From d654fe0e41071bd769b920c08b30f302951eb638 Mon Sep 17 00:00:00 2001
From: Matthew Olsson <matthewcolsson@gmail.com>
Date: Mon, 24 May 2021 13:41:40 -0700
Subject: LibPDF: Differentiate Value's null and empty states

---
 Userland/Libraries/LibPDF/Parser.cpp |  2 +-
 Userland/Libraries/LibPDF/Value.cpp  |  3 +++
 Userland/Libraries/LibPDF/Value.h    | 12 +++++++++++-
 3 files changed, 15 insertions(+), 2 deletions(-)

(limited to 'Userland/Libraries/LibPDF')

diff --git a/Userland/Libraries/LibPDF/Parser.cpp b/Userland/Libraries/LibPDF/Parser.cpp
index 8ec0adabae..7ec53eb15c 100644
--- a/Userland/Libraries/LibPDF/Parser.cpp
+++ b/Userland/Libraries/LibPDF/Parser.cpp
@@ -268,7 +268,7 @@ Value Parser::parse_value()
     if (m_reader.matches("null")) {
         m_reader.move_by(4);
         consume_whitespace();
-        return Value();
+        return Value(Value::NullTag {});
     }
 
     if (m_reader.matches("true")) {
diff --git a/Userland/Libraries/LibPDF/Value.cpp b/Userland/Libraries/LibPDF/Value.cpp
index a254d78ea0..0248356fa6 100644
--- a/Userland/Libraries/LibPDF/Value.cpp
+++ b/Userland/Libraries/LibPDF/Value.cpp
@@ -19,6 +19,7 @@ Value& Value::operator=(const Value& other)
 {
     m_type = other.m_type;
     switch (m_type) {
+    case Type::Empty:
     case Type::Null:
         break;
     case Type::Bool:
@@ -45,6 +46,8 @@ Value& Value::operator=(const Value& other)
 String Value::to_string(int indent) const
 {
     switch (m_type) {
+    case Type::Empty:
+        return "<empty>";
     case Type::Null:
         return "null";
     case Type::Bool:
diff --git a/Userland/Libraries/LibPDF/Value.h b/Userland/Libraries/LibPDF/Value.h
index cb75a92662..f6b3b61899 100644
--- a/Userland/Libraries/LibPDF/Value.h
+++ b/Userland/Libraries/LibPDF/Value.h
@@ -23,6 +23,14 @@ public:
     static constexpr auto max_ref_generation_index = (1 << 15) - 1; // 2 ^ 14 - 1
 
     Value()
+        : m_type(Type::Empty)
+    {
+    }
+
+    struct NullTag {
+    };
+
+    Value(NullTag)
         : m_type(Type::Null)
     {
     }
@@ -70,6 +78,7 @@ public:
 
     Value& operator=(const Value& other);
 
+    [[nodiscard]] ALWAYS_INLINE bool is_empty() const { return m_type == Type::Empty; }
     [[nodiscard]] ALWAYS_INLINE bool is_null() const { return m_type == Type::Null; }
     [[nodiscard]] ALWAYS_INLINE bool is_bool() const { return m_type == Type::Bool; }
     [[nodiscard]] ALWAYS_INLINE bool is_int() const { return m_type == Type::Int; }
@@ -124,12 +133,13 @@ public:
 
     [[nodiscard]] ALWAYS_INLINE NonnullRefPtr<Object> as_object() const { return *m_as_object; }
 
-    [[nodiscard]] ALWAYS_INLINE explicit operator bool() const { return !is_null(); }
+    [[nodiscard]] ALWAYS_INLINE explicit operator bool() const { return !is_empty(); }
 
     [[nodiscard]] String to_string(int indent = 0) const;
 
 private:
     enum class Type {
+        Empty,
         Null,
         Bool,
         Int,
-- 
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