The Tor Browser: gfx/skia/trunk/src/core/SkClipStack.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkClipStack.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkClipStack.cpp

Sat, 03 Jan 2015 20:18:00 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Sat, 03 Jan 2015 20:18:00 +0100
branch: TOR_BUG_3246
changeset 7: 129ffea94266
permissions: -rw-r--r--

Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkClipStack.h"
 #include "SkPath.h"
 #include "SkThread.h"
 #include <new>
 // 0-2 are reserved for invalid, empty & wide-open
 static const int32_t kFirstUnreservedGenID = 3;
 int32_t SkClipStack::gGenID = kFirstUnreservedGenID;
 SkClipStack::Element::Element(const Element& that) {
     switch (that.getType()) {
         case kEmpty_Type:
             fPath.reset();
             break;
         case kRect_Type: // Rect uses rrect
         case kRRect_Type:
             fPath.reset();
             fRRect = that.fRRect;
             break;
         case kPath_Type:
             fPath.set(that.getPath());
             break;
     }
     fSaveCount = that.fSaveCount;
     fOp = that.fOp;
     fType = that.fType;
     fDoAA = that.fDoAA;
     fFiniteBoundType = that.fFiniteBoundType;
     fFiniteBound = that.fFiniteBound;
     fIsIntersectionOfRects = that.fIsIntersectionOfRects;
     fGenID = that.fGenID;
 }
 bool SkClipStack::Element::operator== (const Element& element) const {
     if (this == &element) {
         return true;
     }
     if (fOp != element.fOp ||
         fType != element.fType ||
         fDoAA != element.fDoAA ||
         fSaveCount != element.fSaveCount) {
         return false;
     }
     switch (fType) {
         case kPath_Type:
             return this->getPath() == element.getPath();
         case kRRect_Type:
             return fRRect == element.fRRect;
         case kRect_Type:
             return this->getRect() == element.getRect();
         case kEmpty_Type:
             return true;
         default:
             SkDEBUGFAIL("Unexpected type.");
             return false;
     }
 }
 void SkClipStack::Element::invertShapeFillType() {
     switch (fType) {
         case kRect_Type:
             fPath.init();
             fPath.get()->addRect(this->getRect());
             fPath.get()->setFillType(SkPath::kInverseEvenOdd_FillType);
             fType = kPath_Type;
             break;
         case kRRect_Type:
             fPath.init();
             fPath.get()->addRRect(fRRect);
             fPath.get()->setFillType(SkPath::kInverseEvenOdd_FillType);
             fType = kPath_Type;
             break;
         case kPath_Type:
             fPath.get()->toggleInverseFillType();
             break;
         case kEmpty_Type:
             // Should this set to an empty, inverse filled path?
             break;
     }
 }
 void SkClipStack::Element::initPath(int saveCount, const SkPath& path, SkRegion::Op op,
                                     bool doAA) {
     if (!path.isInverseFillType()) {
         if (SkPath::kNone_PathAsRect != path.asRect()) {
             this->initRect(saveCount, path.getBounds(), op, doAA);
             return;
         }
         SkRect ovalRect;
         if (path.isOval(&ovalRect)) {
             SkRRect rrect;
             rrect.setOval(ovalRect);
             this->initRRect(saveCount, rrect, op, doAA);
             return;
         }
     }
     fPath.set(path);
     fType = kPath_Type;
     this->initCommon(saveCount, op, doAA);
 }
 void SkClipStack::Element::asPath(SkPath* path) const {
     switch (fType) {
         case kEmpty_Type:
             path->reset();
             break;
         case kRect_Type:
             path->reset();
             path->addRect(this->getRect());
             break;
         case kRRect_Type:
             path->reset();
             path->addRRect(fRRect);
             break;
         case kPath_Type:
             *path = *fPath.get();
             break;
     }
 }
 void SkClipStack::Element::setEmpty() {
     fType = kEmpty_Type;
     fFiniteBound.setEmpty();
     fFiniteBoundType = kNormal_BoundsType;
     fIsIntersectionOfRects = false;
     fRRect.setEmpty();
     fPath.reset();
     fGenID = kEmptyGenID;
     SkDEBUGCODE(this->checkEmpty();)
 }
 void SkClipStack::Element::checkEmpty() const {
     SkASSERT(fFiniteBound.isEmpty());
     SkASSERT(kNormal_BoundsType == fFiniteBoundType);
