JSArray.cpp 47.9 KB
Newer Older
darin's avatar
darin committed
1 2
/*
 *  Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
3
 *  Copyright (C) 2003, 2007, 2008, 2009 Apple Inc. All rights reserved.
darin's avatar
darin committed
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
 *  Copyright (C) 2003 Peter Kelly (pmk@post.com)
 *  Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#include "config.h"
darin@apple.com's avatar
darin@apple.com committed
24
#include "JSArray.h"
darin's avatar
darin committed
25

darin@apple.com's avatar
darin@apple.com committed
26
#include "ArrayPrototype.h"
27
#include "CachedCall.h"
28
#include "Error.h"
29
#include "Executable.h"
darin's avatar
darin committed
30
#include "PropertyNameArray.h"
ap@webkit.org's avatar
ap@webkit.org committed
31
#include <wtf/AVLTree.h>
32
#include <wtf/Assertions.h>
33
#include <wtf/OwnPtr.h>
34
#include <Operations.h>
darin's avatar
darin committed
35

36
using namespace std;
ap@webkit.org's avatar
ap@webkit.org committed
37
using namespace WTF;
bdash's avatar
bdash committed
38

39
namespace JSC {
darin's avatar
darin committed
40

ggaren@apple.com's avatar
ggaren@apple.com committed
41 42
ASSERT_CLASS_FITS_IN_CELL(JSArray);

barraclough@apple.com's avatar
barraclough@apple.com committed
43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
// Overview of JSArray
//
// Properties of JSArray objects may be stored in one of three locations:
//   * The regular JSObject property map.
//   * A storage vector.
//   * A sparse map of array entries.
//
// Properties with non-numeric identifiers, with identifiers that are not representable
// as an unsigned integer, or where the value is greater than  MAX_ARRAY_INDEX
// (specifically, this is only one property - the value 0xFFFFFFFFU as an unsigned 32-bit
// integer) are not considered array indices and will be stored in the JSObject property map.
//
// All properties with a numeric identifer, representable as an unsigned integer i,
// where (i <= MAX_ARRAY_INDEX), are an array index and will be stored in either the
// storage vector or the sparse map.  An array index i will be handled in the following
// fashion:
//
//   * Where (i < MIN_SPARSE_ARRAY_INDEX) the value will be stored in the storage vector.
//   * Where (MIN_SPARSE_ARRAY_INDEX <= i <= MAX_STORAGE_VECTOR_INDEX) the value will either
//     be stored in the storage vector or in the sparse array, depending on the density of
//     data that would be stored in the vector (a vector being used where at least
//     (1 / minDensityMultiplier) of the entries would be populated).
//   * Where (MAX_STORAGE_VECTOR_INDEX < i <= MAX_ARRAY_INDEX) the value will always be stored
//     in the sparse array.

// The definition of MAX_STORAGE_VECTOR_LENGTH is dependant on the definition storageSize
// function below - the MAX_STORAGE_VECTOR_LENGTH limit is defined such that the storage
ggaren@apple.com's avatar
ggaren@apple.com committed
70 71 72
// size calculation cannot overflow.  (sizeof(ArrayStorage) - sizeof(JSValue)) +
// (vectorLength * sizeof(JSValue)) must be <= 0xFFFFFFFFU (which is maximum value of size_t).
#define MAX_STORAGE_VECTOR_LENGTH static_cast<unsigned>((0xFFFFFFFFU - (sizeof(ArrayStorage) - sizeof(JSValue))) / sizeof(JSValue))
barraclough@apple.com's avatar
barraclough@apple.com committed
73 74 75 76 77

// These values have to be macros to be used in max() and min() without introducing
// a PIC branch in Mach-O binaries, see <rdar://problem/5971391>.
#define MIN_SPARSE_ARRAY_INDEX 10000U
#define MAX_STORAGE_VECTOR_INDEX (MAX_STORAGE_VECTOR_LENGTH - 1)
78
// 0xFFFFFFFF is a bit weird -- is not an array index even though it's an integer.
barraclough@apple.com's avatar
barraclough@apple.com committed
79
#define MAX_ARRAY_INDEX 0xFFFFFFFEU
darin's avatar
darin committed
80

81 82 83 84 85 86 87 88
// The value BASE_VECTOR_LEN is the maximum number of vector elements we'll allocate
// for an array that was created with a sepcified length (e.g. a = new Array(123))
#define BASE_VECTOR_LEN 4U
    
// The upper bound to the size we'll grow a zero length array when the first element
// is added.
#define FIRST_VECTOR_GROW 4U

darin's avatar
darin committed
89
// Our policy for when to use a vector and when to use a sparse map.
barraclough@apple.com's avatar
barraclough@apple.com committed
90 91
// For all array indices under MIN_SPARSE_ARRAY_INDEX, we always use a vector.
// When indices greater than MIN_SPARSE_ARRAY_INDEX are involved, we use a vector
darin's avatar
darin committed
92 93 94
// as long as it is 1/8 full. If more sparse than that, we use a map.
static const unsigned minDensityMultiplier = 8;

