Import 'mls-rs-codec-derive' crateupstream

Request Document: go/android-rust-importing-crates
For CL Reviewers: go/android3p#cl-review
For Build Team: go/ab-third-party-imports
Bug: http://b/328421132
Test: m libmls_rs_codec_derive

Change-Id: Ic22fe8e47f7914ca2ce4d565404353c79dd4a6d4

12 files changed, 652 insertions, 0 deletions

diff --git a/.cargo_vcs_info.json b/.cargo_vcs_info.json
new file mode 100644
index 0000000..425a46d
--- /dev/null
+++ b/.cargo_vcs_info.json
@@ -0,0 +1,6 @@
+{
+  "git": {
+    "sha1": "d0b115d2ea4754006341ba23e5910d741c6263c9"
+  },
+  "path_in_vcs": "mls-rs-codec-derive"
+}
\ No newline at end of file
diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..3962e13
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,20 @@
+// This file is generated by cargo_embargo.
+// Do not modify this file as changes will be overridden on upgrade.
+
+// TODO: Add license.
+rust_proc_macro {
+    name: "libmls_rs_codec_derive",
+    crate_name: "mls_rs_codec_derive",
+    cargo_env_compat: true,
+    cargo_pkg_version: "0.1.0",
+    srcs: ["src/lib.rs"],
+    edition: "2021",
+    rustlibs: [
+        "libdarling",
+        "libproc_macro2",
+        "libquote",
+        "libsyn",
+    ],
+    product_available: true,
+    vendor_available: true,
+}
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..34f52a1
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,101 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "darling"
+version = "0.20.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0209d94da627ab5605dcccf08bb18afa5009cfbef48d8a8b7d7bdbc79be25c5e"
+dependencies = [
+ "darling_core",
+ "darling_macro",
+]
+
+[[package]]
+name = "darling_core"
+version = "0.20.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "177e3443818124b357d8e76f53be906d60937f0d3a90773a664fa63fa253e621"
+dependencies = [
+ "fnv",
+ "ident_case",
+ "proc-macro2",
+ "quote",
+ "strsim",
+ "syn",
+]
+
+[[package]]
+name = "darling_macro"
+version = "0.20.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "836a9bbc7ad63342d6d6e7b815ccab164bc77a2d95d84bc3117a8c0d5c98e2d5"
+dependencies = [
+ "darling_core",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "fnv"
+version = "1.0.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
+
+[[package]]
+name = "ident_case"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9e0384b61958566e926dc50660321d12159025e767c18e043daf26b70104c39"
+
+[[package]]
+name = "mls-rs-codec-derive"
+version = "0.1.0"
+dependencies = [
+ "darling",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.71"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75cb1540fadbd5b8fbccc4dddad2734eba435053f725621c070711a14bb5f4b8"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.33"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5267fca4496028628a95160fc423a33e8b2e6af8a5302579e322e4b520293cae"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
+[[package]]
+name = "syn"
+version = "2.0.43"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ee659fb5f3d355364e1f3e5bc10fb82068efbf824a1e9d1c9504244a6469ad53"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3354b9ac3fae1ff6755cb6db53683adb661634f67557942dea4facebec0fee4b"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..a9bd0b8
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,38 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+edition = "2021"
+name = "mls-rs-codec-derive"
+version = "0.1.0"
+description = "Derive macro crate for mls-rs-codec"
+homepage = "https://github.com/awslabs/mls-rs"
+keywords = [
+    "mls",
+    "mls-rs",
+]
+license = "Apache-2.0 OR MIT"
+repository = "https://github.com/awslabs/mls-rs"
+
+[lib]
+proc-macro = true
+
+[dependencies.darling]
+version = "0.20.3"
+
+[dependencies.proc-macro2]
+version = "1.0.54"
+
+[dependencies.quote]
+version = "1.0.26"
+
+[dependencies.syn]
+version = "2"
diff --git a/LICENSE b/LICENSE
new file mode 120000
index 0000000..4ce7dad
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1 @@
+LICENSE-apache
\ No newline at end of file
diff --git a/LICENSE-apache b/LICENSE-apache
new file mode 100644
index 0000000..831fbc5
--- /dev/null
+++ b/LICENSE-apache
@@ -0,0 +1,176 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
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+      "Licensor" shall mean the copyright owner or entity authorized by
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+      outstanding shares, or (iii) beneficial ownership of such entity.
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+      "You" (or "Your") shall mean an individual or Legal Entity
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+      "Work" shall mean the work of authorship, whether in Source or
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+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, orother modifications
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+      "Contribution" shall mean any work of authorship, including
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+          of the NOTICE file are for informational purposes only and
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+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
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+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
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+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
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+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
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+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
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+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
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+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
diff --git a/LICENSE-mit b/LICENSE-mit
new file mode 100644
index 0000000..e547c4a
--- /dev/null
+++ b/LICENSE-mit
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including  without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to  the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN  NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/METADATA b/METADATA
new file mode 100644
index 0000000..57145a7
--- /dev/null
+++ b/METADATA
@@ -0,0 +1,20 @@
+name: "mls-rs-codec-derive"
+description: "Derive macro crate for mls-rs-codec"
+third_party {
+  identifier {
+    type: "crates.io"
+    value: "https://crates.io/crates/mls-rs-codec-derive"
+  }
+  identifier {
+    type: "Archive"
+    value: "https://static.crates.io/crates/mls-rs-codec-derive/mls-rs-codec-derive-0.1.0.crate"
+  }
+  version: "0.1.0"
+  # Dual-licensed, using the least restrictive per go/thirdpartylicenses#same.
