SafePointer.hh

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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 SafePointer.hh
 *
 * Declaration of SafePointer class and utility classes and types related
 * to ReferenceManager.
 *
 * @author Pekka Jääskeläinen 2003 (pjaaskel-no.spam-cs.tut.fi)
 * @note reviewed 29 Aug 2003 by rm, ml, ac, tr
 *
 * @note rating: yellow
 */
 
#ifndef TTA_SAFEPOINTER_HH
#define TTA_SAFEPOINTER_HH
 
#include <cstddef> // NULL
#include <set>
#include <map>
#include <list>
#include <iterator>
#include <sstream>
 
//#include "hash_map.hh"
#include "Application.hh"
#include "ReferenceKey.hh"
#include "Exception.hh" // IllegalParameters, UnresolvedReference
 
namespace TPEF {
 
class SafePointable;
 
/**
 *
 * Contains classes, utility classes and types related to reference managing.
 *
 */
namespace ReferenceManager {
 
class SafePointer;
 
///////////////////////////////////////////////////////////////////////////////
// SafePointerList
///////////////////////////////////////////////////////////////////////////////
/**
 * List of SafePointers that are all pointing to the same object.
 *
 */
class SafePointerList {
public:
    /// Type of the container to hold the SafePointers in.
    typedef std::list<SafePointer*> SafePointerListType;
 
    /// Type of the list length value.
    typedef std::string::size_type LengthType;
 
    SafePointerList();
    SafePointerList(SafePointerList &aList);
 
    virtual ~SafePointerList();
 
    void setReference(const SafePointable* obj);
    SafePointable* reference() const;
 
    void append(SafePointer* newSafePointer);
    void append(SafePointerList* anotherSafePointerList);
 
    SafePointer* front() const;
 
    void cleanup();
    void cleanupDead();
 
    LengthType length() const;
 
private:
    /// Object that SafePointers in this list are pointing to.
    SafePointable* reference_;
 
    /// Container for SafePointers.
    SafePointerListType list_;
};
 
/**
 * Class containing all the hash functions if hash_map is
 * used. However the use of hash_map will make program very slow
 * unless MapTools::containsValue() is not optimised for 
 * hash_tables or that function should be circumvented.
 */
class HashFunctions {
public:
    size_t operator()(const SectionIndexKey& key) const {
        return key.index()^
            (static_cast<size_t>(key.sectionId()) <<
             ((sizeof(size_t) - sizeof(SectionId)) *
              BYTE_BITWIDTH));
    }
 
    size_t operator()(const SectionOffsetKey& key) const {
        return key.offset()^
            (static_cast<size_t>(key.sectionId()) <<
             ((sizeof(size_t) - sizeof(SectionId)) *
              BYTE_BITWIDTH));
    }
 
    size_t operator()(const FileOffsetKey& key) const {
        return key.fileOffset();
    }
 
    size_t operator()(const SectionKey& key) const {
        return key.sectionId();
    }
 
    size_t operator()(const SafePointable* const & key) const {
        return reinterpret_cast<size_t>(key);
    }
};
 
// TODO: for hash map implementation check SafePointer.cc line 424 TODO
//       MapTools::containsValue call takes very long time for hash maps..
 
/// Unordered set of SafePointers.
typedef std::set<SafePointer*> SafePointerSet;
 
/// Map for SafePointers that are requested using SectionIndexKeys.
typedef std::map<SectionIndexKey, SafePointerList*> SectionIndexMap;
//typedef hash_map<SectionIndexKey, SafePointerList*,
//                 HashFunctions> SectionIndexMap;
 
/// Map for SafePointers that are requested using SectionOffsetKeys.
typedef std::map<SectionOffsetKey, SafePointerList*> SectionOffsetMap;
//typedef hash_map<SectionOffsetKey, SafePointerList*,
//                 HashFunctions> SectionOffsetMap;
 
/// Map for SafePointers that are requested using FileOffsetKeys.
typedef std::map<FileOffsetKey, SafePointerList*> FileOffsetMap;
//typedef hash_map<FileOffsetKey, SafePointerList*,
//                 HashFunctions> FileOffsetMap;
 
/// Map for SafePointers that are requested using SectionKeys.
typedef std::map<SectionKey, SafePointerList*> SectionMap;
//typedef hash_map<SectionKey, SafePointerList*,
//                 HashFunctions> SectionMap;
 
 
/// Map for resolved references, that is SafePointers that are pointing to
/// the created object.
typedef std::map<const SafePointable*, SafePointerList*> ReferenceMap;
//typedef hash_map<const SafePointable*, SafePointerList*,
//                 HashFunctions> ReferenceMap;
 
 
///////////////////////////////////////////////////////////////////////////////
// SafePointer
///////////////////////////////////////////////////////////////////////////////
/**
 * Indirection for object references.
 *
 * Allows updating references later on, thus allows referencing objects that
 * are created later. Helps with the dangling pointers problem, too.
 *
 * References to objects that are not created yet are made with different kind
 * of keys. These keys refer for example to sections and offsets in source
 * binary file while reading the binary. After the binary is read and the
 * object model of binary is constructed, these keys and keytables have no use.
 */
class SafePointer {
public:
    virtual ~SafePointer();
 