95
const ClassInfo JSArray::s_info = {"Array", &JSNonFinalObject::s_info, 0, 0, CREATE_METHOD_TABLE(JSArray)};
darin's avatar
darin committed
96

97 98 99 100 101
// We keep track of the size of the last array after it was grown.  We use this
// as a simple heuristic for as the value to grow the next array from size 0.
// This value is capped by the constant FIRST_VECTOR_GROW defined above.
static unsigned lastArraySize = 0;

darin's avatar
darin committed
102 103
static inline size_t storageSize(unsigned vectorLength)
{
barraclough@apple.com's avatar
barraclough@apple.com committed
104 105 106 107
    ASSERT(vectorLength <= MAX_STORAGE_VECTOR_LENGTH);

    // MAX_STORAGE_VECTOR_LENGTH is defined such that provided (vectorLength <= MAX_STORAGE_VECTOR_LENGTH)
    // - as asserted above - the following calculation cannot overflow.
ggaren@apple.com's avatar
ggaren@apple.com committed
108
    size_t size = (sizeof(ArrayStorage) - sizeof(JSValue)) + (vectorLength * sizeof(JSValue));
barraclough@apple.com's avatar
barraclough@apple.com committed
109 110
    // Assertion to detect integer overflow in previous calculation (should not be possible, provided that
    // MAX_STORAGE_VECTOR_LENGTH is correctly defined).
ggaren@apple.com's avatar
ggaren@apple.com committed
111
    ASSERT(((size - (sizeof(ArrayStorage) - sizeof(JSValue))) / sizeof(JSValue) == vectorLength) && (size >= (sizeof(ArrayStorage) - sizeof(JSValue))));
barraclough@apple.com's avatar
barraclough@apple.com committed
112 113

    return size;
darin's avatar
darin committed
114 115 116 117 118 119 120
}

static inline bool isDenseEnoughForVector(unsigned length, unsigned numValues)
{
    return length / minDensityMultiplier <= numValues;
}

121 122
#if !CHECK_ARRAY_CONSISTENCY

darin@apple.com's avatar
darin@apple.com committed
123
inline void JSArray::checkConsistency(ConsistencyCheckType)
124 125 126 127 128
{
}

#endif

129
JSArray::JSArray(VPtrStealingHackType)
130
    : JSNonFinalObject(VPtrStealingHack)
131 132 133
{
}

134 135
JSArray::JSArray(JSGlobalData& globalData, Structure* structure)
    : JSNonFinalObject(globalData, structure)
weinig@apple.com's avatar
weinig@apple.com committed
136
{
137 138 139 140 141
}

void JSArray::finishCreation(JSGlobalData& globalData)
{
    Base::finishCreation(globalData);
142 143
    ASSERT(inherits(&s_info));

weinig@apple.com's avatar
weinig@apple.com committed
144 145
    unsigned initialCapacity = 0;

146 147
    m_storage = static_cast<ArrayStorage*>(fastZeroedMalloc(storageSize(initialCapacity)));
    m_storage->m_allocBase = m_storage;
148
    m_indexBias = 0;
149
    m_vectorLength = initialCapacity;
weinig@apple.com's avatar
weinig@apple.com committed
150 151

    checkConsistency();
152 153

    Heap::heap(this)->reportExtraMemoryCost(storageSize(0));
weinig@apple.com's avatar
weinig@apple.com committed
154 155
}

156
void JSArray::finishCreation(JSGlobalData& globalData, unsigned initialLength, ArrayCreationMode creationMode)
darin's avatar
darin committed
157
{
158
    Base::finishCreation(globalData);
159 160
    ASSERT(inherits(&s_info));

161 162 163 164
    unsigned initialCapacity;
    if (creationMode == CreateCompact)
        initialCapacity = initialLength;
    else
165 166
        initialCapacity = min(BASE_VECTOR_LEN, MIN_SPARSE_ARRAY_INDEX);
    
167 168 169
    m_storage = static_cast<ArrayStorage*>(fastMalloc(storageSize(initialCapacity)));
    m_storage->m_allocBase = m_storage;
    m_storage->m_length = initialLength;
170
    m_indexBias = 0;
171
    m_vectorLength = initialCapacity;
172 173 174
    m_storage->m_sparseValueMap = 0;
    m_storage->subclassData = 0;
    m_storage->reportedMapCapacity = 0;
darin's avatar
darin committed
175

176 177
    if (creationMode == CreateCompact) {
#if CHECK_ARRAY_CONSISTENCY
178
        m_storage->m_inCompactInitialization = !!initialCapacity;
179
#endif
180 181
        m_storage->m_length = 0;
        m_storage->m_numValuesInVector = initialCapacity;
182 183
    } else {
#if CHECK_ARRAY_CONSISTENCY
184
        storage->m_inCompactInitialization = false;
185
#endif
186 187
        m_storage->m_length = initialLength;
        m_storage->m_numValuesInVector = 0;
188
        WriteBarrier<Unknown>* vector = m_storage->m_vector;
189
        for (size_t i = 0; i < initialCapacity; ++i)
190
            vector[i].clear();
191
    }
192