     SkASSERT(!fIsIntersectionOfRects);
     SkASSERT(kEmptyGenID == fGenID);
     SkASSERT(!fPath.isValid());
 }
 bool SkClipStack::Element::canBeIntersectedInPlace(int saveCount, SkRegion::Op op) const {
     if (kEmpty_Type == fType &&
         (SkRegion::kDifference_Op == op || SkRegion::kIntersect_Op == op)) {
         return true;
     }
     // Only clips within the same save/restore frame (as captured by
     // the save count) can be merged
     return  fSaveCount == saveCount &&
             SkRegion::kIntersect_Op == op &&
             (SkRegion::kIntersect_Op == fOp || SkRegion::kReplace_Op == fOp);
 }
 bool SkClipStack::Element::rectRectIntersectAllowed(const SkRect& newR, bool newAA) const {
     SkASSERT(kRect_Type == fType);
     if (fDoAA == newAA) {
         // if the AA setting is the same there is no issue
         return true;
     }
     if (!SkRect::Intersects(this->getRect(), newR)) {
         // The calling code will correctly set the result to the empty clip
         return true;
     }
     if (this->getRect().contains(newR)) {
         // if the new rect carves out a portion of the old one there is no
         // issue
         return true;
     }
     // So either the two overlap in some complex manner or newR contains oldR.
     // In the first, case the edges will require different AA. In the second,
     // the AA setting that would be carried forward is incorrect (e.g., oldR
     // is AA while newR is BW but since newR contains oldR, oldR will be
     // drawn BW) since the new AA setting will predominate.
     return false;
 }
 // a mirror of combineBoundsRevDiff
 void SkClipStack::Element::combineBoundsDiff(FillCombo combination, const SkRect& prevFinite) {
     switch (combination) {
         case kInvPrev_InvCur_FillCombo:
             // In this case the only pixels that can remain set
             // are inside the current clip rect since the extensions
             // to infinity of both clips cancel out and whatever
             // is outside of the current clip is removed
             fFiniteBoundType = kNormal_BoundsType;
             break;
         case kInvPrev_Cur_FillCombo:
             // In this case the current op is finite so the only pixels
             // that aren't set are whatever isn't set in the previous
             // clip and whatever this clip carves out
             fFiniteBound.join(prevFinite);
             fFiniteBoundType = kInsideOut_BoundsType;
             break;
         case kPrev_InvCur_FillCombo:
             // In this case everything outside of this clip's bound
             // is erased, so the only pixels that can remain set
             // occur w/in the intersection of the two finite bounds
             if (!fFiniteBound.intersect(prevFinite)) {
                 this->setEmpty();
             } else {
                 fFiniteBoundType = kNormal_BoundsType;
             }
             break;
         case kPrev_Cur_FillCombo:
             // The most conservative result bound is that of the
             // prior clip. This could be wildly incorrect if the
             // second clip either exactly matches the first clip
             // (which should yield the empty set) or reduces the
             // size of the prior bound (e.g., if the second clip
             // exactly matched the bottom half of the prior clip).
             // We ignore these two possibilities.
             fFiniteBound = prevFinite;
             break;
         default:
             SkDEBUGFAIL("SkClipStack::Element::combineBoundsDiff Invalid fill combination");
             break;
     }
 }
 void SkClipStack::Element::combineBoundsXOR(int combination, const SkRect& prevFinite) {
     switch (combination) {
         case kInvPrev_Cur_FillCombo:       // fall through
         case kPrev_InvCur_FillCombo:
             // With only one of the clips inverted the result will always
             // extend to infinity. The only pixels that may be un-writeable
             // lie within the union of the two finite bounds
             fFiniteBound.join(prevFinite);
             fFiniteBoundType = kInsideOut_BoundsType;
             break;
         case kInvPrev_InvCur_FillCombo:
             // The only pixels that can survive are within the
             // union of the two bounding boxes since the extensions
             // to infinity of both clips cancel out
             // fall through!
