Native input dispatch rewrite work in progress.

The old dispatch mechanism has been left in place and continues to
be used by default for now.  To enable native input dispatch,
edit the ENABLE_NATIVE_DISPATCH constant in WindowManagerPolicy.

Includes part of the new input event NDK API.  Some details TBD.

To wire up input dispatch, as the ViewRoot adds a window to the
window session it receives an InputChannel object as an output
argument.  The InputChannel encapsulates the file descriptors for a
shared memory region and two pipe end-points.  The ViewRoot then
provides the InputChannel to the InputQueue.  Behind the
scenes, InputQueue simply attaches handlers to the native PollLoop object
that underlies the MessageQueue.  This way MessageQueue doesn't need
to know anything about input dispatch per-se, it just exposes (in native
code) a PollLoop that other components can use to monitor file descriptor
state changes.

There can be zero or more targets for any given input event.  Each
input target is specified by its input channel and some parameters
including flags, an X/Y coordinate offset, and the dispatch timeout.
An input target can request either synchronous dispatch (for foreground apps)
or asynchronous dispatch (fire-and-forget for wallpapers and "outside"
targets).  Currently, finding the appropriate input targets for an event
requires a call back into the WindowManagerServer from native code.
In the future this will be refactored to avoid most of these callbacks
except as required to handle pending focus transitions.

End-to-end event dispatch mostly works!

To do: event injection, rate limiting, ANRs, testing, optimization, etc.

