Add nodes types for the TypeSystem library in Rust

Summary:
This diff introduces the building blocks (~data model) for the Rust's `TypeSystem` library, which mirrors the [C++ version](https://fburl.com/code/a8tjzcm3).

This crate provides representations for all Thrift types, e.g. primitives, containers, and user-defined types, as a shared type graph with immutable nodes. The `TypeRef` enum provides a descriptor for a given node, while the specific nodes themselves provide access to their structural properties.

## Note

See the C++ implementation & rest of the diff stack for more details on "TypeSystem".

Reviewed By: praihan

Differential Revision: D96817822

fbshipit-source-id: c871cf6ebe58b4a3b6428b97fc9c20d555942d76

Author: sadroeck

thrift/lib/rust/dynamic/BUCK

@@ -0,0 +1,17 @@
+load("@fbsource//tools/build_defs:fbsource_utils.bzl", "is_fbcode")
+load("@fbsource//xplat/thrift:defs.bzl", "thrift_rust_library")
+
+oncall("thrift_dynamic")
+
+thrift_rust_library(
+    name = "thrift_type_system",
+    srcs = glob(["type_system/**/*.rs"]),
+    allow_oss_build = False,
+    crate_root = "type_system/lib.rs",
+    unittests = is_fbcode(),
+    deps = [
+        "fbsource//third-party/rust:thiserror",
+        "//thrift/lib/thrift:record-rust",
+        "//thrift/lib/thrift:type_id-rust",
+    ],
+)

thrift/lib/rust/dynamic/Cargo.toml

@@ -0,0 +1,15 @@
+# @generated by autocargo from //thrift/lib/rust/dynamic:thrift_type_system
+
+[package]
+name = "thrift_type_system"
+version = "0.0.1+unstable"
+authors = ["Daniel Xu <dlxu@fb.com>", "Facebook"]
+edition = "2024"
+repository = "https://github.com/facebook/fbthrift"
+license = "Apache-2.0"
+
+[lib]
+path = "type_system/lib.rs"
+
+[dependencies]
+thiserror = "2.0.18"

thrift/lib/rust/dynamic/type_system/containers.rs

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+use crate::type_ref::TypeRef;
+
+/// Thrift `list<T>` type descriptor.
+#[derive(Clone, Debug)]
+pub struct ListType {
+    pub(crate) element: TypeRef,
+}
+
+impl ListType {
+    pub fn element_type(&self) -> &TypeRef {
+        &self.element
+    }
+}
+
+/// Thrift `set<T>` type descriptor.
+#[derive(Clone, Debug)]
+pub struct SetType {
+    pub(crate) element: TypeRef,
+}
+
+impl SetType {
+    pub fn element_type(&self) -> &TypeRef {
+        &self.element
+    }
+}
+
+/// Thrift `map<K, V>` type descriptor.
+#[derive(Clone, Debug)]
+pub struct MapType {
+    pub(crate) key: TypeRef,
+    pub(crate) value: TypeRef,
+}
+
+impl MapType {
+    pub fn key_type(&self) -> &TypeRef {
+        &self.key
+    }
+
+    pub fn value_type(&self) -> &TypeRef {
+        &self.value
+    }
+}

thrift/lib/rust/dynamic/type_system/error.rs

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/// Errors produced when validating or querying type definitions.
+#[derive(Debug, thiserror::Error)]
+pub enum InvalidTypeError {
+    #[error("Unknown URI: {0}")]
+    UnknownUri(String),
+    #[error("Duplicate field ID {0} in {1}")]
+    DuplicateFieldId(i16, String),
+    #[error("Duplicate field name '{0}' in {1}")]
+    DuplicateFieldName(String, String),
+    #[error("Non-optional field {0} in union {1}")]
+    NonOptionalUnionField(i16, String),
+    #[error("Duplicate enum value {0} in {1}")]
+    DuplicateEnumValue(i32, String),
+    #[error("Duplicate enum name '{0}' in {1}")]
+    DuplicateEnumName(String, String),
+    #[error("Accessed {expected} but TypeRef is {actual}")]
+    WrongKind {
+        expected: &'static str,
+        actual: &'static str,
+    },
+    #[error("Duplicate URI: {0}")]
+    DuplicateUri(String),
+    #[error("Opaque alias target must not be user-defined: {0}")]
+    InvalidOpaqueAlias(String),
+    #[error("Unresolvable TypeId in {uri}: {detail}")]
+    UnresolvableTypeId { uri: String, detail: String },
+    #[error("Empty TypeId")]
+    EmptyTypeId,
+    #[error("Too many fields ({0}) in {1}, maximum is 65535")]
+    TooManyFields(usize, String),
+}

thrift/lib/rust/dynamic/type_system/lib.rs

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//! In-memory representation of a Thrift type system.
+//!
+//! Models all Thrift type definitions — primitives, containers, and
+//! user-defined types — as a shared, cheaply-cloneable type graph.
+//! Designed for construction from (and round-tripping to)
+//! [`SerializableTypeSystem`].
+
+pub mod containers;
+pub mod error;
+pub mod nodes;
+pub mod type_ref;
+
+pub use containers::ListType;
+pub use containers::MapType;
+pub use containers::SetType;
+pub use error::InvalidTypeError;
+pub use nodes::AnnotationsMap;
+pub use nodes::EnumNode;
+pub use nodes::EnumValue;
+pub use nodes::FieldDefinition;
+pub use nodes::FieldIdentity;
+pub use nodes::OpaqueAliasNode;
+pub use nodes::PresenceQualifier;
+pub use nodes::StructNode;
+pub use nodes::StructuredNode;
+pub use nodes::UnionNode;
+pub use type_ref::DefinitionRef;
+pub use type_ref::Kind;
+pub use type_ref::TypeRef;