Builder class for SkLayerDrawLooper.

src/effects/SkLayerDrawLooper.cpp

Index: src/effects/SkLayerDrawLooper.cpp
diff --git a/src/effects/SkLayerDrawLooper.cpp b/src/effects/SkLayerDrawLooper.cpp
index 6c7c3cef0cb04f2529fc3e21fd5688d3a7b19fed..6705060bf7919518925aac83c993cc1965a53bac 100644
--- a/src/effects/SkLayerDrawLooper.cpp
+++ b/src/effects/SkLayerDrawLooper.cpp
@@ -229,6 +229,7 @@ SkLayerDrawLooper::SkLayerDrawLooper(SkReadBuffer& buffer)
           fCurrRec(NULL) {
     int count = buffer.readInt();
 
+    Builder builder;
     for (int i = 0; i < count; i++) {
         LayerInfo info;
         info.fFlagsMask = buffer.readInt();
@@ -236,8 +237,9 @@ SkLayerDrawLooper::SkLayerDrawLooper(SkReadBuffer& buffer)
         info.fColorMode = (SkXfermode::Mode)buffer.readInt();
         buffer.readPoint(&info.fOffset);
         info.fPostTranslate = buffer.readBool();
-        buffer.readPaint(this->addLayerOnTop(info));
+        buffer.readPaint(builder.addLayerOnTop(info));
     }
+    builder.initLooperAndReset(this);

[scroggo, 2014/02/11 14:48:37]

I think the main place this will be called is readFlattenable(). What if we made
the caller call the builder instead of using this constructor? Other
flattenables we create builders for can work the same way.

     SkASSERT(count == fCount);
 
 #ifdef SK_DEBUG
@@ -347,3 +349,71 @@ void SkLayerDrawLooper::toString(SkString* str) const {
     }
 }
 #endif
+
+SkLayerDrawLooper::Builder::Builder()
+        : fRecs(NULL),
+          fTopRec(NULL),
+          fCount(0) {
+}
+
+SkLayerDrawLooper::Builder::~Builder() {
+    Rec* rec = fRecs;
+    while (rec) {
+        Rec* next = rec->fNext;
+        SkDELETE(rec);
+        rec = next;
+    }
+}
+
+SkPaint* SkLayerDrawLooper::Builder::addLayer(const LayerInfo& info) {
+    fCount += 1;
+
+    Rec* rec = SkNEW(Rec);
+    rec->fNext = fRecs;
+    rec->fInfo = info;
+    fRecs = rec;
+    if (NULL == fTopRec) {
+        fTopRec = rec;
+    }
+
+    return &rec->fPaint;
+}
+
+void SkLayerDrawLooper::Builder::addLayer(SkScalar dx, SkScalar dy) {
+    LayerInfo info;
+
+    info.fOffset.set(dx, dy);
+    (void)this->addLayer(info);
+}
+
+SkPaint* SkLayerDrawLooper::Builder::addLayerOnTop(const LayerInfo& info) {
+    fCount += 1;
+
+    Rec* rec = SkNEW(Rec);
+    rec->fNext = NULL;
+    rec->fInfo = info;
+    if (NULL == fRecs) {
+        fRecs = rec;
+    } else {
+        SkASSERT(NULL != fTopRec);
+        fTopRec->fNext = rec;
+    }
+    fTopRec = rec;
+
+    return &rec->fPaint;
+}
+
+SkLayerDrawLooper* SkLayerDrawLooper::Builder::detachLooper() {
+    SkLayerDrawLooper* looper = SkNEW(SkLayerDrawLooper);
+    initLooperAndReset(looper);
+    return looper;
+}
+
+void SkLayerDrawLooper::Builder::initLooperAndReset(SkLayerDrawLooper* looper) {
+    looper->fCount = fCount;
+    looper->fRecs = fRecs;
+
+    fCount = 0;
+    fRecs = NULL;
+    fTopRec = NULL;
+}