Java API for mojo system.

mojo/system/android/src/org/chromium/mojo/system/CoreImpl.java

Index: mojo/system/android/src/org/chromium/mojo/system/CoreImpl.java
diff --git a/mojo/system/android/src/org/chromium/mojo/system/CoreImpl.java b/mojo/system/android/src/org/chromium/mojo/system/CoreImpl.java
new file mode 100644
index 0000000000000000000000000000000000000000..9d174bd26aa27f626908bbd74fa00e9081d900ec
--- /dev/null
+++ b/mojo/system/android/src/org/chromium/mojo/system/CoreImpl.java
@@ -0,0 +1,573 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.mojo.system;
+
+import org.chromium.base.CalledByNative;
+import org.chromium.base.JNINamespace;
+import org.chromium.mojo.system.DataPipe.ConsumerHandle;
+import org.chromium.mojo.system.DataPipe.ProducerHandle;
+import org.chromium.mojo.system.SharedBufferHandle.DuplicateOptions;
+import org.chromium.mojo.system.SharedBufferHandle.MapFlags;
+
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Implementation of {@link Core}.
+ */
+@JNINamespace("mojo::android")
+public class CoreImpl implements Core {

[bulach, 2014/04/17 13:15:42]

nit: can these impl classes be package-private?

[qsr, 2014/04/17 13:50:24]

 Most of those can, this one can't. We need to get the singleton. And probably
from other place than here.

[bulach, 2014/04/17 14:04:50]

looks like the getInstance() is only called on tests for now, and hopefully
won't be used outside this package in the future, right?
probably best to keep it package-private for now, and make it public later on if
needed, and even then, it'd probably be nicer to expose a separate class
returning the getInstance() as a Core rather than a CoreImpl...

+
+    /**
+     * Discard flag for the |MojoReadData| operation.
+     */
+    private static final int MOJO_READ_DATA_FLAG_DISCARD = 1 << 1;
+
+    /**
+     * The singleton instance.
+     */
+    private static Core sINSTANCE = null;
+
+    /**
+     * @return the instance.
+     */
+    public static synchronized Core getInstance() {
+        if (sINSTANCE == null) {
+            sINSTANCE = new CoreImpl();
+        }
+        return sINSTANCE;
+    }
+
+    private CoreImpl() {
+        nativeConstructor();
+    }
+
+    /**
+     * @see Core#getTimeTicksNow()
+     */
+    @Override
+    public long getTimeTicksNow() {
+        return nativeGetTimeTicksNow();
+    }
+
+    /**
+     * @see Core#waitMany(List, long)
+     */
+    @Override
+    public WaitManyResult waitMany(List<Pair<Handle, WaitFlags>> handles, long deadline) {
+        // Allocate a direct buffer to allow native code not to reach back to java. Buffer will
+        // contain all mojo handles, followed by all flags values.
+        ByteBuffer buffer = allocateDirectBuffer(handles.size() * 8);
+        int index = 0;
+        for (Pair<Handle, WaitFlags> handle : handles) {
+            HandleImpl realHandler = (HandleImpl) handle.first;
+            buffer.putInt(4 * index, realHandler.getMojoHandle());

[bulach, 2014/04/17 13:15:42]

nit: there's a lot of "* 4" in this file... perhaps extract this into a static
final int HANDLE_SIZE = 4 ?

...should it ever grow... :)

[qsr, 2014/04/17 13:50:24]

 Done, but I really do not see it growing anytime soon. Will break every
messages. Moreover, not all 4s are handle size, some are flag size. But I will
extract both.

