tdelibs/kjs/property_map.cpp

/*
 *  This file is part of the KDE libraries
 *  Copyright (C) 2003 Apple Computer, Inc.
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 *
 */

#include "property_map.h"

#include "object.h"
#include "reference_list.h"

#include <assert.h>

#define DEBUG_PROPERTIES 0
#define DO_CONSISTENCY_CHECK 0
#define DUMP_STATISTICS 0
#define USE_SINGLE_ENTRY 1

// At the time I added USE_SINGLE_ENTRY, the optimization still gave a 1.5%
// performance boost to the iBench JavaScript benchmark so I didn't remove it.

#if !DO_CONSISTENCY_CHECK
#define checkConsistency() ((void)0)
#endif

namespace KJS {

#if DUMP_STATISTICS

static int numProbes;
static int numCollisions;

struct PropertyMapStatisticsExitLogger { ~PropertyMapStatisticsExitLogger(); };

static PropertyMapStatisticsExitLogger logger;

PropertyMapStatisticsExitLogger::~PropertyMapStatisticsExitLogger()
{
    printf("\nKJS::PropertyMap statistics\n\n");
    printf("%d probes\n", numProbes);
    printf("%d collisions (%.1f%%)\n", numCollisions, 100.0 * numCollisions / numProbes);
}

#endif

struct PropertyMapHashTable
{
    int sizeMask;
    int size;
    int keyCount;

    // gets initialized in expand, an array that stores insert order of a particular hash
    int *hashToIndex; // NOTE: is one based 1,2,3 etc..

    // keeps trac on how many insertions we have made, cant use keyCount because delete a key in the middle messes things
    int indexCount;

    PropertyMapHashTableEntry entries[1];
};

class SavedProperty {
public:
    Identifier key;
    Value value;
    int attributes;
};

SavedProperties::SavedProperties() : _count(0), _properties(0) { }

SavedProperties::~SavedProperties()
{
    delete [] _properties;
}

// Algorithm concepts from Algorithms in C++, Sedgewick.

PropertyMap::PropertyMap() : _table(0)
{
}

PropertyMap::~PropertyMap()
{
    if (!_table) {
#if USE_SINGLE_ENTRY
        UString::Rep *key = _singleEntry.key;
        if (key)
            key->deref();
#endif
        return;
    }

    for (int i = 0; i < _table->size; i++) {
        UString::Rep *key = _table->entries[i].key;
        if (key)
	  key->deref();
    }
    // fredrik added to cleanup sortorder
    if (_table)
        delete [] _table->hashToIndex;

    free(_table);
}

void PropertyMap::clear()
{
    if (!_table) {
#if USE_SINGLE_ENTRY
        UString::Rep *key = _singleEntry.key;
        if (key) {
            key->deref();
            _singleEntry.key = 0;
        }
#endif
        return;
    }

    for (int i = 0; i < _table->size; i++) {
        UString::Rep *key = _table->entries[i].key;
        if (key) {
            key->deref();
            _table->entries[i].key = 0;
        }
    }
    _table->keyCount = 0;
}

inline int PropertyMap::hash(const UString::Rep *s) const
{
    return s->hash() & _table->sizeMask;
}

ValueImp *PropertyMap::get(const Identifier &name, int &attributes) const
{
    assert(!name.isNull());

    UString::Rep *rep = name._ustring.rep;

    if (!_table) {
#if USE_SINGLE_ENTRY
        UString::Rep *key = _singleEntry.key;
        if (rep == key) {
            attributes = _singleEntry.attributes;
            return _singleEntry.value;
        }
#endif
        return 0;
    }

    int i = hash(rep);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[i].key && _table->entries[i].key != rep;
#endif
    while (UString::Rep *key = _table->entries[i].key) {
        if (rep == key) {
            attributes = _table->entries[i].attributes;
            return _table->entries[i].value;
        }
        i = (i + 1) & _table->sizeMask;
    }
    return 0;
}

ValueImp *PropertyMap::get(const Identifier &name) const
{
    assert(!name.isNull());

    UString::Rep *rep = name._ustring.rep;

    if (!_table) {
#if USE_SINGLE_ENTRY
        UString::Rep *key = _singleEntry.key;
        if (rep == key)
            return _singleEntry.value;
#endif
        return 0;
    }

    int i = hash(rep);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[i].key && _table->entries[i].key != rep;
#endif
    while (UString::Rep *key = _table->entries[i].key) {
        if (rep == key)
            return _table->entries[i].value;
        i = (i + 1) & _table->sizeMask;
    }
    return 0;
}