193
    checkConsistency();
194
    
195
    Heap::heap(this)->reportExtraMemoryCost(storageSize(initialCapacity));
darin's avatar
darin committed
196 197
}

198
void JSArray::finishCreation(JSGlobalData& globalData, const ArgList& list)
darin's avatar
darin committed
199
{
200
    Base::finishCreation(globalData);
201 202
    ASSERT(inherits(&s_info));

203
    unsigned initialCapacity = list.size();
204 205 206 207 208 209 210 211 212 213
    unsigned initialStorage;
    
    // If the ArgList is empty, allocate space for 3 entries.  This value empirically
    // works well for benchmarks.
    if (!initialCapacity)
        initialStorage = 3;
    else
        initialStorage = initialCapacity;
    
    m_storage = static_cast<ArrayStorage*>(fastMalloc(storageSize(initialStorage)));
214
    m_storage->m_allocBase = m_storage;
215
    m_indexBias = 0;
216
    m_storage->m_length = initialCapacity;
217
    m_vectorLength = initialStorage;
218 219 220 221
    m_storage->m_numValuesInVector = initialCapacity;
    m_storage->m_sparseValueMap = 0;
    m_storage->subclassData = 0;
    m_storage->reportedMapCapacity = 0;
222
#if CHECK_ARRAY_CONSISTENCY
223
    m_storage->m_inCompactInitialization = false;
224
#endif
darin's avatar
darin committed
225

ggaren's avatar
ggaren committed
226
    size_t i = 0;
227
    WriteBarrier<Unknown>* vector = m_storage->m_vector;
darin@apple.com's avatar
darin@apple.com committed
228 229
    ArgList::const_iterator end = list.end();
    for (ArgList::const_iterator it = list.begin(); it != end; ++it, ++i)
230
        vector[i].set(globalData, this, *it);
231
    for (; i < initialStorage; i++)
232
        vector[i].clear();
darin's avatar
darin committed
233

234
    checkConsistency();
235

236
    Heap::heap(this)->reportExtraMemoryCost(storageSize(initialStorage));
darin's avatar
darin committed
237 238
}

darin@apple.com's avatar
darin@apple.com committed
239
JSArray::~JSArray()
darin's avatar
darin committed
240
{
ap@apple.com's avatar
ap@apple.com committed
241
    ASSERT(vptr() == JSGlobalData::jsArrayVPtr);
242 243
    checkConsistency(DestructorConsistencyCheck);

244 245
    delete m_storage->m_sparseValueMap;
    fastFree(m_storage->m_allocBase);
darin's avatar
darin committed
246 247
}

248
bool JSArray::getOwnPropertySlotVirtual(ExecState* exec, unsigned i, PropertySlot& slot)
darin's avatar
darin committed
249
{
250 251 252 253 254 255 256
    return getOwnPropertySlot(this, exec, i, slot);
}

bool JSArray::getOwnPropertySlot(JSCell* cell, ExecState* exec, unsigned i, PropertySlot& slot)
{
    JSArray* thisObject = static_cast<JSArray*>(cell);
    ArrayStorage* storage = thisObject->m_storage;
257
    
ggaren@apple.com's avatar
ggaren@apple.com committed
258
    if (i >= storage->m_length) {
barraclough@apple.com's avatar
barraclough@apple.com committed
259
        if (i > MAX_ARRAY_INDEX)
260
            return thisObject->getOwnPropertySlotVirtual(exec, Identifier::from(exec, i), slot);
darin's avatar
darin committed
261 262 263
        return false;
    }

264
    if (i < thisObject->m_vectorLength) {
265 266 267
        JSValue value = storage->m_vector[i].get();
        if (value) {
            slot.setValue(value);
darin's avatar
darin committed
268 269 270
            return true;
        }
    } else if (SparseArrayValueMap* map = storage->m_sparseValueMap) {
barraclough@apple.com's avatar
barraclough@apple.com committed
271
        if (i >= MIN_SPARSE_ARRAY_INDEX) {
darin@apple.com's avatar
darin@apple.com committed
272 273
            SparseArrayValueMap::iterator it = map->find(i);
            if (it != map->end()) {
274
                slot.setValue(it->second.get());
darin@apple.com's avatar
darin@apple.com committed
275 276
                return true;
            }
darin's avatar
darin committed
277 278 279
        }
    }

280
    return JSObject::getOwnPropertySlot(thisObject, exec, Identifier::from(exec, i), slot);
darin's avatar
darin committed
281 282
}