+  license_type: NOTICE
+  last_upgrade_date {
+    year: 2024
+    month: 1
+    day: 4
+  }
+}
diff --git a/MODULE_LICENSE_APACHE2 b/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/MODULE_LICENSE_APACHE2
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..48bea6e
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1,2 @@
+# Bug component: 688011
+include platform/prebuilts/rust:main:/OWNERS
diff --git a/cargo_embargo.json b/cargo_embargo.json
new file mode 100644
index 0000000..cb908d7
--- /dev/null
+++ b/cargo_embargo.json
@@ -0,0 +1,3 @@
+{
+  "run_cargo": false
+}
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..3c7603f
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,276 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// Copyright by contributors to this project.
+// SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+use darling::{
+    ast::{self, Fields},
+    FromDeriveInput, FromField, FromVariant,
+};
+use proc_macro2::TokenStream;
+use quote::quote;
+use syn::{parse_macro_input, parse_quote, DeriveInput, Expr, Generics, Ident, Index, Path};
+
+enum Operation {
+    Size,
+    Encode,
+    Decode,
+}
+
+impl Operation {
+    fn path(&self) -> Path {
+        match self {
+            Operation::Size => parse_quote! { mls_rs_codec::MlsSize },
+            Operation::Encode => parse_quote! { mls_rs_codec::MlsEncode },
+            Operation::Decode => parse_quote! { mls_rs_codec::MlsDecode },
+        }
+    }
+
+    fn call(&self) -> TokenStream {
+        match self {
+            Operation::Size => quote! { mls_encoded_len },
+            Operation::Encode => quote! { mls_encode },
+            Operation::Decode => quote! { mls_decode },
+        }
+    }
+
+    fn extras(&self) -> TokenStream {
+        match self {
+            Operation::Size => quote! {},
+            Operation::Encode => quote! { , writer },
+            Operation::Decode => quote! { reader },
+        }
+    }
+
+    fn is_result(&self) -> bool {
+        match self {
+            Operation::Size => false,
+            Operation::Encode => true,
+            Operation::Decode => true,
+        }
+    }
+}
+
+#[derive(Debug, FromField)]
+#[darling(attributes(mls_codec))]
+struct MlsFieldReceiver {
+    ident: Option<Ident>,
+    with: Option<Path>,
+}
+
+impl MlsFieldReceiver {
+    pub fn call_tokens(&self, index: Index) -> TokenStream {
+        if let Some(ref ident) = self.ident {
+            quote! { &self.#ident }
+        } else {
+            quote! { &self.#index }
+        }
+    }
+
+    pub fn name(&self, index: Index) -> TokenStream {
+        if let Some(ref ident) = self.ident {
+            quote! {#ident: }
+        } else {
+            quote! { #index: }
+        }
+    }
+}
+
+#[derive(Debug, FromVariant)]
+#[darling(attributes(mls_codec))]
+struct MlsVariantReceiver {
+    ident: Ident,
+    discriminant: Option<Expr>,
+    fields: ast::Fields<MlsFieldReceiver>,
+}
+
+#[derive(FromDeriveInput)]
+#[darling(attributes(mls_codec))]
+struct MlsInputReceiver {
+    ident: Ident,
+    generics: Generics,
+    data: ast::Data<MlsVariantReceiver, MlsFieldReceiver>,
+}
+
+impl MlsInputReceiver {
+    fn handle_input(&self, operation: Operation) -> TokenStream {
+        match self.data {
+            ast::Data::Struct(ref s) => struct_impl(s, operation),
+            ast::Data::Enum(ref e) => enum_impl(&self.ident, e, operation),
+        }
+    }
+}
+
+fn enum_impl(ident: &Ident, variants: &[MlsVariantReceiver], operation: Operation) -> TokenStream {
+    let handle_error = operation.is_result().then_some(quote! { ? });
+    let path = operation.path();
+    let call = operation.call();
+    let extras = operation.extras();
+    let enum_name = &ident;
+
+    if matches!(operation, Operation::Decode) {
+        let cases = variants.iter().map(|variant| {
+            let variant_name = &variant.ident;
+
+            // TODO: Calculate discriminant and support integers that are assumed types like u16,
+            // u32 etc based on repr()
+            let discriminant = &variant
+                .discriminant
+                .clone()
+                .expect("Enum discriminants must be explicitly defined");
+
+            // TODO: Support more than 1 field
+            match variant.fields.len() {
+                0 => quote! { #discriminant => Ok(#enum_name::#variant_name), },
+                1 =>{
+                    let path = variant.fields.fields[0].with.as_ref().unwrap_or(&path);
+                    quote! { #discriminant => Ok(#enum_name::#variant_name(#path::#call(#extras) #handle_error)), }
+                },
+                _ => panic!("Enum discriminants with more than 1 field are not currently supported")