         case kPrev_Cur_FillCombo:
             // The most conservative bound for xor is the
             // union of the two bounds. If the two clips exactly overlapped
             // the xor could yield the empty set. Similarly the xor
             // could reduce the size of the original clip's bound (e.g.,
             // if the second clip exactly matched the bottom half of the
             // first clip). We ignore these two cases.
             fFiniteBound.join(prevFinite);
             fFiniteBoundType = kNormal_BoundsType;
             break;
         default:
             SkDEBUGFAIL("SkClipStack::Element::combineBoundsXOR Invalid fill combination");
             break;
     }
 }
 // a mirror of combineBoundsIntersection
 void SkClipStack::Element::combineBoundsUnion(int combination, const SkRect& prevFinite) {
     switch (combination) {
         case kInvPrev_InvCur_FillCombo:
             if (!fFiniteBound.intersect(prevFinite)) {
                 fFiniteBound.setEmpty();
                 fGenID = kWideOpenGenID;
             }
             fFiniteBoundType = kInsideOut_BoundsType;
             break;
         case kInvPrev_Cur_FillCombo:
             // The only pixels that won't be drawable are inside
             // the prior clip's finite bound
             fFiniteBound = prevFinite;
             fFiniteBoundType = kInsideOut_BoundsType;
             break;
         case kPrev_InvCur_FillCombo:
             // The only pixels that won't be drawable are inside
             // this clip's finite bound
             break;
         case kPrev_Cur_FillCombo:
             fFiniteBound.join(prevFinite);
             break;
         default:
             SkDEBUGFAIL("SkClipStack::Element::combineBoundsUnion Invalid fill combination");
             break;
     }
 }
 // a mirror of combineBoundsUnion
 void SkClipStack::Element::combineBoundsIntersection(int combination, const SkRect& prevFinite) {
     switch (combination) {
         case kInvPrev_InvCur_FillCombo:
             // The only pixels that aren't writable in this case
             // occur in the union of the two finite bounds
             fFiniteBound.join(prevFinite);
             fFiniteBoundType = kInsideOut_BoundsType;
             break;
         case kInvPrev_Cur_FillCombo:
             // In this case the only pixels that will remain writeable
             // are within the current clip
             break;
         case kPrev_InvCur_FillCombo:
             // In this case the only pixels that will remain writeable
             // are with the previous clip
             fFiniteBound = prevFinite;
             fFiniteBoundType = kNormal_BoundsType;
             break;
         case kPrev_Cur_FillCombo:
             if (!fFiniteBound.intersect(prevFinite)) {
                 this->setEmpty();
             }
             break;
         default:
             SkDEBUGFAIL("SkClipStack::Element::combineBoundsIntersection Invalid fill combination");
             break;
     }
 }
 // a mirror of combineBoundsDiff
 void SkClipStack::Element::combineBoundsRevDiff(int combination, const SkRect& prevFinite) {
     switch (combination) {
         case kInvPrev_InvCur_FillCombo:
             // The only pixels that can survive are in the
             // previous bound since the extensions to infinity in
             // both clips cancel out
             fFiniteBound = prevFinite;
             fFiniteBoundType = kNormal_BoundsType;
             break;
         case kInvPrev_Cur_FillCombo:
             if (!fFiniteBound.intersect(prevFinite)) {
                 this->setEmpty();
             } else {
                 fFiniteBoundType = kNormal_BoundsType;
             }
             break;
         case kPrev_InvCur_FillCombo:
             fFiniteBound.join(prevFinite);
             fFiniteBoundType = kInsideOut_BoundsType;
             break;
         case kPrev_Cur_FillCombo:
             // Fall through - as with the kDifference_Op case, the
             // most conservative result bound is the bound of the
             // current clip. The prior clip could reduce the size of this
             // bound (as in the kDifference_Op case) but we are ignoring
             // those cases.
