/*
|
* =====================================================================================
|
*
|
* Filename: robust.h
|
*
|
* Description:
|
*
|
* Version: 1.0
|
* Created: 2021年04月27日 10时04分29秒
|
* Revision: none
|
* Compiler: gcc
|
*
|
* Author: Li Chao (), lichao@aiotlink.com
|
* Organization:
|
*
|
* =====================================================================================
|
*/
|
|
#ifndef ROBUST_Q31RCWYU
|
#define ROBUST_Q31RCWYU
|
|
#include "log.h"
|
#include <atomic>
|
#include <chrono>
|
#include <memory>
|
#include <string.h>
|
#include <string>
|
#include <sys/types.h>
|
#include <unistd.h>
|
|
namespace robust
|
{
|
|
using namespace std::chrono;
|
using namespace std::chrono_literals;
|
constexpr uint64_t MaskBits(int nbits) { return (uint64_t(1) << nbits) - 1; }
|
|
void QuickSleep();
|
|
class RobustReqRep
|
{
|
typedef uint32_t State;
|
typedef std::string Msg;
|
typedef std::chrono::steady_clock::duration Duration;
|
|
public:
|
enum ErrorCode {
|
eSuccess = 0,
|
eTimeout = EAGAIN,
|
eSizeError = EINVAL,
|
};
|
|
explicit RobustReqRep(const uint32_t max_len) :
|
capacity_(max_len), state_(eStateInit), timestamp_(Duration(0)), size_(0) {}
|
|
void PutReady() { state_.store(eStateReady); }
|
bool Ready() const { return state_.load() == eStateReady; }
|
uint32_t capacity() const { return capacity_; }
|
|
int ClientRequest(const Msg &request, Msg &reply)
|
{
|
int r = ClientWriteRequest(request);
|
if (r == eSuccess) {
|
r = ClientReadReply(reply);
|
}
|
return r;
|
}
|
int ClientReadReply(Msg &reply);
|
int ClientWriteRequest(const Msg &request);
|
int ServerReadRequest(Msg &request);
|
int ServerWriteReply(const Msg &reply);
|
|
private:
|
RobustReqRep(const RobustReqRep &);
|
RobustReqRep(RobustReqRep &&);
|
RobustReqRep &operator=(const RobustReqRep &) = delete;
|
RobustReqRep &operator=(RobustReqRep &&) = delete;
|
|
enum {
|
eStateInit = 0,
|
eStateReady = 0x19833891,
|
eClientWriteBegin,
|
eClientWriteEnd,
|
eServerReadBegin,
|
eServerReadEnd,
|
eServerWriteBegin,
|
eServerWriteEnd,
|
eClientReadBegin,
|
eClientReadEnd = eStateReady,
|
};
|
bool StateCas(State exp, State val);
|
void Write(const Msg &msg)
|
{
|
size_.store(msg.size());
|
memcpy(buf, msg.data(), msg.size());
|
}
|
void Read(Msg &msg) { msg.assign(buf, size_.load()); }
|
|
const uint32_t capacity_;
|
std::atomic<State> state_;
|
static_assert(sizeof(State) == sizeof(state_), "atomic should has no extra data.");
|
std::atomic<Duration> timestamp_;
|
std::atomic<int32_t> size_;
|
char buf[4];
|
};
|
|
class PidLocker
|
{
|
public:
|
typedef int locker_t;
|
enum { eLockerBits = sizeof(locker_t) * 8 };
|
static locker_t this_locker()
|
{
|
static locker_t val = getpid();
|
return val;
|
}
|
static bool is_alive(locker_t locker) { return true; }
|
};
|
|
class RobustPidLocker
|
{
|
public:
|
typedef int locker_t;
|
enum { eLockerBits = sizeof(locker_t) * 8 };
|
static locker_t this_locker()
|
{
|
static locker_t val = getpid();
|
return val;
|
}
|
static bool is_alive(locker_t locker)
|
{
|
char buf[64] = {0};
|
snprintf(buf, sizeof(buf) - 1, "/proc/%d/stat", locker);
|
return access(buf, F_OK) == 0;
