annotate vamp-client/CapnpRRClient.h @ 116:d15cb1151d76

Add JSON support directly to the server. Had hoped to avoid this (using Capnp as canonical in the server and then converting externally as necessary) but it's just too useful for debugging purposes when bundled with client app

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

#ifndef PIPER_CAPNP_CLIENT_H
#define PIPER_CAPNP_CLIENT_H

#include "Loader.h"
#include "PluginClient.h"
#include "PluginStub.h"
#include "SynchronousTransport.h"

#include "vamp-support/AssignedPluginHandleMapper.h"
#include "vamp-capnp/VampnProto.h"

#include <capnp/serialize.h>

namespace piper_vamp {
namespace client {

/**
 * Client for a request-response Piper server, i.e. using the
 * RpcRequest/RpcResponse structures with a single process call rather
 * than having individual RPC methods, with a synchronous transport
 * such as a subprocess pipe arrangement. Only one request can be
 * handled at a time. This class is thread-safe if and only if it is
 * constructed with a thread-safe SynchronousTransport implementation.
 */
class CapnpRRClient : public PluginClient,
		      public Loader
{
    // unsigned to avoid undefined behaviour on possible wrap
    typedef uint32_t ReqId;

    class CompletenessChecker : public MessageCompletenessChecker {
    public:
        bool isComplete(const std::vector<char> &message) const override {
            auto karr = toKJArray(message);
            size_t words = karr.size();
            size_t expected = capnp::expectedSizeInWordsFromPrefix(karr);
            if (words > expected) {
                std::cerr << "WARNING: obtained more data than expected ("
                          << words << " " << sizeof(capnp::word)
                          << "-byte words, expected "
                          << expected << ")" << std::endl;
            }
            return words >= expected;
        }
    };
    
public:
    CapnpRRClient(SynchronousTransport *transport) : //!!! ownership? shared ptr?
        m_transport(transport),
        m_completenessChecker(new CompletenessChecker) {
        transport->setCompletenessChecker(m_completenessChecker);
    }

    ~CapnpRRClient() {
        delete m_completenessChecker;
    }

    //!!! obviously, factor out all repetitive guff

    //!!! list and load are supposed to be called by application code,
    //!!! but the rest are only supposed to be called by the plugin --
    //!!! sort out the api here

    // Loader methods:

    ListResponse
    listPluginData() override {

        if (!m_transport->isOK()) {
            throw std::runtime_error("Piper server failed to start");
        }

        capnp::MallocMessageBuilder message;
	piper::RpcRequest::Builder builder = message.initRoot<piper::RpcRequest>();
        VampnProto::buildRpcRequest_List(builder);
        ReqId id = getId();
        builder.getId().setNumber(id);

	auto karr = call(message);

        capnp::FlatArrayMessageReader responseMessage(karr);
        piper::RpcResponse::Reader reader = responseMessage.getRoot<piper::RpcResponse>();

        checkResponseType(reader, piper::RpcResponse::Response::Which::LIST, id);

        ListResponse lr;
        VampnProto::readListResponse(lr, reader.getResponse().getList());
        return lr;
    }
    
    LoadResponse
    loadPlugin(const LoadRequest &req) override {

        if (!m_transport->isOK()) {
            throw std::runtime_error("Piper server failed to start");
        }

        LoadResponse resp;
        PluginHandleMapper::Handle handle = serverLoad(req.pluginKey,
                                                       req.inputSampleRate,
                                                       req.adapterFlags,
                                                       resp.staticData,
                                                       resp.defaultConfiguration);

        Vamp::Plugin *plugin = new PluginStub(this,
                                              req.pluginKey,
                                              req.inputSampleRate,
                                              req.adapterFlags,
                                              resp.staticData,
                                              resp.defaultConfiguration);

        m_mapper.addPlugin(handle, plugin);

        resp.plugin = plugin;
        return resp;
    }

    // PluginClient methods:
    
    virtual
    Vamp::Plugin::OutputList
    configure(PluginStub *plugin,
              PluginConfiguration config) override {

        if (!m_transport->isOK()) {
            throw std::runtime_error("Piper server failed to start");
        }

        ConfigurationRequest request;
        request.plugin = plugin;
        request.configuration = config;

        capnp::MallocMessageBuilder message;
        piper::RpcRequest::Builder builder = message.initRoot<piper::RpcRequest>();

        VampnProto::buildRpcRequest_Configure(builder, request, m_mapper);
        ReqId id = getId();
        builder.getId().setNumber(id);

	auto karr = call(message);

        capnp::FlatArrayMessageReader responseMessage(karr);
        piper::RpcResponse::Reader reader = responseMessage.getRoot<piper::RpcResponse>();

        //!!! handle (explicit) error case

        checkResponseType(reader, piper::RpcResponse::Response::Which::CONFIGURE, id);

        ConfigurationResponse cr;
        VampnProto::readConfigurationResponse(cr,
                                              reader.getResponse().getConfigure(),
                                              m_mapper);

        return cr.outputs;
    };
    
    virtual
    Vamp::Plugin::FeatureSet
    process(PluginStub *plugin,
            std::vector<std::vector<float> > inputBuffers,
            Vamp::RealTime timestamp) override {

        if (!m_transport->isOK()) {
            throw std::runtime_error("Piper server failed to start");
        }

        ProcessRequest request;
        request.plugin = plugin;
        request.inputBuffers = inputBuffers;
        request.timestamp = timestamp;
        
        capnp::MallocMessageBuilder message;
        piper::RpcRequest::Builder builder = message.initRoot<piper::RpcRequest>();
        VampnProto::buildRpcRequest_Process(builder, request, m_mapper);
	ReqId id = getId();
        builder.getId().setNumber(id);

	auto karr = call(message);

        capnp::FlatArrayMessageReader responseMessage(karr);
        piper::RpcResponse::Reader reader = responseMessage.getRoot<piper::RpcResponse>();

