github.com/minio/minio@v0.0.0-20240328213742-3f72439b8a27/internal/bpool/bpool.go (about)

     1  // Copyright (c) 2015-2023 MinIO, Inc.
     2  //
     3  // This file is part of MinIO Object Storage stack
     4  //
     5  // This program is free software: you can redistribute it and/or modify
     6  // it under the terms of the GNU Affero General Public License as published by
     7  // the Free Software Foundation, either version 3 of the License, or
     8  // (at your option) any later version.
     9  //
    10  // This program is distributed in the hope that it will be useful
    11  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    12  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    13  // GNU Affero General Public License for more details.
    14  //
    15  // You should have received a copy of the GNU Affero General Public License
    16  // along with this program.  If not, see <http://www.gnu.org/licenses/>.
    17  
    18  package bpool
    19  
    20  import "github.com/klauspost/reedsolomon"
    21  
    22  // BytePoolCap implements a leaky pool of []byte in the form of a bounded channel.
    23  type BytePoolCap struct {
    24  	c    chan []byte
    25  	w    int
    26  	wcap int
    27  }
    28  
    29  // NewBytePoolCap creates a new BytePool bounded to the given maxSize, with new
    30  // byte arrays sized based on width.
    31  func NewBytePoolCap(maxSize uint64, width int, capwidth int) (bp *BytePoolCap) {
    32  	if capwidth > 0 && capwidth < 64 {
    33  		panic("buffer capped with smaller than 64 bytes is not supported")
    34  	}
    35  	if capwidth > 0 && width > capwidth {
    36  		panic("buffer length cannot be > capacity of the buffer")
    37  	}
    38  	return &BytePoolCap{
    39  		c:    make(chan []byte, maxSize),
    40  		w:    width,
    41  		wcap: capwidth,
    42  	}
    43  }
    44  
    45  // Populate - populates and pre-warms the byte pool, this function is non-blocking.
    46  func (bp *BytePoolCap) Populate() {
    47  	for _, buf := range reedsolomon.AllocAligned(cap(bp.c), bp.wcap) {
    48  		bp.Put(buf[:bp.w])
    49  	}
    50  }
    51  
    52  // Get gets a []byte from the BytePool, or creates a new one if none are
    53  // available in the pool.
    54  func (bp *BytePoolCap) Get() (b []byte) {
    55  	select {
    56  	case b = <-bp.c:
    57  		// reuse existing buffer
    58  	default:
    59  		// create new aligned buffer
    60  		if bp.wcap > 0 {
    61  			b = reedsolomon.AllocAligned(1, bp.wcap)[0][:bp.w]
    62  		} else {
    63  			b = reedsolomon.AllocAligned(1, bp.w)[0]
    64  		}
    65  	}
    66  	return
    67  }
    68  
    69  // Put returns the given Buffer to the BytePool.
    70  func (bp *BytePoolCap) Put(b []byte) {
    71  	select {
    72  	case bp.c <- b:
    73  		// buffer went back into pool
    74  	default:
    75  		// buffer didn't go back into pool, just discard
    76  	}
    77  }
    78  
    79  // Width returns the width of the byte arrays in this pool.
    80  func (bp *BytePoolCap) Width() (n int) {
    81  	return bp.w
    82  }
    83  
    84  // WidthCap returns the cap width of the byte arrays in this pool.
    85  func (bp *BytePoolCap) WidthCap() (n int) {
    86  	return bp.wcap
    87  }