Bug 1279117 - Add SurfacePipe::WritePixelsToRow(). r=njn

2024-11-25 13:51:41 +00:00 · 2016-06-10 14:44:24 -07:00 · 2016-06-10 14:44:24 -07:00 · 020ad7a755
commit 020ad7a755
parent 1b06c54c9f
2 changed files with 373 additions and 34 deletions
--- a/image/SurfacePipe.h
+++ b/image/SurfacePipe.h
@ -166,42 +166,46 @@ public:
  template <typename PixelType, typename Func>
  WriteState WritePixels(Func aFunc)
  {
-    MOZ_ASSERT(mPixelSize == 1 || mPixelSize == 4);
-    MOZ_ASSERT_IF(mPixelSize == 1, sizeof(PixelType) == sizeof(uint8_t));
-    MOZ_ASSERT_IF(mPixelSize == 4, sizeof(PixelType) == sizeof(uint32_t));
+    Maybe<WriteState> result;
+    while (!(result = DoWritePixelsToRow<PixelType>(Forward<Func>(aFunc)))) { }

-    while (!IsSurfaceFinished()) {
-      PixelType* rowPtr = reinterpret_cast<PixelType*>(mRowPointer);
+    return *result;
+  }

-      for (; mCol < mInputSize.width; ++mCol) {
-        NextPixel<PixelType> result = aFunc();
-        if (result.template is<PixelType>()) {
-          rowPtr[mCol] = result.template as<PixelType>();
-          continue;
-        }
-
-        switch (result.template as<WriteState>()) {
-          case WriteState::NEED_MORE_DATA:
-            return WriteState::NEED_MORE_DATA;
-
-          case WriteState::FINISHED:
-            ZeroOutRestOfSurface<PixelType>();
-            return WriteState::FINISHED;
-
-          case WriteState::FAILURE:
-            // Note that we don't need to record this anywhere, because this
-            // indicates an error in aFunc, and there's nothing wrong with our
-            // machinery. The caller can recover as needed and continue writing to
-            // the row.
-            return WriteState::FAILURE;
-        }
-      }
-
-      AdvanceRow();  // We've finished the row.
-    }
-
-    // We've finished the entire surface.
-    return WriteState::FINISHED;
+  /**
+   * A variant of WritePixels() that writes a single row of pixels to the
+   * surface one at a time by repeatedly calling a lambda that yields pixels.
+   * WritePixelsToRow() is completely memory safe.
+   *
+   * Writing continues until every pixel in the row has been written to. If the
+   * surface is complete at that pointer, WriteState::FINISHED is returned;
+   * otherwise, WritePixelsToRow() returns WriteState::NEED_MORE_DATA. The
+   * lambda can terminate writing early by returning a WriteState itself, which
+   * WritePixelsToRow() will return to the caller.
+   *
+   * The template parameter PixelType must be uint8_t (for paletted surfaces) or
+   * uint32_t (for BGRA/BGRX surfaces) and must be in agreement with the pixel
+   * size passed to ConfigureFilter().
+   *
+   * XXX(seth): We'll remove all support for paletted surfaces in bug 1247520,
+   * which means we can remove the PixelType template parameter from this
+   * method.
+   *
+   * @param aFunc A lambda that functions as a generator, yielding the next
+   *              pixel in the surface each time it's called. The lambda must
+   *              return a NextPixel<PixelType> value.
+   *
+   * @return A WriteState value indicating the lambda generator's state.
+   *         WritePixels() itself will return WriteState::FINISHED if writing
+   *         the entire surface has finished, or WriteState::NEED_MORE_DATA if
+   *         writing the row has finished, regardless of the lambda's internal
+   *         state.
+   */
+  template <typename PixelType, typename Func>
+  WriteState WritePixelsToRow(Func aFunc)
+  {
+    return DoWritePixelsToRow<PixelType>(Forward<Func>(aFunc))
+           .valueOr(WriteState::NEED_MORE_DATA);
  }

  /**
@ -442,6 +446,60 @@ protected:

 private:

