lib/DispatcherBase_cpp.template

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

//#include "DispatcherBase.h"
//#include "Parser.h"

{% for namespace in config.protocol.namespace %}
namespace {{namespace}} {
{% endfor %}

// static
DispatchResponse DispatchResponse::OK()
{
    DispatchResponse result;
    result.m_status = kSuccess;
    result.m_errorCode = kParseError;
    return result;
}

// static
DispatchResponse DispatchResponse::Error(const String& error)
{
    DispatchResponse result;
    result.m_status = kError;
    result.m_errorCode = kServerError;
    result.m_errorMessage = error;
    return result;
}

// static
DispatchResponse DispatchResponse::InternalError()
{
    DispatchResponse result;
    result.m_status = kError;
    result.m_errorCode = kInternalError;
    result.m_errorMessage = "Internal error";
    return result;
}

// static
DispatchResponse DispatchResponse::FallThrough()
{
    DispatchResponse result;
    result.m_status = kFallThrough;
    result.m_errorCode = kParseError;
    return result;
}

// static
const char DispatcherBase::kInvalidParamsString[] = "Invalid parameters";

DispatcherBase::WeakPtr::WeakPtr(DispatcherBase* dispatcher) : m_dispatcher(dispatcher) { }

DispatcherBase::WeakPtr::~WeakPtr()
{
    if (m_dispatcher)
        m_dispatcher->m_weakPtrs.erase(this);
}

DispatcherBase::Callback::Callback(std::unique_ptr<DispatcherBase::WeakPtr> backendImpl, int callId)
    : m_backendImpl(std::move(backendImpl))
    , m_callId(callId) { }

DispatcherBase::Callback::~Callback() = default;

void DispatcherBase::Callback::dispose()
{
    m_backendImpl = nullptr;
}

void DispatcherBase::Callback::sendIfActive(std::unique_ptr<protocol::DictionaryValue> partialMessage, const DispatchResponse& response)
{
    if (!m_backendImpl || !m_backendImpl->get())
        return;
    m_backendImpl->get()->sendResponse(m_callId, response, std::move(partialMessage));
    m_backendImpl = nullptr;
}

DispatcherBase::DispatcherBase(FrontendChannel* frontendChannel)
    : m_frontendChannel(frontendChannel) { }

DispatcherBase::~DispatcherBase()
{
    clearFrontend();
}

// static
bool DispatcherBase::getCommandName(const String& message, String* result)
{
    std::unique_ptr<protocol::Value> value = StringUtil::parseJSON(message);
    if (!value)
        return false;

    protocol::DictionaryValue* object = DictionaryValue::cast(value.get());
    if (!object)
        return false;

    if (!object->getString("method", result))
        return false;

    return true;
}

void DispatcherBase::sendResponse(int callId, const DispatchResponse& response, std::unique_ptr<protocol::DictionaryValue> result)
{
    if (response.status() == DispatchResponse::kError) {
        reportProtocolError(callId, response.errorCode(), response.errorMessage(), nullptr);
        return;
    }

    std::unique_ptr<protocol::DictionaryValue> responseMessage = DictionaryValue::create();
    responseMessage->setInteger("id", callId);
    responseMessage->setObject("result", std::move(result));
    if (m_frontendChannel)
        m_frontendChannel->sendProtocolResponse(callId, responseMessage->toJSONString());
}

void DispatcherBase::sendResponse(int callId, const DispatchResponse& response)
{
    sendResponse(callId, response, DictionaryValue::create());
}

static void reportProtocolErrorTo(FrontendChannel* frontendChannel, int callId, DispatchResponse::ErrorCode code, const String& errorMessage, ErrorSupport* errors)
{
    if (!frontendChannel)
        return;
    std::unique_ptr<protocol::DictionaryValue> error = DictionaryValue::create();
    error->setInteger("code", code);
    error->setString("message", errorMessage);
    if (errors && errors->hasErrors())
        error->setString("data", errors->errors());
    std::unique_ptr<protocol::DictionaryValue> message = DictionaryValue::create();
    message->setObject("error", std::move(error));
    message->setInteger("id", callId);
    frontendChannel->sendProtocolResponse(callId, message->toJSONString());
}