283
bool JSArray::getOwnPropertySlotVirtual(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
darin's avatar
darin committed
284
{
285 286 287 288 289 290
    return getOwnPropertySlot(this, exec, propertyName, slot);
}

bool JSArray::getOwnPropertySlot(JSCell* cell, ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
{
    JSArray* thisObject = static_cast<JSArray*>(cell);
darin's avatar
darin committed
291
    if (propertyName == exec->propertyNames().length) {
292
        slot.setValue(jsNumber(thisObject->length()));
darin's avatar
darin committed
293 294 295 296
        return true;
    }

    bool isArrayIndex;
297
    unsigned i = propertyName.toArrayIndex(isArrayIndex);
darin's avatar
darin committed
298
    if (isArrayIndex)
299
        return JSArray::getOwnPropertySlot(thisObject, exec, i, slot);
darin's avatar
darin committed
300

301
    return JSObject::getOwnPropertySlot(thisObject, exec, propertyName, slot);
darin's avatar
darin committed
302 303
}

304 305 306
bool JSArray::getOwnPropertyDescriptor(ExecState* exec, const Identifier& propertyName, PropertyDescriptor& descriptor)
{
    if (propertyName == exec->propertyNames().length) {
307
        descriptor.setDescriptor(jsNumber(length()), DontDelete | DontEnum);
308 309
        return true;
    }
310

311
    ArrayStorage* storage = m_storage;
312 313
    
    bool isArrayIndex;
314
    unsigned i = propertyName.toArrayIndex(isArrayIndex);
315
    if (isArrayIndex) {
316
        if (i >= storage->m_length)
317
            return false;
318
        if (i < m_vectorLength) {
319
            WriteBarrier<Unknown>& value = storage->m_vector[i];
320
            if (value) {
321
                descriptor.setDescriptor(value.get(), 0);
322 323
                return true;
            }
324
        } else if (SparseArrayValueMap* map = storage->m_sparseValueMap) {
325 326 327
            if (i >= MIN_SPARSE_ARRAY_INDEX) {
                SparseArrayValueMap::iterator it = map->find(i);
                if (it != map->end()) {
328
                    descriptor.setDescriptor(it->second.get(), 0);
329 330 331 332 333 334 335 336
                    return true;
                }
            }
        }
    }
    return JSObject::getOwnPropertyDescriptor(exec, propertyName, descriptor);
}

337
void JSArray::putVirtual(ExecState* exec, const Identifier& propertyName, JSValue value, PutPropertySlot& slot)
darin's avatar
darin committed
338
{
339 340 341 342 343 344 345
    put(this, exec, propertyName, value, slot);
}

// ECMA 15.4.5.1
void JSArray::put(JSCell* cell, ExecState* exec, const Identifier& propertyName, JSValue value, PutPropertySlot& slot)
{
    JSArray* thisObject = static_cast<JSArray*>(cell);
darin's avatar
darin committed
346
    bool isArrayIndex;
347
    unsigned i = propertyName.toArrayIndex(isArrayIndex);
darin's avatar
darin committed
348
    if (isArrayIndex) {
349
        put(thisObject, exec, i, value);
darin's avatar
darin committed
350 351 352 353
        return;
    }

    if (propertyName == exec->propertyNames().length) {
weinig@apple.com's avatar
weinig@apple.com committed
354 355
        unsigned newLength = value.toUInt32(exec);
        if (value.toNumber(exec) != static_cast<double>(newLength)) {
356
            throwError(exec, createRangeError(exec, "Invalid array length"));
darin's avatar
darin committed
357 358
            return;
        }
359
        thisObject->setLength(newLength);
darin's avatar
darin committed
360 361 362
        return;
    }

363
    JSObject::put(thisObject, exec, propertyName, value, slot);
darin's avatar
darin committed
364 365
}

366
void JSArray::putVirtual(ExecState* exec, unsigned i, JSValue value)
darin's avatar
darin committed
367
{
368 369
    put(this, exec, i, value);
}
370

371 372 373 374 375 376
void JSArray::put(JSCell* cell, ExecState* exec, unsigned i, JSValue value)
{
    JSArray* thisObject = static_cast<JSArray*>(cell);
    thisObject->checkConsistency();

    ArrayStorage* storage = thisObject->m_storage;
377 378

    unsigned length = storage->m_length;
barraclough@apple.com's avatar
barraclough@apple.com committed
379
    if (i >= length && i <= MAX_ARRAY_INDEX) {
darin's avatar
darin committed
380
        length = i + 1;
381
        storage->m_length = length;
darin's avatar
darin committed
382 383
    }

384
    if (i < thisObject->m_vectorLength) {
385
        WriteBarrier<Unknown>& valueSlot = storage->m_vector[i];
386
        if (valueSlot) {
387 388
            valueSlot.set(exec->globalData(), thisObject, value);
            thisObject->checkConsistency();
389 390
            return;
        }
391
        valueSlot.set(exec->globalData(), thisObject, value);
392
        ++storage->m_numValuesInVector;
393
        thisObject->checkConsistency();
darin's avatar
darin committed
394 395 396
        return;
    }

