Merge pull request #979 from m-holger/const

In FUTURE make various QPDFObjectHandle methods const

include/qpdf/QPDF.hh

@@ -796,12 +796,13 @@ class QPDF
     class Resolver
     {
         friend class QPDFObject;
+        friend class QPDF_Unresolved;
 
       private:
-        static void
+        static QPDFObject*
-        resolve(QPDF* qpdf, QPDFObjGen const& og)
+        resolved(QPDF* qpdf, QPDFObjGen og)
         {
-            qpdf->resolve(og);
+            return qpdf->resolve(og);
         }
     };
 
@@ -1061,7 +1062,7 @@ 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);

include/qpdf/QPDFObjectHandle.hh

@@ -22,23 +22,27 @@
 #ifndef QPDFOBJECTHANDLE_HH
 #define QPDFOBJECTHANDLE_HH
 
-#include <qpdf/Constants.h>
+#ifdef QPDF_FUTURE
-#include <qpdf/DLL.h>
+# include <qpdf/QPDFObjectHandle_future.hh>
-#include <qpdf/Types.h>
+#else
 
-#include <functional>
+# include <qpdf/Constants.h>
-#include <map>
+# include <qpdf/DLL.h>
-#include <memory>
+# include <qpdf/Types.h>
-#include <set>
-#include <string>
-#include <vector>
 
-#include <qpdf/Buffer.hh>
+# include <functional>
-#include <qpdf/InputSource.hh>
+# include <map>
-#include <qpdf/JSON.hh>
+# include <memory>
-#include <qpdf/PointerHolder.hh> // unused -- remove in qpdf 12 (see #785)
+# include <set>
-#include <qpdf/QPDFObjGen.hh>
+# include <string>
-#include <qpdf/QPDFTokenizer.hh>
+# include <vector>
+
+# include <qpdf/Buffer.hh>
+# include <qpdf/InputSource.hh>
+# include <qpdf/JSON.hh>
+# include <qpdf/PointerHolder.hh> // unused -- remove in qpdf 12 (see #785)
+# include <qpdf/QPDFObjGen.hh>
+# include <qpdf/QPDFTokenizer.hh>
 
 class Pipeline;
 class QPDF;
@@ -291,13 +295,6 @@ class QPDFObjectHandle
     QPDF_DLL
     QPDFObjectHandle& operator=(QPDFObjectHandle const&) = default;
 
-#ifdef QPDF_FUTURE
-    QPDF_DLL
-    QPDFObjectHandle(QPDFObjectHandle&&) = default;
-    QPDF_DLL
-    QPDFObjectHandle& operator=(QPDFObjectHandle&&) = default;
-#endif
-
     QPDF_DLL
     inline bool isInitialized() const;
 
@@ -1363,24 +1360,23 @@ class QPDFObjectHandle
     void writeJSON(int json_version, JSON::Writer& p, bool dereference_indirect = false);
 
   private:
-    QPDF_Array* asArray();
+    QPDF_Array* asArray() const;
-    QPDF_Bool* asBool();
+    QPDF_Bool* asBool() const;
-    QPDF_Dictionary* asDictionary();
+    QPDF_Dictionary* asDictionary() const;
-    QPDF_InlineImage* asInlineImage();
+    QPDF_InlineImage* asInlineImage() const;
-    QPDF_Integer* asInteger();
+    QPDF_Integer* asInteger() const;
-    QPDF_Name* asName();
+    QPDF_Name* asName() const;
-    QPDF_Null* asNull();
+    QPDF_Null* asNull() const;
-    QPDF_Operator* asOperator();
+    QPDF_Operator* asOperator() const;
-    QPDF_Real* asReal();
+    QPDF_Real* asReal() const;
-    QPDF_Reserved* asReserved();
+    QPDF_Reserved* asReserved() const;
-    QPDF_Stream* asStream();
+    QPDF_Stream* asStream() const;
-    QPDF_Stream* asStreamWithAssert();
+    QPDF_Stream* asStreamWithAssert() const;
-    QPDF_String* asString();
+    QPDF_String* asString() const;
 
