This source file includes following definitions.
- segmentIndex
- offsetInSegment
- allocateSegment
- freeSegment
- statsMutex
- liveBuffers
- sizeComparator
- snippetForBuffer
- printStats
- didCreateSharedBuffer
- willDestroySharedBuffer
- m_buffer
- m_buffer
- m_buffer
- m_buffer
- m_buffer
- adoptVector
- size
- data
- append
- append
- append
- clear
- copy
- mergeSegmentsIntoBuffer
- getSomeData
- getAsArrayBuffer
- getAsSkData
- lock
- unlock
- isLocked
#include "config.h"
#include "platform/SharedBuffer.h"
#include "wtf/unicode/Unicode.h"
#include "wtf/unicode/UTF8.h"
#undef SHARED_BUFFER_STATS
#ifdef SHARED_BUFFER_STATS
#include "wtf/DataLog.h"
#include "wtf/MainThread.h"
#endif
using namespace std;
namespace WebCore {
static const unsigned segmentSize = 0x1000;
static const unsigned segmentPositionMask = 0x0FFF;
static inline unsigned segmentIndex(unsigned position)
{
return position / segmentSize;
}
static inline unsigned offsetInSegment(unsigned position)
{
return position & segmentPositionMask;
}
static inline char* allocateSegment()
{
return static_cast<char*>(fastMalloc(segmentSize));
}
static inline void freeSegment(char* p)
{
fastFree(p);
}
#ifdef SHARED_BUFFER_STATS
static Mutex& statsMutex()
{
DEFINE_STATIC_LOCAL(Mutex, mutex, ());
return mutex;
}
static HashSet<SharedBuffer*>& liveBuffers()
{
DEFINE_STATIC_LOCAL(HashSet<SharedBuffer*>, buffers, ());
return buffers;
}
static bool sizeComparator(SharedBuffer* a, SharedBuffer* b)
{
return a->size() > b->size();
}
static CString snippetForBuffer(SharedBuffer* sharedBuffer)
{
const unsigned kMaxSnippetLength = 64;
char* snippet = 0;
unsigned snippetLength = std::min(sharedBuffer->size(), kMaxSnippetLength);
CString result = CString::newUninitialized(snippetLength, snippet);
const char* segment;
unsigned offset = 0;
while (unsigned segmentLength = sharedBuffer->getSomeData(segment, offset)) {
unsigned length = std::min(segmentLength, snippetLength - offset);
memcpy(snippet + offset, segment, length);
offset += segmentLength;
if (offset >= snippetLength)
break;
}
for (unsigned i = 0; i < snippetLength; ++i) {
if (!isASCIIPrintable(snippet[i]))
snippet[i] = '?';
}
return result;
}
static void printStats(void*)
{
MutexLocker locker(statsMutex());
Vector<SharedBuffer*> buffers;
for (HashSet<SharedBuffer*>::const_iterator iter = liveBuffers().begin(); iter != liveBuffers().end(); ++iter)
buffers.append(*iter);
std::sort(buffers.begin(), buffers.end(), sizeComparator);
dataLogF("---- Shared Buffer Stats ----\n");
for (size_t i = 0; i < buffers.size() && i < 64; ++i) {
CString snippet = snippetForBuffer(buffers[i]);
dataLogF("Buffer size=%8u %s\n", buffers[i]->size(), snippet.data());
}
}
static void didCreateSharedBuffer(SharedBuffer* buffer)
{
MutexLocker locker(statsMutex());
liveBuffers().add(buffer);
callOnMainThread(printStats, 0);
}
static void willDestroySharedBuffer(SharedBuffer* buffer)
{
MutexLocker locker(statsMutex());
liveBuffers().remove(buffer);
}
#endif
SharedBuffer::SharedBuffer()
: m_size(0)
, m_buffer(PurgeableVector::NotPurgeable)
{
#ifdef SHARED_BUFFER_STATS
didCreateSharedBuffer(this);
#endif
}
SharedBuffer::SharedBuffer(size_t size)
: m_size(size)
, m_buffer(PurgeableVector::NotPurgeable)
{
m_buffer.reserveCapacity(size);
m_buffer.grow(size);
#ifdef SHARED_BUFFER_STATS
didCreateSharedBuffer(this);
#endif
}
SharedBuffer::SharedBuffer(const char* data, int size)
: m_size(0)
, m_buffer(PurgeableVector::NotPurgeable)
{
if (size < 0)
CRASH();
append(data, size);
#ifdef SHARED_BUFFER_STATS
didCreateSharedBuffer(this);
#endif
}
SharedBuffer::SharedBuffer(const char* data, int size, PurgeableVector::PurgeableOption purgeable)
: m_size(0)
, m_buffer(purgeable)
{
if (size < 0)
CRASH();
append(data, size);
#ifdef SHARED_BUFFER_STATS
didCreateSharedBuffer(this);
#endif
}
SharedBuffer::SharedBuffer(const unsigned char* data, int size)
: m_size(0)
, m_buffer(PurgeableVector::NotPurgeable)
{
if (size < 0)
CRASH();
append(reinterpret_cast<const char*>(data), size);
#ifdef SHARED_BUFFER_STATS
didCreateSharedBuffer(this);
#endif
}
SharedBuffer::~SharedBuffer()
{
clear();
#ifdef SHARED_BUFFER_STATS
willDestroySharedBuffer(this);
#endif
}
PassRefPtr<SharedBuffer> SharedBuffer::adoptVector(Vector<char>& vector)
{
RefPtr<SharedBuffer> buffer = create();
buffer->m_buffer.adopt(vector);
buffer->m_size = buffer->m_buffer.size();
return buffer.release();
}
unsigned SharedBuffer::size() const
