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timfeltimfel
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specialize on reading SeekableByteChannels to allocate smaller buffers
1 parent 3a23e7f commit fb7fe73

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+81
-45
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1 file changed

+81
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‎graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/PosixModuleBuiltins.java

Lines changed: 81 additions & 45 deletions
Original file line numberDiff line numberDiff line change
@@ -64,6 +64,7 @@
6464
import com.oracle.graal.python.builtins.CoreFunctions;
6565
import com.oracle.graal.python.builtins.PythonBuiltins;
6666
import com.oracle.graal.python.builtins.modules.PosixModuleBuiltinsFactory.ConvertPathlikeObjectNodeGen;
67+
import com.oracle.graal.python.builtins.modules.PosixModuleBuiltinsFactory.ReadFromChannelNodeGen;
6768
import com.oracle.graal.python.builtins.modules.PosixModuleBuiltinsFactory.StatNodeFactory;
6869
import com.oracle.graal.python.builtins.objects.PNone;
6970
import com.oracle.graal.python.builtins.objects.bytes.OpaqueBytes;
@@ -836,77 +837,112 @@ public static WriteNode create() {
836837
}
837838
}
838839

839-
@Builtin(name = "read", fixedNumOfPositionalArgs = 2)
840-
@GenerateNodeFactory
841-
@TypeSystemReference(PythonArithmeticTypes.class)
842-
public abstract static class ReadNode extends PythonFileNode {
843-
private static final int MAX_READ = Integer.MAX_VALUE / 2;
840+
abstract static class ReadFromChannelNode extends PNodeWithContext {
841+
private final BranchProfile gotException = BranchProfile.create();
844842

845-
@Specialization(guards = "readOpaque(frame)")
846-
Object readOpaque(@SuppressWarnings("unused") VirtualFrame frame, int fd, @SuppressWarnings("unused") Object requestedSize,
847-
@Cached("createClassProfile()") ValueProfile channelClassProfile,
848-
@Cached("createBinaryProfile()") ConditionProfile instanceofProfile,
849-
@Cached("create()") BranchProfile gotException) {
850-
Channel channel = getResources().getFileChannel(fd, channelClassProfile);
843+
abstract ByteSequenceStorage execute(Channel channel, int size);
844+
845+
@Specialization
846+
ByteSequenceStorage readSeekable(SeekableByteChannel channel, int size) {
847+
long availableSize;
851848
try {
852-
ByteSequenceStorage bytes = doRead(channel, MAX_READ, channelClassProfile, instanceofProfile);
853-
return new OpaqueBytes(Arrays.copyOf(bytes.getInternalByteArray(), bytes.length()));
849+
availableSize = channel.size() - channel.position();
854850
} catch (IOException e) {
855851
gotException.enter();
856852
throw raise(OSError, e.getMessage());
857853
}
854+
if (availableSize > ReadNode.MAX_READ) {
855+
availableSize = ReadNode.MAX_READ;
856+
}
857+
int sz = (int) Math.min(availableSize, size);
858+
return readReadable(channel, sz);
858859
}
859860

860-
@Specialization(guards = "!readOpaque(frame)")
861-
Object read(@SuppressWarnings("unused") VirtualFrame frame, int fd, long requestedSize,
862-
@Cached("createClassProfile()") ValueProfile channelClassProfile,
863-
@Cached("createBinaryProfile()") ConditionProfile instanceofProfile,
864-
@Cached("create()") BranchProfile gotException) {
865-
Channel channel = getResources().getFileChannel(fd, channelClassProfile);
866-
try {
867-
ByteSequenceStorage array = doRead(channel, (int) requestedSize, channelClassProfile, instanceofProfile);
868-
return factory().createBytes(array);
869-
} catch (IOException e) {
870-
gotException.enter();
871-
throw raise(OSError, e.getMessage());
861+
@Specialization
862+
ByteSequenceStorage readReadable(ReadableByteChannel channel, int size) {
863+
int sz = Math.min(size, ReadNode.MAX_READ);
864+
ByteBuffer dst = allocateBuffer(sz);
865+
int readSize = readIntoBuffer(channel, dst);
866+
byte[] array;
867+
if (readSize <= 0) {
868+
array = new byte[0];
869+
readSize = 0;
870+
} else {
871+
array = getByteBufferArray(dst);
872872
}
873+
ByteSequenceStorage byteSequenceStorage = new ByteSequenceStorage(array);
874+
byteSequenceStorage.setNewLength(readSize);
875+
return byteSequenceStorage;
873876
}
874877