+  /**
+   * An internal method used to implement both WritePixels() and
+   * WritePixelsToRow(). Those methods differ only in their behavior after a row
+   * is successfully written - WritePixels() continues to write another row,
+   * while WritePixelsToRow() returns to the caller. This method writes a single
+   * row and returns Some() if we either finished the entire surface or the
+   * lambda returned a WriteState indicating that we should return to the
+   * caller. If the row was successfully written without either of those things
+   * happening, it returns Nothing(), allowing WritePixels() and
+   * WritePixelsToRow() to implement their respective behaviors.
+   */
+  template <typename PixelType, typename Func>
+  Maybe<WriteState> DoWritePixelsToRow(Func aFunc)
+  {
+    MOZ_ASSERT(mPixelSize == 1 || mPixelSize == 4);
+    MOZ_ASSERT_IF(mPixelSize == 1, sizeof(PixelType) == sizeof(uint8_t));
+    MOZ_ASSERT_IF(mPixelSize == 4, sizeof(PixelType) == sizeof(uint32_t));
+
+    if (IsSurfaceFinished()) {
+      return Some(WriteState::FINISHED);  // We're already done.
+    }
+
+    PixelType* rowPtr = reinterpret_cast<PixelType*>(mRowPointer);
+
+    for (; mCol < mInputSize.width; ++mCol) {
+      NextPixel<PixelType> result = aFunc();
+      if (result.template is<PixelType>()) {
+        rowPtr[mCol] = result.template as<PixelType>();
+        continue;
+      }
+
+      switch (result.template as<WriteState>()) {
+        case WriteState::NEED_MORE_DATA:
+          return Some(WriteState::NEED_MORE_DATA);
+
+        case WriteState::FINISHED:
+          ZeroOutRestOfSurface<PixelType>();
+          return Some(WriteState::FINISHED);
+
+        case WriteState::FAILURE:
+          // Note that we don't need to record this anywhere, because this
+          // indicates an error in aFunc, and there's nothing wrong with our
+          // machinery. The caller can recover as needed and continue writing to
+          // the row.
+          return Some(WriteState::FAILURE);
+      }
+    }
+
+    AdvanceRow();  // We've finished the row.
+
+    return IsSurfaceFinished() ? Some(WriteState::FINISHED)
+                               : Nothing();
+  }
+
  template <typename PixelType>
  void ZeroOutRestOfSurface()
  {
@ -546,6 +604,19 @@ public:
    return mHead->WritePixels<PixelType>(Forward<Func>(aFunc));
  }

+  /**
+   * A variant of WritePixels() that writes a single row of pixels to the
+   * surface one at a time by repeatedly calling a lambda that yields pixels.
+   * WritePixelsToRow() is completely memory safe.
+   *
+   * @see SurfaceFilter::WritePixelsToRow() for the canonical documentation.
+   */
+  template <typename PixelType, typename Func>
+  WriteState WritePixelsToRow(Func aFunc)
+  {
+    return mHead->WritePixelsToRow<PixelType>(Forward<Func>(aFunc));
+  }
+
  /**
   * Write a row to the surface by copying from a buffer. This is bounds checked
   * and memory safe with respect to the surface, but care must still be taken
--- a/image/test/gtest/TestSurfaceSink.cpp
+++ b/image/test/gtest/TestSurfaceSink.cpp
@ -310,6 +310,138 @@ TEST(ImageSurfaceSink, SurfaceSinkWritePixelsEarlyExit)
  });
 }

+TEST(ImageSurfaceSink, SurfaceSinkWritePixelsToRow)
+{
+  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
+    // Write the first 99 rows of our 100x100 surface and verify that even
+    // though our lambda will yield pixels forever, only one row is written per
+    // call to WritePixelsToRow().
+    for (int row = 0; row < 99; ++row) {
+      uint32_t count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint32_t>([&]{
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(100u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mOutputSpaceRect);
+
+      CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, row + 1));
+    }
+
+    // Write the final line, which should finish the surface.
+    uint32_t count = 0;
+    WriteState result = aSink->WritePixelsToRow<uint32_t>([&]{
+      ++count;
+      return AsVariant(BGRAColor::Green().AsPixel());
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(100u, count);
+
+    // Note that the final invalid rect we expect here is only the last row;
+    // that's because we called TakeInvalidRect() repeatedly in the loop above.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 99, 100, 1),
+                                    IntRect(0, 99, 100, 1));
+
+    // Check that the generated image is correct.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint32_t>([&]{
+      count++;
+      return AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, 100));
+  });
+}
+
+TEST(ImageSurfaceSink, SurfaceSinkWritePixelsToRowEarlyExit)
+{
+  auto checkEarlyExit =
+    [](Decoder* aDecoder, SurfaceSink* aSink, WriteState aState) {
+    // Write half a row of green pixels and then exit early with |aState|. If
+    // the lambda keeps getting called, we'll write red pixels, which will cause
+    // the test to fail.
+    uint32_t count = 0;
+    auto result = aSink->WritePixelsToRow<uint32_t>([&]() -> NextPixel<uint32_t> {
+      if (count == 50) {
+        return AsVariant(aState);
+      }
+      return count++ < 50 ? AsVariant(BGRAColor::Green().AsPixel())
+                          : AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(aState, result);
+    EXPECT_EQ(50u, count);
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 50, 1));
+
+    if (aState != WriteState::FINISHED) {
+      // We should still be able to write more at this point.
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Verify that we can resume the same row and still stop at the end.
+      count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint32_t>([&]{
+        ++count;
+        return AsVariant(BGRAColor::Green().AsPixel());
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+      CheckGeneratedImage(aDecoder, IntRect(0, 0, 100, 1));
+
+      return;
+    }
+
+    // We should've finished the surface at this point.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint32_t>([&]{
+      count++;
+      return AsVariant(BGRAColor::Red().AsPixel());
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedImage(aDecoder, IntRect(0, 0, 50, 1));
+  };
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::NEED_MORE_DATA);
+  });
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FAILURE);
+  });
+
+  WithSurfaceSink<Orient::NORMAL>([&](Decoder* aDecoder, SurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FINISHED);
+  });
+}
+
 TEST(ImageSurfaceSink, SurfaceSinkWriteBuffer)
 {
  WithSurfaceSink<Orient::NORMAL>([](Decoder* aDecoder, SurfaceSink* aSink) {
@ -996,6 +1128,142 @@ TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsEarlyExit)
  });
 }

