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/AutoConditionLock.h b/services/camera/libcameraservice/utils/AutoConditionLock.h
new file mode 100644
index 0000000..9a3eafc
--- /dev/null
+++ b/services/camera/libcameraservice/utils/AutoConditionLock.h
@@ -0,0 +1,99 @@
+/*
+ * 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_SCOPED_CONDITION_H
+#define ANDROID_SERVICE_UTILS_SCOPED_CONDITION_H
+
+#include <utils/Timers.h>
+#include <utils/Condition.h>
+#include <utils/Errors.h>
+#include <utils/Mutex.h>
+
+#include <memory>
+
+namespace android {
+
+/**
+ * WaitableMutexWrapper can be used with AutoConditionLock to construct scoped locks for the
+ * wrapped Mutex with timeouts for lock acquisition.
+ */
+class WaitableMutexWrapper {
+ friend class AutoConditionLock;
+public:
+ /**
+ * Construct the ConditionManger with the given Mutex.
+ */
+ WaitableMutexWrapper(Mutex* mutex);
+
+ virtual ~WaitableMutexWrapper();
+private:
+ Mutex* mMutex;
+ bool mState;
+ Condition mCondition;
+};
+
+/**
+ * AutoConditionLock is a scoped lock similar to Mutex::Autolock, but allows timeouts to be
+ * specified for lock acquisition.
+ *
+ * AutoConditionLock is used with a WaitableMutexWrapper to lock/unlock the WaitableMutexWrapper's
+ * wrapped Mutex, and wait/set/signal the WaitableMutexWrapper's wrapped condition. To use this,
+ * call AutoConditionLock::waitAndAcquire to get an instance. This will:
+ * - Lock the given WaitableMutexWrapper's mutex.
+ * - Wait for the WaitableMutexWrapper's condition to become false, or timeout.
+ * - Set the WaitableMutexWrapper's condition to true.
+ *
+ * When the AutoConditionLock goes out of scope and is destroyed, this will:
+ * - Set the WaitableMutexWrapper's condition to false.
+ * - Signal threads waiting on this condition to wakeup.
+ * - Release WaitableMutexWrapper's mutex.
+ */
+class AutoConditionLock final {
+public:
+ AutoConditionLock() = delete;
+ AutoConditionLock(const AutoConditionLock& other) = delete;
+ AutoConditionLock & operator=(const AutoConditionLock&) = delete;
+
+ ~AutoConditionLock();
+
+ /**
+ * Make a new AutoConditionLock from a given WaitableMutexWrapper, waiting up to waitTime
+ * nanoseconds to acquire the WaitableMutexWrapper's wrapped lock.
+ *
+ * Return an empty unique_ptr if this fails, or a timeout occurs.
+ */
+ static std::unique_ptr<AutoConditionLock> waitAndAcquire(
+ const std::shared_ptr<WaitableMutexWrapper>& manager, nsecs_t waitTime);
+
+ /**
+ * Make a new AutoConditionLock from a given WaitableMutexWrapper, waiting indefinitely to
+ * acquire the WaitableMutexWrapper's wrapped lock.
+ *
+ * Return an empty unique_ptr if this fails.
+ */
+ static std::unique_ptr<AutoConditionLock> waitAndAcquire(
+ const std::shared_ptr<WaitableMutexWrapper>& manager);
+private:
+ AutoConditionLock(const std::shared_ptr<WaitableMutexWrapper>& manager);
+
+ std::shared_ptr<WaitableMutexWrapper> mManager;
+ Mutex::Autolock mAutoLock;
+};
+
+}; // namespace android
+
+#endif // ANDROID_SERVICE_UTILS_SCOPED_CONDITION_H