v8::internal::StringTracker Class Reference

#include <api.h>

Collaboration diagram for v8::internal::StringTracker:

Public Member Functions
void	RecordWrite (Handle< String > string)
bool	IsFreshUnusedString (Handle< String > string)

Private Member Functions
	StringTracker ()
bool	IsUseCountLow (Address top)
void	IncrementUseCount (Address top)
	DISALLOW_COPY_AND_ASSIGN (StringTracker)

Static Private Member Functions
static bool	IsFreshString (Address string, Address top)

Private Attributes
int	use_count_
Address	last_top_
Isolate *	isolate_

Static Private Attributes
static const int	kFreshnessLimit = 1024
static const int	kUseLimit = 32

Friends
class	Isolate

Detailed Description

Definition at line 395 of file api.h.

Constructor & Destructor Documentation

StringTracker()

v8::internal::StringTracker::StringTracker ( )

inlineprivate

Definition at line 418 of file api.h.

: use_count_(0), last_top_(NULL), isolate_(NULL) { }

Member Function Documentation

DISALLOW_COPY_AND_ASSIGN()

v8::internal::StringTracker::DISALLOW_COPY_AND_ASSIGN ( StringTracker  )

private

IncrementUseCount()

void v8::internal::StringTracker::IncrementUseCount ( Address  top )

inlineprivate

Definition at line 429 of file api.h.

                                             {
    if (last_top_ != top) {
      use_count_ = 0;
      last_top_ = top;
    }
    ++use_count_;
  }

References last_top_, and use_count_.

Referenced by RecordWrite().

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IsFreshString()

static bool v8::internal::StringTracker::IsFreshString ( Address  string, Address  top  )

inlinestaticprivate

Definition at line 420 of file api.h.

                                                                {
    return top - kFreshnessLimit <= string && string <= top;
  }

References kFreshnessLimit.

Referenced by IsFreshUnusedString(), and RecordWrite().

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IsFreshUnusedString()

bool v8::internal::StringTracker::IsFreshUnusedString ( Handle< String >  string )

inline

Definition at line 411 of file api.h.

                                                         {
    Address address = reinterpret_cast<Address>(*string);
    Address top = isolate_->heap()->NewSpaceTop();
    return IsFreshString(address, top) && IsUseCountLow(top);
  }

References v8::internal::Isolate::heap(), IsFreshString(), isolate_, IsUseCountLow(), and v8::internal::Heap::NewSpaceTop().

Referenced by v8::String::CanMakeExternal(), and v8::String::MakeExternal().

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IsUseCountLow()

bool v8::internal::StringTracker::IsUseCountLow ( Address  top )

inlineprivate

Definition at line 424 of file api.h.

                                         {
    if (last_top_ != top) return true;
    return use_count_ < kUseLimit;
  }

References kUseLimit, last_top_, and use_count_.

Referenced by IsFreshUnusedString().

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RecordWrite()

void v8::internal::StringTracker::RecordWrite ( Handle< String >  string )

inline

Definition at line 400 of file api.h.

                                          {
    Address address = reinterpret_cast<Address>(*string);
    Address top = isolate_->heap()->NewSpaceTop();
    if (IsFreshString(address, top)) {
      IncrementUseCount(top);
    }
  }

References v8::internal::Isolate::heap(), IncrementUseCount(), IsFreshString(), isolate_, and v8::internal::Heap::NewSpaceTop().

Referenced by v8::WriteHelper().

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Friends And Related Function Documentation

Isolate

friend class Isolate

friend

Definition at line 451 of file api.h.

Member Data Documentation

isolate_

Isolate* v8::internal::StringTracker::isolate_

private

Definition at line 443 of file api.h.

Referenced by v8::internal::Isolate::Init(), IsFreshUnusedString(), and RecordWrite().

kFreshnessLimit

const int v8::internal::StringTracker::kFreshnessLimit = 1024

staticprivate

Definition at line 446 of file api.h.

Referenced by IsFreshString().

kUseLimit

const int v8::internal::StringTracker::kUseLimit = 32

staticprivate

Definition at line 449 of file api.h.

Referenced by IsUseCountLow().

last_top_

Address v8::internal::StringTracker::last_top_

private

Definition at line 441 of file api.h.

Referenced by IncrementUseCount(), and IsUseCountLow().

use_count_

int v8::internal::StringTracker::use_count_

private

Definition at line 438 of file api.h.

Referenced by IncrementUseCount(), and IsUseCountLow().

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The documentation for this class was generated from the following file:

• /mnt/V8SourceCode/src/api.h