Add QPDFObjectHandle::getJSON()

ChangeLog

@@ -1,5 +1,9 @@
 2018-12-18  Jay Berkenbilt  <ejb@ql.org>
 
+	* New method QPDFObjectHandle::getJSON() returns a JSON object
+	with a partial representation of the object. See
+	QPDFObjectHandle.hh for a detailed description.
+
 	* Add a simple JSON serializer. This is not a complete or
 	general-purpose JSON library. It allows assembly and serialization
 	of JSON structures with some restrictions, which are described in

include/qpdf/QPDFObject.hh

@@ -24,6 +24,7 @@
 
 #include <qpdf/DLL.h>
 #include <qpdf/PointerHolder.hh>
+#include <qpdf/JSON.hh>
 
 #include <string>
 
@@ -62,6 +63,7 @@ class QPDFObject
 
     virtual ~QPDFObject() {}
     virtual std::string unparse() = 0;
+    virtual JSON getJSON() = 0;
 
     // Return a unique type code for the object
     virtual object_type_e getTypeCode() const = 0;

include/qpdf/QPDFObjectHandle.hh

@@ -733,6 +733,25 @@ class QPDFObjectHandle
     QPDF_DLL
     std::string unparseBinary();
 
+    // Return encoded as JSON. For most object types, there is an
+    // obvious mapping. The JSON is generated as follows:
+    // * Names are encoded as strings representing the normalized value of
+    //   getName()
+    // * Indirect references are encoded as strings containing "obj gen R"
+    // * Strings are encoded as UTF-8 strings with unrepresentable binary
+    //   characters encoded as \uHHHH
+    // * Encoding streams just encodes the stream's dictionary; the stream
+    //   data is not represented
+    // * Object types that are only valid in content streams (inline
+    //   image, operator) as well as "reserved" objects are not
+    //   representable and will be serialized as "null".
+    // If dereference_indirect is true and this is an indirect object,
+    // show the actual contents of the object. The effect of
+    // dereference_indirect applies only to this object. It is not
+    // recursive.
+    QPDF_DLL
+    JSON getJSON(bool dereference_indirect = false);
+
     // Legacy helper methods for commonly performed operations on
     // pages. Newer code should use QPDFPageObjectHelper instead. The
     // specification and behavior of these methods are the same as the

libqpdf/QPDFObjectHandle.cc

@@ -1235,6 +1235,25 @@ QPDFObjectHandle::unparseBinary()
     }
 }
 
+JSON
+QPDFObjectHandle::getJSON(bool dereference_indirect)
+{
+    if ((! dereference_indirect) && this->isIndirect())
+    {
+        return JSON::makeString(unparse());
+    }
+    else
+    {
+        if (this->m->reserved)
+        {
+            throw std::logic_error(
+                "QPDFObjectHandle: attempting to unparse a reserved object");
+        }
+        dereference();
+        return this->m->obj->getJSON();
+    }
+}
+
 QPDFObjectHandle
 QPDFObjectHandle::wrapInArray()
 {

libqpdf/QPDF_Array.cc

@@ -35,6 +35,18 @@ QPDF_Array::unparse()
     return result;
 }
 
+JSON
+QPDF_Array::getJSON()
+{
+    JSON j = JSON::makeArray();
+    for (std::vector<QPDFObjectHandle>::iterator iter = this->items.begin();
+	 iter != this->items.end(); ++iter)
+    {
+        j.addArrayElement((*iter).getJSON());
+    }
+    return j;
+}
+
 QPDFObject::object_type_e
 QPDF_Array::getTypeCode() const
 {

libqpdf/QPDF_Bool.cc

@@ -15,6 +15,12 @@ QPDF_Bool::unparse()
     return (val ? "true" : "false");
 }
 
+JSON
+QPDF_Bool::getJSON()
+{
+    return JSON::makeBool(this->val);
+}
+
 QPDFObject::object_type_e
 QPDF_Bool::getTypeCode() const
 {

libqpdf/QPDF_Dictionary.cc

@@ -39,6 +39,20 @@ QPDF_Dictionary::unparse()
     return result;
 }
 
+JSON
+QPDF_Dictionary::getJSON()
+{
+    JSON j = JSON::makeDictionary();
+    for (std::map<std::string, QPDFObjectHandle>::iterator iter =
+	     this->items.begin();
+	 iter != this->items.end(); ++iter)
+    {
+        j.addDictionaryMember(QPDF_Name::normalizeName((*iter).first),
+                              (*iter).second.getJSON());
+    }
+    return j;
+}
+
 QPDFObject::object_type_e
 QPDF_Dictionary::getTypeCode() const
 {

libqpdf/QPDF_InlineImage.cc

@@ -17,6 +17,12 @@ QPDF_InlineImage::unparse()
     return this->val;
 }
 
+JSON
+QPDF_InlineImage::getJSON()
+{
+    return JSON::makeNull();
+}
+
 QPDFObject::object_type_e
 QPDF_InlineImage::getTypeCode() const
 {

libqpdf/QPDF_Integer.cc

@@ -17,6 +17,12 @@ QPDF_Integer::unparse()
     return QUtil::int_to_string(this->val);
 }
 
+JSON
+QPDF_Integer::getJSON()
+{
+    return JSON::makeInt(this->val);
+}
+
 QPDFObject::object_type_e
 QPDF_Integer::getTypeCode() const
 {

libqpdf/QPDF_Name.cc

@@ -44,6 +44,12 @@ QPDF_Name::unparse()
     return normalizeName(this->name);
 }
 