    SafePointable* pointer() const;
    void setPointer(SafePointable* object);
 
    static bool isAlive(SafePointer* pointerToCheck);
    static bool isReferenced(const SafePointable* object);
 
    static void addObjectReference(
        SectionIndexKey key, const SafePointable* obj);
    static void addObjectReference(
        SectionOffsetKey key, const SafePointable* obj);
    static void addObjectReference(FileOffsetKey key, const SafePointable* obj);
    static void addObjectReference(SectionKey key, const SafePointable* obj);
 
    static SectionIndexKey sectionIndexKeyFor(const SafePointable* obj);
    static SectionOffsetKey sectionOffsetKeyFor(const SafePointable* obj);
    static FileOffsetKey fileOffsetKeyFor(const SafePointable* obj);
    static SectionKey sectionKeyFor(const SafePointable* obj);
 
    static void notifyDeleted(const SafePointable* obj);
    static void notifyDeleted(SafePointer* safePointer);
 
    static void resolve();
 
    static void cleanupKeyTables();
    static void cleanup();
 
    template <typename MapType>
    static bool unresolvedReferences(const MapType& mapToCheck,
                                     const ReferenceKey **unresolvedKey);
 
    static const SafePointer* replaceReference(
        const SafePointer* old, SafePointable* obj);
 
    static void replaceAllReferences(
        SafePointable* newObj, SafePointable* oldObj);
 
    /// The default SafePointer that is used in null references.
    static const SafePointer null;
 
#ifndef NDEBUG
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
/**
 * Creates SafePointer with debug data of creation place of pointer.
 *
 * Just calls debugCreate method, with full parameters.
 *
 * Creation place of SafePointer is very important to know
 * because it's very hard to find where SafePointer that points
 * to wrong place was created.
 */
#define CREATE_SAFEPOINTER(x) \
    ReferenceManager::SafePointer::debugCreate( x , __FILE__, __LINE__)
 
    // Debug methods... don't delete.
 
    // methods for testing
    static const SectionIndexMap* SIMap();
    static const SafePointerList* SIMapAt(SectionIndexKey k);
    static const SectionOffsetMap* SOMap();
    static const SafePointerList* SOMapAt(SectionOffsetKey k);
    static const FileOffsetMap* FOMap();
    static const SafePointerList* FOMapAt(FileOffsetKey k);
    static const ReferenceMap* RMap();
    static const SafePointerList* RMapAt(SafePointable* k);
    static const SectionMap* SMap();
    static const SafePointerList* SMapAt(SectionKey k);
 
    // methods to set and get debug string
    void setDebugString(std::string aStr);
    std::string debugString() const;
 
    template <typename ObjType>
    static SafePointer* debugCreate(ObjType obj, const char *file, int line);
 
#endif // DOXYGEN_SHOULD_SKIP_THIS
 
#else
 
/**
 * Creates SafePointer without debug data.
 *
 * Just calls genericCreate method.
 */
#define CREATE_SAFEPOINTER(x) \
    ReferenceManager::SafePointer::genericCreate(x)
#endif
 
    template <typename ObjType>
    static SafePointer* genericCreate(ObjType obj);
 
 
protected:
    SafePointer(SectionIndexKey key);
    SafePointer(SectionOffsetKey key);
    SafePointer(FileOffsetKey key);
    SafePointer(SectionKey key);
    SafePointer(SafePointable* object);
 
    template <typename KeyType, typename MapType>
    void genericRegisterPointer(
        const KeyType& key,
        MapType& destinationMap,
        SafePointer* newSafePointer);
 
    template <typename KeyType, typename MapType>
    static void genericAddObjectReference(
        const KeyType& key, MapType& destinationMap, const SafePointable* obj);
 
    template <typename KeyType, typename MapType>
    static KeyType genericKeyFor(const SafePointable* obj, MapType& sourceMap);
 
    template <typename MapType>
    static void safelyCleanupKeyTable(
        MapType& sourceMap,
        std::set<SafePointerList*>&
        listsToDelete);
 
private:
 
    /// The reference to the real object.
    SafePointable* object_;
 
    /// Map of SafePointers that are requested using SectionIndexKeys.
    static SectionIndexMap* sectionIndexMap_;
 
    /// Map of SafePointers that are requested using SectionOffsetKeys.
    static SectionOffsetMap* sectionOffsetMap_;
 
    /// Map of SafePointers that are requested using FileOffsetKeys.
    static FileOffsetMap* fileOffsetMap_;
 
    /// Map of SafePointers that are requested using SectionKeys.
    static SectionMap* sectionMap_;
 
    /// Map of SafePointers that have resolved references.
    static ReferenceMap* referenceMap_;
 
    /// Set that cointains all alive (not deleted) SafePointers for extra
    /// safety.
    static SafePointerSet* aliveSafePointers_;
 
    // KeyFor cache stuff to make genericKeyFor function to work O(1) speed
    // after first call
 
    /// Key type for cache, void* is pointer to key map
    /// (sectioMap_, sectionOffsetMap, ...)
    typedef std::pair<const SafePointable*, void*> KeyForCacheKey;
    typedef std::map<KeyForCacheKey,const ReferenceKey*> KeyForCacheMap;
 
    /// Map for cache.
    static KeyForCacheMap* keyForCache_;
 
    /// Assignment not allowed.
    SafePointer& operator=(SafePointer&);
 
    /// Copying not allowed.
    SafePointer(SafePointer&);
 
#ifndef NDEBUG
    std::string debugString_;
#endif
 
};
 
} // namespace ReferenceManager
}
 
#include "SafePointer.icc"
 
#endif