1 files changed, 221 insertions, 0 deletions
diff --git a/gfx/2d/SourceSurfaceSkia.cpp b/gfx/2d/SourceSurfaceSkia.cpp
new file mode 100644
index 0000000000..4fc459d6cb
--- /dev/null
+++ b/gfx/2d/SourceSurfaceSkia.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Logging.h"
+#include "SourceSurfaceSkia.h"
+#include "HelpersSkia.h"
+#include "DrawTargetSkia.h"
+#include "skia/include/core/SkData.h"
+#include "skia/include/core/SkImage.h"
+#include "skia/include/core/SkSurface.h"
+#include "mozilla/CheckedInt.h"
+
+namespace mozilla::gfx {
+
+SourceSurfaceSkia::SourceSurfaceSkia()
+    : mFormat(SurfaceFormat::UNKNOWN),
+      mStride(0),
+      mDrawTarget(nullptr),
+      mChangeMutex("SourceSurfaceSkia::mChangeMutex"),
+      mIsMapped(false) {}
+
+SourceSurfaceSkia::~SourceSurfaceSkia() {
+  // if mIsMapped is true then mChangeMutex will be locked
+  // which will cause problems during destruction.
+  MOZ_RELEASE_ASSERT(!mIsMapped);
+}
+
+IntSize SourceSurfaceSkia::GetSize() const { return mSize; }
+
+SurfaceFormat SourceSurfaceSkia::GetFormat() const { return mFormat; }
+
+// This is only ever called by the DT destructor, which can only ever happen
+// from one place at a time. Therefore it doesn't need to hold the ChangeMutex
+// as mSurface is never read to directly and is just there to keep the object
+// alive, which itself is refcounted in a thread-safe manner.
+void SourceSurfaceSkia::GiveSurface(SkSurface* aSurface) {
+  mSurface.reset(aSurface);
+  mDrawTarget = nullptr;
+}
+
+sk_sp<SkImage> SourceSurfaceSkia::GetImage(Maybe<MutexAutoLock>* aLock) {
+  // If we were provided a lock object, we can let the caller access
+  // a shared SkImage and we know it won't go away while the lock is held.
+  // Otherwise we need to call DrawTargetWillChange to ensure we have our
+  // own SkImage.
+  if (aLock) {
+    MOZ_ASSERT(aLock->isNothing());
+    aLock->emplace(mChangeMutex);
+
+    // Now that we are locked, we can check mDrawTarget. If it's null, then
+    // we're not shared and we can unlock eagerly.
+    if (!mDrawTarget) {
+      aLock->reset();
+    }
+  } else {
+    DrawTargetWillChange();
+  }
+  sk_sp<SkImage> image = mImage;
+  return image;
+}
+
+static sk_sp<SkData> MakeSkData(void* aData, int32_t aHeight, size_t aStride) {
+  CheckedInt<size_t> size = aStride;
+  size *= aHeight;
+  if (size.isValid()) {
+    void* mem = sk_malloc_flags(size.value(), 0);
+    if (mem) {
+      if (aData) {
+        memcpy(mem, aData, size.value());
+      }
+      return SkData::MakeFromMalloc(mem, size.value());
+    }
+  }
+  return nullptr;
+}
+
+static sk_sp<SkImage> ReadSkImage(const sk_sp<SkImage>& aImage,
+                                  const SkImageInfo& aInfo, size_t aStride,
+                                  int aX = 0, int aY = 0) {
+  if (sk_sp<SkData> data = MakeSkData(nullptr, aInfo.height(), aStride)) {
+    if (aImage->readPixels(aInfo, data->writable_data(), aStride, aX, aY,
+                           SkImage::kDisallow_CachingHint)) {
+      return SkImage::MakeRasterData(aInfo, data, aStride);
+    }
+  }
+  return nullptr;
+}
+
+bool SourceSurfaceSkia::InitFromData(unsigned char* aData, const IntSize& aSize,
+                                     int32_t aStride, SurfaceFormat aFormat) {
+  sk_sp<SkData> data = MakeSkData(aData, aSize.height, aStride);
+  if (!data) {
+    return false;
+  }
+
+  SkImageInfo info = MakeSkiaImageInfo(aSize, aFormat);
+  mImage = SkImage::MakeRasterData(info, data, aStride);
+  if (!mImage) {
+    return false;
+  }
+
+  mSize = aSize;
+  mFormat = aFormat;
+  mStride = aStride;
+  return true;
+}
+
+bool SourceSurfaceSkia::InitFromImage(const sk_sp<SkImage>& aImage,
+                                      SurfaceFormat aFormat,
+                                      DrawTargetSkia* aOwner) {
+  if (!aImage) {
+    return false;
+  }
+
+  mSize = IntSize(aImage->width(), aImage->height());
+
+  // For the raster image case, we want to use the format and stride
+  // information that the underlying raster image is using, which is
+  // reliable.
