Move bound and isFinite into pathref

src/core/SkPathRef.h

Index: src/core/SkPathRef.h
===================================================================
--- src/core/SkPathRef.h	(revision 11438)
+++ src/core/SkPathRef.h	(working copy)
@@ -129,6 +129,40 @@
     }
 
     /**
+     *  Returns true if all of the points in this path are finite, meaning there
+     *  are no infinities and no NaNs.
+     */
+    bool isFinite() const {
+        if (fBoundsIsDirty) {
+            this->computeBounds();
+        }
+        return SkToBool(fIsFinite);
+    }
+
+    bool hasComputedBounds() const {
+        return !fBoundsIsDirty;
+    }
+
+    /** Returns the bounds of the path's points. If the path contains 0 or 1
+        points, the bounds is set to (0,0,0,0), and isEmpty() will return true.
+        Note: this bounds may be larger than the actual shape, since curves
+        do not extend as far as their control points.
+    */
+    const SkRect& getBounds() const {        
+        if (fBoundsIsDirty) {
+            this->computeBounds();
+        }
+        return fBounds;
+    }
+
+    void setBounds(const SkRect& rect) {
+        SkASSERT(rect.fLeft <= rect.fRight && rect.fTop <= rect.fBottom);
+        fBounds = rect;
+        fBoundsIsDirty = false;
+        fIsFinite = fBounds.isFinite();
+    }
+
+    /**
      * Transforms a path ref by a matrix, allocating a new one only if necessary.
      */
     static void CreateTransformedCopy(SkAutoTUnref<SkPathRef>* dst,
@@ -143,22 +177,66 @@
             }
             return;
         }
+
         bool dstUnique = (*dst)->unique();
-        if (&src == *dst && dstUnique) {
-            matrix.mapPoints((*dst)->fPoints, (*dst)->fPointCnt);
-            return;
-        } else if (!dstUnique) {
+        if (!dstUnique) {
             dst->reset(SkNEW(SkPathRef));
+            (*dst)->resetToSize(src.fVerbCnt, src.fPointCnt, src.fConicWeights.count());
+            memcpy((*dst)->verbsMemWritable(), src.verbsMemBegin(), src.fVerbCnt * sizeof(uint8_t));
+            (*dst)->fConicWeights = src.fConicWeights;
         }
-        (*dst)->resetToSize(src.fVerbCnt, src.fPointCnt, src.fConicWeights.count());
-        memcpy((*dst)->verbsMemWritable(), src.verbsMemBegin(), src.fVerbCnt * sizeof(uint8_t));
+
+        // Need to check this here in case (&src == dst)
+        bool canXformBounds = !src.fBoundsIsDirty && matrix.rectStaysRect() && src.countPoints() > 1;
+
         matrix.mapPoints((*dst)->fPoints, src.points(), src.fPointCnt);
-        (*dst)->fConicWeights = src.fConicWeights;
+
+        /*
+         *  Here we optimize the bounds computation, by noting if the bounds are
+         *  already known, and if so, we just transform those as well and mark
+         *  them as "known", rather than force the transformed path to have to
+         *  recompute them.
+         *
+         *  Special gotchas if the path is effectively empty (<= 1 point) or
+         *  if it is non-finite. In those cases bounds need to stay empty,
+         *  regardless of the matrix.
+         */
+        if (canXformBounds) {
+            (*dst)->fBoundsIsDirty = false;
+            if (src.fIsFinite) {
+                matrix.mapRect(&(*dst)->fBounds, src.fBounds);
+                if (!((*dst)->fIsFinite = (*dst)->fBounds.isFinite())) {
+                    (*dst)->fBounds.setEmpty();
+                }
+            } else {
+                (*dst)->fIsFinite = false;
+                (*dst)->fBounds.setEmpty();
+            }
+        } else {
+            (*dst)->fBoundsIsDirty = true;
+        }
+
         (*dst)->validate();
     }
 
