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4833719: (bf) Views of MappedByteBuffers are not MappedByteBuffers, and cannot be forced

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Reviewed-by: adinn
This commit is contained in:
Brian Burkhalter 2021-03-25 15:30:50 +00:00
parent 8307aa6dcb
commit b006f22f1f
3 changed files with 214 additions and 13 deletions
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57
src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template
View file

@ -198,11 +198,18 @@ class Direct$Type$Buffer$RW$$BO$
// For duplicates and slices
//
Direct$Type$Buffer$RW$$BO$(DirectBuffer db, // package-private
int mark, int pos, int lim, int cap,
int off, MemorySegmentProxy segment)
int mark, int pos, int lim, int cap, int off,
#if[byte]
FileDescriptor fd, boolean isSync,
#end[byte]
MemorySegmentProxy segment)
{
#if[rw]
super(mark, pos, lim, cap, segment);
super(mark, pos, lim, cap,
#if[byte]
fd, isSync,
#end[byte]
segment);
address = ((Buffer)db).address + off;
#if[byte]
cleaner = null;
@ -210,7 +217,11 @@ class Direct$Type$Buffer$RW$$BO$
Object attachment = db.attachment();
att = (attachment == null ? db : attachment);
#else[rw]
super(db, mark, pos, lim, cap, off, segment);
super(db, mark, pos, lim, cap, off,
#if[byte]
fd, isSync,
#end[byte]
segment);
this.isReadOnly = true;
#end[rw]
}
@ -220,17 +231,27 @@ class Direct$Type$Buffer$RW$$BO$
return null;
}
public $Type$Buffer slice() {
public {#if[byte]?Mapped$Type$Buffer:$Type$Buffer} slice() {
int pos = this.position();
int lim = this.limit();
int rem = (pos <= lim ? lim - pos : 0);
int off = (pos << $LG_BYTES_PER_VALUE$);
assert (off >= 0);
return new Direct$Type$Buffer$RW$$BO$(this, -1, 0, rem, rem, off, segment);
return new Direct$Type$Buffer$RW$$BO$(this,
-1,
0,
rem,
rem,
off,
#if[byte]
fileDescriptor(),
isSync(),
#end[byte]
segment);
}
@Override
public $Type$Buffer slice(int index, int length) {
public {#if[byte]?Mapped$Type$Buffer:$Type$Buffer} slice(int index, int length) {
Objects.checkFromIndexSize(index, length, limit());
return new Direct$Type$Buffer$RW$$BO$(this,
-1,
@ -238,16 +259,25 @@ class Direct$Type$Buffer$RW$$BO$
length,
length,
index << $LG_BYTES_PER_VALUE$,
#if[byte]
fileDescriptor(),
isSync(),
#end[byte]
segment);
}
public $Type$Buffer duplicate() {
public {#if[byte]?Mapped$Type$Buffer:$Type$Buffer} duplicate() {
return new Direct$Type$Buffer$RW$$BO$(this,
this.markValue(),
this.position(),
this.limit(),
this.capacity(),
0, segment);
0,
#if[byte]
fileDescriptor(),
isSync(),
#end[byte]
segment);
}
public $Type$Buffer asReadOnlyBuffer() {
@ -257,7 +287,12 @@ class Direct$Type$Buffer$RW$$BO$
this.position(),
this.limit(),
this.capacity(),
0, segment);
0,
#if[byte]
fileDescriptor(),
isSync(),
#end[byte]
segment);
#else[rw]
return duplicate();
#end[rw]
@ -506,7 +541,7 @@ class Direct$Type$Buffer$RW$$BO$
#end[rw]
}
public $Type$Buffer compact() {
public {#if[byte]?Mapped$Type$Buffer:$Type$Buffer} compact() {
#if[rw]
int pos = position();
int lim = limit();

54
src/java.base/share/classes/java/nio/MappedByteBuffer.java
View file

@ -152,10 +152,20 @@ public abstract class MappedByteBuffer
* @return true if the file was mapped using one of the sync map
* modes, otherwise false.
*/
private boolean isSync() {
final boolean isSync() { // package-private
return isSync;
}
/**
* Returns the {@code FileDescriptor} associated with this
* {@code MappedByteBuffer}.
*
* @return the buffer's file descriptor; may be {@code null}
*/
final FileDescriptor fileDescriptor() { // package-private
return fd;
}
/**
* Tells whether or not this buffer's content is resident in physical
* memory.
@ -205,7 +215,10 @@ public abstract class MappedByteBuffer
/**
* Forces any changes made to this buffer's content to be written to the
* storage device containing the mapped file.
* storage device containing the mapped file. The region starts at index
* zero in this buffer and is {@code capacity()} bytes. An invocation of
* this method behaves in exactly the same way as the invocation
* {@link force(int,int) force(0,capacity())}.
*
* <p> If the file mapped into this buffer resides on a local storage
* device then when this method returns it is guaranteed that all changes
@ -362,4 +375,41 @@ public abstract class MappedByteBuffer
super.rewind();
return this;
}
/**
* {@inheritDoc}
*
* <p> Reading bytes into physical memory by invoking {@code load()} on the
* returned buffer, or writing bytes to the storage device by invoking
* {@code force()} on the returned buffer, will only act on the sub-range
* of this buffer that the returned buffer represents, namely
* {@code [position(),limit())}.
*/
@Override
public abstract MappedByteBuffer slice();
/**
* {@inheritDoc}
*
* <p> Reading bytes into physical memory by invoking {@code load()} on the
* returned buffer, or writing bytes to the storage device by invoking
* {@code force()} on the returned buffer, will only act on the sub-range
* of this buffer that the returned buffer represents, namely
* {@code [index,index+length)}, where {@code index} and {@code length} are
* assumed to satisfy the preconditions.
*/
@Override
public abstract MappedByteBuffer slice(int index, int length);
/**
* {@inheritDoc}
*/
@Override
public abstract MappedByteBuffer duplicate();
/**
* {@inheritDoc}
*/
@Override
public abstract MappedByteBuffer compact();
}