AK: Convert AK::Format formatting helpers to returning ErrorOr<void>

This isn't a complete conversion to ErrorOr<void>, but a good chunk.
The end goal here is to propagate buffer allocation failures to the
caller, and allow the use of TRY() with formatting functions.

AK/Format.h

@@ -11,6 +11,8 @@
 #include <AK/AllOf.h>
 #include <AK/AnyOf.h>
 #include <AK/Array.h>
+#include <AK/Error.h>
+#include <AK/Forward.h>
 #include <AK/Optional.h>
 #include <AK/StringView.h>
 
@@ -125,7 +127,7 @@ struct TypeErasedParameter {
 
     const void* value;
     Type type;
-    void (*formatter)(TypeErasedFormatParams&, FormatBuilder&, FormatParser&, const void* value);
+    ErrorOr<void> (*formatter)(TypeErasedFormatParams&, FormatBuilder&, FormatParser&, void const* value);
 };
 
 class FormatBuilder {
@@ -148,18 +150,18 @@ public:
     {
     }
 
-    void put_padding(char fill, size_t amount);
+    ErrorOr<void> put_padding(char fill, size_t amount);
 
-    void put_literal(StringView value);
+    ErrorOr<void> put_literal(StringView value);
 
-    void put_string(
+    ErrorOr<void> put_string(
         StringView value,
         Align align = Align::Left,
         size_t min_width = 0,
         size_t max_width = NumericLimits<size_t>::max(),
         char fill = ' ');
 
-    void put_u64(
+    ErrorOr<void> put_u64(
         u64 value,
         u8 base = 10,
         bool prefix = false,
@@ -171,7 +173,7 @@ public:
         SignMode sign_mode = SignMode::OnlyIfNeeded,
         bool is_negative = false);
 
-    void put_i64(
+    ErrorOr<void> put_i64(
         i64 value,
         u8 base = 10,
         bool prefix = false,
@@ -183,7 +185,7 @@ public:
         SignMode sign_mode = SignMode::OnlyIfNeeded);
 
 #ifndef KERNEL
-    void put_f80(
+    ErrorOr<void> put_f80(
         long double value,
         u8 base = 10,
         bool upper_case = false,
@@ -193,7 +195,7 @@ public:
         char fill = ' ',
         SignMode sign_mode = SignMode::OnlyIfNeeded);
 
-    void put_f64(
+    ErrorOr<void> put_f64(
         double value,
         u8 base = 10,
         bool upper_case = false,
@@ -205,7 +207,7 @@ public:
         SignMode sign_mode = SignMode::OnlyIfNeeded);
 #endif
 
-    void put_hexdump(
+    ErrorOr<void> put_hexdump(
         ReadonlyBytes,
         size_t width,
         char fill = ' ');
@@ -233,12 +235,12 @@ private:
 };
 
 template<typename T>
-void __format_value(TypeErasedFormatParams& params, FormatBuilder& builder, FormatParser& parser, const void* value)
+ErrorOr<void> __format_value(TypeErasedFormatParams& params, FormatBuilder& builder, FormatParser& parser, const void* value)
 {
     Formatter<T> formatter;
 
     formatter.parse(params, parser);
-    formatter.format(builder, *static_cast<const T*>(value));
+    return formatter.format(builder, *static_cast<const T*>(value));
 }
 
 template<typename... Parameters>
@@ -298,7 +300,7 @@ struct Formatter<T, typename EnableIf<IsIntegral<T>>::Type> : StandardFormatter
     {
     }
 
-    void format(FormatBuilder&, T value);
+    ErrorOr<void> format(FormatBuilder&, T);
 };
 
 template<>
@@ -309,7 +311,7 @@ struct Formatter<StringView> : StandardFormatter {
     {
     }
 
-    void format(FormatBuilder&, StringView value);
+    ErrorOr<void> format(FormatBuilder&, StringView);
 };
 
 template<typename T>
@@ -320,12 +322,12 @@ requires(HasFormatter<T>) struct Formatter<Vector<T>> : StandardFormatter {
         : StandardFormatter(move(formatter))
     {
     }
-    void format(FormatBuilder& builder, Vector<T> value)
+    ErrorOr<void> format(FormatBuilder& builder, Vector<T> value)
     {
         if (m_mode == Mode::Pointer) {
             Formatter<FlatPtr> formatter { *this };
-            formatter.format(builder, reinterpret_cast<FlatPtr>(value.data()));
-            return;
+            TRY(formatter.format(builder, reinterpret_cast<FlatPtr>(value.data())));
+            return {};
         }
 
         if (m_sign_mode != FormatBuilder::SignMode::Default)
@@ -343,33 +345,34 @@ requires(HasFormatter<T>) struct Formatter<Vector<T>> : StandardFormatter {
         m_precision = m_precision.value_or(NumericLimits<size_t>::max());
 
