Add SkImageInfoValidConversion() and SkImageInfoIsValid

The idea is share these standards for the following:
SkImage::readPixels()
SkCanvas::readPixels()
SkCanvas::writePixels()
SkBitmap::readPixels()
SkPixmap::readPixels()

On the raster side, SkPixmap::readPixels() is the right
place to check, because all raster calls go through
there eventually.  Then at lower levels (ex: SkPixelInfo),
we can assert.

There's not really a unifying location for gpu calls,
so I've added this in multiple places.  I haven't really
dug into the gpu code to SkASSERT() on invalid cases
that we will have already caught.

Follow-up work:
Similar refactor for SkReadPixelRec::trim().
Code cleanup in SkPixelInfo::CopyPixels()

BUG=skia:6021

Change-Id: I91ecce10e46c1a6530f0af24a9eb8226dbecaaa2
Reviewed-on: https://skia-review.googlesource.com/6887
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Reed <reed@google.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 258713c537..1dec0f6371 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -26,6 +26,7 @@
 #include "SkImageCacherator.h"
 #include "SkImageFilter.h"
 #include "SkImageFilterCache.h"
+#include "SkImageInfoPriv.h"
 #include "SkImage_Base.h"
 #include "SkLatticeIter.h"
 #include "SkMaskFilter.h"
@@ -194,6 +195,10 @@ bool SkGpuDevice::onReadPixels(const SkImageInfo& dstInfo, void* dstPixels, size
                                int x, int y) {
     ASSERT_SINGLE_OWNER
 
+    if (!SkImageInfoValidConversion(dstInfo, this->imageInfo())) {
+        return false;
+    }
+
     return fRenderTargetContext->readPixels(dstInfo, dstPixels, dstRowBytes, x, y);
 }
 
@@ -201,6 +206,10 @@ bool SkGpuDevice::onWritePixels(const SkImageInfo& srcInfo, const void* srcPixel
                                 size_t srcRowBytes, int x, int y) {
     ASSERT_SINGLE_OWNER
 
+    if (!SkImageInfoValidConversion(this->imageInfo(), srcInfo)) {
+        return false;
+    }
+
     return fRenderTargetContext->writePixels(srcInfo, srcPixels, srcRowBytes, x, y);
 }