Change-Id: I8c36b2b9e0a2d27392040ecda0f51b636456de25

1 files changed, 288 insertions, 0 deletions

diff --git a/core/jni/android_view_InputChannel.cpp b/core/jni/android_view_InputChannel.cpp
new file mode 100644
index 0000000..47bb073
--- /dev/null
+++ b/core/jni/android_view_InputChannel.cpp
@@ -0,0 +1,288 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "InputChannel-JNI"
+
+#include "JNIHelp.h"
+
+#include <android_runtime/AndroidRuntime.h>
+#include <binder/Parcel.h>
+#include <utils/Log.h>
+#include <ui/InputTransport.h>
+#include "android_view_InputChannel.h"
+#include "android_util_Binder.h"
+
+namespace android {
+
+// ----------------------------------------------------------------------------
+
+static struct {
+    jclass clazz;
+
+    jfieldID mPtr;   // native object attached to the DVM InputChannel
+    jmethodID ctor;
+} gInputChannelClassInfo;
+
+// ----------------------------------------------------------------------------
+
+class NativeInputChannel {
+public:
+    NativeInputChannel(const sp<InputChannel>& inputChannel);
+    ~NativeInputChannel();
+
+    inline sp<InputChannel> getInputChannel() { return mInputChannel; }
+
+    void setDisposeCallback(InputChannelObjDisposeCallback callback, void* data);
+    void invokeAndRemoveDisposeCallback(JNIEnv* env, jobject obj);
+
+private:
+    sp<InputChannel> mInputChannel;
+    InputChannelObjDisposeCallback mDisposeCallback;
+    void* mDisposeData;
+};
+
+// ----------------------------------------------------------------------------
+
+NativeInputChannel::NativeInputChannel(const sp<InputChannel>& inputChannel) :
+    mInputChannel(inputChannel), mDisposeCallback(NULL) {
+}
+
+NativeInputChannel::~NativeInputChannel() {
+}
+
+void NativeInputChannel::setDisposeCallback(InputChannelObjDisposeCallback callback, void* data) {
+    mDisposeCallback = callback;
+    mDisposeData = data;
+}
+
+void NativeInputChannel::invokeAndRemoveDisposeCallback(JNIEnv* env, jobject obj) {
+    if (mDisposeCallback) {
+        mDisposeCallback(env, obj, mInputChannel, mDisposeData);
+        mDisposeCallback = NULL;
+        mDisposeData = NULL;
+    }
+}
+
+// ----------------------------------------------------------------------------
+
+static NativeInputChannel* android_view_InputChannel_getNativeInputChannel(JNIEnv* env,
+        jobject inputChannelObj) {
+    jint intPtr = env->GetIntField(inputChannelObj, gInputChannelClassInfo.mPtr);
+    return reinterpret_cast<NativeInputChannel*>(intPtr);
+}
+
+static void android_view_InputChannel_setNativeInputChannel(JNIEnv* env, jobject inputChannelObj,
+        NativeInputChannel* nativeInputChannel) {
+    env->SetIntField(inputChannelObj, gInputChannelClassInfo.mPtr,
+             reinterpret_cast<jint>(nativeInputChannel));
+}
+
+sp<InputChannel> android_view_InputChannel_getInputChannel(JNIEnv* env, jobject inputChannelObj) {
+    NativeInputChannel* nativeInputChannel =
+            android_view_InputChannel_getNativeInputChannel(env, inputChannelObj);
+    return nativeInputChannel != NULL ? nativeInputChannel->getInputChannel() : NULL;
+}
+
+void android_view_InputChannel_setDisposeCallback(JNIEnv* env, jobject inputChannelObj,
+        InputChannelObjDisposeCallback callback, void* data) {
+    NativeInputChannel* nativeInputChannel =
+            android_view_InputChannel_getNativeInputChannel(env, inputChannelObj);
+    if (nativeInputChannel == NULL) {
+        LOGW("Cannot set dispose callback because input channel object has not been initialized.");
+    } else {
+        nativeInputChannel->setDisposeCallback(callback, data);
+    }
+}
+
+static jobject android_view_InputChannel_createInputChannel(JNIEnv* env,
+        NativeInputChannel* nativeInputChannel) {
+    jobject inputChannelObj = env->NewObject(gInputChannelClassInfo.clazz,
+            gInputChannelClassInfo.ctor);
+    android_view_InputChannel_setNativeInputChannel(env, inputChannelObj, nativeInputChannel);
+    return inputChannelObj;
+}
+
+static jobjectArray android_view_InputChannel_nativeOpenInputChannelPair(JNIEnv* env,
+        jclass clazz, jstring nameObj) {
+    const char* nameChars = env->GetStringUTFChars(nameObj, NULL);
+    String8 name(nameChars);
+    env->ReleaseStringUTFChars(nameObj, nameChars);
+
+    InputChannel* serverChannel;
+    InputChannel* clientChannel;
+    status_t result = InputChannel::openInputChannelPair(name, & serverChannel, & clientChannel);
+
+    if (result) {
+        LOGE("Could not open input channel pair.  status=%d", result);
+        jniThrowRuntimeException(env, "Could not open input channel pair.");
+        return NULL;
+    }
+
+    // TODO more robust error checking
+    jobject serverChannelObj = android_view_InputChannel_createInputChannel(env,
+            new NativeInputChannel(serverChannel));
+    jobject clientChannelObj = android_view_InputChannel_createInputChannel(env,
+            new NativeInputChannel(clientChannel));
+
+    jobjectArray channelPair = env->NewObjectArray(2, gInputChannelClassInfo.clazz, NULL);
+    env->SetObjectArrayElement(channelPair, 0, serverChannelObj);
+    env->SetObjectArrayElement(channelPair, 1, clientChannelObj);
+    return channelPair;
+}
+
+static void android_view_InputChannel_nativeDispose(JNIEnv* env, jobject obj, jboolean finalized) {
+    NativeInputChannel* nativeInputChannel =
+            android_view_InputChannel_getNativeInputChannel(env, obj);
+    if (nativeInputChannel) {
+        if (finalized) {
+            LOGW("Input channel object '%s' was finalized without being disposed!",
+                    nativeInputChannel->getInputChannel()->getName().string());
+        }
+
