AK: Add JsonObject::get...() methods that return Optional

`get()` is intended as a replacement for `get_deprecated()` and `get_ptr
()`. The former returns the same value for "key not found" and "key
found and contains `null`" which is ambiguous. The latter returns a raw
pointer which is spooky. Returning `Optional<JsonValue const&>` covers
all the previous uses for these.

The `get_foo()` methods are helpers to make user code less verbose. Most
of the time, we only want a specific type of value: if we want a number
and get a string, we respond the same as if the value was not there at
all. These make that easier to express.

This also adjusts the `has_i32()` method and friends to examine the
value instead of just looking at the underlying type.

2 files changed, 189 insertions, 22 deletions

diff --git a/AK/JsonObject.cpp b/AK/JsonObject.cpp
index e55c2eea0d..51fe34a7ea 100644
--- a/AK/JsonObject.cpp
+++ b/AK/JsonObject.cpp
@@ -67,6 +67,111 @@ JsonValue const* JsonObject::get_ptr(StringView key) const
     return &(*it).value;
 }
 
+Optional<JsonValue const&> JsonObject::get(StringView key) const
+{
+    auto it = m_members.find(key);
+    if (it == m_members.end())
+        return {};
+    return it->value;
+}
+
+Optional<i8> JsonObject::get_i8(StringView key) const
+{
+    return get_integer<i8>(key);
+}
+
+Optional<u8> JsonObject::get_u8(StringView key) const
+{
+    return get_integer<u8>(key);
+}
+
+Optional<i16> JsonObject::get_i16(StringView key) const
+{
+    return get_integer<i16>(key);
+}
+
+Optional<u16> JsonObject::get_u16(StringView key) const
+{
+    return get_integer<u16>(key);
+}
+
+Optional<i32> JsonObject::get_i32(StringView key) const
+{
+    return get_integer<i32>(key);
+}
+
+Optional<u32> JsonObject::get_u32(StringView key) const
+{
+    return get_integer<u32>(key);
+}
+
+Optional<i64> JsonObject::get_i64(StringView key) const
+{
+    return get_integer<i64>(key);
+}
+
+Optional<u64> JsonObject::get_u64(StringView key) const
+{
+    return get_integer<u64>(key);
+}
+
+Optional<FlatPtr> JsonObject::get_addr(StringView key) const
+{
+    return get_integer<FlatPtr>(key);
+}
+
+Optional<bool> JsonObject::get_bool(StringView key) const
+{
+    auto maybe_value = get(key);
+    if (maybe_value.has_value() && maybe_value->is_bool())
+        return maybe_value->as_bool();
+    return {};
+}
+
+#if !defined(KERNEL)
+Optional<DeprecatedString> JsonObject::get_deprecated_string(StringView key) const
+{
+    auto maybe_value = get(key);
+    if (maybe_value.has_value() && maybe_value->is_string())
+        return maybe_value->as_string();
+    return {};
+}
+#endif
+
+Optional<JsonObject const&> JsonObject::get_object(StringView key) const
+{
+    auto maybe_value = get(key);
+    if (maybe_value.has_value() && maybe_value->is_object())
+        return maybe_value->as_object();
+    return {};
+}
+
+Optional<JsonArray const&> JsonObject::get_array(StringView key) const
+{
+    auto maybe_value = get(key);
+    if (maybe_value.has_value() && maybe_value->is_array())
+        return maybe_value->as_array();
+    return {};
+}
+
+#if !defined(KERNEL)
+Optional<double> JsonObject::get_double(StringView key) const
+{
+    auto maybe_value = get(key);
+    if (maybe_value.has_value() && maybe_value->is_double())
+        return maybe_value->as_double();
+    return {};
+}
+
+Optional<float> JsonObject::get_float(StringView key) const
+{
+    auto maybe_value = get(key);
+    if (maybe_value.has_value() && maybe_value->is_double())
+        return static_cast<float>(maybe_value->as_double());
+    return {};
+}
+#endif
+
 bool JsonObject::has(StringView key) const
 {
     return m_members.contains(key);
@@ -74,69 +179,93 @@ bool JsonObject::has(StringView key) const
 
 bool JsonObject::has_null(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_null();
+    auto value = get(key);
+    return value.has_value() && value->is_null();
 }
 
 bool JsonObject::has_bool(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_bool();
+    auto value = get(key);
+    return value.has_value() && value->is_bool();
 }
 
