feat(core/binding-macro): Add read and write proc-macro. (nervosn…

…etwork#49)

Cargo.toml

@@ -49,6 +49,8 @@ members = [
   "core/mempool",
   "core/network",
   "core/storage",
+  "core/binding",
+  "core/binding-macro",
 
   "protocol",
 ]

core/binding-macro/Cargo.toml

@@ -6,4 +6,15 @@ edition = "2018"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
+[lib]
+proc-macro = true
+
 [dependencies]
+syn = { version = "1.0", features = ["full"] }
+proc-macro2 = "1.0"
+quote = "1.0"
+
+[dev-dependencies]
+protocol = { path = "../../protocol" }
+json = "0.12"
+bytes = "0.4"

core/binding-macro/src/lib.rs

@@ -1,7 +1,70 @@
-#[cfg(test)]
-mod tests {
-    #[test]
-    fn it_works() {
-        assert_eq!(2 + 2, 4);
-    }
+extern crate proc_macro;
+
+mod read_write;
+
+use proc_macro::TokenStream;
+
+use crate::read_write::verify_read_or_write;
+
+// `#[read]` marks a service method as readable.
+//
+// Methods marked with this macro will have:
+//  Methods with this macro allow access (readable) from outside (RPC or other
+// services).
+//
+// - Verification
+//  1. Is it a struct method marked with #[service]?
+//  2. Is visibility private?
+//  3. Does function generics constrain `fn f<Context: RequestContext>`?
+//  4. Parameter signature contains `&self and ctx:Context`?
+//  5. Is the return value `ProtocolResult <JsonValue>`?
+//
+// example:
+//
+// struct Service;
+// #[service]
+// impl Service {
+//     #[read]
+//     fn test_read_fn<Context: RequestContext>(
+//         &self,
+//         _ctx: Context,
+//     ) -> ProtocolResult<JsonValue> {
+//         Ok(JsonValue::Null)
+//     }
+// }
+#[proc_macro_attribute]
+pub fn read(_: TokenStream, item: TokenStream) -> TokenStream {
+    verify_read_or_write(item, false)
+}
+
+// `#[write]` marks a service method as writeable.
+//
+// Methods marked with this macro will have:
+// - Accessibility
+//  Methods with this macro allow access (writeable) from outside (RPC or other
+// services).
+//
+// - Verification
+//  1. Is it a struct method marked with #[service]?
+//  2. Is visibility private?
+//  3. Does function generics constrain `fn f<Context: RequestContext>`?
+//  4. Parameter signature contains `&mut self and ctx:Context`?
+//  5. Is the return value `ProtocolResult <JsonValue>`?
+//
+// example:
+//
+// struct Service;
+// #[service]
+// impl Service {
+//     #[write]
+//     fn test_write_fn<Context: RequestContext>(
+//         &mut self,
+//         _ctx: Context,
+//     ) -> ProtocolResult<JsonValue> {
+//         Ok(JsonValue::Null)
+//     }
+// }
+#[proc_macro_attribute]
+pub fn write(_: TokenStream, item: TokenStream) -> TokenStream {
+    verify_read_or_write(item, true)
 }

