Sketch splitting SkPicture into an interface and SkBigPicture.

include/core/SkPicture.h

Index: include/core/SkPicture.h
diff --git a/include/core/SkPicture.h b/include/core/SkPicture.h
index 88dfdf106678683adb263efaf9f76bb9274f68a8..88b8440bb739c65b64500f82b93b88e96365ec59 100644
--- a/include/core/SkPicture.h
+++ b/include/core/SkPicture.h
@@ -5,61 +5,31 @@
  * found in the LICENSE file.
  */
 
-
 #ifndef SkPicture_DEFINED
 #define SkPicture_DEFINED
 
 #include "SkImageDecoder.h"
 #include "SkRefCnt.h"
-#include "SkTDArray.h"
+#include "SkTypes.h"
 
-#if SK_SUPPORT_GPU
 class GrContext;
-#endif
-
+class SkBigPicture;
 class SkBitmap;
-class SkBBoxHierarchy;
 class SkCanvas;
-class SkData;
 class SkPictureData;
 class SkPixelSerializer;
 class SkStream;
 class SkWStream;
-
 struct SkPictInfo;
 
-class SkRecord;
-
-namespace SkRecords {
-    class CollectLayers;
-};
-
 /** \class SkPicture
 
-    The SkPicture class records the drawing commands made to a canvas, to
-    be played back at a later time.
+    An SkPicture records drawing commands made to a canvas to be played back at a later time.
+    This base class handles serialization and a few other miscellany.
 */
-class SK_API SkPicture : public SkNVRefCnt<SkPicture> {
+class SK_API SkPicture : public SkRefCnt {
 public:
-    // AccelData provides a base class for device-specific acceleration data.
-    class AccelData : public SkRefCnt {
-    public:
-        typedef uint8_t Domain;
-        typedef uint32_t Key;
-
-        AccelData(Key key) : fKey(key) { }
-
-        const Key& getKey() const { return fKey; }
-
-        // This entry point allows user's to get a unique domain prefix
-        // for their keys
-        static Domain GenerateDomain();
-    private:
-        Key fKey;
-    };
-
-    /**  PRIVATE / EXPERIMENTAL -- do not call */
-    const AccelData* EXPERIMENTAL_getAccelData(AccelData::Key) const;
+    virtual ~SkPicture();
 
     /**
      *  Function signature defining a function that sets up an SkBitmap from encoded data. On
@@ -95,8 +65,6 @@ public:
      */
     static SkPicture* CreateFromBuffer(SkReadBuffer&);
 
-    ~SkPicture();
-
     /**
     *  Subclasses of this can be passed to playback(). During the playback
     *  of the picture, this callback will periodically be invoked. If its
@@ -107,11 +75,8 @@ public:
     *  calls to save(), restore will automatically be called to return the state
     *  to the same level it was before the playback call was made.
     */
-    class SK_API AbortCallback {
-    public:
-        AbortCallback() {}
+    struct SK_API AbortCallback {

[reed1, 2015/04/29 20:21:53]

this change *may* generate warnings for existing clients/subclasses. why from
class to struct?

[mtklein, 2015/04/29 20:46:22]

Just seemed struct-y, given its all-pubic nature.

[mtklein, 2015/04/30 16:17:03]

Undone.

         virtual ~AbortCallback() {}
-
         virtual bool abort() = 0;
     };
 
@@ -122,16 +87,14 @@ public:
         @param canvas the canvas receiving the drawing commands.
         @param callback a callback that allows interruption of playback
     */
-    void playback(SkCanvas* canvas, AbortCallback* = NULL) const;
-
-    /** Return the cull rect used when creating this picture: { 0, 0, cullWidth, cullHeight }.
-        It does not necessarily reflect the bounds of what has been recorded into the picture.
-        @return the cull rect used to create this picture
-    */
-    SkRect cullRect() const { return fCullRect; }
+    virtual void playback(SkCanvas*, AbortCallback* = NULL) const = 0;

[reed1, 2015/04/29 20:21:53]

general comment (not important in the early stages per-se) -- wrapping the
onVirtuals with public nonVirtuals is a zero-cost trick, but allows us in the
future to add common debug checks/stats/caching w/o needing to rev the
subclasses.

e.g.

void playback(...) {
    this->onPlayback(...);
}

[mtklein, 2015/04/29 20:46:22]

Right.  I figured it'd not be very helpful here, given that all subclasses must
live in the Skia codebase, so can be changed in the same CL.