+  // For the GPU case (for which peekPixels is false), we can't easily
+  // figure this information out. It is better to report the originally
+  // intended format and stride that we will convert to if this GPU
+  // image is ever read back into a raster image.
+  SkPixmap pixmap;
+  if (aImage->peekPixels(&pixmap)) {
+    mFormat =
+        aFormat != SurfaceFormat::UNKNOWN
+            ? aFormat
+            : SkiaColorTypeToGfxFormat(pixmap.colorType(), pixmap.alphaType());
+    mStride = pixmap.rowBytes();
+  } else if (aFormat != SurfaceFormat::UNKNOWN) {
+    mFormat = aFormat;
+    SkImageInfo info = MakeSkiaImageInfo(mSize, mFormat);
+    mStride = SkAlign4(info.minRowBytes());
+  } else {
+    return false;
+  }
+
+  mImage = aImage;
+
+  if (aOwner) {
+    mDrawTarget = aOwner;
+  }
+
+  return true;
+}
+
+already_AddRefed<SourceSurface> SourceSurfaceSkia::ExtractSubrect(
+    const IntRect& aRect) {
+  if (!mImage || aRect.IsEmpty() || !GetRect().Contains(aRect)) {
+    return nullptr;
+  }
+  SkImageInfo info = MakeSkiaImageInfo(aRect.Size(), mFormat);
+  size_t stride = SkAlign4(info.minRowBytes());
+  sk_sp<SkImage> subImage = ReadSkImage(mImage, info, stride, aRect.x, aRect.y);
+  if (!subImage) {
+    return nullptr;
+  }
+  RefPtr<SourceSurfaceSkia> surface = new SourceSurfaceSkia;
+  if (!surface->InitFromImage(subImage)) {
+    return nullptr;
+  }
+  return surface.forget().downcast<SourceSurface>();
+}
+
+uint8_t* SourceSurfaceSkia::GetData() {
+  if (!mImage) {
+    return nullptr;
+  }
+  SkPixmap pixmap;
+  if (!mImage->peekPixels(&pixmap)) {
+    gfxCriticalError() << "Failed accessing pixels for Skia raster image";
+  }
+  return reinterpret_cast<uint8_t*>(pixmap.writable_addr());
+}
+
+bool SourceSurfaceSkia::Map(MapType, MappedSurface* aMappedSurface)
+    MOZ_NO_THREAD_SAFETY_ANALYSIS {
+  mChangeMutex.Lock();
+  aMappedSurface->mData = GetData();
+  aMappedSurface->mStride = Stride();
+  mIsMapped = !!aMappedSurface->mData;
+  bool isMapped = mIsMapped;
+  if (!mIsMapped) {
+    mChangeMutex.Unlock();
+  }
+  // Static analysis will warn due to a conditional Unlock
+  MOZ_PUSH_IGNORE_THREAD_SAFETY
+  return isMapped;
+  MOZ_POP_THREAD_SAFETY
+}
+
+void SourceSurfaceSkia::Unmap() MOZ_NO_THREAD_SAFETY_ANALYSIS {
+  mChangeMutex.AssertCurrentThreadOwns();
+  MOZ_ASSERT(mIsMapped);
+  mIsMapped = false;
+  mChangeMutex.Unlock();
+}
+
+void SourceSurfaceSkia::DrawTargetWillChange() {
+  MutexAutoLock lock(mChangeMutex);
+  if (mDrawTarget.exchange(nullptr)) {
+    // Raster snapshots do not use Skia's internal copy-on-write mechanism,
+    // so we need to do an explicit copy here.
+    // GPU snapshots, for which peekPixels is false, will already be dealt
+    // with automatically via the internal copy-on-write mechanism, so we
+    // don't need to do anything for them here.
+    SkPixmap pixmap;
+    if (mImage->peekPixels(&pixmap)) {
+      mImage = ReadSkImage(mImage, pixmap.info(), pixmap.rowBytes());
+      if (!mImage) {
+        gfxCriticalError() << "Failed copying Skia raster snapshot";
+      }
+    }
+  }
+}
+
+}  // namespace mozilla::gfx