             break;
         default:
             SkDEBUGFAIL("SkClipStack::Element::combineBoundsRevDiff Invalid fill combination");
             break;
     }
 }
 void SkClipStack::Element::updateBoundAndGenID(const Element* prior) {
     // We set this first here but we may overwrite it later if we determine that the clip is
     // either wide-open or empty.
     fGenID = GetNextGenID();
     // First, optimistically update the current Element's bound information
     // with the current clip's bound
     fIsIntersectionOfRects = false;
     switch (fType) {
         case kRect_Type:
             fFiniteBound = this->getRect();
             fFiniteBoundType = kNormal_BoundsType;
             if (SkRegion::kReplace_Op == fOp ||
                 (SkRegion::kIntersect_Op == fOp && NULL == prior) ||
                 (SkRegion::kIntersect_Op == fOp && prior->fIsIntersectionOfRects &&
                     prior->rectRectIntersectAllowed(this->getRect(), fDoAA))) {
                 fIsIntersectionOfRects = true;
             }
             break;
         case kRRect_Type:
             fFiniteBound = fRRect.getBounds();
             fFiniteBoundType = kNormal_BoundsType;
             break;
         case kPath_Type:
             fFiniteBound = fPath.get()->getBounds();
             if (fPath.get()->isInverseFillType()) {
                 fFiniteBoundType = kInsideOut_BoundsType;
             } else {
                 fFiniteBoundType = kNormal_BoundsType;
             }
             break;
         case kEmpty_Type:
             SkDEBUGFAIL("We shouldn't get here with an empty element.");
             break;
     }
     if (!fDoAA) {
         // Here we mimic a non-anti-aliased scanline system. If there is
         // no anti-aliasing we can integerize the bounding box to exclude
         // fractional parts that won't be rendered.
         // Note: the left edge is handled slightly differently below. We
         // are a bit more generous in the rounding since we don't want to
         // risk missing the left pixels when fLeft is very close to .5
         fFiniteBound.set(SkScalarFloorToScalar(fFiniteBound.fLeft+0.45f),
                          SkScalarRoundToScalar(fFiniteBound.fTop),
                          SkScalarRoundToScalar(fFiniteBound.fRight),
                          SkScalarRoundToScalar(fFiniteBound.fBottom));
     }
     // Now determine the previous Element's bound information taking into
     // account that there may be no previous clip
     SkRect prevFinite;
     SkClipStack::BoundsType prevType;
     if (NULL == prior) {
         // no prior clip means the entire plane is writable
         prevFinite.setEmpty();   // there are no pixels that cannot be drawn to
         prevType = kInsideOut_BoundsType;
     } else {
         prevFinite = prior->fFiniteBound;
         prevType = prior->fFiniteBoundType;
     }
     FillCombo combination = kPrev_Cur_FillCombo;
     if (kInsideOut_BoundsType == fFiniteBoundType) {
         combination = (FillCombo) (combination | 0x01);
     }
     if (kInsideOut_BoundsType == prevType) {
         combination = (FillCombo) (combination | 0x02);
     }
     SkASSERT(kInvPrev_InvCur_FillCombo == combination ||
                 kInvPrev_Cur_FillCombo == combination ||
                 kPrev_InvCur_FillCombo == combination ||
                 kPrev_Cur_FillCombo == combination);
     // Now integrate with clip with the prior clips
     switch (fOp) {
         case SkRegion::kDifference_Op:
             this->combineBoundsDiff(combination, prevFinite);
             break;
         case SkRegion::kXOR_Op:
             this->combineBoundsXOR(combination, prevFinite);
             break;
         case SkRegion::kUnion_Op:
             this->combineBoundsUnion(combination, prevFinite);
             break;
         case SkRegion::kIntersect_Op:
             this->combineBoundsIntersection(combination, prevFinite);
             break;
         case SkRegion::kReverseDifference_Op:
             this->combineBoundsRevDiff(combination, prevFinite);
             break;
         case SkRegion::kReplace_Op:
             // Replace just ignores everything prior
             // The current clip's bound information is already filled in
             // so nothing to do
             break;
         default:
             SkDebugf("SkRegion::Op error\n");
             SkASSERT(0);
             break;
     }
 }
 // This constant determines how many Element's are allocated together as a block in
 // the deque. As such it needs to balance allocating too much memory vs.