|
}
|
};
|
|
class ExpiredLocker
|
{
|
public:
|
typedef int64_t locker_t;
|
enum { eLockerBits = 63 };
|
static locker_t this_locker() { return Now(); }
|
static bool is_alive(locker_t locker)
|
{
|
return Now() < locker + steady_clock::duration(10s).count();
|
}
|
|
private:
|
static locker_t Now() { return steady_clock::now().time_since_epoch().count(); }
|
};
|
|
template <class LockerT>
|
class CasMutex
|
{
|
typedef typename LockerT::locker_t locker_t;
|
static inline locker_t this_locker() { return LockerT::this_locker(); }
|
static inline bool is_alive(locker_t locker) { return LockerT::is_alive(locker); }
|
static const uint64_t kLockerMask = MaskBits(LockerT::eLockerBits);
|
static_assert(LockerT::eLockerBits < 64, "locker size must be smaller than 64 bit!");
|
|
public:
|
CasMutex() :
|
meta_(0) {}
|
int try_lock()
|
{
|
const auto t = steady_clock::now().time_since_epoch().count();
|
auto old = meta_.load();
|
int r = 0;
|
if (!Locked(old)) {
|
r = MetaCas(old, Meta(1, this_locker()));
|
} else if (!is_alive(Locker(old))) {
|
r = static_cast<int>(MetaCas(old, Meta(1, this_locker()))) << 1;
|
if (r) {
|
LOG_DEBUG() << "captured locker " << int64_t(Locker(old)) << " -> " << int64_t(this_locker()) << ", locker = " << r;
|
}
|
}
|
return r;
|
}
|
int lock()
|
{
|
int r = 0;
|
do {
|
r = try_lock();
|
} while (r == 0);
|
return r;
|
}
|
void unlock()
|
{
|
auto old = meta_.load();
|
if (Locked(old) && Locker(old) == this_locker()) {
|
MetaCas(old, Meta(0, this_locker()));
|
}
|
}
|
|
private:
|
std::atomic<uint64_t> meta_;
|
bool Locked(uint64_t meta) { return (meta >> 63) == 1; }
|
locker_t Locker(uint64_t meta) { return meta & kLockerMask; }
|
uint64_t Meta(uint64_t lk, locker_t lid) { return (lk << 63) | lid; }
|
bool MetaCas(uint64_t exp, uint64_t val) { return meta_.compare_exchange_strong(exp, val); }
|
};
|
|
typedef CasMutex<RobustPidLocker> Mutex;
|
|
template <class Lock>
|
class Guard
|
{
|
public:
|
Guard(Lock &l) :
|
l_(l) { l_.lock(); }
|
~Guard() { l_.unlock(); }
|
|
private:
|
Guard(const Guard &);
|
Guard(Guard &&);
|
Lock &l_;
|
};
|
|
template <class D, class Alloc = std::allocator<D>>
|
class CircularBuffer
|
{
|
typedef uint32_t size_type;
|
typedef uint32_t count_type;
|
typedef uint64_t meta_type;
|
static size_type Pos(meta_type meta) { return meta & 0xFFFFFFFF; }
|
static count_type Count(meta_type meta) { return meta >> 32; }
|
static meta_type Meta(meta_type count, size_type pos) { return (count << 32) | pos; }
|
|
public:
|
typedef D Data;
|
|
CircularBuffer(const size_type cap) :
|
CircularBuffer(cap, Alloc()) {}
|
CircularBuffer(const size_type cap, Alloc const &al) :
|
capacity_(cap + 1), mhead_(0), mtail_(0), al_(al), buf(al_.allocate(capacity_))
|
{
|
if (!buf) {
|
throw("robust CircularBuffer allocate error: alloc buffer failed, out of mem!");
|
} else {
|
memset(&buf[0], 0, sizeof(D) * capacity_);
|
}
|
}
|
~CircularBuffer() { al_.deallocate(buf, capacity_); }
|
|
bool push_back(const Data d)
|
{
|
Guard<Mutex> guard(mutex_);
|
auto old = mtail();
|
auto pos = Pos(old);
|
auto full = ((capacity_ + pos + 1 - head()) % capacity_ == 0);