397
    thisObject->putSlowCase(exec, i, value);
398 399
}

ggaren@apple.com's avatar
ggaren@apple.com committed
400
NEVER_INLINE void JSArray::putSlowCase(ExecState* exec, unsigned i, JSValue value)
401
{
402
    ArrayStorage* storage = m_storage;
403
    
darin's avatar
darin committed
404
    SparseArrayValueMap* map = storage->m_sparseValueMap;
ap@webkit.org's avatar
ap@webkit.org committed
405

barraclough@apple.com's avatar
barraclough@apple.com committed
406 407
    if (i >= MIN_SPARSE_ARRAY_INDEX) {
        if (i > MAX_ARRAY_INDEX) {
weinig@apple.com's avatar
weinig@apple.com committed
408
            PutPropertySlot slot;
409
            putVirtual(exec, Identifier::from(exec, i), value, slot);
410 411 412
            return;
        }

ap@webkit.org's avatar
ap@webkit.org committed
413
        // We miss some cases where we could compact the storage, such as a large array that is being filled from the end
414
        // (which will only be compacted as we reach indices that are less than MIN_SPARSE_ARRAY_INDEX) - but this makes the check much faster.
barraclough@apple.com's avatar
barraclough@apple.com committed
415
        if ((i > MAX_STORAGE_VECTOR_INDEX) || !isDenseEnoughForVector(i + 1, storage->m_numValuesInVector + 1)) {
ap@webkit.org's avatar
ap@webkit.org committed
416 417 418 419
            if (!map) {
                map = new SparseArrayValueMap;
                storage->m_sparseValueMap = map;
            }
420

421 422 423 424
            WriteBarrier<Unknown> temp;
            pair<SparseArrayValueMap::iterator, bool> result = map->add(i, temp);
            result.first->second.set(exec->globalData(), this, value);
            if (!result.second) // pre-existing entry
425 426 427 428 429 430 431
                return;

            size_t capacity = map->capacity();
            if (capacity != storage->reportedMapCapacity) {
                Heap::heap(this)->reportExtraMemoryCost((capacity - storage->reportedMapCapacity) * (sizeof(unsigned) + sizeof(JSValue)));
                storage->reportedMapCapacity = capacity;
            }
darin's avatar
darin committed
432 433 434 435
            return;
        }
    }

ap@webkit.org's avatar
ap@webkit.org committed
436 437 438
    // We have decided that we'll put the new item into the vector.
    // Fast case is when there is no sparse map, so we can increase the vector size without moving values from it.
    if (!map || map->isEmpty()) {
barraclough@apple.com's avatar
barraclough@apple.com committed
439
        if (increaseVectorLength(i + 1)) {
440
            storage = m_storage;
441
            storage->m_vector[i].set(exec->globalData(), this, value);
442
            ++storage->m_numValuesInVector;
barraclough@apple.com's avatar
barraclough@apple.com committed
443 444 445
            checkConsistency();
        } else
            throwOutOfMemoryError(exec);
darin's avatar
darin committed
446 447 448
        return;
    }

ap@webkit.org's avatar
ap@webkit.org committed
449 450
    // Decide how many values it would be best to move from the map.
    unsigned newNumValuesInVector = storage->m_numValuesInVector + 1;
451
    unsigned newVectorLength = getNewVectorLength(i + 1);
452
    for (unsigned j = max(m_vectorLength, MIN_SPARSE_ARRAY_INDEX); j < newVectorLength; ++j)
darin's avatar
darin committed
453
        newNumValuesInVector += map->contains(j);
barraclough@apple.com's avatar
barraclough@apple.com committed
454
    if (i >= MIN_SPARSE_ARRAY_INDEX)
ap@webkit.org's avatar
ap@webkit.org committed
455
        newNumValuesInVector -= map->contains(i);
darin's avatar
darin committed
456
    if (isDenseEnoughForVector(newVectorLength, newNumValuesInVector)) {
457
        unsigned needLength = max(i + 1, storage->m_length);
darin's avatar
darin committed
458
        unsigned proposedNewNumValuesInVector = newNumValuesInVector;
barraclough@apple.com's avatar
barraclough@apple.com committed
459
        // If newVectorLength is already the maximum - MAX_STORAGE_VECTOR_LENGTH - then do not attempt to grow any further.
460
        while ((newVectorLength < needLength) && (newVectorLength < MAX_STORAGE_VECTOR_LENGTH)) {
461
            unsigned proposedNewVectorLength = getNewVectorLength(newVectorLength + 1);
barraclough@apple.com's avatar
barraclough@apple.com committed
462
            for (unsigned j = max(newVectorLength, MIN_SPARSE_ARRAY_INDEX); j < proposedNewVectorLength; ++j)
darin's avatar
darin committed
463 464 465 466 467 468 469 470
                proposedNewNumValuesInVector += map->contains(j);
            if (!isDenseEnoughForVector(proposedNewVectorLength, proposedNewNumValuesInVector))
                break;
            newVectorLength = proposedNewVectorLength;
            newNumValuesInVector = proposedNewNumValuesInVector;
        }
    }

