通过 Libra 学习 Protobuf

cargo install protobuf
cargo install protobuf-codegen

syntax = "proto3";

package types;
// Account state as a whole.
// After execution, updates to accounts are passed in this form to storage for
// persistence.
message AccountState {
    // Account address
    bytes address = 1;
    // Account state blob
    bytes blob = 2;
}

protoc --rust_out . accountstate.proto

#[derive(PartialEq,Clone,Default)]
pub struct AccountState {
    // message fields
    pub address: ::std::vec::Vec<u8>,
    pub blob: ::std::vec::Vec<u8>,
    // special fields
    pub unknown_fields: ::protobuf::UnknownFields,
    pub cached_size: ::protobuf::CachedSize,
}

impl<'a> ::std::default::Default for &'a AccountState {
    fn default() -> &'a AccountState {
        <AccountState as ::protobuf::Message>::default_instance()
    }
}

impl AccountState {
    pub fn new() -> AccountState {
        ::std::default::Default::default()
    }

    // bytes address = 1;


    pub fn get_address(&self) -> &[u8] {
        &self.address
    }
    pub fn clear_address(&mut self) {
        self.address.clear();
    }

    // Param is passed by value, moved
    pub fn set_address(&mut self, v: ::std::vec::Vec<u8>) {
        self.address = v;
    }

    // Mutable pointer to the field.
    // If field is not initialized, it is initialized with default value first.
    pub fn mut_address(&mut self) -> &mut ::std::vec::Vec<u8> {
        &mut self.address
    }

    // Take field
    pub fn take_address(&mut self) -> ::std::vec::Vec<u8> {
        ::std::mem::replace(&mut self.address, ::std::vec::Vec::new())
    }

    // bytes blob = 2;


    pub fn get_blob(&self) -> &[u8] {
        &self.blob
    }
    pub fn clear_blob(&mut self) {
        self.blob.clear();
    }

    // Param is passed by value, moved
    pub fn set_blob(&mut self, v: ::std::vec::Vec<u8>) {
        self.blob = v;
    }

    // Mutable pointer to the field.
    // If field is not initialized, it is initialized with default value first.
    pub fn mut_blob(&mut self) -> &mut ::std::vec::Vec<u8> {
        &mut self.blob
    }

    // Take field
    pub fn take_blob(&mut self) -> ::std::vec::Vec<u8> {
        ::std::mem::replace(&mut self.blob, ::std::vec::Vec::new())
    }
}

fn main() {
    let proto_root = "src/proto";
    let dependent_root = "../../types/src/proto";

    build_helpers::build_helpers::compile_proto(
        proto_root,
        vec![dependent_root],
        false, /* generate_client_code */
    );
}

pub fn compile_proto(proto_root: &str, dependent_roots: Vec<&str>, generate_client_code: bool) {
   let mut additional_includes = vec![];
   for dependent_root in dependent_roots {
       // First compile dependent directories
       compile_dir(
           &dependent_root,
           vec![], /* additional_includes */
           false,  /* generate_client_code */
       );
       additional_includes.push(Path::new(dependent_root).to_path_buf());
   }
   // Now compile this directory
   compile_dir(&proto_root, additional_includes, generate_client_code);
}

// Compile all of the proto files in proto_root directory and use the additional
// includes when compiling.
pub fn compile_dir(
   proto_root: &str,
   additional_includes: Vec<PathBuf>,
   generate_client_code: bool,
) {
   for entry in WalkDir::new(proto_root) {
       let p = entry.unwrap();
       if p.file_type().is_dir() {
           continue;
       }

       let path = p.path();
       if let Some(ext) = path.extension() {
           if ext != "proto" {
               continue;
           }
           println!("cargo:rerun-if-changed={}", path.display());
           compile(&path, &additional_includes, generate_client_code);
       }
   }
}

fn compile(path: &Path, additional_includes: &[PathBuf], generate_client_code: bool) {
   ...
}

fn compile(path: &Path, additional_includes: &[PathBuf], generate_client_code: bool) {
    let parent = path.parent().unwrap();
    let mut src_path = parent.to_owned().to_path_buf();
    src_path.push("src");

    let mut includes = Vec::from(additional_includes);
    //写成additional_includes.to_owned()也是可以的
    let mut includes = additional_includes.to_owned(); //最终都会调用slice的to_vec
    includes.push(parent.to_path_buf());
    ....
}

/// Helper to construct and parse [`proto::storage::GetAccountStateWithProofByStateRootRequest`]
///
/// It does so by implementing `IntoProto` and `FromProto`,
/// providing `into_proto` and `from_proto`.
#[derive(PartialEq, Eq, Clone, FromProto, IntoProto)]
#[ProtoType(crate::proto::storage::GetAccountStateWithProofByStateRootRequest)]
pub struct GetAccountStateWithProofByStateRootRequest {
    /// The access path to query with.
    pub address: AccountAddress,

    /// the state root hash the query is based on.
    pub state_root_hash: HashValue,
}
/// Helper to construct and parse [`proto::storage::GetAccountStateWithProofByStateRootResponse`]
///
/// It does so by implementing `IntoProto` and `FromProto`,
/// providing `into_proto` and `from_proto`.
#[derive(PartialEq, Eq, Clone)]
pub struct GetAccountStateWithProofByStateRootResponse {
    /// The account state blob requested.
    pub account_state_blob: Option<AccountStateBlob>,

    /// The state root hash the query is based on.
    pub sparse_merkle_proof: SparseMerkleProof,
}

impl FromProto for GetAccountStateWithProofByStateRootResponse {
    type ProtoType = crate::proto::storage::GetAccountStateWithProofByStateRootResponse;

    fn from_proto(mut object: Self::ProtoType) -> Result<Self> {
        let account_state_blob = if object.has_account_state_blob() {
            Some(AccountStateBlob::from_proto(
                object.take_account_state_blob(),
            )?)
        } else {
            None
        };
        Ok(Self {
            account_state_blob,
            sparse_merkle_proof: SparseMerkleProof::from_proto(object.take_sparse_merkle_proof())?,
        })
    }
}

impl IntoProto for GetAccountStateWithProofByStateRootResponse {
    type ProtoType = crate::proto::storage::GetAccountStateWithProofByStateRootResponse;

    fn into_proto(self) -> Self::ProtoType {
        let mut object = Self::ProtoType::new();

        if let Some(account_state_blob) = self.account_state_blob {
            object.set_account_state_blob(account_state_blob.into_proto());
        }
        object.set_sparse_merkle_proof(self.sparse_merkle_proof.into_proto());
        object
    }
}