-    static SkPathRef* CreateFromBuffer(SkRBuffer* buffer) {
+    static SkPathRef* CreateFromBuffer(SkRBuffer* buffer
+#ifndef DELETE_THIS_CODE_WHEN_SKPS_ARE_REBUILT_AT_V14_AND_ALL_OTHER_INSTANCES_TOO
+        , bool newFormat, int32_t oldPacked
+#endif
+        ) {
         SkPathRef* ref = SkNEW(SkPathRef);
+#ifndef DELETE_THIS_CODE_WHEN_SKPS_ARE_REBUILT_AT_V14_AND_ALL_OTHER_INSTANCES_TOO
+        if (newFormat) {
+#endif
+            int32_t packed = buffer->readU32();
+
+            ref->fIsFinite = (packed >> kIsFinite_SerializationShift) & 1;
+#ifndef DELETE_THIS_CODE_WHEN_SKPS_ARE_REBUILT_AT_V14_AND_ALL_OTHER_INSTANCES_TOO
+        } else {
+            ref->fIsFinite = (oldPacked >> SkPath::kOldIsFinite_SerializationShift) & 1;
+        }
+#endif
+
         ref->fGenerationID = buffer->readU32();
         int32_t verbCount = buffer->readS32();
         int32_t pointCount = buffer->readS32();
@@ -171,6 +249,8 @@
         buffer->read(ref->verbsMemWritable(), verbCount * sizeof(uint8_t));
         buffer->read(ref->fPoints, pointCount * sizeof(SkPoint));
         buffer->read(ref->fConicWeights.begin(), conicCount * sizeof(SkScalar));
+        buffer->read(&ref->fBounds, sizeof(SkRect));
+        ref->fBoundsIsDirty = false;
         return ref;
     }
 
@@ -182,6 +262,7 @@
     static void Rewind(SkAutoTUnref<SkPathRef>* pathRef) {
         if ((*pathRef)->unique()) {
             (*pathRef)->validate();
+            (*pathRef)->fBoundsIsDirty = true;  // this also invalidates fIsFinite
             (*pathRef)->fVerbCnt = 0;
             (*pathRef)->fPointCnt = 0;
             (*pathRef)->fFreeSpace = (*pathRef)->currSize();
@@ -294,6 +375,13 @@
         this->validate();
         SkDEBUGCODE(size_t beforePos = buffer->pos();)
 
+        // Call getBounds() to ensure (as a side-effect) that fBounds
+        // and fIsFinite are computed.
+        const SkRect& bounds = this->getBounds();
+
+        int32_t packed = ((fIsFinite & 1) << kIsFinite_SerializationShift);
+        buffer->write32(packed);
+
         // TODO: write gen ID here. Problem: We don't know if we're cross process or not from
         // SkWBuffer. Until this is fixed we write 0.
         buffer->write32(0);
@@ -303,6 +391,7 @@
         buffer->write(verbsMemBegin(), fVerbCnt * sizeof(uint8_t));
         buffer->write(fPoints, fPointCnt * sizeof(SkPoint));
         buffer->write(fConicWeights.begin(), fConicWeights.bytes());
+        buffer->write(&bounds, sizeof(bounds));
 
         SkASSERT(buffer->pos() - beforePos == (size_t) this->writeSize());
     }
@@ -311,14 +400,20 @@
      * Gets the number of bytes that would be written in writeBuffer()
      */
     uint32_t writeSize() {
-        return 4 * sizeof(uint32_t) +
+        return 5 * sizeof(uint32_t) +
                fVerbCnt * sizeof(uint8_t) +
                fPointCnt * sizeof(SkPoint) +
-               fConicWeights.bytes();
+               fConicWeights.bytes() +
+               sizeof(SkRect);
     }
 
 private:
+    enum SerializationOffsets {
+        kIsFinite_SerializationShift = 25,  // requires 1 bit
+    };
+
     SkPathRef() {
+        fBoundsIsDirty = true;    // this also invalidates fIsFinite
         fPointCnt = 0;
         fVerbCnt = 0;
         fVerbs = NULL;
@@ -339,9 +434,34 @@
         // We could call genID() here to force a real ID (instead of 0). However, if we're making
         // a copy then presumably we intend to make a modification immediately afterwards.
         fGenerationID = ref.fGenerationID;
+        fBoundsIsDirty = ref.fBoundsIsDirty;
+        if (!fBoundsIsDirty) {
+            fBounds = ref.fBounds;
+            fIsFinite = ref.fIsFinite;
+        }
         this->validate();
     }
 
