Minor simplifications/optimizations to AbstractByteBuf methods (#9845)

Motivation

While working on other changes I noticed some opportunities to
streamline a few things in AbstractByteBuf.

Modifications

- Avoid duplicate ensureAccessible() checks in discard(Some)ReadBytes()
and ensureWritable0(int) methods
- Simplify ensureWritable0(int) logic
- Make some conditional checks more concise

Result

Cleaner, possibly faster code
This commit is contained in:
Nick Hill 2019-12-05 02:32:21 -08:00 committed by Norman Maurer
parent a322addb17
commit 63d33b390a

View File

@ -213,8 +213,8 @@ public abstract class AbstractByteBuf extends ByteBuf {
@Override
public ByteBuf discardReadBytes() {
ensureAccessible();
if (readerIndex == 0) {
ensureAccessible();
return this;
}
@ -224,6 +224,7 @@ public abstract class AbstractByteBuf extends ByteBuf {
adjustMarkers(readerIndex);
readerIndex = 0;
} else {
ensureAccessible();
adjustMarkers(readerIndex);
writerIndex = readerIndex = 0;
}
@ -232,23 +233,23 @@ public abstract class AbstractByteBuf extends ByteBuf {
@Override
public ByteBuf discardSomeReadBytes() {
if (readerIndex > 0) {
if (readerIndex == writerIndex) {
ensureAccessible();
adjustMarkers(readerIndex);
writerIndex = readerIndex = 0;
return this;
}
if (readerIndex >= capacity() >>> 1) {
setBytes(0, this, readerIndex, writerIndex - readerIndex);
writerIndex -= readerIndex;
adjustMarkers(readerIndex);
readerIndex = 0;
return this;
}
}
ensureAccessible();
if (readerIndex == 0) {
return this;
}
if (readerIndex == writerIndex) {
adjustMarkers(readerIndex);
writerIndex = readerIndex = 0;
return this;
}
if (readerIndex >= capacity() >>> 1) {
setBytes(0, this, readerIndex, writerIndex - readerIndex);
writerIndex -= readerIndex;
adjustMarkers(readerIndex);
readerIndex = 0;
}
return this;
}
@ -277,34 +278,28 @@ public abstract class AbstractByteBuf extends ByteBuf {
@Override
public ByteBuf ensureWritable(int minWritableBytes) {
checkPositiveOrZero(minWritableBytes, "minWritableBytes");
ensureWritable0(minWritableBytes);
ensureWritable0(checkPositiveOrZero(minWritableBytes, "minWritableBytes"));
return this;
}
final void ensureWritable0(int minWritableBytes) {
ensureAccessible();
if (minWritableBytes <= writableBytes()) {
final int writerIndex = writerIndex();
final int targetCapacity = writerIndex + minWritableBytes;
if (targetCapacity <= capacity()) {
ensureAccessible();
return;
}
final int writerIndex = writerIndex();
if (checkBounds) {
if (minWritableBytes > maxCapacity - writerIndex) {
throw new IndexOutOfBoundsException(String.format(
"writerIndex(%d) + minWritableBytes(%d) exceeds maxCapacity(%d): %s",
writerIndex, minWritableBytes, maxCapacity, this));
}
if (checkBounds && targetCapacity > maxCapacity) {
ensureAccessible();
throw new IndexOutOfBoundsException(String.format(
"writerIndex(%d) + minWritableBytes(%d) exceeds maxCapacity(%d): %s",
writerIndex, minWritableBytes, maxCapacity, this));
}
// Normalize the current capacity to the power of 2.
int minNewCapacity = writerIndex + minWritableBytes;
int newCapacity = alloc().calculateNewCapacity(minNewCapacity, maxCapacity);
int fastCapacity = writerIndex + maxFastWritableBytes();
// Grow by a smaller amount if it will avoid reallocation
if (newCapacity > fastCapacity && minNewCapacity <= fastCapacity) {
newCapacity = fastCapacity;
}
// Normalize the target capacity to the power of 2.
final int fastWritable = maxFastWritableBytes();
int newCapacity = fastWritable >= minWritableBytes ? writerIndex + fastWritable
: alloc().calculateNewCapacity(targetCapacity, maxCapacity);
// Adjust to the new capacity.
capacity(newCapacity);
@ -330,15 +325,9 @@ public abstract class AbstractByteBuf extends ByteBuf {
return 3;
}
// Normalize the current capacity to the power of 2.
int minNewCapacity = writerIndex + minWritableBytes;
int newCapacity = alloc().calculateNewCapacity(minNewCapacity, maxCapacity);
int fastCapacity = writerIndex + maxFastWritableBytes();
// Grow by a smaller amount if it will avoid reallocation
if (newCapacity > fastCapacity && minNewCapacity <= fastCapacity) {
newCapacity = fastCapacity;
}
int fastWritable = maxFastWritableBytes();
int newCapacity = fastWritable >= minWritableBytes ? writerIndex + fastWritable
: alloc().calculateNewCapacity(writerIndex + minWritableBytes, maxCapacity);
// Adjust to the new capacity.
capacity(newCapacity);
@ -1474,28 +1463,23 @@ public abstract class AbstractByteBuf extends ByteBuf {
* than the specified value.
*/
protected final void checkReadableBytes(int minimumReadableBytes) {
checkPositiveOrZero(minimumReadableBytes, "minimumReadableBytes");
checkReadableBytes0(minimumReadableBytes);
checkReadableBytes0(checkPositiveOrZero(minimumReadableBytes, "minimumReadableBytes"));
}
protected final void checkNewCapacity(int newCapacity) {
ensureAccessible();
if (checkBounds) {
if (newCapacity < 0 || newCapacity > maxCapacity()) {
throw new IllegalArgumentException("newCapacity: " + newCapacity +
" (expected: 0-" + maxCapacity() + ')');
}
if (checkBounds && (newCapacity < 0 || newCapacity > maxCapacity())) {
throw new IllegalArgumentException("newCapacity: " + newCapacity +
" (expected: 0-" + maxCapacity() + ')');
}
}
private void checkReadableBytes0(int minimumReadableBytes) {
ensureAccessible();
if (checkBounds) {
if (readerIndex > writerIndex - minimumReadableBytes) {
throw new IndexOutOfBoundsException(String.format(
"readerIndex(%d) + length(%d) exceeds writerIndex(%d): %s",
readerIndex, minimumReadableBytes, writerIndex, this));
}
if (checkBounds && readerIndex > writerIndex - minimumReadableBytes) {
throw new IndexOutOfBoundsException(String.format(
"readerIndex(%d) + length(%d) exceeds writerIndex(%d): %s",
readerIndex, minimumReadableBytes, writerIndex, this));
}
}