|
if (!full) {
|
buf[pos] = d;
|
return mtail_.compare_exchange_strong(old, next(old));
|
}
|
return false;
|
}
|
bool pop_front(Data &d)
|
{
|
Guard<Mutex> guard(mutex_);
|
auto old = mhead();
|
auto pos = Pos(old);
|
if (!(pos == tail())) {
|
d = buf[pos];
|
return mhead_.compare_exchange_strong(old, next(old));
|
} else {
|
return false;
|
}
|
}
|
|
private:
|
CircularBuffer(const CircularBuffer &);
|
CircularBuffer(CircularBuffer &&);
|
CircularBuffer &operator=(const CircularBuffer &) = delete;
|
CircularBuffer &operator=(CircularBuffer &&) = delete;
|
|
meta_type next(meta_type meta) const { return Meta(Count(meta) + 1, (Pos(meta) + 1) % capacity_); }
|
size_type head() const { return Pos(mhead()); }
|
size_type tail() const { return Pos(mtail()); }
|
meta_type mhead() const { return mhead_.load(); }
|
meta_type mtail() const { return mtail_.load(); }
|
// data
|
const size_type capacity_;
|
Mutex mutex_;
|
std::atomic<meta_type> mhead_;
|
std::atomic<meta_type> mtail_;
|
Alloc al_;
|
typename Alloc::pointer buf = nullptr;
|
};
|
|
template <unsigned PowerSize = 4, class Int = int64_t>
|
class AtomicQueue
|
{
|
public:
|
typedef uint32_t size_type;
|
typedef Int Data;
|
typedef std::atomic<Data> AData;
|
static_assert(sizeof(Data) == sizeof(AData));
|
enum {
|
power = PowerSize,
|
capacity = (1 << power),
|
mask = capacity - 1,
|
};
|
|
AtomicQueue() { memset(this, 0, sizeof(*this)); }
|
size_type head() const { return head_.load(); }
|
size_type tail() const { return tail_.load(); }
|
bool like_empty() const { return head() == tail() && Empty(buf[head()]); }
|
bool like_full() const { return head() == tail() && !Empty(buf[head()]); }
|
bool push(const Data d, bool try_more = false)
|
{
|
bool r = false;
|
size_type i = 0;
|
do {
|
auto pos = tail();
|
if (tail_.compare_exchange_strong(pos, Next(pos))) {
|
auto cur = buf[pos].load();
|
r = Empty(cur) && buf[pos].compare_exchange_strong(cur, Enc(d));
|
}
|
} while (try_more && !r && ++i < capacity);
|
return r;
|
}
|
bool pop(Data &d, bool try_more = false)
|
{
|
bool r = false;
|
Data cur;
|
size_type i = 0;
|
do {
|
auto pos = head();
|
if (head_.compare_exchange_strong(pos, Next(pos))) {
|
cur = buf[pos].load();
|
r = !Empty(cur) && buf[pos].compare_exchange_strong(cur, 0);
|
}
|
} while (try_more && !r && ++i < capacity);
|
if (r) { d = Dec(cur); }
|
return r;
|
}
|
|
private:
|
static_assert(std::is_integral<Data>::value, "Data must be integral type!");
|
static_assert(std::is_signed<Data>::value, "Data must be signed type!");
|
static_assert(PowerSize < 10, "RobustQ63 max size is 2^10!");
|
|
static inline bool Empty(const Data d) { return (d & 1) == 0; } // lowest bit 1 means data ok.
|
static inline Data Enc(const Data d) { return (d << 1) | 1; } // lowest bit 1 means data ok.
|
static inline Data Dec(const Data d) { return d >> 1; } // lowest bit 1 means data ok.
|
static size_type Next(const size_type index) { return (index + 1) & mask; }
|
|
std::atomic<size_type> head_;
|
std::atomic<size_type> tail_;
|
AData buf[capacity];
|
};
|
|
} // namespace robust
|
#endif // end of include guard: ROBUST_Q31RCWYU
|