 bool JsonObject::has_string(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_string();
+    auto value = get(key);
+    return value.has_value() && value->is_string();
+}
+
+bool JsonObject::has_i8(StringView key) const
+{
+    auto value = get(key);
+    return value.has_value() && value->is_integer<i8>();
+}
+
+bool JsonObject::has_u8(StringView key) const
+{
+    auto value = get(key);
+    return value.has_value() && value->is_integer<u8>();
+}
+
+bool JsonObject::has_i16(StringView key) const
+{
+    auto value = get(key);
+    return value.has_value() && value->is_integer<i16>();
+}
+
+bool JsonObject::has_u16(StringView key) const
+{
+    auto value = get(key);
+    return value.has_value() && value->is_integer<u16>();
 }
 
 bool JsonObject::has_i32(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_i32();
+    auto value = get(key);
+    return value.has_value() && value->is_integer<i32>();
 }
 
 bool JsonObject::has_u32(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_u32();
+    auto value = get(key);
+    return value.has_value() && value->is_integer<u32>();
 }
 
 bool JsonObject::has_i64(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_i64();
+    auto value = get(key);
+    return value.has_value() && value->is_integer<i64>();
 }
 
 bool JsonObject::has_u64(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_u64();
+    auto value = get(key);
+    return value.has_value() && value->is_integer<u64>();
 }
 
 bool JsonObject::has_number(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_number();
+    auto value = get(key);
+    return value.has_value() && value->is_number();
 }
 
 bool JsonObject::has_array(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_array();
+    auto value = get(key);
+    return value.has_value() && value->is_array();
 }
 
 bool JsonObject::has_object(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_object();
+    auto value = get(key);
+    return value.has_value() && value->is_object();
 }
 
 #ifndef KERNEL
 bool JsonObject::has_double(StringView key) const
 {
-    auto const* value = get_ptr(key);
-    return value && value->is_double();
+    auto value = get(key);
+    return value.has_value() && value->is_double();
 }
 #endif
 
diff --git a/AK/JsonObject.h b/AK/JsonObject.h
index 7622a7b783..5e1e8e9376 100644
--- a/AK/JsonObject.h
+++ b/AK/JsonObject.h
@@ -44,6 +44,10 @@ public:
     [[nodiscard]] bool has_null(StringView key) const;
     [[nodiscard]] bool has_bool(StringView key) const;
     [[nodiscard]] bool has_string(StringView key) const;
+    [[nodiscard]] bool has_i8(StringView key) const;
+    [[nodiscard]] bool has_u8(StringView key) const;
+    [[nodiscard]] bool has_i16(StringView key) const;
+    [[nodiscard]] bool has_u16(StringView key) const;
     [[nodiscard]] bool has_i32(StringView key) const;
     [[nodiscard]] bool has_u32(StringView key) const;
     [[nodiscard]] bool has_i64(StringView key) const;
@@ -55,6 +59,40 @@ public:
     [[nodiscard]] bool has_double(StringView key) const;
 #endif
 
+    Optional<JsonValue const&> get(StringView key) const;
+
+    template<Integral T>
+    Optional<T> get_integer(StringView key) const
+    {
+        auto maybe_value = get(key);
+        if (maybe_value.has_value() && maybe_value->is_integer<T>())
+            return maybe_value->as_integer<T>();
+        return {};
+    }
+
+    Optional<i8> get_i8(StringView key) const;
+    Optional<u8> get_u8(StringView key) const;
+    Optional<i16> get_i16(StringView key) const;
+    Optional<u16> get_u16(StringView key) const;
+    Optional<i32> get_i32(StringView key) const;
+    Optional<u32> get_u32(StringView key) const;
+    Optional<i64> get_i64(StringView key) const;
+    Optional<u64> get_u64(StringView key) const;
+    Optional<FlatPtr> get_addr(StringView key) const;
+    Optional<bool> get_bool(StringView key) const;
+
+#if !defined(KERNEL)
+    Optional<DeprecatedString> get_deprecated_string(StringView key) const;
+#endif
+
+    Optional<JsonObject const&> get_object(StringView key) const;
+    Optional<JsonArray const&> get_array(StringView key) const;
+
+#if !defined(KERNEL)
+    Optional<double> get_double(StringView key) const;
+    Optional<float> get_float(StringView key) const;
+#endif
+
     void set(DeprecatedString const& key, JsonValue value);
 
     template<typename Callback>