+            }
+        });
+
+        return quote! {
+            let discriminant = #path::#call(#extras)#handle_error;
+
+            match discriminant {
+                #(#cases)*
+                _ => Err(mls_rs_codec::Error::UnsupportedEnumDiscriminant),
+            }
+        };
+    }
+
+    let cases = variants.iter().map(|variant| {
+        let variant_name = &variant.ident;
+
+        let discriminant = &variant
+            .discriminant
+            .clone()
+            .expect("Enum discriminants must be explicitly defined");
+
+        let (parameter, field) = if variant.fields.is_empty() {
+            (None, None)
+        } else {
+            let path = variant.fields.fields[0].with.as_ref().unwrap_or(&path);
+
+            let start = match operation {
+                Operation::Size => Some(quote! { + }),
+                Operation::Encode => Some(quote! {;}),
+                Operation::Decode => None,
+            };
+
+            (
+                Some(quote! {(ref val)}),
+                Some(quote! { #start #path::#call (val #extras) #handle_error }),
+            )
+        };
+
+        let discrim = quote! { #path::#call (&#discriminant #extras) #handle_error };
+
+        quote! { #enum_name::#variant_name #parameter => { #discrim #field }}
+    });
+
+    let enum_impl = quote! {
+        match self {
+            #(#cases)*
+        }
+    };
+
+    if operation.is_result() {
+        quote! {
+            Ok(#enum_impl)
+        }
+    } else {
+        enum_impl
+    }
+}
+
+fn struct_impl(s: &Fields<MlsFieldReceiver>, operation: Operation) -> TokenStream {
+    let recurse = s.fields.iter().enumerate().map(|(index, field)| {
+        let (call_tokens, field_name) = match operation {
+            Operation::Size | Operation::Encode => {
+                (field.call_tokens(Index::from(index)), quote! {})
+            }
+            Operation::Decode => (quote! {}, field.name(Index::from(index))),
+        };
+
+        let handle_error = operation.is_result().then_some(quote! { ? });
+        let path = field.with.clone().unwrap_or(operation.path());
+        let call = operation.call();
+        let extras = operation.extras();
+
+        quote! {
+           #field_name #path::#call (#call_tokens #extras) #handle_error
+        }
+    });
+
+    match operation {
+        Operation::Size => quote! { 0 #(+ #recurse)* },
+        Operation::Encode => quote! { #(#recurse;)* Ok(()) },
+        Operation::Decode => quote! { Ok(Self { #(#recurse,)* }) },
+    }
+}
+
+fn derive_impl<F>(
+    input: proc_macro::TokenStream,
+    trait_name: TokenStream,
+    function_def: TokenStream,
+    internals: F,
+) -> proc_macro::TokenStream
+where
+    F: FnOnce(&MlsInputReceiver) -> TokenStream,
+{
+    let input = parse_macro_input!(input as DeriveInput);
+    let input = MlsInputReceiver::from_derive_input(&input).unwrap();
+
+    let name = &input.ident;
+
+    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();
+
+    // Generate an expression to sum up the heap size of each field.
+    let function_impl = internals(&input);
+
+    let expanded = quote! {
+        // The generated impl.
+        impl #impl_generics #trait_name for #name #ty_generics #where_clause {
+            #function_def {
+                #function_impl
+            }
+        }
+    };
+
+    // Hand the output tokens back to the compiler.
+    proc_macro::TokenStream::from(expanded)
+}
+
+#[proc_macro_derive(MlsSize, attributes(mls_codec))]
+pub fn derive_size(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let trait_name = quote! { mls_rs_codec::MlsSize };
+    let function_def = quote! {fn mls_encoded_len(&self) -> usize };
+
+    derive_impl(input, trait_name, function_def, |input| {
+        input.handle_input(Operation::Size)
+    })
+}
+
+#[proc_macro_derive(MlsEncode, attributes(mls_codec))]
+pub fn derive_encode(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let trait_name = quote! { mls_rs_codec::MlsEncode };
+
+    let function_def = quote! { fn mls_encode(&self, writer: &mut mls_rs_codec::Vec<u8>) -> Result<(), mls_rs_codec::Error> };
+
+    derive_impl(input, trait_name, function_def, |input| {
+        input.handle_input(Operation::Encode)
+    })
+}
+
+#[proc_macro_derive(MlsDecode, attributes(mls_codec))]
+pub fn derive_decode(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let trait_name = quote! { mls_rs_codec::MlsDecode };
+
+    let function_def =
+        quote! { fn mls_decode(reader: &mut &[u8]) -> Result<Self, mls_rs_codec::Error> };
+
+    derive_impl(input, trait_name, function_def, |input| {
+        input.handle_input(Operation::Decode)
+    })
+}