        //!!! handle (explicit) error case

        checkResponseType(reader, piper::RpcResponse::Response::Which::PROCESS, id);

        ProcessResponse pr;
        VampnProto::readProcessResponse(pr,
                                        reader.getResponse().getProcess(),
                                        m_mapper);

        return pr.features;
    }

    virtual Vamp::Plugin::FeatureSet
    finish(PluginStub *plugin) override {

        if (!m_transport->isOK()) {
            throw std::runtime_error("Piper server failed to start");
        }

        FinishRequest request;
        request.plugin = plugin;
        
        capnp::MallocMessageBuilder message;
        piper::RpcRequest::Builder builder = message.initRoot<piper::RpcRequest>();

        VampnProto::buildRpcRequest_Finish(builder, request, m_mapper);
        ReqId id = getId();
        builder.getId().setNumber(id);
        
	auto karr = call(message);

        capnp::FlatArrayMessageReader responseMessage(karr);
        piper::RpcResponse::Reader reader = responseMessage.getRoot<piper::RpcResponse>();

        //!!! handle (explicit) error case

        checkResponseType(reader, piper::RpcResponse::Response::Which::FINISH, id);

        FinishResponse pr;
        VampnProto::readFinishResponse(pr,
                                       reader.getResponse().getFinish(),
                                       m_mapper);

        m_mapper.removePlugin(m_mapper.pluginToHandle(plugin));

	// Don't delete the plugin. It's the plugin that is supposed
	// to be calling us here
        
        return pr.features;
    }

    virtual void
    reset(PluginStub *plugin,
          PluginConfiguration config) override {

        // Reload the plugin on the server side, and configure it as requested
        
        if (!m_transport->isOK()) {
            throw std::runtime_error("Piper server failed to start");
        }

        if (m_mapper.havePlugin(plugin)) {
            (void)finish(plugin); // server-side unload
        }

        PluginStaticData psd;
        PluginConfiguration defaultConfig;
        PluginHandleMapper::Handle handle =
            serverLoad(plugin->getPluginKey(),
                       plugin->getInputSampleRate(),
                       plugin->getAdapterFlags(),
                       psd, defaultConfig);

        m_mapper.addPlugin(handle, plugin);

        (void)configure(plugin, config);
    }
    
private:
    AssignedPluginHandleMapper m_mapper;
    ReqId getId() {
        //!!! todo: mutex
        static ReqId m_nextId = 0;
        return m_nextId++;
    }

    static
    kj::Array<capnp::word>
    toKJArray(const std::vector<char> &buffer) {
	// We could do this whole thing with fewer copies, but let's
	// see whether it matters first
        size_t wordSize = sizeof(capnp::word);
	size_t words = buffer.size() / wordSize;
	kj::Array<capnp::word> karr(kj::heapArray<capnp::word>(words));
	memcpy(karr.begin(), buffer.data(), words * wordSize);
	return karr;
    }

    void
    checkResponseType(const piper::RpcResponse::Reader &r,
                      piper::RpcResponse::Response::Which type,
                      ReqId id) {
        
        if (r.getResponse().which() != type) {
	    std::cerr << "checkResponseType: wrong response type (received "
		      << int(r.getResponse().which()) << ", expected "
		      << int(type) << ")"
		      << std::endl;
            throw std::runtime_error("Wrong response type");
        }
        if (ReqId(r.getId().getNumber()) != id) {
	    std::cerr << "checkResponseType: wrong response id (received "
		      << r.getId().getNumber() << ", expected " << id << ")"
		      << std::endl;
            throw std::runtime_error("Wrong response id");
        }
    }

    kj::Array<capnp::word>
    call(capnp::MallocMessageBuilder &message) {
        auto arr = capnp::messageToFlatArray(message);
        auto responseBuffer = m_transport->call(arr.asChars().begin(),
                                                arr.asChars().size());
	return toKJArray(responseBuffer);
    }
    
    PluginHandleMapper::Handle
    serverLoad(std::string key, float inputSampleRate, int adapterFlags,
               PluginStaticData &psd,
               PluginConfiguration &defaultConfig) {

        LoadRequest request;
        request.pluginKey = key;
        request.inputSampleRate = inputSampleRate;
        request.adapterFlags = adapterFlags;

        capnp::MallocMessageBuilder message;
        piper::RpcRequest::Builder builder = message.initRoot<piper::RpcRequest>();

        VampnProto::buildRpcRequest_Load(builder, request);
        ReqId id = getId();
        builder.getId().setNumber(id);

	auto karr = call(message);

        //!!! ... --> will also need some way to kill this process
        //!!! (from another thread)

        capnp::FlatArrayMessageReader responseMessage(karr);
        piper::RpcResponse::Reader reader = responseMessage.getRoot<piper::RpcResponse>();

        //!!! handle (explicit) error case

        checkResponseType(reader, piper::RpcResponse::Response::Which::LOAD, id);
        
        const piper::LoadResponse::Reader &lr = reader.getResponse().getLoad();
        VampnProto::readExtractorStaticData(psd, lr.getStaticData());
        VampnProto::readConfiguration(defaultConfig, lr.getDefaultConfiguration());
        return lr.getHandle();
    };     

private:
    SynchronousTransport *m_transport; //!!! I don't own this, but should I?
    CompletenessChecker *m_completenessChecker; // I own this
};

}
}

#endif