471
    void* baseStorage = storage->m_allocBase;
472 473
    
    if (!tryFastRealloc(baseStorage, storageSize(newVectorLength + m_indexBias)).getValue(baseStorage)) {
barraclough@apple.com's avatar
barraclough@apple.com committed
474 475 476
        throwOutOfMemoryError(exec);
        return;
    }
darin's avatar
darin committed
477

478
    m_storage = reinterpret_cast_ptr<ArrayStorage*>(static_cast<char*>(baseStorage) + m_indexBias * sizeof(JSValue));
479 480
    m_storage->m_allocBase = baseStorage;
    storage = m_storage;
481
    
482
    unsigned vectorLength = m_vectorLength;
483
    WriteBarrier<Unknown>* vector = storage->m_vector;
484

darin's avatar
darin committed
485 486
    if (newNumValuesInVector == storage->m_numValuesInVector + 1) {
        for (unsigned j = vectorLength; j < newVectorLength; ++j)
487
            vector[j].clear();
barraclough@apple.com's avatar
barraclough@apple.com committed
488
        if (i > MIN_SPARSE_ARRAY_INDEX)
ap@webkit.org's avatar
ap@webkit.org committed
489
            map->remove(i);
darin's avatar
darin committed
490
    } else {
barraclough@apple.com's avatar
barraclough@apple.com committed
491
        for (unsigned j = vectorLength; j < max(vectorLength, MIN_SPARSE_ARRAY_INDEX); ++j)
492 493
            vector[j].clear();
        JSGlobalData& globalData = exec->globalData();
barraclough@apple.com's avatar
barraclough@apple.com committed
494
        for (unsigned j = max(vectorLength, MIN_SPARSE_ARRAY_INDEX); j < newVectorLength; ++j)
495
            vector[j].set(globalData, this, map->take(j).get());
darin's avatar
darin committed
496 497
    }

498
    ASSERT(i < newVectorLength);
darin's avatar
darin committed
499

500
    m_vectorLength = newVectorLength;
darin's avatar
darin committed
501
    storage->m_numValuesInVector = newNumValuesInVector;
ap@webkit.org's avatar
ap@webkit.org committed
502

503
    storage->m_vector[i].set(exec->globalData(), this, value);
504 505

    checkConsistency();
506 507

    Heap::heap(this)->reportExtraMemoryCost(storageSize(newVectorLength) - storageSize(vectorLength));
darin's avatar
darin committed
508 509
}

510
bool JSArray::deletePropertyVirtual(ExecState* exec, const Identifier& propertyName)
darin's avatar
darin committed
511
{
512 513 514 515 516 517
    return deleteProperty(this, exec, propertyName);
}

bool JSArray::deleteProperty(JSCell* cell, ExecState* exec, const Identifier& propertyName)
{
    JSArray* thisObject = static_cast<JSArray*>(cell);
darin's avatar
darin committed
518
    bool isArrayIndex;
519
    unsigned i = propertyName.toArrayIndex(isArrayIndex);
darin's avatar
darin committed
520
    if (isArrayIndex)
521
        return thisObject->deletePropertyVirtual(exec, i);
darin's avatar
darin committed
522 523 524 525

    if (propertyName == exec->propertyNames().length)
        return false;

526
    return JSObject::deleteProperty(thisObject, exec, propertyName);
darin's avatar
darin committed
527 528
}

529
bool JSArray::deletePropertyVirtual(ExecState* exec, unsigned i)
darin's avatar
darin committed
530
{
531 532
    return deleteProperty(this, exec, i);
}
533

534 535 536 537 538 539
bool JSArray::deleteProperty(JSCell* cell, ExecState* exec, unsigned i)
{
    JSArray* thisObject = static_cast<JSArray*>(cell);
    thisObject->checkConsistency();

    ArrayStorage* storage = thisObject->m_storage;
540
    
541
    if (i < thisObject->m_vectorLength) {
542
        WriteBarrier<Unknown>& valueSlot = storage->m_vector[i];
543
        if (!valueSlot) {
544
            thisObject->checkConsistency();
545 546
            return false;
        }
547
        valueSlot.clear();
548
        --storage->m_numValuesInVector;
549
        thisObject->checkConsistency();
550
        return true;
darin's avatar
darin committed
551 552 553
    }

    if (SparseArrayValueMap* map = storage->m_sparseValueMap) {
barraclough@apple.com's avatar
barraclough@apple.com committed
554
        if (i >= MIN_SPARSE_ARRAY_INDEX) {
darin@apple.com's avatar
darin@apple.com committed
555 556 557
            SparseArrayValueMap::iterator it = map->find(i);
            if (it != map->end()) {
                map->remove(it);
558
                thisObject->checkConsistency();
darin@apple.com's avatar
darin@apple.com committed
559 560
                return true;
            }
darin's avatar
darin committed
561 562 563
        }
    }