{
return m_size;
}
const char* SharedBuffer::data() const
{
mergeSegmentsIntoBuffer();
return m_buffer.data();
}
void SharedBuffer::append(SharedBuffer* data)
{
const char* segment;
size_t position = 0;
while (size_t length = data->getSomeData(segment, position)) {
append(segment, length);
position += length;
}
}
void SharedBuffer::append(const char* data, unsigned length)
{
ASSERT(isLocked());
if (!length)
return;
ASSERT(m_size >= m_buffer.size());
unsigned positionInSegment = offsetInSegment(m_size - m_buffer.size());
m_size += length;
if (m_size <= segmentSize) {
m_buffer.append(data, length);
return;
}
char* segment;
if (!positionInSegment) {
segment = allocateSegment();
m_segments.append(segment);
} else
segment = m_segments.last() + positionInSegment;
unsigned segmentFreeSpace = segmentSize - positionInSegment;
unsigned bytesToCopy = min(length, segmentFreeSpace);
for (;;) {
memcpy(segment, data, bytesToCopy);
if (static_cast<unsigned>(length) == bytesToCopy)
break;
length -= bytesToCopy;
data += bytesToCopy;
segment = allocateSegment();
m_segments.append(segment);
bytesToCopy = min(length, segmentSize);
}
}
void SharedBuffer::append(const Vector<char>& data)
{
append(data.data(), data.size());
}
void SharedBuffer::clear()
{
for (unsigned i = 0; i < m_segments.size(); ++i)
freeSegment(m_segments[i]);
m_segments.clear();
m_size = 0;
m_buffer.clear();
}
PassRefPtr<SharedBuffer> SharedBuffer::copy() const
{
RefPtr<SharedBuffer> clone(adoptRef(new SharedBuffer));
clone->m_size = m_size;
clone->m_buffer.reserveCapacity(m_size);
clone->m_buffer.append(m_buffer.data(), m_buffer.size());
if (!m_segments.isEmpty()) {
const char* segment = 0;
unsigned position = m_buffer.size();
while (unsigned segmentSize = getSomeData(segment, position)) {
clone->m_buffer.append(segment, segmentSize);
position += segmentSize;
}
ASSERT(position == clone->size());
}
return clone.release();
}
void SharedBuffer::mergeSegmentsIntoBuffer() const
{
unsigned bufferSize = m_buffer.size();
if (m_size > bufferSize) {
m_buffer.reserveCapacity(m_size);
unsigned bytesLeft = m_size - bufferSize;
for (unsigned i = 0; i < m_segments.size(); ++i) {
unsigned bytesToCopy = min(bytesLeft, segmentSize);
m_buffer.append(m_segments[i], bytesToCopy);
bytesLeft -= bytesToCopy;
freeSegment(m_segments[i]);
}
m_segments.clear();
}
}
unsigned SharedBuffer::getSomeData(const char*& someData, unsigned position) const
{
ASSERT(isLocked());
unsigned totalSize = size();
if (position >= totalSize) {
someData = 0;
return 0;
}
ASSERT_WITH_SECURITY_IMPLICATION(position < m_size);
unsigned consecutiveSize = m_buffer.size();
if (position < consecutiveSize) {
someData = m_buffer.data() + position;
return consecutiveSize - position;
}
position -= consecutiveSize;
unsigned segments = m_segments.size();
unsigned maxSegmentedSize = segments * segmentSize;
unsigned segment = segmentIndex(position);
if (segment < segments) {
unsigned bytesLeft = totalSize - consecutiveSize;
unsigned segmentedSize = min(maxSegmentedSize, bytesLeft);
unsigned positionInSegment = offsetInSegment(position);
someData = m_segments[segment] + positionInSegment;
return segment == segments - 1 ? segmentedSize - position : segmentSize - positionInSegment;
}
ASSERT_NOT_REACHED();
return 0;
}
PassRefPtr<ArrayBuffer> SharedBuffer::getAsArrayBuffer() const
{
RefPtr<ArrayBuffer> arrayBuffer = ArrayBuffer::createUninitialized(static_cast<unsigned>(size()), 1);
const char* segment = 0;
unsigned position = 0;
while (unsigned segmentSize = getSomeData(segment, position)) {
memcpy(static_cast<char*>(arrayBuffer->data()) + position, segment, segmentSize);
position += segmentSize;
}
if (position != arrayBuffer->byteLength()) {
ASSERT_NOT_REACHED();
return nullptr;
}
return arrayBuffer;
}
PassRefPtr<SkData> SharedBuffer::getAsSkData() const
{
unsigned bufferLength = size();
char* buffer = static_cast<char*>(sk_malloc_throw(bufferLength));
const char* segment = 0;
unsigned position = 0;
while (unsigned segmentSize = getSomeData(segment, position)) {
memcpy(buffer + position, segment, segmentSize);
position += segmentSize;
}
if (position != bufferLength) {
ASSERT_NOT_REACHED();
return nullptr;
}
return adoptRef(SkData::NewFromMalloc(buffer, bufferLength));
}
bool SharedBuffer::lock()
{
return m_buffer.lock();
}
void SharedBuffer::unlock()
{
mergeSegmentsIntoBuffer();
m_buffer.unlock();
}
bool SharedBuffer::isLocked() const
{
return m_buffer.isLocked();
}
}