static void reportProtocolErrorTo(FrontendChannel* frontendChannel, DispatchResponse::ErrorCode code, const String& errorMessage)
{
    if (!frontendChannel)
        return;
    std::unique_ptr<protocol::DictionaryValue> error = DictionaryValue::create();
    error->setInteger("code", code);
    error->setString("message", errorMessage);
    std::unique_ptr<protocol::DictionaryValue> message = DictionaryValue::create();
    message->setObject("error", std::move(error));
    frontendChannel->sendProtocolNotification(message->toJSONString());
}

void DispatcherBase::reportProtocolError(int callId, DispatchResponse::ErrorCode code, const String& errorMessage, ErrorSupport* errors)
{
    reportProtocolErrorTo(m_frontendChannel, callId, code, errorMessage, errors);
}

void DispatcherBase::clearFrontend()
{
    m_frontendChannel = nullptr;
    for (auto& weak : m_weakPtrs)
        weak->dispose();
    m_weakPtrs.clear();
}

std::unique_ptr<DispatcherBase::WeakPtr> DispatcherBase::weakPtr()
{
    std::unique_ptr<DispatcherBase::WeakPtr> weak(new DispatcherBase::WeakPtr(this));
    m_weakPtrs.insert(weak.get());
    return weak;
}

UberDispatcher::UberDispatcher(FrontendChannel* frontendChannel)
    : m_frontendChannel(frontendChannel) { }

void UberDispatcher::registerBackend(const String& name, std::unique_ptr<protocol::DispatcherBase> dispatcher)
{
    m_dispatchers[name] = std::move(dispatcher);
}

DispatchResponse::Status UberDispatcher::dispatch(std::unique_ptr<Value> parsedMessage)
{
    if (!parsedMessage) {
        reportProtocolErrorTo(m_frontendChannel, DispatchResponse::kParseError, "Message must be a valid JSON");
        return DispatchResponse::kError;
    }
    std::unique_ptr<protocol::DictionaryValue> messageObject = DictionaryValue::cast(std::move(parsedMessage));
    if (!messageObject) {
        reportProtocolErrorTo(m_frontendChannel, DispatchResponse::kInvalidRequest, "Message must be an object");
        return DispatchResponse::kError;
    }

    int callId = 0;
    protocol::Value* callIdValue = messageObject->get("id");
    bool success = callIdValue && callIdValue->asInteger(&callId);
    if (!success) {
        reportProtocolErrorTo(m_frontendChannel, DispatchResponse::kInvalidRequest, "Message must have integer 'id' porperty");
        return DispatchResponse::kError;
    }

    protocol::Value* methodValue = messageObject->get("method");
    String method;
    success = methodValue && methodValue->asString(&method);
    if (!success) {
        reportProtocolErrorTo(m_frontendChannel, callId, DispatchResponse::kInvalidRequest, "Message must have string 'method' porperty", nullptr);
        return DispatchResponse::kError;
    }

    size_t dotIndex = method.find(".");
    if (dotIndex == StringUtil::kNotFound) {
        reportProtocolErrorTo(m_frontendChannel, callId, DispatchResponse::kMethodNotFound, "'" + method + "' wasn't found", nullptr);
        return DispatchResponse::kError;
    }
    String domain = StringUtil::substring(method, 0, dotIndex);
    auto it = m_dispatchers.find(domain);
    if (it == m_dispatchers.end()) {
        reportProtocolErrorTo(m_frontendChannel, callId, DispatchResponse::kMethodNotFound, "'" + method + "' wasn't found", nullptr);
        return DispatchResponse::kError;
    }
    return it->second->dispatch(callId, method, std::move(messageObject));
}

UberDispatcher::~UberDispatcher() = default;

{% for namespace in config.protocol.namespace %}
} // namespace {{namespace}}
{% endfor %}