#if DEBUG_PROPERTIES
static void printAttributes(int attributes)
{
    if (attributes == 0)
        printf ("None ");
    if (attributes & ReadOnly)
        printf ("ReadOnly ");
    if (attributes & DontEnum)
        printf ("DontEnum ");
    if (attributes & DontDelete)
        printf ("DontDelete ");
    if (attributes & Internal)
        printf ("Internal ");
    if (attributes & Function)
        printf ("Function ");
}
#endif

void PropertyMap::put(const Identifier &name, ValueImp *value, int attributes)
{
    assert(!name.isNull());
    assert(value != 0);

#if DO_CONSISTENCY_CHECK // speed, why call a stub if we dont need to??
    checkConsistency();
#endif

    UString::Rep *rep = name._ustring.rep;

#if DEBUG_PROPERTIES
    printf("adding property %s, attributes = 0x%08x (", name.ascii(), attributes);
    printAttributes(attributes);
    printf(")\n");
#endif

#if USE_SINGLE_ENTRY
    if (!_table) {
        UString::Rep *key = _singleEntry.key;
        if (key) {
            if (rep == key) {
                _singleEntry.value = value;
                return;
            }
        } else {
            rep->ref();
            _singleEntry.key = rep;
            _singleEntry.value = value;
            _singleEntry.attributes = attributes;
            checkConsistency();
            return;
        }
    }
#endif
    if (!_table || _table->keyCount * 2 >= _table->size)
        expand();
    int i = hash(rep);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[i].key && _table->entries[i].key != rep;
#endif
    while (UString::Rep *key = _table->entries[i].key) {
        if (rep == key) {
            // Put a new value in an existing hash table entry.
            _table->entries[i].value = value;
            // Attributes are intentionally not updated.
            return;
        }
        i = (i + 1) & _table->sizeMask;
    }

    // Create a new hash table entry.
    rep->ref();
    _table->entries[i].key = rep;
    _table->entries[i].value = value;
    _table->entries[i].attributes = attributes;
    ++_table->keyCount;

    // store insert order
    _table->indexCount++;
    _table->hashToIndex[i] = _table->indexCount;

#if DO_CONSISTENCY_CHECK// speed, why call a stub if we dont need to??
    checkConsistency();
#endif
}

inline void PropertyMap::insert(UString::Rep *key, ValueImp *value, int attributes)
{
    assert(_table);

    int i = hash(key);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[i].key && _table->entries[i].key != key;
#endif
    while (_table->entries[i].key)
        i = (i + 1) & _table->sizeMask;

    _table->entries[i].key = key;
    _table->entries[i].value = value;
    _table->entries[i].attributes = attributes;
}

void PropertyMap::expand()
{
#if DO_CONSISTENCY_CHECK// speed, why call a stub if we dont need to??
    checkConsistency();
#endif
    Table *oldTable = _table;

    int oldTableSize = oldTable ? oldTable->size : 0;

    int newTableSize = oldTableSize ? oldTableSize * 2 : 16;

    // Is this realy the best way? wouldnt it be easier to use new/delete on an array instead
    // and do a pointer in Table to that array, that way we wouldnt need to delete the whole _table
    // every time we need to expand
    _table = (Table *)calloc(1, sizeof(Table) + ((newTableSize - 1) * sizeof(Entry)) );

    int *p = new int[newTableSize];
    for (int i = 0; i < newTableSize; i++)
        p[i] = 0;

    _table->hashToIndex = p;

    _table->size = newTableSize;

    _table->sizeMask = newTableSize - 1;

    _table->keyCount = oldTable ? oldTable->keyCount : 0;

    _table->indexCount = oldTable ? oldTable->indexCount : 0;

#if USE_SINGLE_ENTRY
    UString::Rep *key = _singleEntry.key;
    if (key) {
        insert(key, _singleEntry.value, _singleEntry.attributes);
        _table->keyCount++;
        _singleEntry.key = 0;

