Bridge.cc

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/*
    Copyright (c) 2002-2009 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file Bridge.cc
 *
 * Implementation of Bridge class.
 *
 * @author Lasse Laasonen 2003 (lasse.laasonen-no.spam-tut.fi)
 * @note reviewed 10 Jun 2004 by vpj, am, tr, ll
 * @note rating: red
 */
 
#include <set>
 
#include "Bridge.hh"
#include "Machine.hh"
#include "Bus.hh"
#include "MachineTester.hh"
#include "MachineTestReporter.hh"
#include "MOMTextGenerator.hh"
#include "Application.hh"
#include "AssocTools.hh"
#include "ObjectState.hh"
 
using std::string;
using std::set;
using boost::format;
 
namespace TTAMachine {
 
// initialization of static data members
const string Bridge::OSNAME_BRIDGE = "bridge";
const string Bridge::OSKEY_SOURCE_BUS = "source";
const string Bridge::OSKEY_DESTINATION_BUS = "destination";
 
 
/**
 * Constructor.
 *
 * @param name Name of the bridge.
 * @param sourceBus Bus from which the bridge reads data.
 * @param destinationBus Bus to which the bridge writes data.
 * @exception IllegalRegistration If the given source and destination buses
 *                                are not registered to the same machine.
 * @exception ComponentAlreadyExists If there is another bridge by the same
 *                                   name in the machine which contains the
 *                                   source and destination buses.
 * @exception IllegalConnectivity If the bridge cannot be created because it
 *                                would violate a connectivity constraint.
 * @exception IllegalParameters If the given buses are the same instance.
 * @exception InvalidName If the given name is not a valid component name.
 */
Bridge::Bridge(const string& name, Bus& sourceBus, Bus& destinationBus)
    : Component(name), sourceBus_(NULL), destinationBus_(NULL) {
    const string procName = "Bridge::Bridge";
 
    if (&sourceBus == &destinationBus) {
        throw IllegalParameters(__FILE__, __LINE__, procName);
    }
 
    sourceBus.ensureRegistration(destinationBus);
    MachineTester& tester = sourceBus.machine()->machineTester();
    if (!tester.canBridge(sourceBus, destinationBus)) {
        string errorMsg = MachineTestReporter::bridgingError(
            sourceBus, destinationBus, tester);
        throw IllegalConnectivity(__FILE__, __LINE__, procName, errorMsg);
    }
 
    setMachine(*sourceBus.machine());
    setSourceAndDestination(sourceBus, destinationBus);
}
 
/**
 * Constructor.
 *
 * Creates a skeleton objects with name only. This constructor should be used
 * by Machine::loadState only. Do not use this constructor.
 *
 * @param state The ObjectState instance.
 * @param mach The machine to which the bridge belongs.
 * @exception ObjectStateLoadingException If the machine already has a bridge
 *                                        by the same name as the coming name
 *                                        of this bridge or if the
 *                                        ObjectState instance is invalid.
 */
Bridge::Bridge(const ObjectState* state, Machine& mach)
    : Component(state), sourceBus_(NULL), destinationBus_(NULL) {
    Machine::BridgeNavigator bridgeNav = mach.bridgeNavigator();
 
    if (!bridgeNav.hasItem(name())) {
        setMachine(mach);
    } else {
        MOMTextGenerator textGenerator;
        format errorMsg = textGenerator.text(MOMTextGenerator::
                                             TXT_BRIDGE_EXISTS_BY_SAME_NAME);
        errorMsg % name();
        string procName = "Bridge::Bridge";
        throw ObjectStateLoadingException(__FILE__, __LINE__, procName,
                                          errorMsg.str());
    }
}
 
/**
 * Destructor.
 */
Bridge::~Bridge() {
    unsetMachine();
}
 
 
/**
 * Sets the name of the bridge.
 *
 * @param name Name of the bridge.
 * @exception ComponentAlreadyExists If a bridge with the given name is
 *                                   already in the same machine.
 * @exception InvalidName If the given name is not a valid component name.
 */
void
Bridge::setName(const string& name) {
    if (name == this->name()) {
        return;
    }
 
    if (machine() != NULL) {
        if (machine()->bridgeNavigator().hasItem(name)) {
            string procName = "Bridge::setName";
            throw ComponentAlreadyExists(__FILE__, __LINE__, procName);
        } else {
            Component::setName(name);
        }
    } else {
        Component::setName(name);
    }
}
 
