camera2: Add camera client eviction enforcement.
- This updates the CameraService to implement client
eviction behavior based on process priority.
Bug: 19186859
Change-Id: I646939b1cdf1a2237c4e5044164d55a2542cf36e
diff --git a/services/camera/libcameraservice/utils/RingBuffer.h b/services/camera/libcameraservice/utils/RingBuffer.h
new file mode 100644
index 0000000..df7c00e
--- /dev/null
+++ b/services/camera/libcameraservice/utils/RingBuffer.h
@@ -0,0 +1,361 @@
+/*
+ * Copyright (C) 2015 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 ANDROID_SERVICE_UTILS_RING_BUFFER_H
+#define ANDROID_SERVICE_UTILS_RING_BUFFER_H
+
+#include <utils/Log.h>
+#include <cutils/compiler.h>
+
+#include <iterator>
+#include <utility>
+#include <vector>
+
+namespace android {
+
+/**
+ * A RingBuffer class that maintains an array of objects that can grow up to a certain size.
+ * Elements added to the RingBuffer are inserted in the logical front of the buffer, and
+ * invalidate all current iterators for that RingBuffer object.
+ */
+template <class T>
+class RingBuffer final {
+public:
+
+ /**
+ * Construct a RingBuffer that can grow up to the given length.
+ */
+ RingBuffer(size_t length);
+
+ /**
+ * Forward iterator to this class. Implements an std:forward_iterator.
+ */
+ class iterator : public std::iterator<std::forward_iterator_tag, T> {
+ public:
+ iterator(T* ptr, size_t size, size_t pos, size_t ctr);
+
+ iterator& operator++();
+
+ iterator operator++(int);
+
+ bool operator==(const iterator& rhs);
+
+ bool operator!=(const iterator& rhs);
+
+ T& operator*();
+
+ T* operator->();
+
+ private:
+ T* mPtr;
+ size_t mSize;
+ size_t mPos;
+ size_t mCtr;
+ };
+
+ /**
+ * Constant forward iterator to this class. Implements an std:forward_iterator.
+ */
+ class const_iterator : public std::iterator<std::forward_iterator_tag, T> {
+ public:
+ const_iterator(const T* ptr, size_t size, size_t pos, size_t ctr);
+
+ const_iterator& operator++();
+
+ const_iterator operator++(int);
+
+ bool operator==(const const_iterator& rhs);
+
+ bool operator!=(const const_iterator& rhs);
+
+ const T& operator*();
+
+ const T* operator->();
+
+ private:
+ const T* mPtr;
+ size_t mSize;
+ size_t mPos;
+ size_t mCtr;
+ };
+
+ /**
+ * Adds item to the front of this RingBuffer. If the RingBuffer is at its maximum length,
+ * this will result in the last element being replaced (this is done using the element's
+ * assignment operator).
+ *
+ * All current iterators are invalidated.
+ */
+ void add(const T& item);
+
+ /**
+ * Moves item to the front of this RingBuffer. Following a call to this, item should no
+ * longer be used. If the RingBuffer is at its maximum length, this will result in the
+ * last element being replaced (this is done using the element's assignment operator).
+ *
+ * All current iterators are invalidated.
+ */
+ void add(T&& item);
+
+ /**
+ * Construct item in-place in the front of this RingBuffer using the given arguments. If
+ * the RingBuffer is at its maximum length, this will result in the last element being
+ * replaced (this is done using the element's assignment operator).
+ *
+ * All current iterators are invalidated.
+ */
+ template <class... Args>
+ void emplace(Args&&... args);
+
+ /**
+ * Get an iterator to the front of this RingBuffer.
+ */
+ iterator begin();
+
+ /**
+ * Get an iterator to the end of this RingBuffer.
+ */
+ iterator end();
+
+ /**
+ * Get a const_iterator to the front of this RingBuffer.
+ */
+ const_iterator begin() const;
+
+ /**
+ * Get a const_iterator to the end of this RingBuffer.