         Formatter<T> content_fmt;
-        builder.put_literal("[ "sv);
+        TRY(builder.put_literal("[ "sv));
         bool first = true;
         for (auto& content : value) {
             if (!first) {
-                builder.put_literal(", "sv);
+                TRY(builder.put_literal(", "sv));
                 content_fmt = Formatter<T> {};
             }
             first = false;
-            content_fmt.format(builder, content);
+            TRY(content_fmt.format(builder, content));
         }
-        builder.put_literal(" ]"sv);
+        TRY(builder.put_literal(" ]"sv));
+        return {};
     }
 };
 
 template<>
 struct Formatter<ReadonlyBytes> : Formatter<StringView> {
-    void format(FormatBuilder& builder, ReadonlyBytes value)
+    ErrorOr<void> format(FormatBuilder& builder, ReadonlyBytes value)
     {
         if (m_mode == Mode::Pointer) {
             Formatter<FlatPtr> formatter { *this };
-            formatter.format(builder, reinterpret_cast<FlatPtr>(value.data()));
-        } else if (m_mode == Mode::Default || m_mode == Mode::HexDump) {
-            m_mode = Mode::HexDump;
-            Formatter<StringView>::format(builder, value);
-        } else {
-            Formatter<StringView>::format(builder, value);
+            return formatter.format(builder, reinterpret_cast<FlatPtr>(value.data()));
         }
+        if (m_mode == Mode::Default || m_mode == Mode::HexDump) {
+            m_mode = Mode::HexDump;
+            return Formatter<StringView>::format(builder, value);
+        }
+        return Formatter<StringView>::format(builder, value);
     }
 };
 
@@ -379,14 +382,13 @@ struct Formatter<Bytes> : Formatter<ReadonlyBytes> {
 
 template<>
 struct Formatter<const char*> : Formatter<StringView> {
-    void format(FormatBuilder& builder, const char* value)
+    ErrorOr<void> format(FormatBuilder& builder, const char* value)
     {
         if (m_mode == Mode::Pointer) {
             Formatter<FlatPtr> formatter { *this };
-            formatter.format(builder, reinterpret_cast<FlatPtr>(value));
-        } else {
-            Formatter<StringView>::format(builder, value);
+            return formatter.format(builder, reinterpret_cast<FlatPtr>(value));
         }
+        return Formatter<StringView>::format(builder, value);
     }
 };
 template<>
@@ -397,14 +399,13 @@ struct Formatter<char[Size]> : Formatter<const char*> {
 };
 template<size_t Size>
 struct Formatter<unsigned char[Size]> : Formatter<StringView> {
-    void format(FormatBuilder& builder, const unsigned char* value)
+    ErrorOr<void> format(FormatBuilder& builder, const unsigned char* value)
     {
         if (m_mode == Mode::Pointer) {
             Formatter<FlatPtr> formatter { *this };
-            formatter.format(builder, reinterpret_cast<FlatPtr>(value));
-        } else {
-            Formatter<StringView>::format(builder, { value, Size });
+            return formatter.format(builder, reinterpret_cast<FlatPtr>(value));
         }
+        Formatter<StringView>::format(builder, { value, Size });
     }
 };
 template<>
@@ -416,33 +417,33 @@ struct Formatter<FlyString> : Formatter<StringView> {
 
 template<typename T>
 struct Formatter<T*> : StandardFormatter {
-    void format(FormatBuilder& builder, T* value)
+    ErrorOr<void> format(FormatBuilder& builder, T* value)
     {
         if (m_mode == Mode::Default)
             m_mode = Mode::Pointer;
 
