replicant-frameworks_native/include/private/surfaceflinger/SharedBufferStack.h
Mathias Agopian b296533607 cleanup. waitForCondition() now uses polymorphsim instead of templtes
the reason for the above change is that waitForCondition() had become
large over time, mainly to handle error cases, using inlines to
evaluate the condition doesn't buys us much anymore while it increases
code size.

Change-Id: I2595d850832628954b900ab8bb1796c863447bc7
2010-04-28 16:12:54 -07:00

336 lines
9.6 KiB
C++

/*
* Copyright (C) 2007 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_SF_SHARED_BUFFER_STACK_H
#define ANDROID_SF_SHARED_BUFFER_STACK_H
#include <stdint.h>
#include <sys/types.h>
#include <cutils/compiler.h>
#include <utils/Debug.h>
#include <utils/threads.h>
#include <utils/String8.h>
#include <ui/Rect.h>
namespace android {
// ---------------------------------------------------------------------------
/*
* These classes manage a stack of buffers in shared memory.
*
* SharedClient: represents a client with several stacks
* SharedBufferStack: represents a stack of buffers
* SharedBufferClient: manipulates the SharedBufferStack from the client side
* SharedBufferServer: manipulates the SharedBufferStack from the server side
*
* Buffers can be dequeued until there are none available, they can be locked
* unless they are in use by the server, which is only the case for the last
* dequeue-able buffer. When these various conditions are not met, the caller
* waits until the condition is met.
*
*
* CAVEATS:
*
* In the current implementation there are several limitations:
* - buffers must be locked in the same order they've been dequeued
* - buffers must be enqueued in the same order they've been locked
* - dequeue() is not reentrant
* - no error checks are done on the condition above
*
*/
// When changing these values, the COMPILE_TIME_ASSERT at the end of this
// file need to be updated.
const unsigned int NUM_LAYERS_MAX = 31;
const unsigned int NUM_BUFFER_MAX = 16;
const unsigned int NUM_DISPLAY_MAX = 4;
// ----------------------------------------------------------------------------
class Region;
class SharedBufferStack;
class SharedClient;
// ----------------------------------------------------------------------------
// 4 * (11 + 7 + (1 + 2*NUM_RECT_MAX) * NUM_BUFFER_MAX) * NUM_LAYERS_MAX
// 4 * (11 + 7 + (1 + 2*7)*16) * 31
// 1032 * 31
// = ~27 KiB (31992)
class SharedBufferStack
{
friend class SharedClient;
friend class SharedBufferBase;
friend class SharedBufferClient;
friend class SharedBufferServer;
public:
struct Statistics { // 4 longs
typedef int32_t usecs_t;
usecs_t totalTime;
usecs_t reserved[3];
};
struct SmallRect {
uint16_t l, t, r, b;
};
struct FlatRegion { // 52 bytes = 4 * (1 + 2*N)
static const unsigned int NUM_RECT_MAX = 6;
uint32_t count;
SmallRect rects[NUM_RECT_MAX];
};
struct BufferData {
FlatRegion dirtyRegion;
SmallRect crop;
};
SharedBufferStack();
void init(int32_t identity);
status_t setDirtyRegion(int buffer, const Region& reg);
status_t setCrop(int buffer, const Rect& reg);
Region getDirtyRegion(int buffer) const;
// these attributes are part of the conditions/updates
volatile int32_t head; // server's current front buffer
volatile int32_t available; // number of dequeue-able buffers
volatile int32_t queued; // number of buffers waiting for post
volatile int32_t inUse; // buffer currently in use by SF
volatile status_t status; // surface's status code
// not part of the conditions
volatile int32_t reallocMask;
int32_t identity; // surface's identity (const)
int32_t reserved32[6];
Statistics stats;
int32_t reserved;
BufferData buffers[NUM_BUFFER_MAX]; // 960 bytes
};
// ----------------------------------------------------------------------------
// 4 KB max
class SharedClient
{
public:
SharedClient();
~SharedClient();
status_t validate(size_t token) const;
uint32_t getIdentity(size_t token) const;
private:
friend class SharedBufferBase;
friend class SharedBufferClient;
friend class SharedBufferServer;
// FIXME: this should be replaced by a lock-less primitive
Mutex lock;
Condition cv;
SharedBufferStack surfaces[ NUM_LAYERS_MAX ];
};
// ============================================================================
class SharedBufferBase
{
public:
SharedBufferBase(SharedClient* sharedClient, int surface, int num,