core/binding-macro/src/read_write.rs

@@ -0,0 +1,173 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::punctuated::Punctuated;
+use syn::{
+    parse_macro_input, FnArg, GenericArgument, GenericParam, Generics, ImplItemMethod, Path,
+    PathArguments, ReturnType, Token, Type, TypeParamBound, Visibility,
+};
+
+pub fn verify_read_or_write(item: TokenStream, mutable: bool) -> TokenStream {
+    let method_item = parse_macro_input!(item as ImplItemMethod);
+
+    let visibility = &method_item.vis;
+    let inputs = &method_item.sig.inputs;
+    let generics = &method_item.sig.generics;
+    let ret_type = &method_item.sig.output;
+
+    // TODO(@yejiayu): verify #[service]
+
+    verify_visibiity(visibility);
+
+    verify_inputs(inputs, generics, mutable);
+
+    verify_ret_type(ret_type);
+
+    TokenStream::from(quote! {#method_item})
+}
+
+fn verify_visibiity(visibility: &Visibility) {
+    match visibility {
+        Visibility::Inherited => {}
+        _ => panic!("The visibility of read/write method must be private"),
+    };
+}
+
+fn verify_inputs(inputs: &Punctuated<FnArg, Token![,]>, generics: &Generics, mutable: bool) {
+    if inputs.len() < 2 {
+        panic!("The two required parameters are missing: `&self/&mut self` and `RequestContext`.")
+    }
+
+    if mutable {
+        if !arg_is_mutable_receiver(&inputs[0]) {
+            panic!("The receiver must be `&mut self`.")
+        }
+    } else {
+        if !arg_is_inmutable_receiver(&inputs[0]) {
+            panic!("The receiver must be `&self`.")
+        }
+    }
+    arg_is_request_context(&inputs[1], generics);
+}
+
+fn verify_ret_type(ret_type: &ReturnType) {
+    let real_ret_type = match ret_type {
+        ReturnType::Type(_, t) => t.as_ref(),
+        _ => panic!("The return type of read/write method must be protocol::ProtocolResult"),
+    };
+
+    match real_ret_type {
+        Type::Path(type_path) => {
+            let path = &type_path.path;
+            let args = get_protocol_result_args(&path)
+                .expect("The return type of read/write method must be protocol::ProtocolResult");
+
+            match args {
+                PathArguments::AngleBracketed(arg) => {
+                    let generic_args = &arg.args;
+                    let generic_type = &generic_args[0];
+                    generic_type_is_jsonvalue(generic_type);
+                }
+                _ => panic!("The return value of read/write method must be json::JsonValue"),
+            };
+        }
+        _ => panic!("The return type of read/write method must be protocol::ProtocolResult"),
+    }
+}
+
+fn get_protocol_result_args(path: &Path) -> Option<&PathArguments> {
+    // ::<a>::<b>
+    if path.leading_colon.is_some() {
+        return None;
+    }
+
+    // ProtocolResult<T>
+    if path.segments.len() == 1 && path.segments[0].ident == "ProtocolResult" {
+        return Some(&path.segments[0].arguments);
+    }
+
+    return None;
+}
+
+fn path_is_jsonvalue(path: &Path) -> bool {
+    // ::<a>::<b>
+    if path.leading_colon.is_some() {
+        return false;
+    }
+
+    // JsonValue
+    path.segments.len() == 1 && path.segments[0].ident == "JsonValue"
+}
+
+fn path_is_request_context(path: &Path, bound_name: &str) -> bool {
+    // ::<a>::<b>
+    if path.leading_colon.is_some() {
+        return false;
+    }
+
+    // RequestContext
+    path.segments.len() == 1 && path.segments[0].ident == bound_name
+}
+
+fn generic_type_is_jsonvalue(generic_type: &GenericArgument) -> bool {
+    match generic_type {
+        GenericArgument::Type(t) => match t {
+            Type::Path(type_path) => path_is_jsonvalue(&type_path.path),
+            _ => false,
+        },
+        _ => false,
+    }
+}
+
+// expect fn foo<Context: RequestContext>
+fn get_bounds_name_of_request_context(generics: &Generics) -> Option<String> {
+    if generics.params.len() != 1 {
+        return None;
+    }
+
+    let generics_type = &generics.params[0];
+
+    if let GenericParam::Type(t) = generics_type {
+        let bound_name = t.ident.to_string();
+
+        if let TypeParamBound::Trait(bound_trait) = &t.bounds[0] {
+            let ident = &bound_trait.path.segments[0].ident;
+            if ident == "RequestContext" {
+                return Some(bound_name);
+            }
+        }
+    }
+
+    None
+}
+
+// expect fn foo<Context: RequestContext>(&self, ctx: Context)
+fn arg_is_request_context(fn_arg: &FnArg, generics: &Generics) -> bool {
+    let ty = match fn_arg {
+        FnArg::Typed(pat_type) => &*pat_type.ty,
+        _ => return false,
+    };
+
+    let bound_name = get_bounds_name_of_request_context(generics)
+        .expect("The `read/write` method must bound the trait `RequestContext`");
+
+    match ty {
+        Type::Path(type_path) => path_is_request_context(&type_path.path, &bound_name),
+        _ => false,
+    }
+}
+
+// expect &mut self
+fn arg_is_mutable_receiver(fn_arg: &FnArg) -> bool {
+    match fn_arg {
+        FnArg::Receiver(receiver) => receiver.reference.is_some() && receiver.mutability.is_some(),
+        _ => false,
+    }
+}
+
+// expect &self
+fn arg_is_inmutable_receiver(fn_arg: &FnArg) -> bool {
+    match fn_arg {
+        FnArg::Receiver(receiver) => receiver.reference.is_some() && receiver.mutability.is_none(),
+        _ => false,
+    }
+}

core/binding-macro/tests/mod.rs

@@ -0,0 +1,79 @@
+#[macro_use]
+extern crate core_binding_macro;
+
+use bytes::Bytes;
+use json::JsonValue;
+
+use protocol::traits::RequestContext;
+use protocol::types::{Address, Hash};
+use protocol::ProtocolResult;
+
+#[test]
+fn test_read() {
+    struct Tests;
+
+    impl Tests {
+        #[read]
+        fn test_read_fn<Context: RequestContext>(
+            &self,
+            _ctx: Context,
+        ) -> ProtocolResult<JsonValue> {
+            Ok(JsonValue::Null)
+        }
+
+        #[write]
+        fn test_write_fn<Context: RequestContext>(
+            &mut self,
+            _ctx: Context,
+        ) -> ProtocolResult<JsonValue> {
+            Ok(JsonValue::Null)
+        }
+    }
+
+    let context = MockRequestContext {};
+
+    let mut t = Tests {};
+    assert_eq!(t.test_read_fn(context.clone()).unwrap(), JsonValue::Null);
+    assert_eq!(t.test_write_fn(context.clone()).unwrap(), JsonValue::Null);
+}
+
+#[derive(Clone)]
+struct MockRequestContext;
+
+impl RequestContext for MockRequestContext {
+    fn sub_cycles(&self, _cycels: u64) -> ProtocolResult<()> {
+        Ok(())
+    }
+
+    fn get_cycles_price(&self) -> ProtocolResult<u64> {
+        Ok(0)
+    }
+
+    fn get_cycles_limit(&self) -> ProtocolResult<u64> {
+        Ok(0)
+    }
+
+    fn get_cycles_used(&self) -> ProtocolResult<u64> {
+        Ok(0)
+    }
+
+    fn get_caller(&self) -> ProtocolResult<Address> {
+        Address::from_hash(Hash::digest(Bytes::from("test")))
+    }
+
+    fn get_current_epoch_id(&self) -> ProtocolResult<u64> {
+        Ok(0)
+    }
+
+    fn get_service_name(&self) -> ProtocolResult<&str> {
+        Ok("service")
+    }
+
+    fn get_service_method(&self) -> ProtocolResult<&str> {
+        Ok("method")
+    }
+
+    fn get_payload(&self) -> ProtocolResult<&str> {
+        Ok("payload")
+    }
+}