commit 368a7a51c652fe39a130ec6f09315df4f7260e53
author Leon Scroggins III <scroggo@google.com> Fri Nov 20 12:23:27 2020 -0500
committer Leon Scroggins <scroggo@google.com> Wed Mar 24 13:25:06 2021 +0000
tree c1f5e2e3e7bd37856a80ef16725622ab156f1002
parent 99abec3d81c873621cc174ff9d2132749887b620

ImageDecoder: use kYes_ZeroInitialized memory

Bug: 183115528
Test: (A)ImageDecoderTest(s) (verify correctness)
Test: monitor showmap_pss_bytes dashboards (verify memory impact)

This lets the decoder leave zero initialized memory untouched. An
Android feature makes untouched zero initialized memory cheaper, and
BitmapFactory takes advantage of it. Do the same for ImageDecoder.

This feature was originally brought up in b/10016979. ImageDecoder saved
memory in other ways, and as I understand it, Android has shifted
towards using (Animated)VectorDrawables. Both of these may have
contributed to us not noticing when we switched from BitmapFactory to
ImageDecoder.

Change-Id: Iecfd1bbfdcc38e1f0bf380b4f4ea5b861cfcf08a

libs/hwui/hwui/ImageDecoder.cpp

diff --git a/libs/hwui/hwui/ImageDecoder.cpp b/libs/hwui/hwui/ImageDecoder.cpp
index ade63e5..5d9fad5 100644
--- a/libs/hwui/hwui/ImageDecoder.cpp
+++ b/libs/hwui/hwui/ImageDecoder.cpp
@@ -45,7 +45,8 @@
     return SkColorSpace::MakeSRGB();
 }
 
-ImageDecoder::ImageDecoder(std::unique_ptr<SkAndroidCodec> codec, sk_sp<SkPngChunkReader> peeker)
+ImageDecoder::ImageDecoder(std::unique_ptr<SkAndroidCodec> codec, sk_sp<SkPngChunkReader> peeker,
+                           SkCodec::ZeroInitialized zeroInit)
     : mCodec(std::move(codec))
     , mPeeker(std::move(peeker))
     , mDecodeSize(mCodec->codec()->dimensions())
@@ -57,6 +58,7 @@
     mTargetSize = swapWidthHeight() ? SkISize { mDecodeSize.height(), mDecodeSize.width() }
                                     : mDecodeSize;
     this->rewind();
+    mOptions.fZeroInitialized = zeroInit;
 }
 
 ImageDecoder::~ImageDecoder() = default;
@@ -446,10 +448,17 @@
                 ALOGE("Failed to invert matrix!");
             }
         }
+
+        // Even if the client did not provide zero initialized memory, the
+        // memory we decode into is.
+        mOptions.fZeroInitialized = SkCodec::kYes_ZeroInitialized;
     }
 
     auto result = mCodec->getAndroidPixels(decodeInfo, decodePixels, decodeRowBytes, &mOptions);
 
+    // The next call to decode() may not provide zero initialized memory.
+    mOptions.fZeroInitialized = SkCodec::kNo_ZeroInitialized;
+
     if (scale || handleOrigin || mCropRect) {
         SkBitmap scaledBm;
         if (!scaledBm.installPixels(outputInfo, pixels, rowBytes)) {

libs/hwui/hwui/ImageDecoder.h

diff --git a/libs/hwui/hwui/ImageDecoder.h b/libs/hwui/hwui/ImageDecoder.h
index cbfffd5..cef2233 100644
--- a/libs/hwui/hwui/ImageDecoder.h
+++ b/libs/hwui/hwui/ImageDecoder.h
@@ -34,8 +34,8 @@
     std::unique_ptr<SkAndroidCodec> mCodec;
     sk_sp<SkPngChunkReader> mPeeker;
 
-    ImageDecoder(std::unique_ptr<SkAndroidCodec> codec,
-                 sk_sp<SkPngChunkReader> peeker = nullptr);
+    ImageDecoder(std::unique_ptr<SkAndroidCodec> codec, sk_sp<SkPngChunkReader> peeker = nullptr,
+                 SkCodec::ZeroInitialized zeroInit = SkCodec::kNo_ZeroInitialized);
     ~ImageDecoder();
 
     SkISize getSampledDimensions(int sampleSize) const;

libs/hwui/jni/ImageDecoder.cpp

diff --git a/libs/hwui/jni/ImageDecoder.cpp b/libs/hwui/jni/ImageDecoder.cpp
index ad7741b..f7b8c01 100644
--- a/libs/hwui/jni/ImageDecoder.cpp
+++ b/libs/hwui/jni/ImageDecoder.cpp
@@ -141,7 +141,8 @@
     }
 
     const bool isNinePatch = peeker->mPatch != nullptr;
-    ImageDecoder* decoder = new ImageDecoder(std::move(androidCodec), std::move(peeker));
+    ImageDecoder* decoder = new ImageDecoder(std::move(androidCodec), std::move(peeker),
+                                             SkCodec::kYes_ZeroInitialized);
     return env->NewObject(gImageDecoder_class, gImageDecoder_constructorMethodID,
                           reinterpret_cast<jlong>(decoder), decoder->width(), decoder->height(),
                           animated, isNinePatch);