commit e3dbedb44cad6c7b7e5c9aae5224d0b0abec9bf4
author junov@chromium.org <junov@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Mon Jul 09 16:03:55 2012 +0000
committer junov@chromium.org <junov@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Mon Jul 09 16:03:55 2012 +0000
tree 1d5769eb89cb752a3a76e41cd1c2fe9e3c98c196
parent 2eb479555b351bc9c77feb3d0873856f7d365b74

Refactoring code in SkPictureRecord that touches fRestoreOffsetStack

Review URL: http://codereview.appspot.com/6350059/
BUG=http://code.google.com/p/chromium/issues/detail?id=133432



git-svn-id: http://skia.googlecode.com/svn/trunk@4472 2bbb7eff-a529-9590-31e7-b0007b416f81

src/core/SkPictureRecord.cpp

diff --git a/src/core/SkPictureRecord.cpp b/src/core/SkPictureRecord.cpp
index a499ee1..a55c9af 100644
--- a/src/core/SkPictureRecord.cpp
+++ b/src/core/SkPictureRecord.cpp
@@ -83,14 +83,8 @@
         return;
     }
 
-    // patch up the clip offsets
-    uint32_t restoreOffset = (uint32_t)fWriter.size();
-    uint32_t offset = fRestoreOffsetStack.top();
-    while (offset) {
-        uint32_t* peek = fWriter.peek32(offset);
-        offset = *peek;
-        *peek = restoreOffset;
-    }
+    fillRestoreOffsetPlaceholdersForCurrentStackLevel(
+        (uint32_t)fWriter.size());
 
     if (fRestoreOffsetStack.count() == fFirstSavedLayerIndex) {
         fFirstSavedLayerIndex = kNoSavedLayerIndex;
@@ -166,21 +160,31 @@
     }
 }
 
-void SkPictureRecord::recordOffsetForRestore(SkRegion::Op op) {
+void SkPictureRecord::fillRestoreOffsetPlaceholdersForCurrentStackLevel(
+    uint32_t restoreOffset) {
+    uint32_t offset = fRestoreOffsetStack.top();
+    while (offset) {
+        uint32_t* peek = fWriter.peek32(offset);
+        offset = *peek;
+        *peek = restoreOffset;
+    }
+}
+
+void SkPictureRecord::recordRestoreOffsetPlaceholder(SkRegion::Op op) {
     if (regionOpExpands(op)) {
         // Run back through any previous clip ops, and mark their offset to
         // be 0, disabling their ability to trigger a jump-to-restore, otherwise
         // they could hide this clips ability to expand the clip (i.e. go from
         // empty to non-empty).
-        uint32_t offset = fRestoreOffsetStack.top();
-        while (offset) {
-            uint32_t* peek = fWriter.peek32(offset);
-            offset = *peek;
-            *peek = 0;
-        }
+        fillRestoreOffsetPlaceholdersForCurrentStackLevel(0);
     }
 
     size_t offset = fWriter.size();
+    // The RestoreOffset field is initially filled with a placeholder
+    // value that points to the offset of the previous RestoreOffset
+    // in the current stack level, thus forming a linked list so that
+    // the restore offsets can be filled in when the corresponding 
+    // restore command is recorded.
     addInt(fRestoreOffsetStack.top());
     fRestoreOffsetStack.top() = offset;
 }
@@ -189,8 +193,7 @@
     addDraw(CLIP_RECT);
     addRect(rect);
     addInt(ClipParams_pack(op, doAA));
-
-    this->recordOffsetForRestore(op);
+    recordRestoreOffsetPlaceholder(op);
 
     validate();
     return this->INHERITED::clipRect(rect, op, doAA);
@@ -200,8 +203,7 @@
     addDraw(CLIP_PATH);
     addPath(path);
     addInt(ClipParams_pack(op, doAA));
-
-    this->recordOffsetForRestore(op);
+    recordRestoreOffsetPlaceholder(op);
 
     validate();
 
@@ -216,8 +218,7 @@
     addDraw(CLIP_REGION);
     addRegion(region);
     addInt(ClipParams_pack(op, false));
-
-    this->recordOffsetForRestore(op);
+    recordRestoreOffsetPlaceholder(op);
 
     validate();
     return this->INHERITED::clipRegion(region, op);