564
    thisObject->checkConsistency();
565

barraclough@apple.com's avatar
barraclough@apple.com committed
566
    if (i > MAX_ARRAY_INDEX)
567
        return thisObject->deletePropertyVirtual(exec, Identifier::from(exec, i));
darin's avatar
darin committed
568 569 570 571

    return false;
}

572
void JSArray::getOwnPropertyNames(ExecState* exec, PropertyNameArray& propertyNames, EnumerationMode mode)
darin's avatar
darin committed
573 574
{
    // FIXME: Filling PropertyNameArray with an identifier for every integer
575 576
    // is incredibly inefficient for large arrays. We need a different approach,
    // which almost certainly means a different structure for PropertyNameArray.
darin's avatar
darin committed
577

578
    ArrayStorage* storage = m_storage;
579
    
580
    unsigned usedVectorLength = min(storage->m_length, m_vectorLength);
darin's avatar
darin committed
581
    for (unsigned i = 0; i < usedVectorLength; ++i) {
582
        if (storage->m_vector[i])
ap@webkit.org's avatar
ap@webkit.org committed
583
            propertyNames.add(Identifier::from(exec, i));
darin's avatar
darin committed
584 585 586 587 588
    }

    if (SparseArrayValueMap* map = storage->m_sparseValueMap) {
        SparseArrayValueMap::iterator end = map->end();
        for (SparseArrayValueMap::iterator it = map->begin(); it != end; ++it)
ap@webkit.org's avatar
ap@webkit.org committed
589
            propertyNames.add(Identifier::from(exec, it->first));
darin's avatar
darin committed
590
    }
591

592 593 594 595
    if (mode == IncludeDontEnumProperties)
        propertyNames.add(exec->propertyNames().length);

    JSObject::getOwnPropertyNames(exec, propertyNames, mode);
darin's avatar
darin committed
596 597
}

598 599 600 601 602
ALWAYS_INLINE unsigned JSArray::getNewVectorLength(unsigned desiredLength)
{
    ASSERT(desiredLength <= MAX_STORAGE_VECTOR_LENGTH);

    unsigned increasedLength;
603
    unsigned maxInitLength = min(m_storage->m_length, 100000U);
604

605 606
    if (desiredLength < maxInitLength)
        increasedLength = maxInitLength;
607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624
    else if (!m_vectorLength)
        increasedLength = max(desiredLength, lastArraySize);
    else {
        // Mathematically equivalent to:
        //   increasedLength = (newLength * 3 + 1) / 2;
        // or:
        //   increasedLength = (unsigned)ceil(newLength * 1.5));
        // This form is not prone to internal overflow.
        increasedLength = desiredLength + (desiredLength >> 1) + (desiredLength & 1);
    }

    ASSERT(increasedLength >= desiredLength);

    lastArraySize = min(increasedLength, FIRST_VECTOR_GROW);

    return min(increasedLength, MAX_STORAGE_VECTOR_LENGTH);
}

darin@apple.com's avatar
darin@apple.com committed
625
bool JSArray::increaseVectorLength(unsigned newLength)
darin's avatar
darin committed
626
{
ap@webkit.org's avatar
ap@webkit.org committed
627 628 629
    // This function leaves the array in an internally inconsistent state, because it does not move any values from sparse value map
    // to the vector. Callers have to account for that, because they can do it more efficiently.

630
    ArrayStorage* storage = m_storage;
darin's avatar
darin committed
631

632
    unsigned vectorLength = m_vectorLength;
darin's avatar
darin committed
633
    ASSERT(newLength > vectorLength);
barraclough@apple.com's avatar
barraclough@apple.com committed
634
    ASSERT(newLength <= MAX_STORAGE_VECTOR_INDEX);
635
    unsigned newVectorLength = getNewVectorLength(newLength);
636
    void* baseStorage = storage->m_allocBase;
darin's avatar
darin committed
637

638
    if (!tryFastRealloc(baseStorage, storageSize(newVectorLength + m_indexBias)).getValue(baseStorage))
ap@webkit.org's avatar
ap@webkit.org committed
639
        return false;
640

641
    storage = m_storage = reinterpret_cast_ptr<ArrayStorage*>(static_cast<char*>(baseStorage) + m_indexBias * sizeof(JSValue));
642
    m_storage->m_allocBase = baseStorage;
643

644
    WriteBarrier<Unknown>* vector = storage->m_vector;
645
    for (unsigned i = vectorLength; i < newVectorLength; ++i)
646
        vector[i].clear();
ap@webkit.org's avatar
ap@webkit.org committed
647

648
    m_vectorLength = newVectorLength;
649 650
    
    Heap::heap(this)->reportExtraMemoryCost(storageSize(newVectorLength) - storageSize(vectorLength));
darin's avatar
darin committed
651

652 653
    return true;
}
darin's avatar
darin committed
654

655 656 657 658 659
bool JSArray::increaseVectorPrefixLength(unsigned newLength)
{
    // This function leaves the array in an internally inconsistent state, because it does not move any values from sparse value map
    // to the vector. Callers have to account for that, because they can do it more efficiently.
    