 // incurring allocation/deallocation thrashing. It should roughly correspond to
 // the deepest save/restore stack we expect to see.
 static const int kDefaultElementAllocCnt = 8;
 SkClipStack::SkClipStack()
     : fDeque(sizeof(Element), kDefaultElementAllocCnt)
     , fSaveCount(0) {
 }
 SkClipStack::SkClipStack(const SkClipStack& b)
     : fDeque(sizeof(Element), kDefaultElementAllocCnt) {
     *this = b;
 }
 SkClipStack::SkClipStack(const SkRect& r)
     : fDeque(sizeof(Element), kDefaultElementAllocCnt)
     , fSaveCount(0) {
     if (!r.isEmpty()) {
         this->clipDevRect(r, SkRegion::kReplace_Op, false);
     }
 }
 SkClipStack::SkClipStack(const SkIRect& r)
     : fDeque(sizeof(Element), kDefaultElementAllocCnt)
     , fSaveCount(0) {
     if (!r.isEmpty()) {
         SkRect temp;
         temp.set(r);
         this->clipDevRect(temp, SkRegion::kReplace_Op, false);
     }
 }
 SkClipStack::~SkClipStack() {
     reset();
 }
 SkClipStack& SkClipStack::operator=(const SkClipStack& b) {
     if (this == &b) {
         return *this;
     }
     reset();
     fSaveCount = b.fSaveCount;
     SkDeque::F2BIter recIter(b.fDeque);
     for (const Element* element = (const Element*)recIter.next();
          element != NULL;
          element = (const Element*)recIter.next()) {
         new (fDeque.push_back()) Element(*element);
     }
     return *this;
 }
 bool SkClipStack::operator==(const SkClipStack& b) const {
     if (this->getTopmostGenID() == b.getTopmostGenID()) {
         return true;
     }
     if (fSaveCount != b.fSaveCount ||
         fDeque.count() != b.fDeque.count()) {
         return false;
     }
     SkDeque::F2BIter myIter(fDeque);
     SkDeque::F2BIter bIter(b.fDeque);
     const Element* myElement = (const Element*)myIter.next();
     const Element* bElement = (const Element*)bIter.next();
     while (myElement != NULL && bElement != NULL) {
         if (*myElement != *bElement) {
             return false;
         }
         myElement = (const Element*)myIter.next();
         bElement = (const Element*)bIter.next();
     }
     return myElement == NULL && bElement == NULL;
 }
 void SkClipStack::reset() {
     // We used a placement new for each object in fDeque, so we're responsible
     // for calling the destructor on each of them as well.
     while (!fDeque.empty()) {
         Element* element = (Element*)fDeque.back();
         element->~Element();
         fDeque.pop_back();
     }
     fSaveCount = 0;
 }
 void SkClipStack::save() {
     fSaveCount += 1;
 }
 void SkClipStack::restore() {
     fSaveCount -= 1;
     restoreTo(fSaveCount);
 }
 void SkClipStack::restoreTo(int saveCount) {
     while (!fDeque.empty()) {
         Element* element = (Element*)fDeque.back();
         if (element->fSaveCount <= saveCount) {
             break;
         }
         element->~Element();
         fDeque.pop_back();
     }
 }
 void SkClipStack::getBounds(SkRect* canvFiniteBound,
                             BoundsType* boundType,
                             bool* isIntersectionOfRects) const {
     SkASSERT(NULL != canvFiniteBound && NULL != boundType);
     Element* element = (Element*)fDeque.back();
     if (NULL == element) {
         // the clip is wide open - the infinite plane w/ no pixels un-writeable
         canvFiniteBound->setEmpty();
         *boundType = kInsideOut_BoundsType;
         if (NULL != isIntersectionOfRects) {
             *isIntersectionOfRects = false;
         }
         return;
     }
     *canvFiniteBound = element->fFiniteBound;
     *boundType = element->fFiniteBoundType;
     if (NULL != isIntersectionOfRects) {
         *isIntersectionOfRects = element->fIsIntersectionOfRects;
     }
 }
 bool SkClipStack::intersectRectWithClip(SkRect* rect) const {
     SkASSERT(NULL != rect);
     SkRect bounds;
     SkClipStack::BoundsType bt;
     this->getBounds(&bounds, &bt);
     if (bt == SkClipStack::kInsideOut_BoundsType) {
         if (bounds.contains(*rect)) {
             return false;
         } else {
             // If rect's x values are both within bound's x range we
             // could clip here. Same for y. But we don't bother to check.