 
-    /** Return a non-zero, unique value representing the picture.
+    /** Return a cull rect for this picture.
+        Ops recorded into this picture that attempt to draw outside the cull might not be drawn.
      */
+    virtual SkRect cullRect() const = 0;
+
+    /** Returns a non-zero value unique among all pictures. */
     uint32_t uniqueID() const;
 
     /**
@@ -140,7 +103,7 @@ public:
      *
      *  TODO: Use serializer to serialize SkImages as well.
      */
-    void serialize(SkWStream*, SkPixelSerializer* serializer = NULL) const;
+    void serialize(SkWStream*, SkPixelSerializer* = NULL) const;
 
     /**
      *  Serialize to a buffer.
@@ -151,7 +114,21 @@ public:
      * Returns true if any bitmaps may be produced when this SkPicture
      * is replayed.
      */
-    bool willPlayBackBitmaps() const;
+    virtual bool willPlayBackBitmaps() const = 0;
+
+    /** Return the approximate number of operations in this picture.  This
+     *  number may be greater or less than the number of SkCanvas calls
+     *  recorded: some calls may be recorded as more than one operation, or some
+     *  calls may be optimized away.
+     */
+    virtual int approximateOpCount() const = 0;
+
+    /** Return true if this picture contains text.
+     */
+    virtual bool hasText() const = 0;
+
+    /** Returns the approximate byte size of this picture, not including large ref'd objects. */
+    virtual size_t approximateBytesUsed() const = 0;
 
     /** Return true if the SkStream/Buffer represents a serialized picture, and
         fills out SkPictInfo. After this function returns, the data source is not
@@ -164,76 +141,22 @@ public:
     static bool InternalOnly_StreamIsSKP(SkStream*, SkPictInfo*);
     static bool InternalOnly_BufferIsSKP(SkReadBuffer*, SkPictInfo*);
 
-    /** Return true if the picture is suitable for rendering on the GPU.
-     */
-
-#if SK_SUPPORT_GPU
-    bool suitableForGpuRasterization(GrContext*, const char ** = NULL) const;
-#endif
+    /** Return true if the picture is suitable for rendering on the GPU.  */
+    virtual bool suitableForGpuRasterization(GrContext*, const char** whyNot = NULL) const = 0;
 
-    /** Return the approximate number of operations in this picture.  This
-     *  number may be greater or less than the number of SkCanvas calls
-     *  recorded: some calls may be recorded as more than one operation, or some
-     *  calls may be optimized away.
-     */
-    int approximateOpCount() const;
-
-    /** Return true if this picture contains text.
-     */
-    bool hasText() const;
+    // Sent via SkMessageBus from destructor.
+    struct DeletionMessage { int32_t fUniqueID; };  // TODO: -> uint32_t?
 
-    // An array of refcounted const SkPicture pointers.
-    class SnapshotArray : ::SkNoncopyable {
-    public:
-        SnapshotArray(const SkPicture* pics[], int count) : fPics(pics), fCount(count) {}
-        ~SnapshotArray() { for (int i = 0; i < fCount; i++) { fPics[i]->unref(); } }
+    // Returns NULL if this is not an SkBigPicture.
+    virtual const SkBigPicture* asSkBigPicture() const { return NULL; }

[reed1, 2015/04/29 20:21:53]

does this guy need to be public?

[mtklein, 2015/04/29 20:46:21]

No, we can friend a bunch of Gr classes instead.  Was easier refactoring things
public, but I'll hide it.

[mtklein, 2015/04/30 16:17:03]

I take it back.  It's really hideous to try to make this private.

 
-        const SkPicture* const* begin() const { return fPics; }
-        int count() const { return fCount; }
-    private:
-        SkAutoTMalloc<const SkPicture*> fPics;
-        int fCount;
-    };
+private:
+    // Subclass whitelist.
+    SkPicture();
+    friend class SkBigPicture;
 
-    // Sent via SkMessageBus from destructor.
-    struct DeletionMessage { int32_t fUniqueID; };
+    virtual int numSlowPaths() const = 0;
 
