Split picture version into min & max supported versions

include/core/SkPicture.h

 
 /*
  * Copyright 2007 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPicture_DEFINED
@@ skipping 224 matching lines @@
     // V14: Add flags word to PathRef serialization
     // V15: Remove A1 bitmpa 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)
 
     // 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
-    static const uint32_t PICTURE_VERSION = 20;
+
+    // Only SKPs within the min/current picture version range (inclusive) can be read.
+    static const uint32_t MIN_PICTURE_VERSION = 19;
+    static const uint32_t CURRENT_PICTURE_VERSION = 20;
 
     // fPlayback, fRecord, fWidth & fHeight are protected to allow derived classes to
     // install their own SkPicturePlayback-derived players,SkPictureRecord-derived
     // recorders and set the picture size
     SkPicturePlayback* fPlayback;
     SkPictureRecord* fRecord;
     int fWidth, fHeight;
 
     // Create a new SkPicture from an existing SkPicturePlayback. Ref count of
     // playback is unchanged.
@@ skipping 30 matching lines @@
  */
 class SK_API SkDrawPictureCallback {
 public:
     SkDrawPictureCallback() {}
     virtual ~SkDrawPictureCallback() {}
 
     virtual bool abortDrawing() = 0;
 };
 
 #endif