ -2372,16 +2366,6 @@ QPDFObjectHandle::assertPageObject()
     }
 }
-inline bool
-QPDFObjectHandle::dereference()
-{
-    if (!isInitialized()) {
-        return false;
-    }
-    this->obj->resolve();
-    return true;
-}
-
 void
 QPDFObjectHandle::warn(QPDF* qpdf, QPDFExc const& e)
 {
@@ -130,8 +130,7 @@ QPDF_Array::unparse()
             for (int j = next; j < key; ++j) {
                 result += "null ";
             }
-            item.second->resolve();
-            auto og = item.second->getObjGen();
+            auto og = item.second->resolved_object()->getObjGen();
             result += og.isIndirect() ? og.unparse(' ') + " R " : item.second->unparse() + " ";
             next = ++key;
         }
@@ -140,8 +139,7 @@ QPDF_Array::unparse()
         }
     } else {
         for (auto const& item: elements) {
-            item->resolve();
-            auto og = item->getObjGen();
+            auto og = item->resolved_object()->getObjGen();
             result += og.isIndirect() ? og.unparse(' ') + " R " : item->unparse() + " ";
         }
     }
 #include <qpdf/QPDF_Unresolved.hh>
-#include <stdexcept>
+#include <qpdf/QPDF.hh>
+#include <qpdf/QPDFObject_private.hh>
 QPDF_Unresolved::QPDF_Unresolved(QPDF* qpdf, QPDFObjGen const& og) :
     QPDFValue(::ot_unresolved, "unresolved", qpdf, og)
@@ -16,19 +17,23 @@ QPDF_Unresolved::create(QPDF* qpdf, QPDFObjGen const&amp; og)
 std::shared_ptr<QPDFObject>
 QPDF_Unresolved::copy(bool shallow)
 {
-    throw std::logic_error("attempted to shallow copy an unresolved QPDFObjectHandle");
-    return nullptr;
+    return QPDF::Resolver::resolved(qpdf, og)->copy(shallow);
 }
 std::string
 QPDF_Unresolved::unparse()
 {
-    throw std::logic_error("attempted to unparse an unresolved QPDFObjectHandle");
-    return "";
+    return QPDF::Resolver::resolved(qpdf, og)->unparse();
 }
 void
 QPDF_Unresolved::writeJSON(int json_version, JSON::Writer& p)
 {
-    throw std::logic_error("attempted to get JSON from an unresolved QPDFObjectHandle");
+    QPDF::Resolver::resolved(qpdf, og)->writeJSON(json_version, p);
+}
+
+std::string
+QPDF_Unresolved::getStringValue() const
+{
+    return QPDF::Resolver::resolved(qpdf, og)->getStringValue();
 }
@@ -5,8 +5,8 @@
 // include/qpdf/QPDFObject.hh. See comments there for an explanation.
 #include <qpdf/Constants.h>
-#include <qpdf/DLL.h>
 #include <qpdf/JSON.hh>
+#include <qpdf/QPDF.hh>
 #include <qpdf/QPDFValue.hh>
 #include <qpdf/Types.h>
@@ -43,18 +43,26 @@ class QPDFObject
     {
         return value->getStringValue();
     }
+    // Return a unique type code for the resolved object
+    qpdf_object_type_e
+    getResolvedTypeCode() const
+    {
+        auto tc = value->type_code;
+        return tc == ::ot_unresolved
+            ? QPDF::Resolver::resolved(value->qpdf, value->og)->value->type_code
+            : tc;
+    }
     // Return a unique type code for the object
     qpdf_object_type_e
-    getTypeCode() const
+    getTypeCode() const noexcept
     {
         return value->type_code;
     }
-
     // Return a string literal that describes the type, useful for debugging and testing
     char const*
     getTypeName() const
     {
-        return value->type_name;
+        return resolved_object()->value->type_name;
     }
     QPDF*
@@ -157,20 +165,23 @@ class QPDFObject
     {
         return value->type_code == ::ot_unresolved;
     }
-    void
-    resolve()
+    const QPDFObject*
+    resolved_object() const
     {
-        if (isUnresolved()) {
-            doResolve();
-        }
+        return isUnresolved() ? QPDF::Resolver::resolved(value->qpdf, value->og) : this;
     }
-    void doResolve();
     template <typename T>
     T*
-    as()
-    {
-        return dynamic_cast<T*>(value.get());
+    as() const
+    {
+        if (auto result = dynamic_cast<T*>(value.get())) {
+            return result;
+        } else {
+            return isUnresolved()
+                ? dynamic_cast<T*>(QPDF::Resolver::resolved(value->qpdf, value->og)->value.get())
+                : nullptr;
+        }
     }
   private:
@@ -11,6 +11,7 @@ class QPDF_Unresolved: public QPDFValue
     std::shared_ptr<QPDFObject> copy(bool shallow = false) override;
     std::string unparse() override;
     void writeJSON(int json_version, JSON::Writer& p) override;
+    std::string getStringValue() const override;
   private:
     QPDF_Unresolved(QPDF* qpdf, QPDFObjGen const& og);