/**
 * Returns the previous bus from location point of view.
 *
 * @return The previous bus.
 */
Bus*
Bridge::previousBus() const {
    if (sourcePrevious_) {
        return sourceBus_;
    } else {
        return destinationBus_;
    }
}
 
 
/**
 * Returns the next bus from location point of view.
 *
 * @return The next bus.
 */
Bus*
Bridge::nextBus() const {
    if (sourcePrevious_) {
        return destinationBus_;
    } else {
        return sourceBus_;
    }
}
 
 
/**
 * Registers the bridge to a machine.
 *
 * @param mach Machine to which the bridge is going to be registered.
 * @exception ComponentAlreadyExists If the given machine already has another
 *                                   bridge by the same name.
 */
void
Bridge::setMachine(Machine& mach) {
    mach.addBridge(*this);
    internalSetMachine(mach);
}
 
/**
 * Removes registration of the bridge from its current machine.
 *
 * The bridge is deleted because it cannot be unregistered from the machine.
 */
void
Bridge::unsetMachine() {
 
    assert(machine() != NULL);
 
    Bus* oldSource = sourceBus_;
    Bus* oldDestination = destinationBus_;
    sourceBus_ = NULL;
    destinationBus_ = NULL;
 
    if (oldSource != NULL) {
        // may be NULL if loading the state from ObjectState has failed
        oldSource->clearDestinationBridge(*this);
    }
 
    if (oldDestination != NULL) {
        // may be NULL if loading the state from ObjectState has failed
        oldDestination->clearSourceBridge(*this);
    }
 
    Machine* mach = machine();
    internalUnsetMachine();
    mach->deleteBridge(*this);
}
 
 
/**
 * Saves the contents to an ObjectState object.
 *
 * @return The newly created ObjectState object.
 */
ObjectState*
Bridge::saveState() const {
    ObjectState* bridge = Component::saveState();
    bridge->setName(OSNAME_BRIDGE);
    string sourceBusName = sourceBus_->name();
    string destinationBusName = destinationBus_->name();
    bridge->setAttribute(OSKEY_SOURCE_BUS, sourceBusName);
    bridge->setAttribute(OSKEY_DESTINATION_BUS, destinationBusName);
    return bridge;
}
 
 
/**
 * Loads its state from the given ObjectState instance.
 *
 * If the bridge is already joining two buses, the function will not work and
 * ObjectStateLoadingException is thrown. This method works only if the
 * bridge was created by the constructor with ObjectState argument.
 *
 * @param state The ObjectState instance.
 * @exception ObjectStateLoadingException If the machine already a bridge by
 *                                        the same name as the coming name
 *                                        of this bridge or if creating
 *                                        references fails or if the given
 *                                        ObjectState instance is invalid.
 */
void
Bridge::loadState(const ObjectState* state) {
    const string procName = "Bridge::loadState";
 
    if (state->name() != OSNAME_BRIDGE) {
        throw ObjectStateLoadingException(__FILE__, __LINE__, procName);
    }
    if (sourceBus() != NULL || destinationBus() != NULL) {
        throw ObjectStateLoadingException(__FILE__, __LINE__, procName);
    }
 
    Component::loadState(state);
 
    try {
        string sourceBusName = state->stringAttribute(OSKEY_SOURCE_BUS);
        string destinationBusName =
            state->stringAttribute(OSKEY_DESTINATION_BUS);
 
        assert(isRegistered());
        Machine::BusNavigator busNav = machine()->busNavigator();
        Bus* source;
        Bus* destination;
        try {
            source = busNav.item(sourceBusName);
            destination = busNav.item(destinationBusName);
        } catch (InstanceNotFound& e) {
            MOMTextGenerator textGenerator;
            format errorMsg = textGenerator.text(
                MOMTextGenerator::TXT_BRIDGE_UNKNOWN_SRC_OR_DST);
            errorMsg % name();
            throw ObjectStateLoadingException(__FILE__, __LINE__, procName,
                                              errorMsg.str());
        }
        MachineTester& tester = machine()->machineTester();
        if (tester.canBridge(*source, *destination)) {
            setSourceAndDestination(*source, *destination);
        } else {
            string errorMsg = MachineTestReporter::bridgingError(
                *source, *destination, tester);
            throw ObjectStateLoadingException(__FILE__, __LINE__, procName,
                                              errorMsg);
        }
 
