package once

// Singleton contains a pointer to T that must be set once.
// Until the value is set all Get() calls will block.
type Singleton[T any] struct {
	v   *T
	set chan struct{}
}

// NewSingleton creates a new unset singleton.
func NewSingleton[T any]() *Singleton[T] {
	return &Singleton[T]{set: make(chan struct{}), v: nil}
}

// Get will return the singleton value.
func (s *Singleton[T]) Get() *T {
	<-s.set
	return s.v

        session.addUserMessage("User 3");
        session.addAssistantMessage("Assistant 3");
        assertEquals(6, session.getMessageCount());

        // Trimming to 3 would start at index 3 (assistant), so it should go back to index 2 (user)
        session.trimHistory(3);

        final List<ChatMessage> messages = session.getMessages();
        assertEquals(4, messages.size());

)

func TestPreparedStmt(t *testing.T) {
	tx := DB.Session(&gorm.Session{PrepareStmt: true})

	if _, ok := tx.ConnPool.(*gorm.PreparedStmtDB); !ok {
		t.Fatalf("should assign PreparedStatement Manager back to database when using PrepareStmt mode")
	}

	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)
	defer cancel()
	txCtx := tx.WithContext(ctx)

	user := *GetUser("prepared_stmt", Config{})

/*
 * Copyright (C) 2023 Block, Inc.
 *
 * 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,

/*
 * Copyright (C) 2024 Block, Inc.
 *
 * 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,

  @Override
  public boolean offer(E e, long timeout, TimeUnit unit) {
    checkNotNull(unit);
    return offer(e); // never need to block
  }

  /**
   * Inserts the specified element into this priority queue. As the queue is unbounded this method
   * will never block.
   *
   * @param e the element to add
   * @throws ClassCastException if the specified element cannot be compared with elements currently

/*
 * Copyright (C) 2025 Block, Inc.
 *
 * 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,

/*
 * Copyright (c) 2022 Block, Inc.
 *
 * 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,

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

import (
	"os"
	"syscall"
)

var (
	// Disallow updating access times
	// Add non-block to avoid syscall to attempt to set epoll on files.
	readMode = os.O_RDONLY | 0x40000 | syscall.O_NONBLOCK // O_NOATIME

	// Write with data sync only used only for `xl.meta` writes

/*
 * Copyright (C) 2025 Block, Inc.
 *
 * 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,