# HG changeset patch
# Parent  36563351309ddbc6c29559ba50a41d005f925abb
Skia does not support big endian. The places to fix are too numerous and upstream (skia, not Mozilla)
has no interest in maintaining big endian.
So here we try to swizzle the input for skia, so that skia always works on LE, and when it comes
out again, we transform back to BE.

diff -r 36563351309d gfx/2d/ConvolutionFilter.cpp
--- a/gfx/2d/ConvolutionFilter.cpp	Mon Sep 09 17:59:28 2019 +0200
+++ b/gfx/2d/ConvolutionFilter.cpp	Tue Sep 10 08:25:13 2019 +0200
@@ -35,9 +35,38 @@
   return true;
 }
 
+static void ByteSwapArray(uint8_t *u8Array, int32_t size) {
+    uint32_t *array = reinterpret_cast<uint32_t*>(u8Array);
+    for (int pxl = 0; pxl < size; ++pxl) {
+        // Use an endian swap to move the bytes, i.e. BGRA -> ARGB.
+        uint32_t rgba = array[pxl];
+        array[pxl] = NativeEndian::swapToLittleEndian(rgba);
+    }
+}
+
 void ConvolutionFilter::ConvolveHorizontally(const uint8_t* aSrc, uint8_t* aDst,
                                              bool aHasAlpha) {
+#if MOZ_BIG_ENDIAN
+    int outputSize = mFilter->numValues();
+
+    // Input size isn't handed in, so we have to calculate it quickly
+    int inputSize = 0;
+    for (int xx = 0; xx < outputSize; ++xx) {
+        // Get the filter that determines the current output pixel.
+        int filterOffset, filterLength;
+        mFilter->FilterForValue(xx, &filterOffset, &filterLength);
+        inputSize = std::max(inputSize, filterOffset + filterLength);
+    }
+
+    ByteSwapArray((uint8_t*)aSrc, inputSize);
+#endif
+
   SkOpts::convolve_horizontally(aSrc, *mFilter, aDst, aHasAlpha);
+
+#if MOZ_BIG_ENDIAN
+    ByteSwapArray((uint8_t*)aSrc, inputSize);
+    ByteSwapArray(aDst, outputSize);
+#endif
 }
 
 void ConvolutionFilter::ConvolveVertically(uint8_t* const* aSrc, uint8_t* aDst,
@@ -49,8 +78,26 @@
   int32_t filterLength;
   auto filterValues =
       mFilter->FilterForValue(aRowIndex, &filterOffset, &filterLength);
+
+#if MOZ_BIG_ENDIAN
+  for (int filterY = 0; filterY < filterLength; filterY++) {
+      // Skia only knows LE, so we have to swizzle the input
+    ByteSwapArray(aSrc[filterY], aRowSize);
+  }
+#endif
+
   SkOpts::convolve_vertically(filterValues, filterLength, aSrc, aRowSize, aDst,
                               aHasAlpha);
+
+#if MOZ_BIG_ENDIAN
+  // After skia is finished, we swizzle back to BE, in case
+  // the input is used again somewhere else
+  for (int filterY = 0; filterY < filterLength; filterY++) {
+    ByteSwapArray(aSrc[filterY], aRowSize);
+  }
+  // The destination array as well
+  ByteSwapArray(aDst, aRowSize);
+#endif
 }
 
 /* ConvolutionFilter::ComputeResizeFactor is derived from Skia's
diff -r 36563351309d gfx/skia/skia/include/core/SkPreConfig.h
--- a/gfx/skia/skia/include/core/SkPreConfig.h	Mon Sep 09 17:59:28 2019 +0200
+++ b/gfx/skia/skia/include/core/SkPreConfig.h	Tue Sep 10 08:25:13 2019 +0200
@@ -73,7 +73,7 @@
       defined(__ppc__) || defined(__hppa) || \
       defined(__PPC__) || defined(__PPC64__) || \
       defined(_MIPSEB) || defined(__ARMEB__) || \
-      defined(__s390__) || \
+      defined(__s390__) || defined(__s390x__) || \
       (defined(__sh__) && defined(__BIG_ENDIAN__)) || \
       (defined(__ia64) && defined(__BIG_ENDIAN__))
          #define SK_CPU_BENDIAN