             return true;
         }
     } else {
         return rect->intersect(bounds);
     }
 }
 bool SkClipStack::quickContains(const SkRect& rect) const {
     Iter iter(*this, Iter::kTop_IterStart);
     const Element* element = iter.prev();
     while (element != NULL) {
         if (SkRegion::kIntersect_Op != element->getOp() && SkRegion::kReplace_Op != element->getOp())
             return false;
         if (element->isInverseFilled()) {
             // Part of 'rect' could be trimmed off by the inverse-filled clip element
             if (SkRect::Intersects(element->getBounds(), rect)) {
                 return false;
             }
         } else {
             if (!element->contains(rect)) {
                 return false;
             }
         }
         if (SkRegion::kReplace_Op == element->getOp()) {
             break;
         }
         element = iter.prev();
     }
     return true;
 }
 void SkClipStack::pushElement(const Element& element) {
     // Use reverse iterator instead of back because Rect path may need previous
     SkDeque::Iter iter(fDeque, SkDeque::Iter::kBack_IterStart);
     Element* prior = (Element*) iter.prev();
     if (NULL != prior) {
         if (prior->canBeIntersectedInPlace(fSaveCount, element.getOp())) {
             switch (prior->fType) {
                 case Element::kEmpty_Type:
                     SkDEBUGCODE(prior->checkEmpty();)
                     return;
                 case Element::kRect_Type:
                     if (Element::kRect_Type == element.getType()) {
                         if (prior->rectRectIntersectAllowed(element.getRect(), element.isAA())) {
                             SkRect isectRect;
                             if (!isectRect.intersect(prior->getRect(), element.getRect())) {
                                 prior->setEmpty();
                                 return;
                             }
                             prior->fRRect.setRect(isectRect);
                             prior->fDoAA = element.isAA();
                             Element* priorPrior = (Element*) iter.prev();
                             prior->updateBoundAndGenID(priorPrior);
                             return;
                         }
                         break;
                     }
                     // fallthrough
                 default:
                     if (!SkRect::Intersects(prior->getBounds(), element.getBounds())) {
                         prior->setEmpty();
                         return;
                     }
                     break;
             }
         } else if (SkRegion::kReplace_Op == element.getOp()) {
             this->restoreTo(fSaveCount - 1);
             prior = (Element*) fDeque.back();
         }
     }
     Element* newElement = SkNEW_PLACEMENT_ARGS(fDeque.push_back(), Element, (element));
     newElement->updateBoundAndGenID(prior);
 }
 void SkClipStack::clipDevRRect(const SkRRect& rrect, SkRegion::Op op, bool doAA) {
     Element element(fSaveCount, rrect, op, doAA);
     this->pushElement(element);
 }
 void SkClipStack::clipDevRect(const SkRect& rect, SkRegion::Op op, bool doAA) {
     Element element(fSaveCount, rect, op, doAA);
     this->pushElement(element);
 }
 void SkClipStack::clipDevPath(const SkPath& path, SkRegion::Op op, bool doAA) {
     Element element(fSaveCount, path, op, doAA);
     this->pushElement(element);
 }
 void SkClipStack::clipEmpty() {
     Element* element = (Element*) fDeque.back();
     if (element && element->canBeIntersectedInPlace(fSaveCount, SkRegion::kIntersect_Op)) {
         element->setEmpty();
     }
     new (fDeque.push_back()) Element(fSaveCount);
     ((Element*)fDeque.back())->fGenID = kEmptyGenID;
 }
