Add template class SingleStateQueue
Change-Id: If7e2bc9b2a216524ee9cbb68682e2634933b4973
diff --git a/include/media/SingleStateQueue.h b/include/media/SingleStateQueue.h
new file mode 100644
index 0000000..04c5fd0
--- /dev/null
+++ b/include/media/SingleStateQueue.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#ifndef SINGLE_STATE_QUEUE_H
+#define SINGLE_STATE_QUEUE_H
+
+// Non-blocking single element state queue, or
+// Non-blocking single-reader / single-writer multi-word atomic load / store
+
+#include <stdint.h>
+
+namespace android {
+
+template<typename T> class SingleStateQueue {
+
+public:
+
+ class Mutator;
+ class Observer;
+
+ struct Shared {
+ // needs to be part of a union so don't define constructor or destructor
+
+ friend class Mutator;
+ friend class Observer;
+
+private:
+ void init() { mAck = 0; mSequence = 0; }
+
+ volatile int32_t mAck;
+#if 0
+ int mPad[7];
+ // cache line boundary
+#endif
+ volatile int32_t mSequence;
+ T mValue;
+ };
+
+ class Mutator {
+ public:
+ Mutator(Shared *shared);
+ /*virtual*/ ~Mutator() { }
+
+ // push new value onto state queue, overwriting previous value;
+ // returns a sequence number which can be used with ack()
+ int32_t push(const T& value);
+
+ // return true if most recent push has been observed
+ bool ack();
+
+ // return true if a push with specified sequence number or later has been observed
+ bool ack(int32_t sequence);
+
+ private:
+ int32_t mSequence;
+ Shared * const mShared;
+ };
+
+ class Observer {
+ public:
+ Observer(Shared *shared);
+ /*virtual*/ ~Observer() { }
+
+ // return true if value has changed
+ bool poll(T& value);
+
+ private:
+ int32_t mSequence;
+ int mSeed; // for PRNG
+ Shared * const mShared;
+ };
+
+#if 0
+ SingleStateQueue(void /*Shared*/ *shared);
+ /*virtual*/ ~SingleStateQueue() { }
+
+ static size_t size() { return sizeof(Shared); }
+#endif
+
+};
+
+} // namespace android
+
+#endif // SINGLE_STATE_QUEUE_H
diff --git a/include/private/media/StaticAudioTrackState.h b/include/private/media/StaticAudioTrackState.h
new file mode 100644
index 0000000..46a5946
--- /dev/null
+++ b/include/private/media/StaticAudioTrackState.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#ifndef STATIC_AUDIO_TRACK_STATE_H
+#define STATIC_AUDIO_TRACK_STATE_H
+
+namespace android {
+
+// Represents a single state of an AudioTrack that was created in static mode (shared memory buffer
+// supplied by the client). This state needs to be communicated from the client to server. As this
+// state is too large to be updated atomically without a mutex, and mutexes aren't allowed here, the
+// state is wrapped by a SingleStateQueue.