         Formatter<FlatPtr> formatter { *this };
-        formatter.format(builder, reinterpret_cast<FlatPtr>(value));
+        return formatter.format(builder, reinterpret_cast<FlatPtr>(value));
     }
 };
 
 template<>
 struct Formatter<char> : StandardFormatter {
-    void format(FormatBuilder&, char value);
+    ErrorOr<void> format(FormatBuilder&, char);
 };
 template<>
 struct Formatter<wchar_t> : StandardFormatter {
-    void format(FormatBuilder& builder, wchar_t value);
+    ErrorOr<void> format(FormatBuilder& builder, wchar_t);
 };
 template<>
 struct Formatter<bool> : StandardFormatter {
-    void format(FormatBuilder&, bool value);
+    ErrorOr<void> format(FormatBuilder&, bool);
 };
 
 #ifndef KERNEL
 template<>
 struct Formatter<float> : StandardFormatter {
-    void format(FormatBuilder&, float value);
+    ErrorOr<void> format(FormatBuilder&, float value);
 };
 template<>
 struct Formatter<double> : StandardFormatter {
@@ -452,7 +453,7 @@ struct Formatter<double> : StandardFormatter {
     {
     }
 
-    void format(FormatBuilder&, double value);
+    ErrorOr<void> format(FormatBuilder&, double);
 };
 
 template<>
@@ -463,13 +464,13 @@ struct Formatter<long double> : StandardFormatter {
     {
     }
 
-    void format(FormatBuilder&, long double value);
+    ErrorOr<void> format(FormatBuilder&, long double value);
 };
 #endif
 
 template<>
 struct Formatter<std::nullptr_t> : Formatter<FlatPtr> {
-    void format(FormatBuilder& builder, std::nullptr_t)
+    ErrorOr<void> format(FormatBuilder& builder, std::nullptr_t)
     {
         if (m_mode == Mode::Default)
             m_mode = Mode::Pointer;
@@ -478,7 +479,7 @@ struct Formatter<std::nullptr_t> : Formatter<FlatPtr> {
     }
 };
 
-void vformat(StringBuilder&, StringView fmtstr, TypeErasedFormatParams&);
+ErrorOr<void> vformat(StringBuilder&, StringView fmtstr, TypeErasedFormatParams&);
 
 #ifndef KERNEL
 void vout(FILE*, StringView fmtstr, TypeErasedFormatParams&, bool newline = false);
@@ -582,16 +583,16 @@ private:
 };
 template<typename T, bool Supported = false>
 struct __FormatIfSupported : Formatter<StringView> {
-    void format(FormatBuilder& builder, const FormatIfSupported<T>&)
+    ErrorOr<void> format(FormatBuilder& builder, FormatIfSupported<T> const&)
     {
-        Formatter<StringView>::format(builder, "?");
+        return Formatter<StringView>::format(builder, "?");
     }
 };
 template<typename T>
 struct __FormatIfSupported<T, true> : Formatter<T> {
-    void format(FormatBuilder& builder, const FormatIfSupported<T>& value)
+    ErrorOr<void> format(FormatBuilder& builder, FormatIfSupported<T> const& value)
     {
-        Formatter<T>::format(builder, value.value());
+        return Formatter<T>::format(builder, value.value());
     }
 };
 template<typename T>
@@ -605,12 +606,22 @@ struct FormatString {
 template<>
 struct Formatter<FormatString> : Formatter<StringView> {
     template<typename... Parameters>
-    void format(FormatBuilder& builder, StringView fmtstr, const Parameters&... parameters)
+    ErrorOr<void> format(FormatBuilder& builder, StringView fmtstr, const Parameters&... parameters)
     {
         VariadicFormatParams variadic_format_params { parameters... };
-        vformat(builder, fmtstr, variadic_format_params);
+        return vformat(builder, fmtstr, variadic_format_params);
+    }
+    ErrorOr<void> vformat(FormatBuilder& builder, StringView fmtstr, TypeErasedFormatParams& params);
+};
+
+template<>
+struct Formatter<Error> : Formatter<FormatString> {
+    ErrorOr<void> format(FormatBuilder& builder, Error const& error)
+    {
+        if (error.is_errno())
+            return Formatter<FormatString>::format(builder, "Error(errno={})", error.code());
+        return Formatter<FormatString>::format(builder, "Error({})", error.string_literal());
     }
-    void vformat(FormatBuilder& builder, StringView fmtstr, TypeErasedFormatParams& params);
 };
 
 } // namespace AK