-    void typeWarning(char const* expected_type, std::string const& warning);
+    void typeWarning(char const* expected_type, std::string const& warning) const;
-    void objectWarning(std::string const& warning);
+    void objectWarning(std::string const& warning) const;
-    void assertType(char const* type_name, bool istype);
+    void assertType(char const* type_name, bool istype) const;
-    inline bool dereference();
     void makeDirect(QPDFObjGen::set& visited, bool stop_at_streams);
     void disconnect();
     void setParsedOffset(qpdf_offset_t offset);
@@ -1400,7 +1396,7 @@ class QPDFObjectHandle
     std::shared_ptr<QPDFObject> obj;
 };
 
-#ifndef QPDF_NO_QPDF_STRING
+# ifndef QPDF_NO_QPDF_STRING
 // This is short for QPDFObjectHandle::parse, so you can do
 
 // auto oh = "<< /Key (value) >>"_qpdf;
@@ -1416,7 +1412,7 @@ QPDF_DLL
 QPDFObjectHandle operator ""_qpdf(char const* v, size_t len);
 /* clang-format on */
 
-#endif // QPDF_NO_QPDF_STRING
+# endif // QPDF_NO_QPDF_STRING
 
 class QPDFObjectHandle::QPDFDictItems
 {
@@ -1638,4 +1634,5 @@ QPDFObjectHandle::isInitialized() const
     return obj != nullptr;
 }
 
+#endif // QPDF_FUTURE
 #endif // QPDFOBJECTHANDLE_HH

libqpdf/QPDF.cc

@@ -1847,11 +1847,11 @@ 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)) {
@@ -1860,7 +1860,7 @@ 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);
 
@@ -1901,6 +1901,7 @@ QPDF::resolve(QPDFObjGen og)
 
     auto result(m->obj_cache[og].object);
     result->setDefaultDescription(this, og);
+    return result.get();
 }
 
 void

libqpdf/QPDFObject.cc

@@ -3,13 +3,6 @@
 #include <qpdf/QPDF.hh>
 #include <qpdf/QPDF_Destroyed.hh>
 
-void
-QPDFObject::doResolve()
-{
-    auto og = value->og;
-    QPDF::Resolver::resolve(value->qpdf, og);
-}
-
 void
 QPDFObject::destroy()
 {

libqpdf/QPDF_Array.cc

@@ -130,8 +130,7 @@ QPDF_Array::unparse()
             for (int j = next; j < key; ++j) {
                 result += "null ";
             }
-            item.second->resolve();
+            auto og = item.second->resolved_object()->getObjGen();
-            auto og = item.second->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->resolved_object()->getObjGen();
-            auto og = item->getObjGen();
             result += og.isIndirect() ? og.unparse(' ') + " R " : item->unparse() + " ";
         }
     }

libqpdf/QPDF_Unresolved.cc

@@ -1,6 +1,7 @@
 #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& og)
 std::shared_ptr<QPDFObject>
 QPDF_Unresolved::copy(bool shallow)
 {
-    throw std::logic_error("attempted to shallow copy an unresolved QPDFObjectHandle");
+    return QPDF::Resolver::resolved(qpdf, og)->copy(shallow);
-    return nullptr;
 }
 
 std::string
 QPDF_Unresolved::unparse()
 {
-    throw std::logic_error("attempted to unparse an unresolved QPDFObjectHandle");
+    return QPDF::Resolver::resolved(qpdf, og)->unparse();
-    return "";
 }
 
 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();
 }

libqpdf/qpdf/QPDFObject_private.hh

@@ -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
+    const QPDFObject*
-    resolve()
+    resolved_object() const
     {
-        if (isUnresolved()) {
+        return isUnresolved() ? QPDF::Resolver::resolved(value->qpdf, value->og) : this;
-            doResolve();
-        }
     }
-    void doResolve();
 
     template <typename T>
     T*
-    as()
+    as() const
     {
-        return dynamic_cast<T*>(value.get());
+        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:

libqpdf/qpdf/QPDF_Unresolved.hh

@@ -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);