+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsToRow)
+{
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    // Write the first 99 rows of our 100x100 surface and verify that even
+    // though our lambda will yield pixels forever, only one row is written per
+    // call to WritePixelsToRow().
+    for (int row = 0; row < 99; ++row) {
+      uint32_t count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint8_t>([&]{
+        ++count;
+        return AsVariant(uint8_t(255));
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(100u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      Maybe<SurfaceInvalidRect> invalidRect = aSink->TakeInvalidRect();
+      EXPECT_TRUE(invalidRect.isSome());
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mInputSpaceRect);
+      EXPECT_EQ(IntRect(0, row, 100, 1), invalidRect->mOutputSpaceRect);
+
+      CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, row + 1));
+    }
+
+    // Write the final line, which should finish the surface.
+    uint32_t count = 0;
+    WriteState result = aSink->WritePixelsToRow<uint8_t>([&]{
+      ++count;
+      return AsVariant(uint8_t(255));
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(100u, count);
+
+    // Note that the final invalid rect we expect here is only the last row;
+    // that's because we called TakeInvalidRect() repeatedly in the loop above.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 99, 100, 1),
+                                    IntRect(0, 99, 100, 1));
+
+    // Check that the generated image is correct.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint8_t>([&]{
+      count++;
+      return AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, 100));
+  });
+}
+
+TEST(ImageSurfaceSink, PalettedSurfaceSinkWritePixelsToRowEarlyExit)
+{
+  auto checkEarlyExit =
+    [](Decoder* aDecoder, PalettedSurfaceSink* aSink, WriteState aState) {
+    // Write half a row of 255s and then exit early with |aState|. If the lambda
+    // keeps getting called, we'll write 128s, which will cause the test to
+    // fail.
+    uint32_t count = 0;
+    auto result = aSink->WritePixelsToRow<uint8_t>([&]() -> NextPixel<uint8_t> {
+      if (count == 50) {
+        return AsVariant(aState);
+      }
+      return count++ < 50 ? AsVariant(uint8_t(255))
+                          : AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(aState, result);
+    EXPECT_EQ(50u, count);
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 50, 1));
+
+    if (aState != WriteState::FINISHED) {
+      // We should still be able to write more at this point.
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+
+      // Verify that we can resume the same row and still stop at the end.
+      count = 0;
+      WriteState result = aSink->WritePixelsToRow<uint8_t>([&]{
+        ++count;
+        return AsVariant(uint8_t(255));
+      });
+
+      EXPECT_EQ(WriteState::NEED_MORE_DATA, result);
+      EXPECT_EQ(50u, count);
+      EXPECT_FALSE(aSink->IsSurfaceFinished());
+      CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 100, 1));
+
+      return;
+    }
+
+    // We should've finished the surface at this point.
+    AssertCorrectPipelineFinalState(aSink,
+                                    IntRect(0, 0, 100, 100),
+                                    IntRect(0, 0, 100, 100));
+
+    // Attempt to write more and make sure that nothing gets written.
+    count = 0;
+    result = aSink->WritePixelsToRow<uint8_t>([&]{
+      count++;
+      return AsVariant(uint8_t(128));
+    });
+
+    EXPECT_EQ(WriteState::FINISHED, result);
+    EXPECT_EQ(0u, count);
+    EXPECT_TRUE(aSink->IsSurfaceFinished());
+
+    // Check that the generated image is still correct.
+    CheckGeneratedPalettedImage(aDecoder, IntRect(0, 0, 50, 1));
+  };
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::NEED_MORE_DATA);
+  });
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                          [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FAILURE);
+  });
+
+  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),
+                  [&](Decoder* aDecoder, PalettedSurfaceSink* aSink) {
+    checkEarlyExit(aDecoder, aSink, WriteState::FINISHED);
+  });
+}
+
 TEST(ImageSurfaceSink, PalettedSurfaceSinkWriteBuffer)
 {
  WithPalettedSurfaceSink(IntRect(0, 0, 100, 100),