    } catch(Exception& e) {
        throw ObjectStateLoadingException(__FILE__, __LINE__, procName,
                                          e.errorMessage());
    }
}
 
/**
 * Adjusts the direction of the bus chain (next/previous).
 *
 * When two bus chains are joined by a new bridge the direction of the
 * destination side chain may have to be changed to verify that the
 * direction of the new longer chain does not change in the middle of the
 * chain. That is, if the source bus of the new bridge is the last of its
 * chain and the destination bus of the new bridge is also the last, the
 * direction of the destination side chain has to be changed such that the
 * destination bus will become the first bus of its chain.
 *
 * @param sourceBus The new source side bus.
 * @param destinationBus The new destination side bus.
 */
void
Bridge::adjustChainDirection(
    const Bus& sourceBus,
    const Bus& destinationBus) {
 
    Machine* mach = sourceBus.machine();
    Machine::BridgeNavigator bridgeNav = mach->bridgeNavigator();
 
    // if another bridge joining the buses is found, see the direction
    // from that bridge
    for (int i = 0; i < bridgeNav.count(); i++) {
        Bridge* bridge = bridgeNav.item(i);
        if (bridge->sourceBus() == &destinationBus &&
            bridge->destinationBus() == &sourceBus) {
            if (bridge->previousBus() == &sourceBus) {
                sourcePrevious_ = true;
            } else {
                sourcePrevious_ = false;
            }
            return;
        }
    }
 
    // change the direction of the bus chain containing destinationBus if
    // needed
    if (!sourceBus.hasNextBus()) {
        sourcePrevious_ = true;
        setFirstOfChain(destinationBus);
    } else {
        sourcePrevious_ = false;
        // find the bus that should be the first bus of destination side
        // chain
        const Bus* otherEnd = &destinationBus;
        while (otherEnd->hasNextBus()) {
            otherEnd = otherEnd->nextBus();
        }
        if (otherEnd != &destinationBus) {
            setFirstOfChain(*otherEnd);
        }
    }
}
 
 
/**
 * Sets the source and destination buses of the bridge.
 *
 * The bridge must not have source and destination buses before calling this
 * method.
 *
 * @param sourceBus The source bus.
 * @param destinationBus The destination bus.
 */
void
Bridge::setSourceAndDestination(Bus& sourceBus, Bus& destinationBus) {
    assert(sourceBus_ == NULL && destinationBus_ == NULL);
    assert(!sourceBus.canWrite(destinationBus));
    assert(!destinationBus.canRead(sourceBus));
    adjustChainDirection(sourceBus, destinationBus);
    sourceBus.setDestinationBridge(*this);
    destinationBus.setSourceBridge(*this);
    sourceBus_ = &sourceBus;
    destinationBus_ = &destinationBus;
}
 
 
/**
 * Sets the given bus to the first bus of the bus chain.
 *
 * That is, changes the direction of the chain if the given bus is currently
 * the last bus of the chain. The given bus must be at the end of chain.
 *
 * @param bus The bus to be set to the first bus of the chain.
 */
void
Bridge::setFirstOfChain(const Bus& bus) {
 
    assert(!(bus.hasPreviousBus() && bus.hasNextBus()));
 
    if (bus.hasNextBus()) {
        // if the bus is already the first
        return;
    } else {
        const Bus* observable = &bus;
 
        // collect the buses of the chain to set
        set<const Bus*> busesInChain;
        busesInChain.insert(observable);
        while (observable->hasPreviousBus()) {
            observable = observable->previousBus();
            busesInChain.insert(observable);
        }
 
        Machine::BridgeNavigator bridgeNav =
            bus.machine()->bridgeNavigator();
        // change (next/previous) direction of each bridge that is joining
        // a bus in the set
        for (int i = 0; i < bridgeNav.count(); i++) {
            Bridge* bridge = bridgeNav.item(i);
            // Source bus or destination bus is NULL only if the bridge
            // was created from ObjectState. Then calling nextBus() is
            // illegal because sourcePrevious_ member is not initialized.
            if (bridge->sourceBus() != NULL &&
                bridge->destinationBus() != NULL &&
                AssocTools::containsKey(busesInChain, bridge->nextBus())) {
                bridge->sourcePrevious_ = !bridge->sourcePrevious_;
            }
        }
    }
}
 
}