SkTileGrid: store insertion order, return results sorted by that.

src/core/SkTileGrid.h

Index: src/core/SkTileGrid.h
diff --git a/src/core/SkTileGrid.h b/src/core/SkTileGrid.h
index c02235a12327aa6911a24f353f465a41abb7d22a..41463310b696fa654c68929cc194c7c90f5a65e7 100644
--- a/src/core/SkTileGrid.h
+++ b/src/core/SkTileGrid.h
@@ -1,4 +1,3 @@
-
 /*
  * Copyright 2012 Google Inc.
  *
@@ -11,27 +10,21 @@
 
 #include "SkBBHFactory.h"
 #include "SkBBoxHierarchy.h"
-#include "SkPictureStateTree.h"
 
 /**
  * Subclass of SkBBoxHierarchy that stores elements in buckets that correspond
  * to tile regions, disposed in a regular grid.  This is useful when the tile
  * structure that will be use in search() calls is known prior to insertion.
- * Calls to search will return in constant time.
- *
- * Note: Current implementation of search() only supports looking-up regions
- * that are an exact match to a single tile.  Implementation could be augmented
- * to support arbitrary rectangles, but performance would be sub-optimal.
  */
 class SkTileGrid : public SkBBoxHierarchy {
 public:
-    SkTileGrid(int xTileCount, int yTileCount, const SkTileGridFactory::TileGridInfo& info);
+    SkTileGrid(int xTiles, int yTiles, const SkTileGridFactory::TileGridInfo& info);
 
     virtual ~SkTileGrid();
 
     /**
      * Insert a data pointer and corresponding bounding box
-     * @param data   The data pointer, may _NOT_ be NULL.
+     * @param data   An arbitrary data pointer, may be NULL.
      * @param bounds The bounding box, should not be empty.
      * @param defer  Ignored; SkTileGrid does not defer insertions.
      */
@@ -47,26 +40,27 @@ public:
 
     virtual void clear() SK_OVERRIDE;
 
-    /**
-     * Gets the number of insertions
-     */
-    virtual int getCount() const SK_OVERRIDE;
+    virtual int getCount() const SK_OVERRIDE { return fCount; }
 
     virtual int getDepth() const SK_OVERRIDE { return -1; }
 
     virtual void rewindInserts() SK_OVERRIDE;
 
-    int tileCount(int x, int y);  // For testing only.
+    // For testing.
+    int tileCount(int x, int y) { return fTiles[y * fXTiles + x].count(); }
 
 private:
-    const SkTDArray<void*>& tile(int x, int y) const;
-    SkTDArray<void*>& tile(int x, int y);
+    struct Entry {
+        size_t order;  // Insertion order.  Used to preserve order when merging multiple tiles.
+        void*  data;
+    };
 
-    int fXTileCount, fYTileCount, fTileCount;
+    const int fXTiles, fYTiles;
     SkTileGridFactory::TileGridInfo fInfo;
-    SkTDArray<void*>* fTileData;
-    int fInsertionCount;
-    SkIRect fGridBounds;
+    size_t fCount;
+
+    // (fXTiles * fYTiles) SkTDArrays, each listing data overlapping that tile in insertion order.
+    SkTDArray<Entry>* fTiles;
 
     typedef SkBBoxHierarchy INHERITED;
 };