+JSON
+QPDF_Name::getJSON()
+{
+    return JSON::makeString(normalizeName(this->name));
+}
+
 QPDFObject::object_type_e
 QPDF_Name::getTypeCode() const
 {

libqpdf/QPDF_Null.cc

@@ -10,6 +10,12 @@ QPDF_Null::unparse()
     return "null";
 }
 
+JSON
+QPDF_Null::getJSON()
+{
+    return JSON::makeNull();
+}
+
 QPDFObject::object_type_e
 QPDF_Null::getTypeCode() const
 {

libqpdf/QPDF_Operator.cc

@@ -17,6 +17,12 @@ QPDF_Operator::unparse()
     return this->val;
 }
 
+JSON
+QPDF_Operator::getJSON()
+{
+    return JSON::makeNull();
+}
+
 QPDFObject::object_type_e
 QPDF_Operator::getTypeCode() const
 {

libqpdf/QPDF_Real.cc

@@ -22,6 +22,12 @@ QPDF_Real::unparse()
     return this->val;
 }
 
+JSON
+QPDF_Real::getJSON()
+{
+    return JSON::makeNumber(this->val);
+}
+
 QPDFObject::object_type_e
 QPDF_Real::getTypeCode() const
 {

libqpdf/QPDF_Reserved.cc

@@ -12,6 +12,13 @@ QPDF_Reserved::unparse()
     return "";
 }
 
+JSON
+QPDF_Reserved::getJSON()
+{
+    throw std::logic_error("attempt to generate JSON from QPDF_Reserved");
+    return JSON::makeNull();
+}
+
 QPDFObject::object_type_e
 QPDF_Reserved::getTypeCode() const
 {

libqpdf/QPDF_Stream.cc

@@ -74,6 +74,12 @@ QPDF_Stream::unparse()
 	QUtil::int_to_string(this->generation) + " R";
 }
 
+JSON
+QPDF_Stream::getJSON()
+{
+    return this->stream_dict.getJSON();
+}
+
 QPDFObject::object_type_e
 QPDF_Stream::getTypeCode() const
 {

libqpdf/QPDF_String.cc

@@ -122,6 +122,12 @@ QPDF_String::unparse()
     return unparse(false);
 }
 
+JSON
+QPDF_String::getJSON()
+{
+    return JSON::makeString(getUTF8Val());
+}
+
 QPDFObject::object_type_e
 QPDF_String::getTypeCode() const
 {

libqpdf/qpdf/QPDF_Array.hh

@@ -12,6 +12,7 @@ class QPDF_Array: public QPDFObject
     QPDF_Array(std::vector<QPDFObjectHandle> const& items);
     virtual ~QPDF_Array();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     virtual void setDescription(QPDF*, std::string const&);

libqpdf/qpdf/QPDF_Bool.hh

@@ -9,6 +9,7 @@ class QPDF_Bool: public QPDFObject
     QPDF_Bool(bool val);
     virtual ~QPDF_Bool();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     bool getVal() const;

libqpdf/qpdf/QPDF_Dictionary.hh

@@ -14,6 +14,7 @@ class QPDF_Dictionary: public QPDFObject
     QPDF_Dictionary(std::map<std::string, QPDFObjectHandle> const& items);
     virtual ~QPDF_Dictionary();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     virtual void setDescription(QPDF*, std::string const&);

libqpdf/qpdf/QPDF_InlineImage.hh

@@ -9,6 +9,7 @@ class QPDF_InlineImage: public QPDFObject
     QPDF_InlineImage(std::string const& val);
     virtual ~QPDF_InlineImage();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     std::string getVal() const;

libqpdf/qpdf/QPDF_Integer.hh

@@ -9,6 +9,7 @@ class QPDF_Integer: public QPDFObject
     QPDF_Integer(long long val);
     virtual ~QPDF_Integer();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     long long getVal() const;

libqpdf/qpdf/QPDF_Name.hh

@@ -9,6 +9,7 @@ class QPDF_Name: public QPDFObject
     QPDF_Name(std::string const& name);
     virtual ~QPDF_Name();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     std::string getName() const;

libqpdf/qpdf/QPDF_Null.hh

@@ -8,6 +8,7 @@ class QPDF_Null: public QPDFObject
   public:
     virtual ~QPDF_Null();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
 };

libqpdf/qpdf/QPDF_Operator.hh

@@ -9,6 +9,7 @@ class QPDF_Operator: public QPDFObject
     QPDF_Operator(std::string const& val);
     virtual ~QPDF_Operator();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     std::string getVal() const;

libqpdf/qpdf/QPDF_Real.hh

@@ -10,6 +10,7 @@ class QPDF_Real: public QPDFObject
     QPDF_Real(double value, int decimal_places = 0);
     virtual ~QPDF_Real();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     std::string getVal();

libqpdf/qpdf/QPDF_Reserved.hh

@@ -8,6 +8,7 @@ class QPDF_Reserved: public QPDFObject
   public:
     virtual ~QPDF_Reserved();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
 };

libqpdf/qpdf/QPDF_Stream.hh

@@ -17,6 +17,7 @@ class QPDF_Stream: public QPDFObject
 		qpdf_offset_t offset, size_t length);
     virtual ~QPDF_Stream();
     virtual std::string unparse();
+    virtual JSON getJSON();
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     virtual void setDescription(QPDF*, std::string const&);

libqpdf/qpdf/QPDF_String.hh

@@ -15,6 +15,7 @@ class QPDF_String: public QPDFObject
     virtual QPDFObject::object_type_e getTypeCode() const;
     virtual char const* getTypeName() const;
     std::string unparse(bool force_binary);
+    virtual JSON getJSON();
     std::string getVal() const;
     std::string getUTF8Val() const;