Replace GrTHash with SkTDynamicHash

src/gpu/GrLayerCache.h

Index: src/gpu/GrLayerCache.h
diff --git a/src/gpu/GrLayerCache.h b/src/gpu/GrLayerCache.h
index 347fa232ab6d7be50363e8fc177802d57067da41..61b6323e5cda1ca942ae966f2a20171343c3dcab 100644
--- a/src/gpu/GrLayerCache.h
+++ b/src/gpu/GrLayerCache.h
@@ -12,9 +12,9 @@
 
 #include "GrAllocPool.h"
 #include "GrAtlas.h"
-#include "GrTHashTable.h"
 #include "GrPictureUtils.h"
 #include "GrRect.h"
+#include "SkTDynamicHash.h"
 
 class SkPicture;
 
@@ -22,9 +22,14 @@ class SkPicture;
 // plot may be used to store layers from multiple pictures.
 struct GrPictureInfo {
 public:
+    // for SkTDynamicHash - just use the pictureID as the hash key
+    static const uint32_t& GetKey(const GrPictureInfo& pictInfo) { return pictInfo.fPictureID; }
+    static uint32_t Hash(const uint32_t& key) { return key; }

[mtklein, 2014/07/17 19:36:20]

Might consider trying SkChecksum::Mix(key) in the future.

[robertphillips, 2014/07/17 20:02:46]

Done.

+
+    // GrPictureInfo proper
     GrPictureInfo(uint32_t pictureID) : fPictureID(pictureID) { }
 
-    uint32_t fPictureID;
+    const uint32_t fPictureID;
 
     GrAtlas::ClientPlotUsage  fPlotUsage;
 };
@@ -37,16 +42,47 @@ public:
 // Atlased layers also get a pointer to the plot in which they reside.
 struct GrCachedLayer {
 public:
+    // For SkTDynamicHash
+    struct Key {
+        Key(uint32_t pictureID, int layerID) : fPictureID(pictureID) , fLayerID(layerID) {}
+
+        bool operator<(const Key& other) const {

[mtklein, 2014/07/17 19:36:20]

SkTDynamicHash won't need this.  Is this dead code?

[robertphillips, 2014/07/17 20:02:47]

Done.

+            if (fPictureID == other.fPictureID) {
+                return fLayerID < other.fLayerID;
+            }
+            return fPictureID < other.fPictureID;
+        }
+
+        bool operator==(const Key& other) const {
+            return fPictureID == other.fPictureID && fLayerID == other.fLayerID;
+        }
+
+        uint32_t getHash() const { return (fPictureID << 16) | fLayerID; }

[mtklein, 2014/07/17 19:36:20]

Again, SkChecksum::Mix() is a good idea.  Using this hash means the table will
ignore fPictureID until it gets up to 65K capacity.

Or even just do SkChecksum::{Compute,Murmur3}(reinterpret_cast<const
uint32_t*>(this), sizeof(*this)); ?

[robertphillips, 2014/07/17 20:02:46]

Done.

+
+        uint32_t getPictureID() const { return fPictureID; }
+        int      getLayerID() const { return fLayerID; }
+
+    private:
+        // ID of the picture of which this layer is a part
+        const uint32_t fPictureID;
+        // fLayerID is the index of this layer in the picture (one of 0 .. #layers).
+        const int      fLayerID;
+    };
+
+    static const Key& GetKey(const GrCachedLayer& layer) { return layer.fKey; }
+    static uint32_t Hash(const Key& key) { return key.getHash(); }

[mtklein, 2014/07/17 19:36:20]

Consider inlining Key::getHash into this?

[robertphillips, 2014/07/17 20:02:47]

Done.

+
+    // GrCachedLayer proper
     GrCachedLayer(uint32_t pictureID, int layerID) 
-        : fPlot(NULL) {
-        fPictureID = pictureID;
-        fLayerID = layerID;
-        fTexture = NULL;
-        fRect = GrIRect16::MakeEmpty();
+        : fKey(pictureID, layerID)
+        , fTexture(NULL)
+        , fRect(GrIRect16::MakeEmpty()),
+	, fPlot(NULL) {

[mtklein, 2014/07/17 19:36:20]

Stray tab?

[robertphillips, 2014/07/17 20:02:46]

Done.

+        SkASSERT(SK_InvalidGenID != pictureID && layerID >= 0);
     }
 
-    uint32_t pictureID() const { return fPictureID; }
-    int layerID() const { return fLayerID; }
+    uint32_t pictureID() const { return fKey.getPictureID(); }
+    int layerID() const { return fKey.getLayerID(); }
 
     // This call takes over the caller's ref
     void setTexture(GrTexture* texture, const GrIRect16& rect) {
@@ -71,12 +107,7 @@ public:
     SkDEBUGCODE(void validate(const GrTexture* backingTexture) const;)
 
 private:
-    // ID of the picture of which this layer is a part
-    uint32_t        fPictureID;
-
-    // fLayerID is only valid when fPicture != kInvalidGenID in which case it
-    // is the index of this layer in the picture (one of 0 .. #layers).
-    int             fLayerID;
+    const Key       fKey;
 
     // fTexture is a ref on the atlasing texture for atlased layers and a
     // ref on a GrTexture for non-atlased textures. In both cases, if this is
@@ -138,11 +169,9 @@ private:
     // is leaked and never cleans itself up we still want to be able to 
     // remove the GrPictureInfo once its layers are purged from all the atlas
     // plots).
-    class PictureKey;
-    GrTHashTable<GrPictureInfo, PictureKey, 7> fPictureHash;
+    SkTDynamicHash<GrPictureInfo, uint32_t> fPictureHash;
 
-    class PictureLayerKey;
-    GrTHashTable<GrCachedLayer, PictureLayerKey, 7> fLayerHash;
+    SkTDynamicHash<GrCachedLayer, GrCachedLayer::Key> fLayerHash;
 
     void initAtlas();
     GrCachedLayer* createLayer(const SkPicture* picture, int layerID);