        // store sort order
        // first get the id of newly inserted key, check for trashed hash, then store it
        int k = hash(key);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[k].key && _table->entries[k].key != key;
#endif
        while (UString::Rep *newKey = _table->entries[k].key) {
             if (key == newKey)
                 break;
             k = (k + 1) & _table->sizeMask;
        }
        _table->indexCount++;
        _table->hashToIndex[k] = _table->indexCount;
    }
#endif

    for (int i = 0; i != oldTableSize; ++i) {
        UString::Rep *key = oldTable->entries[i].key;
        if (key) {
            insert(key, oldTable->entries[i].value, oldTable->entries[i].attributes);

            // store sort order
            // first get the id of newly inserted key, check for trashed hash, then store it
            int k = hash(key);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[k].key && _table->entries[k].key != key;
#endif
            while (UString::Rep *newKey = _table->entries[k].key) {
                if (key == newKey)
                    break;
                k = (k + 1) & _table->sizeMask;
            }
            // store hashindex on the newly inserted entry
            _table->hashToIndex[k] = oldTable->hashToIndex[i];
        }
    }

    if (oldTable){
        delete [] oldTable->hashToIndex;
    }
    free(oldTable);

#if DO_CONSISTENCY_CHECK// speed, why call a stub if we dont need to??
    checkConsistency();
#endif
}

void PropertyMap::remove(const Identifier &name)
{
    assert(!name.isNull());

#if DO_CONSISTENCY_CHECK// speed, why call a stub if we dont need to??
    checkConsistency();
#endif

    UString::Rep *rep = name._ustring.rep;

    UString::Rep *key;

    if (!_table) {
#if USE_SINGLE_ENTRY
        key = _singleEntry.key;
        if (rep == key) {
            key->deref();
            _singleEntry.key = 0;
            checkConsistency();
        }
#endif
        return;
    }

    // Find the thing to remove.
    int i = hash(rep);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[i].key && _table->entries[i].key != rep;
#endif
    while ((key = _table->entries[i].key)) {
        if (rep == key)
            break;
        i = (i + 1) & _table->sizeMask;
    }

    if (!key)
        return;

    // Remove the one key.
    key->deref();
    _table->entries[i].key = 0;
    assert(_table->keyCount >= 1);
    --_table->keyCount;

    // Reinsert all the items to the right in the same cluster.
    while (1) {
        i = (i + 1) & _table->sizeMask;
        key = _table->entries[i].key;
        if (!key)
            break;

        _table->entries[i].key = 0;

        insert(key, _table->entries[i].value, _table->entries[i].attributes);

        // store the index of the new hash
        int k = hash(key);
#if DUMP_STATISTICS
    ++numProbes;
    numCollisions += _table->entries[k].key && _table->entries[k].key != key;
#endif
        while (UString::Rep *newKey = _table->entries[k].key) {
            if (key == newKey)
                break;
            k = (k + 1) & _table->sizeMask;
        }

        // store hashindex on the newly moved entry
        _table->hashToIndex[k] = _table->hashToIndex[i];
    }

#if DO_CONSISTENCY_CHECK// speed, why call a stub if we dont need to??
    checkConsistency();
#endif
}

void PropertyMap::mark() const
{
    if (!_table) {
#if USE_SINGLE_ENTRY
        if (_singleEntry.key) {
            ValueImp *v = _singleEntry.value;
            if (!v->marked())
                v->mark();
        }
#endif
        return;
    }

    for (int i = 0; i != _table->size; ++i) {
        if (_table->entries[i].key) {
            ValueImp *v = _table->entries[i].value;
            if (!v->marked())
                v->mark();
        }
    }
}

void PropertyMap::addEnumerablesToReferenceList(ReferenceList &list, const Object &base) const
{
    if (!_table) {
#if USE_SINGLE_ENTRY
        UString::Rep *key = _singleEntry.key;
        if (key && !(_singleEntry.attributes & DontEnum))
            list.append(Reference(base, Identifier(key)));
#endif
        return;
    }

    // Allocate a buffer to use to sort the keys.
    int indexSize = _table->indexCount + 1; // indexes is one based
    UString::Rep **allKeys = new UString::Rep*[indexSize];

    for (int i = 0; i < indexSize; i++)
        allKeys[i] = NULL;