+ */
+ const_iterator end() const;
+
+ /**
+ * Return a reference to the element at a given index. If the index is out of range for
+ * this ringbuffer, [0, size), the behavior for this is undefined.
+ */
+ T& operator[](size_t index);
+
+ /**
+ * Return a const reference to the element at a given index. If the index is out of range
+ * for this ringbuffer, [0, size), the behavior for this is undefined.
+ */
+ const T& operator[](size_t index) const;
+
+ /**
+ * Return the current size of this RingBuffer.
+ */
+ size_t size() const;
+
+ /**
+ * Remove all elements from this RingBuffer and set the size to 0.
+ */
+ void clear();
+
+private:
+ size_t mFrontIdx;
+ size_t mMaxBufferSize;
+ std::vector<T> mBuffer;
+}; // class RingBuffer
+
+
+template <class T>
+RingBuffer<T>::RingBuffer(size_t length) : mFrontIdx{0}, mMaxBufferSize{length} {}
+
+template <class T>
+RingBuffer<T>::iterator::iterator(T* ptr, size_t size, size_t pos, size_t ctr) :
+ mPtr{ptr}, mSize{size}, mPos{pos}, mCtr{ctr} {}
+
+template <class T>
+typename RingBuffer<T>::iterator& RingBuffer<T>::iterator::operator++() {
+ ++mCtr;
+
+ if (CC_UNLIKELY(mCtr == mSize)) {
+ mPos = mSize;
+ return *this;
+ }
+
+ mPos = ((CC_UNLIKELY(mPos == 0)) ? mSize - 1 : mPos - 1);
+ return *this;
+}
+
+template <class T>
+typename RingBuffer<T>::iterator RingBuffer<T>::iterator::operator++(int) {
+ iterator tmp{mPtr, mSize, mPos, mCtr};
+ ++(*this);
+ return tmp;
+}
+
+template <class T>
+bool RingBuffer<T>::iterator::operator==(const iterator& rhs) {
+ return (mPtr + mPos) == (rhs.mPtr + rhs.mPos);
+}
+
+template <class T>
+bool RingBuffer<T>::iterator::operator!=(const iterator& rhs) {
+ return (mPtr + mPos) != (rhs.mPtr + rhs.mPos);
+}
+
+template <class T>
+T& RingBuffer<T>::iterator::operator*() {
+ return *(mPtr + mPos);
+}
+
+template <class T>
+T* RingBuffer<T>::iterator::operator->() {
+ return mPtr + mPos;
+}
+
+template <class T>
+RingBuffer<T>::const_iterator::const_iterator(const T* ptr, size_t size, size_t pos, size_t ctr) :
+ mPtr{ptr}, mSize{size}, mPos{pos}, mCtr{ctr} {}
+
+template <class T>
+typename RingBuffer<T>::const_iterator& RingBuffer<T>::const_iterator::operator++() {
+ ++mCtr;
+
+ if (CC_UNLIKELY(mCtr == mSize)) {
+ mPos = mSize;
+ return *this;
+ }
+
+ mPos = ((CC_UNLIKELY(mPos == 0)) ? mSize - 1 : mPos - 1);
+ return *this;
+}
+
+template <class T>
+typename RingBuffer<T>::const_iterator RingBuffer<T>::const_iterator::operator++(int) {
+ const_iterator tmp{mPtr, mSize, mPos, mCtr};
+ ++(*this);
+ return tmp;
+}
+
+template <class T>
+bool RingBuffer<T>::const_iterator::operator==(const const_iterator& rhs) {
+ return (mPtr + mPos) == (rhs.mPtr + rhs.mPos);
+}
+
+template <class T>
+bool RingBuffer<T>::const_iterator::operator!=(const const_iterator& rhs) {
+ return (mPtr + mPos) != (rhs.mPtr + rhs.mPos);
+}
+
+template <class T>
+const T& RingBuffer<T>::const_iterator::operator*() {