660
    ArrayStorage* storage = m_storage;
661 662 663 664 665
    
    unsigned vectorLength = m_vectorLength;
    ASSERT(newLength > vectorLength);
    ASSERT(newLength <= MAX_STORAGE_VECTOR_INDEX);
    unsigned newVectorLength = getNewVectorLength(newLength);
666 667

    void* newBaseStorage = fastMalloc(storageSize(newVectorLength + m_indexBias));
668 669 670 671 672
    if (!newBaseStorage)
        return false;
    
    m_indexBias += newVectorLength - newLength;
    
673
    m_storage = reinterpret_cast_ptr<ArrayStorage*>(static_cast<char*>(newBaseStorage) + m_indexBias * sizeof(JSValue));
674

675 676
    memcpy(m_storage, storage, storageSize(0));
    memcpy(&m_storage->m_vector[newLength - m_vectorLength], &storage->m_vector[0], vectorLength * sizeof(JSValue));
677
    
678
    m_storage->m_allocBase = newBaseStorage;
679 680
    m_vectorLength = newLength;
    
681
    fastFree(storage->m_allocBase);
682 683 684 685
    ASSERT(newLength > vectorLength);
    unsigned delta = newLength - vectorLength;
    for (unsigned i = 0; i < delta; i++)
        m_storage->m_vector[i].clear();
686
    Heap::heap(this)->reportExtraMemoryCost(storageSize(newVectorLength) - storageSize(vectorLength));
687
    
ap@webkit.org's avatar
ap@webkit.org committed
688
    return true;
darin's avatar
darin committed
689
}
690
    
darin's avatar
darin committed
691

darin@apple.com's avatar
darin@apple.com committed
692
void JSArray::setLength(unsigned newLength)
darin's avatar
darin committed
693
{
694 695
    ArrayStorage* storage = m_storage;
    
696
#if CHECK_ARRAY_CONSISTENCY
697
    if (!storage->m_inCompactInitialization)
698 699
        checkConsistency();
    else
700
        storage->m_inCompactInitialization = false;
701
#endif
702

703
    unsigned length = storage->m_length;
darin's avatar
darin committed
704 705

    if (newLength < length) {
706
        unsigned usedVectorLength = min(length, m_vectorLength);
darin's avatar
darin committed
707
        for (unsigned i = newLength; i < usedVectorLength; ++i) {
708
            WriteBarrier<Unknown>& valueSlot = storage->m_vector[i];
darin's avatar
darin committed
709
            bool hadValue = valueSlot;
710
            valueSlot.clear();
darin's avatar
darin committed
711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726
            storage->m_numValuesInVector -= hadValue;
        }

        if (SparseArrayValueMap* map = storage->m_sparseValueMap) {
            SparseArrayValueMap copy = *map;
            SparseArrayValueMap::iterator end = copy.end();
            for (SparseArrayValueMap::iterator it = copy.begin(); it != end; ++it) {
                if (it->first >= newLength)
                    map->remove(it->first);
            }
            if (map->isEmpty()) {
                delete map;
                storage->m_sparseValueMap = 0;
            }
        }
    }
aroben@apple.com's avatar
aroben@apple.com committed
727

728
    storage->m_length = newLength;
729 730

    checkConsistency();
darin's avatar
darin committed
731 732
}

ggaren@apple.com's avatar
ggaren@apple.com committed
733
JSValue JSArray::pop()
734 735 736
{
    checkConsistency();

737
    ArrayStorage* storage = m_storage;
738 739
    
    unsigned length = storage->m_length;
740 741 742 743 744
    if (!length)
        return jsUndefined();

    --length;

ggaren@apple.com's avatar
ggaren@apple.com committed
745
    JSValue result;
746

747
    if (length < m_vectorLength) {
748
        WriteBarrier<Unknown>& valueSlot = storage->m_vector[length];
749
        if (valueSlot) {
750
            --storage->m_numValuesInVector;
751 752
            result = valueSlot.get();
            valueSlot.clear();
753
        } else
754 755 756
            result = jsUndefined();
    } else {
        result = jsUndefined();
757
        if (SparseArrayValueMap* map = storage->m_sparseValueMap) {
758 759
            SparseArrayValueMap::iterator it = map->find(length);
            if (it != map->end()) {
760
                result = it->second.get();
761 762 763
                map->remove(it);
                if (map->isEmpty()) {
                    delete map;
764
                    storage->m_sparseValueMap = 0;
765 766 767 768 769
                }
            }
        }
    }

770
    storage->m_length = length;
771 772 773 774 775 776

    checkConsistency();

    return result;
}

ggaren@apple.com's avatar
ggaren@apple.com committed
777
void JSArray::push(ExecState* exec, JSValue value)
778 779
{
    checkConsistency();
780
    
781
    ArrayStorage* storage = m_storage;
782