+        nativeInputChannel->invokeAndRemoveDisposeCallback(env, obj);
+
+        android_view_InputChannel_setNativeInputChannel(env, obj, NULL);
+        delete nativeInputChannel;
+    }
+}
+
+static void android_view_InputChannel_nativeTransferTo(JNIEnv* env, jobject obj,
+        jobject otherObj) {
+    if (android_view_InputChannel_getInputChannel(env, otherObj) != NULL) {
+        jniThrowException(env, "java/lang/IllegalStateException",
+                "Other object already has a native input channel.");
+        return;
+    }
+
+    NativeInputChannel* nativeInputChannel =
+            android_view_InputChannel_getNativeInputChannel(env, obj);
+    android_view_InputChannel_setNativeInputChannel(env, otherObj, nativeInputChannel);
+    android_view_InputChannel_setNativeInputChannel(env, obj, NULL);
+}
+
+static void android_view_InputChannel_nativeReadFromParcel(JNIEnv* env, jobject obj,
+        jobject parcelObj) {
+    if (android_view_InputChannel_getInputChannel(env, obj) != NULL) {
+        jniThrowException(env, "java/lang/IllegalStateException",
+                "This object already has a native input channel.");
+        return;
+    }
+
+    Parcel* parcel = parcelForJavaObject(env, parcelObj);
+    if (parcel) {
+        bool isInitialized = parcel->readInt32();
+        if (isInitialized) {
+            String8 name = parcel->readString8();
+            int32_t ashmemFd = dup(parcel->readFileDescriptor());
+            int32_t receivePipeFd = dup(parcel->readFileDescriptor());
+            int32_t sendPipeFd = dup(parcel->readFileDescriptor());
+            if (ashmemFd < 0 || receivePipeFd < 0 || sendPipeFd < 0) {
+                if (ashmemFd >= 0) ::close(ashmemFd);
+                if (receivePipeFd >= 0) ::close(receivePipeFd);
+                if (sendPipeFd >= 0) ::close(sendPipeFd);
+                jniThrowRuntimeException(env,
+                        "Could not read input channel file descriptors from parcel.");
+                return;
+            }
+
+            InputChannel* inputChannel = new InputChannel(name, ashmemFd,
+                    receivePipeFd, sendPipeFd);
+            NativeInputChannel* nativeInputChannel = new NativeInputChannel(inputChannel);
+
+            android_view_InputChannel_setNativeInputChannel(env, obj, nativeInputChannel);
+        }
+    }
+}
+
+static void android_view_InputChannel_nativeWriteToParcel(JNIEnv* env, jobject obj,
+        jobject parcelObj) {
+    Parcel* parcel = parcelForJavaObject(env, parcelObj);
+    if (parcel) {
+        NativeInputChannel* nativeInputChannel =
+                android_view_InputChannel_getNativeInputChannel(env, obj);
+        if (nativeInputChannel) {
+            sp<InputChannel> inputChannel = nativeInputChannel->getInputChannel();
+
+            parcel->writeInt32(1);
+            parcel->writeString8(inputChannel->getName());
+            parcel->writeDupFileDescriptor(inputChannel->getAshmemFd());
+            parcel->writeDupFileDescriptor(inputChannel->getReceivePipeFd());
+            parcel->writeDupFileDescriptor(inputChannel->getSendPipeFd());
+        } else {
+            parcel->writeInt32(0);
+        }
+    }
+}
+
+static jstring android_view_InputChannel_nativeGetName(JNIEnv* env, jobject obj) {
+    NativeInputChannel* nativeInputChannel =
+            android_view_InputChannel_getNativeInputChannel(env, obj);
+    if (! nativeInputChannel) {
+        return NULL;
+    }
+
+    jstring name = env->NewStringUTF(nativeInputChannel->getInputChannel()->getName().string());
+    return name;
+}
+
+// ----------------------------------------------------------------------------
+
+static JNINativeMethod gInputChannelMethods[] = {
+    /* name, signature, funcPtr */
+    { "nativeOpenInputChannelPair", "(Ljava/lang/String;)[Landroid/view/InputChannel;",
+            (void*)android_view_InputChannel_nativeOpenInputChannelPair },
+    { "nativeDispose", "(Z)V",
+            (void*)android_view_InputChannel_nativeDispose },
+    { "nativeTransferTo", "(Landroid/view/InputChannel;)V",
+            (void*)android_view_InputChannel_nativeTransferTo },
+    { "nativeReadFromParcel", "(Landroid/os/Parcel;)V",
+            (void*)android_view_InputChannel_nativeReadFromParcel },
+    { "nativeWriteToParcel", "(Landroid/os/Parcel;)V",
+            (void*)android_view_InputChannel_nativeWriteToParcel },
+    { "nativeGetName", "()Ljava/lang/String;",
+            (void*)android_view_InputChannel_nativeGetName },
+};
+
+#define FIND_CLASS(var, className) \
+        var = env->FindClass(className); \
+        LOG_FATAL_IF(! var, "Unable to find class " className); \
+        var = jclass(env->NewGlobalRef(var));
+
+#define GET_METHOD_ID(var, clazz, methodName, methodDescriptor) \
+        var = env->GetMethodID(clazz, methodName, methodDescriptor); \
+        LOG_FATAL_IF(! var, "Unable to find method " methodName);
+
+#define GET_FIELD_ID(var, clazz, fieldName, fieldDescriptor) \
+        var = env->GetFieldID(clazz, fieldName, fieldDescriptor); \
+        LOG_FATAL_IF(! var, "Unable to find field " fieldName);
+
+int register_android_view_InputChannel(JNIEnv* env) {
+    int res = jniRegisterNativeMethods(env, "android/view/InputChannel",
+            gInputChannelMethods, NELEM(gInputChannelMethods));
+    LOG_FATAL_IF(res < 0, "Unable to register native methods.");
+
+    FIND_CLASS(gInputChannelClassInfo.clazz, "android/view/InputChannel");
+
+    GET_FIELD_ID(gInputChannelClassInfo.mPtr, gInputChannelClassInfo.clazz,
+            "mPtr", "I");
+    
+    GET_METHOD_ID(gInputChannelClassInfo.ctor, gInputChannelClassInfo.clazz,
+            "<init>", "()V");
+
+    return 0;
+}
+
+} // namespace android