+            buffer.putInt(4 * handles.size() + 4 * index, handle.second.getFlags());
+            index++;
+        }
+        int code = nativeWaitMany(buffer, deadline);
+        WaitManyResult result = new WaitManyResult();
+        // If result is greater than 0, result is the indexed of the available handle. To make sure
+        // it cannot be misinterpreted, set handleIndex to a negative number in case of error.
+        result.setHandleIndex(code);
+        result.setMojoResult(filterMojoResultForWait(code));
+        return result;
+    }
+
+    /**
+     * @see Core#wait(Handle, WaitFlags, long)
+     */
+    @Override
+    public int wait(Handle handle, WaitFlags flags, long deadline) {
+        return filterMojoResultForWait(nativeWait(((HandleImpl) handle).getMojoHandle(),
+                flags.getFlags(), deadline));
+    }
+
+    /**
+     * @see Core#createMessagePipe()
+     */
+    @Override
+    public Pair<MessagePipeHandle, MessagePipeHandle> createMessagePipe() {
+        NativeCreationResult result = nativeCreateMessagePipe();
+        if (result.getMojoResult() != MojoResult.OK) {
+            throw new MojoException(result.getMojoResult());
+        }
+        return Pair.create(
+                new MessagePipeHandleImpl(this, result.getMojoHandle1()),
+                new MessagePipeHandleImpl(this, result.getMojoHandle2()));
+    }
+
+    /**
+     * @see Core#createDataPipe(DataPipe.CreateOptions)
+     */
+    @Override
+    public Pair<ProducerHandle, ConsumerHandle> createDataPipe(DataPipe.CreateOptions options) {
+        ByteBuffer optionsBuffer = null;
+        if (options != null) {
+            optionsBuffer = allocateDirectBuffer(16);
+            optionsBuffer.putInt(0, 16);
+            optionsBuffer.putInt(4, options.getFlags().getFlags());
+            optionsBuffer.putInt(8, options.getElementNumBytes());
+            optionsBuffer.putInt(12, options.getCapacityNumBytes());
+        }
+        NativeCreationResult result = nativeCreateDataPipe(optionsBuffer);
+        if (result.getMojoResult() != MojoResult.OK) {
+            throw new MojoException(result.getMojoResult());
+        }
+        return Pair.create(
+                new DataPipeProducerHandleImpl(this, result.getMojoHandle1()),
+                new DataPipeConsumerHandleImpl(this, result.getMojoHandle2()));
+    }
+
+    /**
+     * @see Core#createSharedBuffer(SharedBufferHandle.CreateOptions, long)
+     */
+    @Override
+    public SharedBufferHandle createSharedBuffer(
+            SharedBufferHandle.CreateOptions options, long numBytes) {
+        ByteBuffer optionsBuffer = null;
+        if (options != null) {
+            optionsBuffer = allocateDirectBuffer(8);
+            optionsBuffer.putInt(0, 8);
+            optionsBuffer.putInt(4, options.getFlags().getFlags());
+        }
+        NativeCreationResult result = nativeCreateSharedBuffer(optionsBuffer, numBytes);
+        if (result.getMojoResult() != MojoResult.OK) {
+            throw new MojoException(result.getMojoResult());
+        }
+        assert result.getMojoHandle2() == 0;
+        return new SharedBufferHandleImpl(this, result.getMojoHandle1());
+    }
+
+    int closeWithResult(int mojoHandle) {
+        return nativeClose(mojoHandle);
+    }
+
+    void close(int mojoHandle) {
+        int mojoResult = nativeClose(mojoHandle);
+        if (mojoResult != MojoResult.OK) {
+            throw new MojoException(mojoResult);
+        }
+    }
+
+    /**
+     * @see MessagePipeHandle#writeMessage(ByteBuffer, List, MessagePipeHandle.WriteFlags)
+     */
+    void writeMessage(MessagePipeHandleImpl pipeHandle, ByteBuffer bytes,
+            List<Handle> handles, MessagePipeHandle.WriteFlags flags) {
+        ByteBuffer handlesBuffer = null;
+        if (handles != null && !handles.isEmpty()) {
+            handlesBuffer = allocateDirectBuffer(handles.size() * 4);
+            for (Handle handle : handles) {
+                HandleImpl realHandle = (HandleImpl) handle;
+                handlesBuffer.putInt(realHandle.getMojoHandle());
+            }
+            handlesBuffer.position(0);
+        }
+        int mojoResult = nativeWriteMessage(pipeHandle.getMojoHandle(), bytes,
+                bytes == null ? 0 : bytes.limit(), handlesBuffer,
+                flags.getFlags());
+        if (mojoResult != MojoResult.OK) {
+            throw new MojoException(mojoResult);
+        }
