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Lock-free JavaDebuggable guard

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This commit is contained in:
LoveSy 2023-06-27 15:31:44 +08:00
parent 8c92a2d5a1
commit 35612201f9
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1 changed files with 40 additions and 8 deletions
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48
lsplant/src/main/jni/lsplant.cc
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@ -615,22 +615,54 @@ std::string GetProxyMethodShorty(JNIEnv *env, jobject proxy_method) {
struct JavaDebuggableGuard {
JavaDebuggableGuard() {
std::unique_lock lk(lock);
if (count.fetch_add(1, std::memory_order_acq_rel) == 0) {
Runtime::Current()->SetJavaDebuggable(
Runtime::RuntimeDebugState::kJavaDebuggableAtInit);
while (true) {
size_t expected = 0;
if (count.compare_exchange_strong(expected, 1, std::memory_order_acq_rel,
std::memory_order_acquire)) {
Runtime::Current()->SetJavaDebuggable(
Runtime::RuntimeDebugState::kJavaDebuggableAtInit);
count.fetch_add(1, std::memory_order_release);
count.notify_all();
break;
}
if (expected == 1) {
count.wait(expected, std::memory_order_acquire);
continue;
}
if (count.compare_exchange_strong(expected, expected + 1, std::memory_order_acq_rel,
std::memory_order_relaxed)) {
break;
}
}
}
~JavaDebuggableGuard() {
std::unique_lock lk(lock);
if (count.fetch_sub(1, std::memory_order_acq_rel) == 1) {
Runtime::Current()->SetJavaDebuggable(Runtime::RuntimeDebugState::kNonJavaDebuggable);
while (true) {
size_t expected = 2;
if (count.compare_exchange_strong(expected, 1, std::memory_order_acq_rel,
std::memory_order_acquire)) {
Runtime::Current()->SetJavaDebuggable(
Runtime::RuntimeDebugState::kNonJavaDebuggable);
count.fetch_sub(1, std::memory_order_release);
count.notify_all();
break;
}
if (expected == 1) {
count.wait(expected, std::memory_order_acquire);
continue;
}
if (count.compare_exchange_strong(expected, expected - 1, std::memory_order_acq_rel,
std::memory_order_relaxed)) {
break;
}
}
}
private:
inline static std::atomic_size_t count{0};
inline static std::mutex lock;
static_assert(std::atomic_size_t::is_always_lock_free, "Unsupported architecture");
static_assert(std::is_same_v<std::atomic_size_t::value_type, size_t>,
"Unsupported architecture");
};
} // namespace