+ return *(mPtr + mPos);
+}
+
+template <class T>
+const T* RingBuffer<T>::const_iterator::operator->() {
+ return mPtr + mPos;
+}
+
+template <class T>
+void RingBuffer<T>::add(const T& item) {
+ if (mBuffer.size() < mMaxBufferSize) {
+ mBuffer.push_back(item);
+ mFrontIdx = ((mFrontIdx + 1) % mMaxBufferSize);
+ return;
+ }
+
+ mBuffer[mFrontIdx] = item;
+ mFrontIdx = ((mFrontIdx + 1) % mMaxBufferSize);
+}
+
+template <class T>
+void RingBuffer<T>::add(T&& item) {
+ if (mBuffer.size() != mMaxBufferSize) {
+ mBuffer.push_back(std::forward<T>(item));
+ mFrontIdx = ((mFrontIdx + 1) % mMaxBufferSize);
+ return;
+ }
+
+ // Only works for types with move assignment operator
+ mBuffer[mFrontIdx] = std::forward<T>(item);
+ mFrontIdx = ((mFrontIdx + 1) % mMaxBufferSize);
+}
+
+template <class T>
+template <class... Args>
+void RingBuffer<T>::emplace(Args&&... args) {
+ if (mBuffer.size() != mMaxBufferSize) {
+ mBuffer.emplace_back(std::forward<Args>(args)...);
+ mFrontIdx = ((mFrontIdx + 1) % mMaxBufferSize);
+ return;
+ }
+
+ // Only works for types with move assignment operator
+ mBuffer[mFrontIdx] = T(std::forward<Args>(args)...);
+ mFrontIdx = ((mFrontIdx + 1) % mMaxBufferSize);
+}
+
+template <class T>
+typename RingBuffer<T>::iterator RingBuffer<T>::begin() {
+ size_t tmp = (mBuffer.size() == 0) ? 0 : mBuffer.size() - 1;
+ return iterator(mBuffer.data(), mBuffer.size(), (mFrontIdx == 0) ? tmp : mFrontIdx - 1, 0);
+}
+
+template <class T>
+typename RingBuffer<T>::iterator RingBuffer<T>::end() {
+ size_t s = mBuffer.size();
+ return iterator(mBuffer.data(), s, s, s);
+}
+
+template <class T>
+typename RingBuffer<T>::const_iterator RingBuffer<T>::begin() const {
+ size_t tmp = (mBuffer.size() == 0) ? 0 : mBuffer.size() - 1;
+ return const_iterator(mBuffer.data(), mBuffer.size(),
+ (mFrontIdx == 0) ? tmp : mFrontIdx - 1, 0);
+}
+
+template <class T>
+typename RingBuffer<T>::const_iterator RingBuffer<T>::end() const {
+ size_t s = mBuffer.size();
+ return const_iterator(mBuffer.data(), s, s, s);
+}
+
+template <class T>
+T& RingBuffer<T>::operator[](size_t index) {
+ LOG_ALWAYS_FATAL_IF(index >= mBuffer.size(), "Index %zu out of bounds, size is %zu.",
+ index, mBuffer.size());
+ size_t pos = (index >= mFrontIdx) ?
+ mBuffer.size() - 1 - (index - mFrontIdx) : mFrontIdx - 1 - index;
+ return mBuffer[pos];
+}
+
+template <class T>
+const T& RingBuffer<T>::operator[](size_t index) const {
+ LOG_ALWAYS_FATAL_IF(index >= mBuffer.size(), "Index %zu out of bounds, size is %zu.",
+ index, mBuffer.size());
+ size_t pos = (index >= mFrontIdx) ?
+ mBuffer.size() - 1 - (index - mFrontIdx) : mFrontIdx - 1 - index;
+ return mBuffer[pos];
+}
+
+template <class T>
+size_t RingBuffer<T>::size() const {
+ return mBuffer.size();
+}
+
+template <class T>
+void RingBuffer<T>::clear() {
+ mBuffer.clear();
+ mFrontIdx = 0;
+}
+
+}; // namespace android
+
+#endif // ANDROID_SERVICE_UTILS_RING_BUFFER_H
+
+