Merge "Improve Font#equals and Font#hashCode for HashMap." (767286e0) · Commits · e / os / android_frameworks_base

graphics/java/android/graphics/fonts/Font.java

+42 −5

Original line number	Diff line number	Diff line
		@@ -523,6 +523,9 @@ public final class Font {
		/**
		* Returns a font file buffer.
		*
		* Duplicate before reading values by {@link ByteBuffer#duplicate()} for avoiding unexpected
		* reading position sharing.
		*
		* @return a font buffer
		*/
		public @NonNull ByteBuffer getBuffer() {
		@@ -628,18 +631,49 @@ public final class Font {
		if (o == this) {
		return true;
		}
		if (o == null \|\| !(o instanceof Font)) {
		if (!(o instanceof Font)) {
		return false;
		}
		Font f = (Font) o;
		return mFontStyle.equals(f.mFontStyle) && f.mTtcIndex == mTtcIndex
		&& Arrays.equals(f.mAxes, mAxes) && f.mBuffer.equals(mBuffer)
		&& Objects.equals(f.mLocaleList, mLocaleList);
		boolean paramEqual = mFontStyle.equals(f.mFontStyle) && f.mTtcIndex == mTtcIndex
		&& Arrays.equals(f.mAxes, mAxes) && Objects.equals(f.mLocaleList, mLocaleList)
		&& Objects.equals(mFile, f.mFile);

		if (!paramEqual) {
		return false;
		}

		// Shortcut for different font buffer check by comparing size.
		if (mBuffer.capacity() != f.mBuffer.capacity()) {
		return false;
		}

		// ByteBuffer#equals compares all bytes which is not performant for e.g HashMap. Since
		// underlying native font object holds buffer address, check if this buffer points exactly
		// the same address as a shortcut of equality. For being compatible with of API30 or before,
		// check buffer position even if the buffer points the same address.
		if (nIsSameBufferAddress(mNativePtr, f.mNativePtr)
		&& mBuffer.position() == f.mBuffer.position()) {
		return true;
		}

		// Unfortunately, need to compare bytes one-by-one since the buffer may be different font
		// file but has the same file size, or two font has same content but they are allocated
		// differently. For being compatible with API30 ore before, compare with ByteBuffer#equals.
		return mBuffer.equals(f.mBuffer);
		}

		@Override
		public int hashCode() {
		return Objects.hash(mFontStyle, mTtcIndex, Arrays.hashCode(mAxes), mBuffer, mLocaleList);
		return Objects.hash(
		mFontStyle,
		mTtcIndex,
		Arrays.hashCode(mAxes),
		// Use Buffer size instead of ByteBuffer#hashCode since ByteBuffer#hashCode traverse
		// data which is not performant e.g. for HashMap. The hash collision are less likely
		// happens because it is unlikely happens the different font files has exactly the
		// same size.
		mLocaleList);
		}

		@Override
		@@ -724,4 +758,7 @@ public final class Font {

		@CriticalNative
		private static native long nGetNativeFontPtr(long ptr);

		@CriticalNative
		private static native boolean nIsSameBufferAddress(long lFontPtr, long rFontPtr);
		}

libs/hwui/jni/fonts/Font.cpp

+11 −0

Original line number	Diff line number	Diff line
		@@ -238,6 +238,16 @@ static jlong Font_getNativeFontPtr(CRITICAL_JNI_PARAMS_COMMA jlong fontHandle) {
		return reinterpret_cast<jlong>(font->font.get());
		}

		// Critical Native
		static jboolean Font_isSameBufferAddress(CRITICAL_JNI_PARAMS_COMMA jlong lFontHandle,
		jlong rFontHandle) {
		FontWrapper* lFont = reinterpret_cast<FontWrapper*>(lFontHandle);
		FontWrapper* rFont = reinterpret_cast<FontWrapper*>(rFontHandle);
		const void* lBufferPtr = lFont->font->typeface()->GetFontData();
		const void* rBufferPtr = rFont->font->typeface()->GetFontData();
		return lBufferPtr == rBufferPtr;
		}

		///////////////////////////////////////////////////////////////////////////////

		struct FontBufferWrapper {
		@@ -287,6 +297,7 @@ static const JNINativeMethod gFontMethods[] = {
		{ "nGetAxisInfo", "(JI)J", (void*) Font_getAxisInfo },
		{ "nGetFontPath", "(J)Ljava/lang/String;", (void*) Font_getFontPath },
		{ "nGetNativeFontPtr", "(J)J", (void*) Font_getNativeFontPtr },
		{ "nIsSameBufferAddress", "(JJ)Z", (void*) Font_isSameBufferAddress },
		};

		static const JNINativeMethod gFontBufferHelperMethods[] = {