lib/rs/src/server/multiplexed.rs

// Licensed to the Apache Software Foundation (ASF) under one
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// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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
//
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use std::collections::HashMap;
use std::convert::Into;

use ::{new_application_error, ApplicationErrorKind};
use ::protocol::{TInputProtocol, TMessageIdentifier, TOutputProtocol, TStoredInputProtocol};

use super::TProcessor;

/// A `TProcessor` that can demux service calls to multiple underlying
/// Thrift services.
///
/// Users register service-specific `TProcessor` instances with a
/// `TMultiplexedProcessor`, and then register that processor with a server
/// implementation. Following that, all incoming service calls are automatically
/// routed to the service-specific `TProcessor`.
///
/// A `TMultiplexedProcessor` can only handle messages sent by a
/// `TMultiplexedOutputProtocol`.
pub struct TMultiplexedProcessor {
    processors: HashMap<String, Box<TProcessor>>,
}

impl TMultiplexedProcessor {
    /// Register a service-specific `processor` for the service named
    /// `service_name`.
    ///
    /// Return `true` if this is the first registration for `service_name`.
    ///
    /// Return `false` if a mapping previously existed (the previous mapping is
    /// *not* overwritten).
    #[cfg_attr(feature = "cargo-clippy", allow(map_entry))]
    pub fn register_processor<S: Into<String>>(&mut self,
                                               service_name: S,
                                               processor: Box<TProcessor>)
                                               -> bool {
        let name = service_name.into();
        if self.processors.contains_key(&name) {
            false
        } else {
            self.processors.insert(name, processor);
            true
        }
    }
}

impl TProcessor for TMultiplexedProcessor {
    fn process(&mut self,
               i_prot: &mut TInputProtocol,
               o_prot: &mut TOutputProtocol)
               -> ::Result<()> {
        let msg_ident = i_prot.read_message_begin()?;
        let sep_index = msg_ident.name
            .find(':')
            .ok_or_else(|| {
                new_application_error(ApplicationErrorKind::Unknown,
                                      "no service separator found in incoming message")
            })?;

        let (svc_name, svc_call) = msg_ident.name.split_at(sep_index);

        match self.processors.get_mut(svc_name) {
            Some(ref mut processor) => {
                let new_msg_ident = TMessageIdentifier::new(svc_call,
                                                            msg_ident.message_type,
                                                            msg_ident.sequence_number);
                let mut proxy_i_prot = TStoredInputProtocol::new(i_prot, new_msg_ident);
                processor.process(&mut proxy_i_prot, o_prot)
            }
            None => {
                Err(new_application_error(ApplicationErrorKind::Unknown,
                                          format!("no processor found for service {}", svc_name)))
            }
        }
    }
}