    // push  valid hashes to the array allKeys, using insert order as index.
    // we need to pass array hashes instead of pointers to keys, because we got
    // memory corruption sometimes, seems that Identifier in below call deletes the key
    int size = _table->size;
    Entry *entries = _table->entries;
    for (int i = 0; i != size; ++i) {
        if (entries[i].key && !(entries[i].attributes & DontEnum)) {
            int idx = _table->hashToIndex[i];
            if (idx) {
                allKeys[idx] = entries[i].key;
            } else { // nonsorted key, failure
                //cout<<"Error with in KJS property_map.addEnumerablesToReferenceList \nUnsorted key"<<endl;
                assert(0==1); // allways throw error if get here
            }
        }
    }
    // Put the keys of the sorted entries into the reference list.
    for (int i = 0; i < indexSize; ++i) {
        if (allKeys[i] != NULL){
            list.append(Reference(base, Identifier(allKeys[i])));
        }
        allKeys[i] = NULL; // dont deallocate key by accident, when we delete allKeys
    }

    // Deallocate the buffer.
    delete [] allKeys;
}

void PropertyMap::addSparseArrayPropertiesToReferenceList(ReferenceList &list, const Object &base) const
{
    // NOTE: I did'nt add sort in this method because It seems to be referenced in ArrayInstanceImp
    // only and arrays are sorted by definition, dont need the extra overhead
    if (!_table) {
#if USE_SINGLE_ENTRY
        UString::Rep *key = _singleEntry.key;
        if (key) {
            UString k(key);
            bool fitsInULong;
            unsigned long i = k.toULong(&fitsInULong);
            if (fitsInULong && i <= 0xFFFFFFFFU)
                list.append(Reference(base, Identifier(key)));
        }
#endif
        return;
    }

    for (int i = 0; i != _table->size; ++i) {
        UString::Rep *key = _table->entries[i].key;
        if (key) {
            UString k(key);
            bool fitsInULong;
            unsigned long i = k.toULong(&fitsInULong);
            if (fitsInULong && i <= 0xFFFFFFFFU)
                list.append(Reference(base, Identifier(key)));
        }
    }
}

void PropertyMap::save(SavedProperties &p) const
{
    int count = 0;

    if (!_table) {
#if USE_SINGLE_ENTRY
        if (_singleEntry.key && !(_singleEntry.attributes & (ReadOnly | DontEnum | Function)))
            ++count;
#endif
    } else {
        for (int i = 0; i != _table->size; ++i)
            if (_table->entries[i].key && !(_table->entries[i].attributes & (ReadOnly | DontEnum | Function)))
                ++count;
    }

    delete [] p._properties;

    p._count = count;

    if (count == 0) {
        p._properties = 0;
        return;
    }

    p._properties = new SavedProperty [count];

    SavedProperty *prop = p._properties;

    if (!_table) {
#if USE_SINGLE_ENTRY
        if (_singleEntry.key && !(_singleEntry.attributes & (ReadOnly | DontEnum | Function))) {
            prop->key = Identifier(_singleEntry.key);
            prop->value = Value(_singleEntry.value);
            prop->attributes = _singleEntry.attributes;
            ++prop;
        }
#endif
    } else {
        for (int i = 0; i != _table->size; ++i) {
            if (_table->entries[i].key && !(_table->entries[i].attributes & (ReadOnly | DontEnum | Function))) {
                prop->key = Identifier(_table->entries[i].key);
                prop->value = Value(_table->entries[i].value);
                prop->attributes = _table->entries[i].attributes;
                ++prop;
            }
        }
    }
}

void PropertyMap::restore(const SavedProperties &p)
{
    for (int i = 0; i != p._count; ++i)
        put(p._properties[i].key, p._properties[i].value.imp(), p._properties[i].attributes);
}

#if DO_CONSISTENCY_CHECK

void PropertyMap::checkConsistency()
{
    if (!_table)
        return;

    int count = 0;
    for (int j = 0; j != _table->size; ++j) {
        UString::Rep *rep = _table->entries[j].key;
        if (!rep)
            continue;
        int i = hash(rep);
        while (UString::Rep *key = _table->entries[i].key) {
            if (rep == key)
                break;
            i = (i + 1) & _table->sizeMask;
        }
        assert(i == j);
        assert(_table->hashToIndex[i] > 0);
        count++;
    }
    assert(count == _table->keyCount);
    assert(_table->size >= 16);
    assert(_table->sizeMask);
    assert(_table->size == _table->sizeMask + 1);
}

#endif // DO_CONSISTENCY_CHECK

} // namespace KJS