875-
private ByteSequenceStorage doRead(Channel channel, int requestedSize, ValueProfile channelClassProfile, ConditionProfile instanceofProfile) throws IOException {
876-
if (instanceofProfile.profile(channelClassProfile.profile(channel) instanceof ReadableByteChannel)) {
877-
ReadableByteChannel readableChannel = (ReadableByteChannel) channel;
878-
int sz = Math.min(requestedSize, MAX_READ);
879-
ByteBuffer dst = allocateBuffer(sz);
880-
int readSize = readIntoBuffer(readableChannel, dst);
881-
byte[] array;
882-
if (readSize <= 0) {
883-
array = new byte[0];
884-
readSize = 0;
885-
} else {
886-
array = getByteBufferArray(dst);
887-
}
888-
ByteSequenceStorage byteSequenceStorage = new ByteSequenceStorage(array);
889-
byteSequenceStorage.setNewLength(readSize);
890-
return byteSequenceStorage;
878+
@Specialization
879+
ByteSequenceStorage readGeneric(Channel channel, int size) {
880+
if (channel instanceof SeekableByteChannel) {
881+
return readSeekable((SeekableByteChannel) channel, size);
882+
} else if (channel instanceof ReadableByteChannel) {
883+
return readReadable((ReadableByteChannel) channel, size);
884+
} else {
885+
throw raise(OSError, "file not opened for reading");
891886
}
892-
throw raise(OSError, "file not opened for reading");
893887
}
894888

895889
@TruffleBoundary(allowInlining = true)
896890
private static byte[] getByteBufferArray(ByteBuffer dst) {
897891
return dst.array();
898892
}
899893

900-
@TruffleBoundary(allowInlining = true, transferToInterpreterOnException = false)
901-
private static int readIntoBuffer(ReadableByteChannel readableChannel, ByteBuffer dst) throws IOException {
902-
return readableChannel.read(dst);
894+
@TruffleBoundary(allowInlining = true)
895+
private int readIntoBuffer(ReadableByteChannel readableChannel, ByteBuffer dst) {
896+
try {
897+
return readableChannel.read(dst);
898+
} catch (IOException e) {
899+
gotException.enter();
900+
throw raise(OSError, e.getMessage());
901+
}
903902
}
904903

905904
@TruffleBoundary(allowInlining = true)
906905
private static ByteBuffer allocateBuffer(int sz) {
907906
return ByteBuffer.allocate(sz);
908907
}
909908

909+
public static ReadFromChannelNode create() {
910+
return ReadFromChannelNodeGen.create();
911+
}
912+
}
913+
914+
@Builtin(name = "read", fixedNumOfPositionalArgs = 2)
915+
@GenerateNodeFactory
916+
@TypeSystemReference(PythonArithmeticTypes.class)
917+
public abstract static class ReadNode extends PythonFileNode {
918+
private static final int MAX_READ = Integer.MAX_VALUE / 2;
919+
920+
@Specialization(guards = "readOpaque(frame)")
921+
Object readOpaque(@SuppressWarnings("unused") VirtualFrame frame, int fd, @SuppressWarnings("unused") Object requestedSize,
922+
@Cached("createClassProfile()") ValueProfile channelClassProfile,
923+
@Cached("create()") ReadFromChannelNode readNode) {
924+
Channel channel = getResources().getFileChannel(fd, channelClassProfile);
925+
ByteSequenceStorage bytes = readNode.execute(channel, MAX_READ);
926+
return new OpaqueBytes(Arrays.copyOf(bytes.getInternalByteArray(), bytes.length()));
927+
}
928+
929+
@Specialization(guards = "!readOpaque(frame)")
930+
Object read(@SuppressWarnings("unused") VirtualFrame frame, int fd, long requestedSize,
931+
@Cached("createClassProfile()") ValueProfile channelClassProfile,
932+
@Cached("create()") BranchProfile tooLarge,
933+
@Cached("create()") ReadFromChannelNode readNode) {
934+
int size;
935+
try {
936+
size = Math.toIntExact(requestedSize);
937+
} catch (ArithmeticException e) {
938+
tooLarge.enter();
939+
size = MAX_READ;
940+
}
941+
Channel channel = getResources().getFileChannel(fd, channelClassProfile);
942+
ByteSequenceStorage array = readNode.execute(channel, size);
943+
return factory().createBytes(array);
944+
}
945+
910946
/**
911947
* @param frame - only used so the DSL sees this as a dynamic check
912948
*/

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