+        // Success means the handles have been invalidated.
+        if (handles != null) {
+            for (Handle handle : handles) {
+                ((HandleImpl) handle).invalidateHandle();
+            }
+        }
+    }
+
+    /**
+     * @see MessagePipeHandle#readMessage(ByteBuffer, int, MessagePipeHandle.ReadFlags)
+     */
+    MessagePipeHandle.ReadMessageResult readMessage(MessagePipeHandleImpl handle,
+            ByteBuffer bytes, int maxNumberOfHandles,
+            MessagePipeHandle.ReadFlags flags) {
+        ByteBuffer handlesBuffer = null;
+        if (maxNumberOfHandles > 0) {
+            handlesBuffer = allocateDirectBuffer(maxNumberOfHandles * 4);
+        }
+        NativeReadMessageResult result = nativeReadMessage(
+                handle.getMojoHandle(), bytes, handlesBuffer, flags.getFlags());
+        if (result.getMojoResult() != MojoResult.OK &&
+                result.getMojoResult() != MojoResult.RESOURCE_EXHAUSTED) {
+            throw new MojoException(result.getMojoResult());
+        }
+
+        if (result.getMojoResult() == MojoResult.OK) {
+            if (bytes != null) {
+                bytes.position(0);
+                bytes.limit(result.getReadMessageResult().getMessageSize());
+            }
+
+            List<UntypedHandle> handles = new ArrayList<UntypedHandle>(
+                    result.getReadMessageResult().getHandlesCount());
+            for (int i = 0; i < result.getReadMessageResult().getHandlesCount(); ++i) {
+                int mojoHandle = handlesBuffer.getInt(4 * i);
+                handles.add(new UntypedHandleImpl(this, mojoHandle));
+            }
+            result.getReadMessageResult().setHandles(handles);
+        }
+        return result.getReadMessageResult();
+    }
+
+    /**
+     * @see DataPipe.ConsumerHandle#discardData(int, DataPipe.ReadFlags)
+     */
+    int discardData(DataPipeConsumerHandleImpl handle, int numBytes,
+            DataPipe.ReadFlags flags) {
+        int result = nativeReadData(handle.getMojoHandle(), null, numBytes,
+                flags.getFlags() | MOJO_READ_DATA_FLAG_DISCARD);
+        if (result < 0) {
+            throw new MojoException(result);
+        }
+        return result;
+    }
+
+    /**
+     * @see DataPipe.ConsumerHandle#readData(ByteBuffer, DataPipe.ReadFlags)
+     */
+    int readData(DataPipeConsumerHandleImpl handle, ByteBuffer elements,
+            DataPipe.ReadFlags flags) {
+        int result = nativeReadData(handle.getMojoHandle(), elements,
+                elements == null ? 0 : elements.capacity(),
+                flags.getFlags());
+        if (result < 0) {
+            throw new MojoException(result);
+        }
+        if (elements != null) {
+            elements.limit(result);
+        }
+        return result;
+    }
+
+    /**
+     * @see DataPipe.ConsumerHandle#beginReadData(int, DataPipe.ReadFlags)
+     */
+    ByteBuffer beginReadData(DataPipeConsumerHandleImpl handle,
+            int numBytes, DataPipe.ReadFlags flags) {
+        NativeCodeAndBufferResult result = nativeBeginReadData(
+                handle.getMojoHandle(),
+                numBytes,
+                flags.getFlags());
+        if (result.getMojoResult() != MojoResult.OK) {
+            throw new MojoException(result.getMojoResult());
+        }
+        return result.getBuffer().asReadOnlyBuffer();
+    }
+
+    /**
+     * @see DataPipe.ConsumerHandle#endReadData(int)
+     */
+    void endReadData(DataPipeConsumerHandleImpl handle,
+            int numBytesRead) {
+        int result = nativeEndReadData(handle.getMojoHandle(), numBytesRead);
+        if (result != MojoResult.OK) {
+            throw new MojoException(result);
+        }
+    }
+
+    /**
+     * @see DataPipe.ProducerHandle#writeData(ByteBuffer, DataPipe.WriteFlags)
+     */
+    int writeData(DataPipeProducerHandleImpl handle, ByteBuffer elements,
+            DataPipe.WriteFlags flags) {
+        return nativeWriteData(handle.getMojoHandle(), elements, elements.limit(),
+                flags.getFlags());
+    }
+
+    /**
+     * @see DataPipe.ProducerHandle#beginWriteData(int, DataPipe.WriteFlags)
+     */
+    ByteBuffer beginWriteData(DataPipeProducerHandleImpl handle,
+            int numBytes, DataPipe.WriteFlags flags) {
+        NativeCodeAndBufferResult result = nativeBeginWriteData(
+                handle.getMojoHandle(),
+                numBytes,
+                flags.getFlags());