+    // Return true if the computed bounds are finite.
+    static bool ComputePtBounds(SkRect* bounds, const SkPathRef& ref) {
+        int count = ref.countPoints();
+        if (count <= 1) {  // we ignore just 1 point (moveto)
+            bounds->setEmpty();
+            return count ? ref.points()->isFinite() : true;
+        } else {
+            return bounds->setBoundsCheck(ref.points(), count);
+        }
+    }
+
+    // called, if dirty, by getBounds()
+    void computeBounds() const {
+        SkDEBUGCODE(this->validate();)
+        SkASSERT(fBoundsIsDirty);
+
+        fIsFinite = ComputePtBounds(&fBounds, *this);
+        fBoundsIsDirty = false;
+    }
+
     /** Makes additional room but does not change the counts or change the genID */
     void incReserve(int additionalVerbs, int additionalPoints) {
         this->validate();
@@ -350,11 +470,12 @@
         this->validate();
     }
 
-    /** Resets the path ref with verbCount verbs and pointCount points, all unitialized. Also
+    /** Resets the path ref with verbCount verbs and pointCount points, all uninitialized. Also
      *  allocates space for reserveVerb additional verbs and reservePoints additional points.*/
     void resetToSize(int verbCount, int pointCount, int conicCount,
                      int reserveVerbs = 0, int reservePoints = 0) {
         this->validate();
+        fBoundsIsDirty = true;      // this also invalidates fIsFinite
         fGenerationID = 0;
 
         size_t newSize = sizeof(uint8_t) * verbCount + sizeof(SkPoint) * pointCount;
@@ -394,6 +515,7 @@
         fVerbCnt += newVerbs;
         fPointCnt += newPoints;
         fFreeSpace -= space;
+        fBoundsIsDirty = true;  // this also invalidates fIsFinite
         this->validate();
     }
 
@@ -437,6 +559,7 @@
         fVerbCnt += 1;
         fPointCnt += pCnt;
         fFreeSpace -= space;
+        fBoundsIsDirty = true;  // this also invalidates fIsFinite
         this->validate();
         return ret;
     }
@@ -524,12 +647,30 @@
         SkASSERT(!(NULL == fVerbs && fVerbCnt));
         SkASSERT(this->currSize() ==
                  fFreeSpace + sizeof(SkPoint) * fPointCnt + sizeof(uint8_t) * fVerbCnt);
+
+#ifdef SK_DEBUG
+        if (!fBoundsIsDirty && !fBounds.isEmpty()) {
+            bool isFinite = true;
+            for (int i = 0; i < fPointCnt; ++i) {
+                SkASSERT(fPoints[i].fX >= fBounds.fLeft && fPoints[i].fX <= fBounds.fRight &&
+                         fPoints[i].fY >= fBounds.fTop && fPoints[i].fY <= fBounds.fBottom);
+                if (!fPoints[i].isFinite()) {
+                    isFinite = false;
+                }
+            }
+            SkASSERT(SkToBool(fIsFinite) == isFinite);
+        }
+#endif
     }
 
     enum {
         kMinSize = 256,
     };
 
+    mutable SkRect      fBounds;
+    mutable uint8_t     fBoundsIsDirty;
+    mutable SkBool8     fIsFinite;    // only meaningful if bounds are valid
+
     SkPoint*            fPoints; // points to begining of the allocation
     uint8_t*            fVerbs; // points just past the end of the allocation (verbs grow backwards)
     int                 fVerbCnt;