-private:
-    // V2 : adds SkPixelRef's generation ID.
-    // V3 : PictInfo tag at beginning, and EOF tag at the end
-    // V4 : move SkPictInfo to be the header
-    // V5 : don't read/write FunctionPtr on cross-process (we can detect that)
-    // V6 : added serialization of SkPath's bounds (and packed its flags tighter)
-    // V7 : changed drawBitmapRect(IRect) to drawBitmapRectToRect(Rect)
-    // V8 : Add an option for encoding bitmaps
-    // V9 : Allow the reader and writer of an SKP disagree on whether to support
-    //      SK_SUPPORT_HINTING_SCALE_FACTOR
-    // V10: add drawRRect, drawOval, clipRRect
-    // V11: modify how readBitmap and writeBitmap store their info.
-    // V12: add conics to SkPath, use new SkPathRef flattening
-    // V13: add flag to drawBitmapRectToRect
-    //      parameterize blurs by sigma rather than radius
-    // V14: Add flags word to PathRef serialization
-    // V15: Remove A1 bitmap config (and renumber remaining configs)
-    // V16: Move SkPath's isOval flag to SkPathRef
-    // V17: SkPixelRef now writes SkImageInfo
-    // V18: SkBitmap now records x,y for its pixelref origin, instead of offset.
-    // V19: encode matrices and regions into the ops stream
-    // V20: added bool to SkPictureImageFilter's serialization (to allow SkPicture serialization)
-    // V21: add pushCull, popCull
-    // V22: SK_PICT_FACTORY_TAG's size is now the chunk size in bytes
-    // V23: SkPaint::FilterLevel became a real enum
-    // V24: SkTwoPointConicalGradient now has fFlipped flag for gradient flipping
-    // V25: SkDashPathEffect now only writes phase and interval array when flattening
-    // V26: Removed boolean from SkColorShader for inheriting color from SkPaint.
-    // V27: Remove SkUnitMapper from gradients (and skia).
-    // V28: No longer call bitmap::flatten inside SkWriteBuffer::writeBitmap.
-    // V29: Removed SaveFlags parameter from save().
-    // V30: Remove redundant SkMatrix from SkLocalMatrixShader.
-    // V31: Add a serialized UniqueID to SkImageFilter.
-    // V32: Removed SkPaintOptionsAndroid from SkPaint
-    // V33: Serialize only public API of effects.
-    // V34: Add SkTextBlob serialization.
     // V35: Store SkRect (rather then width & height) in header
     // V36: Remove (obsolete) alphatype from SkColorTable
     // V37: Added shadow only option to SkDropShadowImageFilter (last version to record CLEAR)
@@ -242,65 +165,20 @@ private:
     // V40: Remove UniqueID serialization from SkImageFilter.
     // V41: Added serialization of SkBitmapSource's filterQuality parameter
 
-    // Note: If the picture version needs to be increased then please follow the
-    // steps to generate new SKPs in (only accessible to Googlers): http://goo.gl/qATVcw
-
     // Only SKPs within the min/current picture version range (inclusive) can be read.
-    static const uint32_t MIN_PICTURE_VERSION = 35;     // Produced by Chrome M39.
-    static const uint32_t CURRENT_PICTURE_VERSION = 41;
+    static const uint32_t MIN_PICTURE_VERSION = 35,     // Produced by Chrome M39.
+                      CURRENT_PICTURE_VERSION = 41;
 
     static_assert(MIN_PICTURE_VERSION <= 41,
                   "Remove kFontFileName and related code from SkFontDescriptor.cpp.");
 
-    void createHeader(SkPictInfo* info) const;
     static bool IsValidPictInfo(const SkPictInfo& info);
-
-    // Takes ownership of the (optional) SnapshotArray.
-    // For performance, we take ownership of the caller's refs on the SkRecord, BBH, and AccelData.
-    SkPicture(const SkRect& cullRect,
-              SkRecord*,
-              SnapshotArray*,
-              SkBBoxHierarchy*,
-              AccelData*,
-              size_t approxBytesUsedBySubPictures);
-
     static SkPicture* Forwardport(const SkPictInfo&, const SkPictureData*);
-    static SkPictureData* Backport(const SkRecord&, const SkPictInfo&,
-                                   SkPicture const* const drawablePics[], int drawableCount);
-
-    // uint32_t fRefCnt; from SkNVRefCnt<SkPicture>
-    mutable uint32_t                      fUniqueID;
-    const SkRect                          fCullRect;
-    SkAutoTUnref<const SkRecord>          fRecord;
-    SkAutoTDelete<const SnapshotArray>    fDrawablePicts;
-    SkAutoTUnref<const SkBBoxHierarchy>   fBBH;
-    SkAutoTUnref<const AccelData>         fAccelData;
-    const size_t                          fApproxBytesUsedBySubPictures;
-
-    // helpers for fDrawablePicts
-    int drawableCount() const;
-    // will return NULL if drawableCount() returns 0
-    SkPicture const* const* drawablePicts() const;
-
-    struct PathCounter;
-
-    struct Analysis {
-        Analysis() {}  // Only used by SkPictureData codepath.
-        explicit Analysis(const SkRecord&);
-
-        bool suitableForGpuRasterization(const char** reason, int sampleCount) const;
 
-        uint8_t     fNumSlowPathsAndDashEffects;
-        bool        fWillPlaybackBitmaps : 1;
-        bool        fHasText             : 1;
-    } fAnalysis;
+    SkPictInfo createHeader() const;
+    SkPictureData* backport() const;
 
-    friend class SkPictureRecorder;            // SkRecord-based constructor.
-    friend class GrLayerHoister;               // access to fRecord
-    friend class ReplaceDraw;
-    friend class SkPictureUtils;
-    friend class SkRecordedDrawable;
+    mutable uint32_t fUniqueID;
 };
-SK_COMPILE_ASSERT(sizeof(SkPicture) <= 88, SkPictureSize);
 
 #endif