a convinient way to derive traits

Author: majabbour

program/rust/Cargo.toml

@@ -7,8 +7,13 @@ edition = "2021"
 license = "Apache 2.0"
 publish = false
 
+[build-dependencies]
+bindgen = "0.60.1"
+
 [dependencies]
 solana-program = "=1.10.29"
+borsh = "0.9"
+
 
 [lib]
 crate-type = ["cdylib", "lib"]

program/rust/build.rs

@@ -1,3 +1,21 @@
+mod build_utils;
+use bindgen;
+use std::collections::HashMap;
+use std::vec::Vec;
+
+
 fn main() {
     println!("cargo:rustc-link-search=../c/target");
+    
+    let borsh_derives: Vec<String> = vec!["BorshSerialize".to_string(), "BorshDeserialize".to_string()];
+
+    let parser = build_utils::DeriveAdderParserCallback{types_to_traits: HashMap::from([
+        ("cmd_hdr", borsh_derives)
+        //map more struct names to traits here, be sure that the definitions of your traites
+        //are included in c_oracle_header.rs
+    ])};
+
+    //generate and write bindings
+    let bindings = bindgen::Builder::default().header("./src/bindings.h").parse_callbacks(Box::new(parser)).generate().expect("Unable to generate bindings");
+    bindings.write_to_file("./bindings.rs").expect("Couldn't write bindings!");
 }

program/rust/build_utils.rs

@@ -0,0 +1,25 @@
+use bindgen;
+use std::panic::UnwindSafe;
+use std::collections::HashMap;
+///This type stores a hashmap from structnames
+///to vectors of trait names, and ensures
+///that the traits of each struct are added to its
+///definition when an instance of this struct
+///is provided as a ParseCallback for bindgen
+#[derive(Debug)]
+pub struct DeriveAdderParserCallback<'a>{
+    pub types_to_traits: HashMap<&'a str, Vec<String>> ,
+}
+
+//this is required to implement the callback trait
+impl UnwindSafe for DeriveAdderParserCallback<'_> {}
+
+impl bindgen::callbacks::ParseCallbacks for DeriveAdderParserCallback<'_>{
+    fn add_derives(&self, _name: &str) -> Vec<String>{
+        let traits = self.types_to_traits.get(_name);
+        match traits{
+            Some(trait_names)=>trait_names.to_vec(),
+            None => vec![],
+        }
+    }
+}

program/rust/src/c_oracle_header.rs

@@ -0,0 +1,8 @@
+#![allow(non_upper_case_globals)]
+#![allow(non_camel_case_types)]
+#![allow(non_snake_case)]
+//All the custom trait imports should go here
+use borsh::{BorshSerialize, BorshDeserialize};
+//bindings.rs is generated by build.rs to include
+//things defined in bindings.h
+include!("../bindings.rs");

program/rust/src/lib.rs

@@ -1,5 +1,3 @@
-//c_oracle_header is auto generated by build_bpf.sh
-//to reflect the current status of oracle.h
 mod c_oracle_header;
 
 //do not link with C during unit tests (which are built in native architecture, unlike libpyth.o) 

scripts/build-bpf.sh

@@ -40,8 +40,8 @@ rm ./target/*-keypair.json
 
 #build Rust and link it with C
 cd "${RUST_DIR}"
-cargo install bindgen
-bindgen ./src/bindings.h -o ./src/c_oracle_header.rs
+#cargo install bindgen
+#bindgen ./src/bindings.h -o ./src/c_oracle_header.rs
 cargo clean
 cargo test
 cargo clean