+struct StaticAudioTrackState {
+ // do not define constructors, destructors, or virtual methods
+ size_t mLoopStart;
+ size_t mLoopEnd;
+ int mLoopCount;
+};
+
+} // namespace android
+
+#endif // STATIC_AUDIO_TRACK_STATE_H
diff --git a/media/libmedia/Android.mk b/media/libmedia/Android.mk
index 52fa3e1..6b48991 100644
--- a/media/libmedia/Android.mk
+++ b/media/libmedia/Android.mk
@@ -53,6 +53,13 @@
SoundPool.cpp \
SoundPoolThread.cpp
+LOCAL_SRC_FILES += ../libnbaio/roundup.c
+
+# for <cutils/atomic-inline.h>
+LOCAL_CFLAGS += -DANDROID_SMP=$(if $(findstring true,$(TARGET_CPU_SMP)),1,0)
+LOCAL_SRC_FILES += SingleStateQueue.cpp
+LOCAL_CFLAGS += -DSINGLE_STATE_QUEUE_INSTANTIATIONS='"SingleStateQueueInstantiations.cpp"'
+
LOCAL_SHARED_LIBRARIES := \
libui libcutils libutils libbinder libsonivox libicuuc libexpat \
libcamera_client libstagefright_foundation \
diff --git a/media/libmedia/SingleStateQueue.cpp b/media/libmedia/SingleStateQueue.cpp
new file mode 100644
index 0000000..3503baa
--- /dev/null
+++ b/media/libmedia/SingleStateQueue.cpp
@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2012 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 <new>
+#include <cutils/atomic.h>
+#include <cutils/atomic-inline.h> // for android_memory_barrier()
+#include <media/SingleStateQueue.h>
+
+namespace android {
+
+template<typename T> SingleStateQueue<T>::Mutator::Mutator(Shared *shared)
+ : mSequence(0), mShared((Shared *) shared)
+{
+ // exactly one of Mutator and Observer must initialize, currently it is Observer
+ //shared->init();
+}
+
+template<typename T> int32_t SingleStateQueue<T>::Mutator::push(const T& value)
+{
+ Shared *shared = mShared;
+ int32_t sequence = mSequence;
+ sequence++;
+ android_atomic_acquire_store(sequence, &shared->mSequence);
+ shared->mValue = value;
+ sequence++;
+ android_atomic_release_store(sequence, &shared->mSequence);
+ mSequence = sequence;
+ // consider signalling a futex here, if we know that observer is waiting
+ return sequence;
+}
+
+template<typename T> bool SingleStateQueue<T>::Mutator::ack()
+{
+ return mShared->mAck - mSequence == 0;
+}
+
+template<typename T> bool SingleStateQueue<T>::Mutator::ack(int32_t sequence)
+{
+ // this relies on 2's complement rollover to detect an ancient sequence number
+ return mShared->mAck - sequence >= 0;
+}
+
+template<typename T> SingleStateQueue<T>::Observer::Observer(Shared *shared)
+ : mSequence(0), mSeed(1), mShared((Shared *) shared)
+{
+ // exactly one of Mutator and Observer must initialize, currently it is Observer
+ shared->init();
+}
+
+template<typename T> bool SingleStateQueue<T>::Observer::poll(T& value)
+{
+ Shared *shared = mShared;
+ int32_t before = shared->mSequence;
+ if (before == mSequence) {
+ return false;
+ }
+ for (int tries = 0; ; ) {
+ const int MAX_TRIES = 5;
+ if (before & 1) {
+ if (++tries >= MAX_TRIES) {
+ return false;
+ }
+ before = shared->mSequence;
+ } else {
+ android_memory_barrier();
+ T temp = shared->mValue;
+ int32_t after = android_atomic_release_load(&shared->mSequence);
+ if (after == before) {
+ value = temp;
+ shared->mAck = before;
+ mSequence = before;
+ return true;
+ }
+ if (++tries >= MAX_TRIES) {
+ return false;
+ }
+ before = after;
+ }
+ }
+}
+
+#if 0
+template<typename T> SingleStateQueue<T>::SingleStateQueue(void /*Shared*/ *shared)
+{
+ ((Shared *) shared)->init();
+}
+#endif
+
+} // namespace android
+
+// hack for gcc
+#ifdef SINGLE_STATE_QUEUE_INSTANTIATIONS
+#include SINGLE_STATE_QUEUE_INSTANTIATIONS
+#endif
diff --git a/media/libmedia/SingleStateQueueInstantiations.cpp b/media/libmedia/SingleStateQueueInstantiations.cpp
new file mode 100644
index 0000000..2afebe9
--- /dev/null
+++ b/media/libmedia/SingleStateQueueInstantiations.cpp
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2012 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 <media/SingleStateQueue.h>
+#include <private/media/StaticAudioTrackState.h>
+
+// FIXME hack for gcc
+
+namespace android {
+
+template class SingleStateQueue<StaticAudioTrackState>; // typedef StaticAudioTrackSingleStateQueue
+
+}
diff --git a/services/audioflinger/Android.mk b/services/audioflinger/Android.mk
index 7daef99..7806f48 100644
--- a/services/audioflinger/Android.mk
+++ b/services/audioflinger/Android.mk
@@ -104,5 +104,4 @@
include $(BUILD_EXECUTABLE)
-
include $(call all-makefiles-under,$(LOCAL_PATH))