int32_t identity);
~SharedBufferBase();
uint32_t getIdentity();
status_t getStatus() const;
size_t getFrontBuffer() const;
String8 dump(char const* prefix) const;
protected:
SharedClient* const mSharedClient;
SharedBufferStack* const mSharedStack;
const int mNumBuffers;
const int mIdentity;
int32_t computeTail() const;
friend struct Update;
friend struct QueueUpdate;
struct ConditionBase {
SharedBufferStack& stack;
inline ConditionBase(SharedBufferBase* sbc)
: stack(*sbc->mSharedStack) { }
virtual ~ConditionBase() { };
virtual bool operator()() const = 0;
virtual const char* name() const = 0;
};
status_t waitForCondition(const ConditionBase& condition);
struct UpdateBase {
SharedBufferStack& stack;
inline UpdateBase(SharedBufferBase* sbb)
: stack(*sbb->mSharedStack) { }
};
template <typename T>
status_t updateCondition(T update);
};
template <typename T>
status_t SharedBufferBase::updateCondition(T update) {
SharedClient& client( *mSharedClient );
Mutex::Autolock _l(client.lock);
ssize_t result = update();
client.cv.broadcast();
return result;
}
// ----------------------------------------------------------------------------
class SharedBufferClient : public SharedBufferBase
{
public:
SharedBufferClient(SharedClient* sharedClient, int surface, int num,
int32_t identity);
ssize_t dequeue();
status_t undoDequeue(int buf);
status_t lock(int buf);
status_t queue(int buf);
bool needNewBuffer(int buffer) const;
status_t setDirtyRegion(int buffer, const Region& reg);
status_t setCrop(int buffer, const Rect& reg);
private:
friend struct Condition;
friend struct DequeueCondition;
friend struct LockCondition;
struct QueueUpdate : public UpdateBase {
inline QueueUpdate(SharedBufferBase* sbb);
inline ssize_t operator()();
};
struct UndoDequeueUpdate : public UpdateBase {
inline UndoDequeueUpdate(SharedBufferBase* sbb);
inline ssize_t operator()();
};
// --
struct DequeueCondition : public ConditionBase {
inline DequeueCondition(SharedBufferClient* sbc);
inline bool operator()() const;
inline const char* name() const { return "DequeueCondition"; }
};
struct LockCondition : public ConditionBase {
int buf;
inline LockCondition(SharedBufferClient* sbc, int buf);
inline bool operator()() const;
inline const char* name() const { return "LockCondition"; }
};
int32_t tail;
int32_t undoDequeueTail;
// statistics...
nsecs_t mDequeueTime[NUM_BUFFER_MAX];
};
// ----------------------------------------------------------------------------
class SharedBufferServer : public SharedBufferBase
{
public:
SharedBufferServer(SharedClient* sharedClient, int surface, int num,
int32_t identity);
ssize_t retireAndLock();
status_t unlock(int buffer);
void setStatus(status_t status);
status_t reallocate();
status_t assertReallocate(int buffer);
int32_t getQueuedCount() const;
Region getDirtyRegion(int buffer) const;
SharedBufferStack::Statistics getStats() const;
private:
struct UnlockUpdate : public UpdateBase {
const int lockedBuffer;
inline UnlockUpdate(SharedBufferBase* sbb, int lockedBuffer);
inline ssize_t operator()();
};
struct RetireUpdate : public UpdateBase {
const int numBuffers;
inline RetireUpdate(SharedBufferBase* sbb, int numBuffers);
inline ssize_t operator()();
};
struct StatusUpdate : public UpdateBase {
const status_t status;
inline StatusUpdate(SharedBufferBase* sbb, status_t status);
inline ssize_t operator()();
};
struct ReallocateCondition : public ConditionBase {
int buf;
inline ReallocateCondition(SharedBufferBase* sbb, int buf);
inline bool operator()() const;
inline const char* name() const { return "ReallocateCondition"; }
};
};
// ===========================================================================
struct display_cblk_t
{
uint16_t w;
uint16_t h;
uint8_t format;
uint8_t orientation;
uint8_t reserved[2];
float fps;
float density;
float xdpi;
float ydpi;
uint32_t pad[2];
};
struct surface_flinger_cblk_t // 4KB max
{
uint8_t connected;
uint8_t reserved[3];
uint32_t pad[7];
display_cblk_t displays[NUM_DISPLAY_MAX];
};
// ---------------------------------------------------------------------------
COMPILE_TIME_ASSERT(sizeof(SharedClient) <= 32768)
COMPILE_TIME_ASSERT(sizeof(surface_flinger_cblk_t) <= 4096)
// ---------------------------------------------------------------------------
}; // namespace android
#endif /* ANDROID_SF_SHARED_BUFFER_STACK_H */