 bool SkClipStack::isWideOpen() const {
     return this->getTopmostGenID() == kWideOpenGenID;
 }
 ///////////////////////////////////////////////////////////////////////////////
 SkClipStack::Iter::Iter() : fStack(NULL) {
 }
 SkClipStack::Iter::Iter(const SkClipStack& stack, IterStart startLoc)
     : fStack(&stack) {
     this->reset(stack, startLoc);
 }
 const SkClipStack::Element* SkClipStack::Iter::next() {
     return (const SkClipStack::Element*)fIter.next();
 }
 const SkClipStack::Element* SkClipStack::Iter::prev() {
     return (const SkClipStack::Element*)fIter.prev();
 }
 const SkClipStack::Element* SkClipStack::Iter::skipToTopmost(SkRegion::Op op) {
     if (NULL == fStack) {
         return NULL;
     }
     fIter.reset(fStack->fDeque, SkDeque::Iter::kBack_IterStart);
     const SkClipStack::Element* element = NULL;
     for (element = (const SkClipStack::Element*) fIter.prev();
          NULL != element;
          element = (const SkClipStack::Element*) fIter.prev()) {
         if (op == element->fOp) {
             // The Deque's iterator is actually one pace ahead of the
             // returned value. So while "element" is the element we want to
             // return, the iterator is actually pointing at (and will
             // return on the next "next" or "prev" call) the element
             // in front of it in the deque. Bump the iterator forward a
             // step so we get the expected result.
             if (NULL == fIter.next()) {
                 // The reverse iterator has run off the front of the deque
                 // (i.e., the "op" clip is the first clip) and can't
                 // recover. Reset the iterator to start at the front.
                 fIter.reset(fStack->fDeque, SkDeque::Iter::kFront_IterStart);
             }
             break;
         }
     }
     if (NULL == element) {
         // There were no "op" clips
         fIter.reset(fStack->fDeque, SkDeque::Iter::kFront_IterStart);
     }
     return this->next();
 }
 void SkClipStack::Iter::reset(const SkClipStack& stack, IterStart startLoc) {
     fStack = &stack;
     fIter.reset(stack.fDeque, static_cast<SkDeque::Iter::IterStart>(startLoc));
 }
 // helper method
 void SkClipStack::getConservativeBounds(int offsetX,
                                         int offsetY,
                                         int maxWidth,
                                         int maxHeight,
                                         SkRect* devBounds,
                                         bool* isIntersectionOfRects) const {
     SkASSERT(NULL != devBounds);
     devBounds->setLTRB(0, 0,
                        SkIntToScalar(maxWidth), SkIntToScalar(maxHeight));
     SkRect temp;
     SkClipStack::BoundsType boundType;
     // temp starts off in canvas space here
     this->getBounds(&temp, &boundType, isIntersectionOfRects);
     if (SkClipStack::kInsideOut_BoundsType == boundType) {
         return;
     }
     // but is converted to device space here
     temp.offset(SkIntToScalar(offsetX), SkIntToScalar(offsetY));
     if (!devBounds->intersect(temp)) {
         devBounds->setEmpty();
     }
 }
 int32_t SkClipStack::GetNextGenID() {
     // TODO: handle overflow.
     return sk_atomic_inc(&gGenID);
 }
 int32_t SkClipStack::getTopmostGenID() const {
     if (fDeque.empty()) {
         return kWideOpenGenID;
     }
     const Element* back = static_cast<const Element*>(fDeque.back());
     if (kInsideOut_BoundsType == back->fFiniteBoundType && back->fFiniteBound.isEmpty()) {
         return kWideOpenGenID;
     }
     return back->getGenID();
 }

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gfx/skia/trunk/src/core/SkClipStack.cpp@129ffea94266 (annotated)

gfx/skia/trunk/src/core/SkClipStack.cpp