+        if (result.getMojoResult() != MojoResult.OK) {
+            throw new MojoException(result.getMojoResult());
+        }
+        return result.getBuffer();
+    }
+
+    /**
+     * @see DataPipe.ProducerHandle#endWriteData(int)
+     */
+    void endWriteData(DataPipeProducerHandleImpl handle,
+            int numBytesWritten) {
+        int result = nativeEndWriteData(handle.getMojoHandle(), numBytesWritten);
+        if (result != MojoResult.OK) {
+            throw new MojoException(result);
+        }
+    }
+
+    /**
+     * @see SharedBufferHandle#duplicate(DuplicateOptions)
+     */
+    SharedBufferHandle duplicate(SharedBufferHandleImpl handle,
+            DuplicateOptions options) {
+        ByteBuffer optionsBuffer = null;
+        if (options != null) {
+            optionsBuffer = allocateDirectBuffer(8);
+            optionsBuffer.putInt(0, 8);
+            optionsBuffer.putInt(4, options.getFlags().getFlags());
+        }
+        NativeCreationResult result = nativeDuplicate(handle.getMojoHandle(),
+                optionsBuffer);
+        if (result.getMojoResult() != MojoResult.OK) {
+            throw new MojoException(result.getMojoResult());
+        }
+        assert result.getMojoHandle2() == 0;
+        return new SharedBufferHandleImpl(this, result.getMojoHandle1());
+    }
+
+    /**
+     * @see SharedBufferHandle#map(long, long, MapFlags)
+     */
+    ByteBuffer map(SharedBufferHandleImpl handle, long offset, long numBytes,
+            MapFlags flags) {
+        NativeCodeAndBufferResult result = nativeMap(handle.getMojoHandle(), offset, numBytes,
+                flags.getFlags());
+        if (result.getMojoResult() != MojoResult.OK) {
+            throw new MojoException(result.getMojoResult());
+        }
+        return result.getBuffer();
+    }
+
+    /**
+     * @see SharedBufferHandle#unmap(ByteBuffer)
+     */
+    void unmap(ByteBuffer buffer) {
+        int result = nativeUnmap(buffer);
+        if (result != MojoResult.OK) {
+            throw new MojoException(result);
+        }
+    }
+
+    private static int filterMojoResultForWait(int code) {
+        if (code >= 0) {
+            return MojoResult.OK;
+        }
+        switch (code) {
+            case MojoResult.DEADLINE_EXCEEDED:
+            case MojoResult.CANCELLED:
+            case MojoResult.FAILED_PRECONDITION:
+                return code;
+            default:
+                throw new MojoException(code);
+        }
+
+    }
+
+    private static ByteBuffer allocateDirectBuffer(int capacity) {
+        ByteBuffer buffer = ByteBuffer.allocateDirect(capacity);
+        buffer.order(ByteOrder.nativeOrder());
+        return buffer;
+    }
+
+    private static class NativeCodeAndBufferResult {
+        private int mMojoResult;
+        private ByteBuffer mBuffer;
+
+        /**
+         * @return the mojoResult
+         */
+        public int getMojoResult() {
+            return mMojoResult;
+        }
+
+        /**
+         * @param mojoResult the mojoResult to set
+         */
+        public void setMojoResult(int mojoResult) {
+            mMojoResult = mojoResult;
+        }
+
+        /**
+         * @return the buffer
+         */
+        public ByteBuffer getBuffer() {
+            return mBuffer;
+        }
+
+        /**
+         * @param buffer the buffer to set
+         */
+        public void setBuffer(ByteBuffer buffer) {
+            mBuffer = buffer;
+        }
+
+    }
+
+    @CalledByNative
+    private static NativeCodeAndBufferResult newNativeCodeAndBufferResult(int mojoResult,
+            ByteBuffer buffer) {
+        NativeCodeAndBufferResult result = new NativeCodeAndBufferResult();
+        result.setMojoResult(mojoResult);
+        result.setBuffer(buffer);
+        return result;
+    }
+
+    private static class NativeReadMessageResult {
+        public int mMojoResult;
+        public MessagePipeHandle.ReadMessageResult mReadMessageResult;
+
+        /**
+         * @return the mojoResult
+         */
+        public int getMojoResult() {
+            return mMojoResult;
+        }
+
+        /**
+         * @param mojoResult the mojoResult to set
+         */
+        public void setMojoResult(int mojoResult) {
+            this.mMojoResult = mojoResult;
+        }
+
+        /**
+         * @return the readMessageResult
+         */
+        public MessagePipeHandle.ReadMessageResult getReadMessageResult() {
+            return mReadMessageResult;
