split libsensor our of libgui 

Test: compile & run
Bug: treble cleanup
Change-Id: I5b2c2a14f7d3b364d25695cf0901c5b08cfb0fc9
diff --git a/libs/sensor/BitTube.cpp b/libs/sensor/BitTube.cpp
new file mode 100644
index 0000000..93555c8
--- /dev/null
+++ b/libs/sensor/BitTube.cpp
@@ -0,0 +1,174 @@
+/*
+ * 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.
+ */
+
+#include <sensor/BitTube.h>
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <binder/Parcel.h>
+
+namespace android {
+// ----------------------------------------------------------------------------
+
+// Socket buffer size.  The default is typically about 128KB, which is much larger than
+// we really need.  So we make it smaller.
+static const size_t DEFAULT_SOCKET_BUFFER_SIZE = 4 * 1024;
+
+
+BitTube::BitTube()
+    : mSendFd(-1), mReceiveFd(-1)
+{
+    init(DEFAULT_SOCKET_BUFFER_SIZE, DEFAULT_SOCKET_BUFFER_SIZE);
+}
+
+BitTube::BitTube(size_t bufsize)
+    : mSendFd(-1), mReceiveFd(-1)
+{
+    init(bufsize, bufsize);
+}
+
+BitTube::BitTube(const Parcel& data)
+    : mSendFd(-1), mReceiveFd(-1)
+{
+    mReceiveFd = dup(data.readFileDescriptor());
+    if (mReceiveFd < 0) {
+        mReceiveFd = -errno;
+        ALOGE("BitTube(Parcel): can't dup filedescriptor (%s)",
+                strerror(-mReceiveFd));
+    }
+}
+
+BitTube::~BitTube()
+{
+    if (mSendFd >= 0)
+        close(mSendFd);
+
+    if (mReceiveFd >= 0)
+        close(mReceiveFd);
+}
+
+void BitTube::init(size_t rcvbuf, size_t sndbuf) {
+    int sockets[2];
+    if (socketpair(AF_UNIX, SOCK_SEQPACKET, 0, sockets) == 0) {
+        size_t size = DEFAULT_SOCKET_BUFFER_SIZE;
+        setsockopt(sockets[0], SOL_SOCKET, SO_RCVBUF, &rcvbuf, sizeof(rcvbuf));
+        setsockopt(sockets[1], SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf));
+        // sine we don't use the "return channel", we keep it small...
+        setsockopt(sockets[0], SOL_SOCKET, SO_SNDBUF, &size, sizeof(size));
+        setsockopt(sockets[1], SOL_SOCKET, SO_RCVBUF, &size, sizeof(size));
+        fcntl(sockets[0], F_SETFL, O_NONBLOCK);
+        fcntl(sockets[1], F_SETFL, O_NONBLOCK);
+        mReceiveFd = sockets[0];
+        mSendFd = sockets[1];
+    } else {
+        mReceiveFd = -errno;
+        ALOGE("BitTube: pipe creation failed (%s)", strerror(-mReceiveFd));
+    }
+}
+
+status_t BitTube::initCheck() const
+{
+    if (mReceiveFd < 0) {
+        return status_t(mReceiveFd);
+    }
+    return NO_ERROR;
+}
+
+int BitTube::getFd() const
+{
+    return mReceiveFd;
+}
+
+int BitTube::getSendFd() const
+{
+    return mSendFd;
+}
+
+ssize_t BitTube::write(void const* vaddr, size_t size)
+{
+    ssize_t err, len;
+    do {
+        len = ::send(mSendFd, vaddr, size, MSG_DONTWAIT | MSG_NOSIGNAL);
+        // cannot return less than size, since we're using SOCK_SEQPACKET
+        err = len < 0 ? errno : 0;
+    } while (err == EINTR);
+    return err == 0 ? len : -err;
+}
+
+ssize_t BitTube::read(void* vaddr, size_t size)
+{
+    ssize_t err, len;
+    do {
+        len = ::recv(mReceiveFd, vaddr, size, MSG_DONTWAIT);
+        err = len < 0 ? errno : 0;
+    } while (err == EINTR);
+    if (err == EAGAIN || err == EWOULDBLOCK) {
+        // EAGAIN means that we have non-blocking I/O but there was
+        // no data to be read. Nothing the client should care about.
+        return 0;
+    }
+    return err == 0 ? len : -err;
+}
+
+status_t BitTube::writeToParcel(Parcel* reply) const
+{
+    if (mReceiveFd < 0)
+        return -EINVAL;
+
+    status_t result = reply->writeDupFileDescriptor(mReceiveFd);
+    close(mReceiveFd);
+    mReceiveFd = -1;
+    return result;
+}
+
+
+ssize_t BitTube::sendObjects(const sp<BitTube>& tube,
+        void const* events, size_t count, size_t objSize)
+{
+    const char* vaddr = reinterpret_cast<const char*>(events);
+    ssize_t size = tube->write(vaddr, count*objSize);
+
+    // should never happen because of SOCK_SEQPACKET
+    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
+            "BitTube::sendObjects(count=%zu, size=%zu), res=%zd (partial events were sent!)",
+            count, objSize, size);
+
+    //ALOGE_IF(size<0, "error %d sending %d events", size, count);
+    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
+}
+
+ssize_t BitTube::recvObjects(const sp<BitTube>& tube,
+        void* events, size_t count, size_t objSize)
+{
+    char* vaddr = reinterpret_cast<char*>(events);
+    ssize_t size = tube->read(vaddr, count*objSize);
+
+    // should never happen because of SOCK_SEQPACKET
+    LOG_ALWAYS_FATAL_IF((size >= 0) && (size % static_cast<ssize_t>(objSize)),
+            "BitTube::recvObjects(count=%zu, size=%zu), res=%zd (partial events were received!)",
+            count, objSize, size);
+
+    //ALOGE_IF(size<0, "error %d receiving %d events", size, count);
+    return size < 0 ? size : size / static_cast<ssize_t>(objSize);
+}
+
+// ----------------------------------------------------------------------------
+}; // namespace android