#ifndef HAKMEM_POOL_TLS_BIND_H
#define HAKMEM_POOL_TLS_BIND_H

#include <stdint.h>
#include <sys/types.h>
#include <sys/syscall.h>
#include <unistd.h>

/**
 * POOL_TLS_BIND_BOX - TID Cache for Fast Same-Thread Detection
 *
 * Box Theory:
 * - Boundary: Thread initialization - cache TID in TLS once
 * - Internal: Hot path uses TID comparison (no gettid syscall)
 * - Fallback: gettid_cached() on first access
 *
 * Performance:
 * - Eliminates repeated gettid() calls from hot path
 * - Simple TID comparison (1 comparison vs registry lookup)
 * - Expected: Reduce cache misses and syscall overhead
 */

// TLS binding for fast TID caching
typedef struct PoolTLSBind {
    pid_t tid;  // My thread ID (cached, 0 = uninitialized)
} PoolTLSBind;

// TLS cache (per-thread, automatically zero-initialized)
extern __thread PoolTLSBind g_pool_tls_bind;

// Inline helper: gettid with caching
static inline pid_t gettid_cached(void) {
    static __thread pid_t cached_tid = 0;
    if (__builtin_expect(cached_tid == 0, 0)) {
        cached_tid = (pid_t)syscall(SYS_gettid);
    }
    return cached_tid;
}

// API

// Get my thread ID (cached in TLS)
static inline pid_t pool_get_my_tid(void) {
    if (__builtin_expect(g_pool_tls_bind.tid == 0, 0)) {
        g_pool_tls_bind.tid = gettid_cached();
    }
    return g_pool_tls_bind.tid;
}

// Fast same-thread check (TID comparison only)
// Returns 1 if owner_tid matches my TID, 0 otherwise
static inline int pool_tls_is_mine_tid(pid_t owner_tid) {
    return owner_tid == pool_get_my_tid();
}

#endif // HAKMEM_POOL_TLS_BIND_H