Introduce private-API `qpdf::String` class and refactor string handling

Added `qpdf::String` class to encapsulate string operations. Updated `QPDFObjectHandle` string methods to utilize `qpdf::String`, streamlined empty string handling, and removed redundant test coverage entries.

Introduce private-API `qpdf::String` class and refactor string handling
Added `qpdf::String` class to encapsulate string operations. Updated `QPDFObjectHandle` string methods to utilize `qpdf::String`, streamlined empty string handling, and removed redundant test coverage entries.
m-holger
1 parent 906034d9
Showing 4 changed files with 118 additions and 37 deletions
libqpdf/QPDFObjectHandle.cc
libqpdf/qpdf/QPDFObjectHandle_private.hh
libqpdf/qpdf/QPDFObject_private.hh
qpdf/qpdf.testcov
@@ -999,50 +999,92 @@ QPDFObjectHandle::getValueAsName(std::string&amp; value) const
     return true;
 }
-// String accessors
+// String methods
+
+QPDFObjectHandle
+QPDFObjectHandle::newString(std::string const& str)
+{
+    return {QPDFObject::create<QPDF_String>(str)};
+}
+
+QPDFObjectHandle
+QPDFObjectHandle::newUnicodeString(std::string const& utf8_str)
+{
+    return {QPDF_String::create_utf16(utf8_str)};
+}
+
+String::String(std::string const& str) :
+    BaseHandle(QPDFObject::create<QPDF_String>(str))
+{
+}
+
+String::String(std::string&& str) :
+    BaseHandle(QPDFObject::create<QPDF_String>(std::move(str)))
+{
+}
+
+std::string const&
+String::value() const
+{
+    auto* s = as<QPDF_String>();
+    if (!s) {
+        throw invalid_error("String");
+    }
+    return s->val;
+}
+
+std::string
+String::utf8_value() const
+{
+    auto* s = as<QPDF_String>();
+    if (!s) {
+        throw invalid_error("String");
+    }
+    return s->getUTF8Val();
+}
 std::string
 QPDFObjectHandle::getStringValue() const
 {
-    if (isString()) {
-        return obj->getStringValue();
-    } else {
+    try {
+        return String(obj).value();
+    } catch (std::invalid_argument&) {
         typeWarning("string", "returning empty string");
-        QTC::TC("qpdf", "QPDFObjectHandle string returning empty string");
-        return "";
+        return {};
     }
 }
 bool
 QPDFObjectHandle::getValueAsString(std::string& value) const
 {
-    if (!isString()) {
+    try {
+        value = String(obj).value();
+        return true;
+    } catch (std::invalid_argument&) {
         return false;
     }
-    value = obj->getStringValue();
-    return true;
 }
 std::string
 QPDFObjectHandle::getUTF8Value() const
 {
-    if (auto str = as<QPDF_String>()) {
-        return str->getUTF8Val();
-    } else {
+    try {
+        return String(obj).utf8_value();
+    } catch (std::invalid_argument&) {
         typeWarning("string", "returning empty string");
-        QTC::TC("qpdf", "QPDFObjectHandle string returning empty utf8");
-        return "";
+        return {};
     }
 }
 bool
 QPDFObjectHandle::getValueAsUTF8(std::string& value) const
 {
-    if (auto str = as<QPDF_String>()) {
-        value = str->getUTF8Val();
+    try {
+        value = String(obj).utf8_value();
         return true;
+    } catch (std::invalid_argument&) {
+        return false;
     }
-    return false;
 }
 // Operator and Inline Image accessors
@@ -1718,18 +1760,6 @@ QPDFObjectHandle::newReal(double value, int decimal_places, bool trim_trailing_z
 }
 QPDFObjectHandle
-QPDFObjectHandle::newString(std::string const& str)
-{
-    return {QPDFObject::create<QPDF_String>(str)};
-}
-
-QPDFObjectHandle
-QPDFObjectHandle::newUnicodeString(std::string const& utf8_str)
-{
-    return {QPDF_String::create_utf16(utf8_str)};
-}
-
-QPDFObjectHandle
 QPDFObjectHandle::newOperator(std::string const& value)
 {
     return {QPDFObject::create<QPDF_Operator>(value)};
@@ -412,15 +412,15 @@ namespace qpdf
         {
         }
-        // Return the name value. If the object is not a valid Name, throw a
-        // std::invalid_argument exception.
+        // Return the name value. If the object is not a valid Name, throw a std::invalid_argument
+        // exception.
         operator std::string() const&
         {
             return value();
         }
-        // Return the integer value. If the object is not a valid integer, throw a
-        // std::invalid_argument exception.
+        // Return the name value. If the object is not a valid name, throw a std::invalid_argument
+        // exception.
         std::string const& value() const;
         // Return true if object value is equal to the 'rhs' value. Return false if the object is
@@ -589,7 +589,54 @@ namespace qpdf
         void warn(std::string const& message);
         static std::map<std::string, std::string> filter_abbreviations;
-    };
+    }; // class Stream
+
+    class String final: public BaseHandle
+    {
+      public:
+        String() = default;
+        String(String const&) = default;
+        String(String&&) = default;
+        String& operator=(String const&) = default;
+        String& operator=(String&&) = default;
+        ~String() = default;
+
+        explicit String(std::string const&);
+        explicit String(std::string&&);
+
+        String(QPDFObjectHandle const& oh) :
+            BaseHandle(oh.type_code() == ::ot_string ? oh : QPDFObjectHandle())
+        {
+        }
+
+        String(QPDFObjectHandle&& oh) :
+            BaseHandle(oh.type_code() == ::ot_string ? std::move(oh) : QPDFObjectHandle())
+        {
+        }
+
+        // Return the string value. If the object is not a valid string, throw a
+        // std::invalid_argument exception.
+        operator std::string() const&
+        {
+            return value();
+        }
+
+        // Return the string value. If the object is not a valid string, throw a
+        // std::invalid_argument exception.
+        std::string const& value() const;
+
+        // Return the string value. If the object is not a valid string, throw a
+        // std::invalid_argument exception.
+        std::string utf8_value() const;
+
+        // Return true if object value is equal to the 'rhs' value. Return false if the object is
+        // not a valid String.
+        friend bool
+        operator==(String const& lhs, std::string_view rhs)
+        {
+            return lhs && lhs.value() == rhs;
+        }
+    }; // class String
     template <typename T>
     T*
@@ -30,6 +30,7 @@ namespace qpdf
     class Integer;
     class Name;
     class Stream;
+    class String;
     namespace impl
     {
@@ -261,6 +262,7 @@ class QPDF_String final
 {
     friend class QPDFObject;
     friend class qpdf::BaseHandle;
+    friend class qpdf::String;
     friend class qpdf::impl::Writer;
   public:
@@ -270,7 +272,11 @@ class QPDF_String final
     std::string getUTF8Val() const;
   private:
-    QPDF_String(std::string val) :
+    QPDF_String(std::string const& val) :
+        val(val)
+    {
+    }
+    QPDF_String(std::string&& val) :
         val(std::move(val))
     {
     }
@@ -174,8 +174,6 @@ QPDFParser eof in parse 0
 QPDFParser eof in parseRemainder 0
 QPDFObjectHandle boolean returning false 0
 QPDFObjectHandle real returning 0.0 0
-QPDFObjectHandle string returning empty string 0
-QPDFObjectHandle string returning empty utf8 0
 QPDFObjectHandle operator returning fake value 0
 QPDFObjectHandle inlineimage returning empty data 0
 QPDFObjectHandle array treating as empty vector 0