Integrate change of Skia upstream.

This is a cherry-pick of the following change:

http://code.google.com/p/skia/source/detail?r=159

We introduce this change for the 'lighter' composite operation. We need kAdd_Mode, which is introduced in this change for the operation.

Patch by Shinichiro Hamaji.

BUG=1619

Review URL: http://codereview.chromium.org/93093


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@14938 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 51 insertions, 34 deletions

diff --git a/skia/sgl/SkDraw.cpp b/skia/sgl/SkDraw.cpp
index 2f0ddff..40b9026 100644
--- a/skia/sgl/SkDraw.cpp
+++ b/skia/sgl/SkDraw.cpp
@@ -911,11 +911,16 @@ void SkDraw::drawBitmapAsMask(const SkBitmap& bitmap,
                 return;
             }
         }
+
         mask.fFormat = SkMask::kA8_Format;
         mask.fRowBytes = SkAlign4(mask.fBounds.width());
+        size_t size = mask.computeImageSize();
+        if (0 == size) {
+            // the mask is too big to allocated, draw nothing
+            return;
+        }
 
         // allocate (and clear) our temp buffer to hold the transformed bitmap
-        size_t size = mask.computeImageSize();
         SkAutoMalloc    storage(size);
         mask.fImage = (uint8_t*)storage.get();
         memset(mask.fImage, 0, size);
@@ -2336,7 +2341,12 @@ bool SkDraw::DrawToMask(const SkPath& devPath, const SkIRect* clipBounds,
     if (SkMask::kComputeBoundsAndRenderImage_CreateMode == mode) {
         mask->fFormat = SkMask::kA8_Format;
         mask->fRowBytes = mask->fBounds.width();
-        mask->fImage = SkMask::AllocImage(mask->computeImageSize());
+        size_t size = mask->computeImageSize();
+        if (0 == size) {
+            // we're too big to allocate the mask, abort
+            return false;
+        }
+        mask->fImage = SkMask::AllocImage(size);
         memset(mask->fImage, 0, mask->computeImageSize());
     }
 
diff --git a/skia/sgl/SkMask.cpp b/skia/sgl/SkMask.cpp
index 1a03b16..337204b 100644
--- a/skia/sgl/SkMask.cpp
+++ b/skia/sgl/SkMask.cpp
@@ -15,41 +15,29 @@
 ** limitations under the License.
 */
 
-#include <limits>
-
+#include "Sk64.h"
 #include "SkMask.h"
 
-size_t SkMask::computeImageSize() const
-{
-    // Prevent too large a number. There is a better fix for this in Skia
-    // trunk where it returns failure.
-    long long size = (long long)fBounds.height() * (long long)fRowBytes;
-    if (size >= std::numeric_limits<size_t>::max() / 2) {
-#ifdef WIN32
-        __debugbreak();
-#else
-        abort();
-#endif
+/** returns the product if it is positive and fits in 31 bits. Otherwise this
+    returns 0.
+ */
+static int32_t safeMul32(int32_t a, int32_t b) {
+    Sk64 size;
+    size.setMul(a, b);
+    if (size.is32() && size.isPos()) {
+        return size.get32();
     }
+    return 0;
+}
 
-    return size;
+size_t SkMask::computeImageSize() const {
+    return safeMul32(fBounds.height(), fRowBytes);
 }
 
-size_t SkMask::computeTotalImageSize() const
-{
+size_t SkMask::computeTotalImageSize() const {
     size_t size = this->computeImageSize();
-
     if (fFormat == SkMask::k3D_Format) {
-        // See computeImageSize for why we want to stop here.
-        if (size > std::numeric_limits<size_t>::max() / 3) {
-#ifdef WIN32
-            __debugbreak();
-#else
-        abort();
-#endif
-        }
-
-        size *= 3;
+        size = safeMul32(size, 3);
     }
     return size;
 }
diff --git a/skia/sgl/SkXfermode.cpp b/skia/sgl/SkXfermode.cpp
index e8a202d..1b2479f 100644
--- a/skia/sgl/SkXfermode.cpp
+++ b/skia/sgl/SkXfermode.cpp
@@ -43,6 +43,16 @@ static U8CPU mulmuldiv255round(U8CPU a, U8CPU b, U8CPU c, U8CPU d) {
     return result;
 }
 
+static unsigned saturated_add(unsigned a, unsigned b) {
+    SkASSERT(a <= 255);
+    SkASSERT(b <= 255);
+    unsigned sum = a + b;
+    if (sum > 255) {
+        sum = 255;
+    }
+    return sum;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 bool SkXfermode::asCoeff(Coeff* src, Coeff* dst) {
@@ -495,6 +505,14 @@ static SkPMColor screen_modeproc(SkPMColor src, SkPMColor dst) {
     return SkPackARGB32(a, r, g, b);
 }
 
+static SkPMColor add_modeproc(SkPMColor src, SkPMColor dst) {
+    unsigned a = saturated_add(SkGetPackedA32(src), SkGetPackedA32(dst));
+    unsigned r = saturated_add(SkGetPackedR32(src), SkGetPackedR32(dst));
+    unsigned g = saturated_add(SkGetPackedG32(src), SkGetPackedG32(dst));
+    unsigned b = saturated_add(SkGetPackedB32(src), SkGetPackedB32(dst));
+    return SkPackARGB32(a, r, g, b);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 
 class SkClearXfermode : public SkProcCoeffXfermode {
@@ -696,6 +714,8 @@ struct ProcCoeff {
     SkXfermode::Coeff   fDC;
 };
 
+#define CANNOT_USE_COEFF    SkXfermode::Coeff(-1)
+
 static const ProcCoeff gProcCoeffs[] = {
     { clear_modeproc,   SkXfermode::kZero_Coeff,    SkXfermode::kZero_Coeff },
     { src_modeproc,     SkXfermode::kOne_Coeff,     SkXfermode::kZero_Coeff },
@@ -709,12 +729,11 @@ static const ProcCoeff gProcCoeffs[] = {
     { srcatop_modeproc, SkXfermode::kDA_Coeff,      SkXfermode::kISA_Coeff },
     { dstatop_modeproc, SkXfermode::kIDA_Coeff,     SkXfermode::kSA_Coeff },
     { xor_modeproc,     SkXfermode::kIDA_Coeff,     SkXfermode::kISA_Coeff },
-    // these two can't be represented as coefficients
-    { darken_modeproc,  SkXfermode::Coeff(-1),      SkXfermode::Coeff(-1) },
-    { lighten_modeproc, SkXfermode::Coeff(-1),      SkXfermode::Coeff(-1) },
-    // these can use coefficients
+    { darken_modeproc,  CANNOT_USE_COEFF,           CANNOT_USE_COEFF },
+    { lighten_modeproc, CANNOT_USE_COEFF,           CANNOT_USE_COEFF },
     { mult_modeproc,    SkXfermode::kZero_Coeff,    SkXfermode::kSC_Coeff },
-    { screen_modeproc,  SkXfermode::kOne_Coeff,     SkXfermode::kISC_Coeff }
+    { screen_modeproc,  SkXfermode::kOne_Coeff,     SkXfermode::kISC_Coeff },
+    { add_modeproc,     CANNOT_USE_COEFF,           CANNOT_USE_COEFF }
 };
 
 SkXfermode* SkPorterDuff::CreateXfermode(SkPorterDuff::Mode mode) {