+        }
+
+        /**
+         * @param readMessageResult the readMessageResult to set
+         */
+        public void setReadMessageResult(MessagePipeHandle.ReadMessageResult readMessageResult) {
+            this.mReadMessageResult = readMessageResult;
+        }
+    }
+
+    @CalledByNative
+    private static NativeReadMessageResult newNativeReadMessageResult(int mojoResult,
+            int messageSize,
+            int handlesCount) {
+        NativeReadMessageResult result = new NativeReadMessageResult();
+        if (mojoResult >= 0) {
+            result.setMojoResult(MojoResult.OK);
+        } else {
+            result.setMojoResult(mojoResult);
+        }
+        MessagePipeHandle.ReadMessageResult readMessageResult =
+                new MessagePipeHandle.ReadMessageResult();
+        readMessageResult.setWasMessageRead(result.getMojoResult() == MojoResult.OK);
+        readMessageResult.setMessageSize(messageSize);
+        readMessageResult.setHandlesCount(handlesCount);
+        result.setReadMessageResult(readMessageResult);
+        return result;
+    }
+
+    private static class NativeCreationResult {
+        private int mMojoResult;
+        private int mMojoHandle1;
+        private int mMojoHandle2;
+
+        /**
+         * @return the mojoResult
+         */
+        public int getMojoResult() {
+            return mMojoResult;
+        }
+
+        /**
+         * @param mojoResult the mojoResult to set
+         */
+        public void setMojoResult(int mojoResult) {
+            mMojoResult = mojoResult;
+        }
+
+        /**
+         * @return the mojoHandle1
+         */
+        public int getMojoHandle1() {
+            return mMojoHandle1;
+        }
+
+        /**
+         * @param mojoHandle1 the mojoHandle1 to set
+         */
+        public void setMojoHandle1(int mojoHandle1) {
+            mMojoHandle1 = mojoHandle1;
+        }
+
+        /**
+         * @return the mojoHandle2
+         */
+        public int getMojoHandle2() {
+            return mMojoHandle2;
+        }
+
+        /**
+         * @param mojoHandle2 the mojoHandle2 to set
+         */
+        public void setMojoHandle2(int mojoHandle2) {
+            mMojoHandle2 = mojoHandle2;
+        }
+    }
+
+    @CalledByNative
+    private static NativeCreationResult newNativeCreationResult(int mojoResult,
+            int mojoHandle1, int mojoHandle2) {
+        NativeCreationResult result = new NativeCreationResult();
+        result.setMojoResult(mojoResult);
+        result.setMojoHandle1(mojoHandle1);
+        result.setMojoHandle2(mojoHandle2);
+        return result;
+    }
+
+    private native void nativeConstructor();
+
+    private native long nativeGetTimeTicksNow();
+
+    private native int nativeWaitMany(ByteBuffer buffer, long deadline);
+
+    private native NativeCreationResult nativeCreateMessagePipe();
+
+    private native NativeCreationResult nativeCreateDataPipe(ByteBuffer optionsBuffer);
+
+    private native NativeCreationResult nativeCreateSharedBuffer(ByteBuffer optionsBuffer,
+            long numBytes);
+
+    private native int nativeClose(int mojoHandle);
+
+    private native int nativeWait(int mojoHandle, int flags, long deadline);
+
+    private native int nativeWriteMessage(int mojoHandle, ByteBuffer bytes, int numBytes,
+            ByteBuffer handlesBuffer, int flags);
+
+    private native NativeReadMessageResult nativeReadMessage(int mojoHandle, ByteBuffer bytes,
+            ByteBuffer handlesBuffer,
+            int flags);
+
+    private native int nativeReadData(int mojoHandle, ByteBuffer elements, int elementsSize,
+            int flags);
+
+    private native NativeCodeAndBufferResult nativeBeginReadData(int mojoHandle, int numBytes,
+            int flags);
+
+    private native int nativeEndReadData(int mojoHandle, int numBytesRead);
+
+    private native int nativeWriteData(int mojoHandle, ByteBuffer elements, int limit, int flags);
+
+    private native NativeCodeAndBufferResult nativeBeginWriteData(int mojoHandle, int numBytes,
+            int flags);
+
+    private native int nativeEndWriteData(int mojoHandle, int numBytesWritten);
+
+    private native NativeCreationResult nativeDuplicate(int mojoHandle, ByteBuffer optionsBuffer);
+
+    private native NativeCodeAndBufferResult nativeMap(int mojoHandle, long offset, long numBytes,
+            int flags);
+
+    private native int nativeUnmap(ByteBuffer buffer);
+
+}