1 files changed, 194 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/mem/buffer_pool.go b/vendor/google.golang.org/grpc/mem/buffer_pool.go
new file mode 100644
index 000000000..c37c58c02
--- /dev/null
+++ b/vendor/google.golang.org/grpc/mem/buffer_pool.go
@@ -0,0 +1,194 @@
+/*
+ *
+ * Copyright 2024 gRPC authors.
+ *
+ * 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,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package mem
+
+import (
+	"sort"
+	"sync"
+
+	"google.golang.org/grpc/internal"
+)
+
+// BufferPool is a pool of buffers that can be shared and reused, resulting in
+// decreased memory allocation.
+type BufferPool interface {
+	// Get returns a buffer with specified length from the pool.
+	Get(length int) *[]byte
+
+	// Put returns a buffer to the pool.
+	Put(*[]byte)
+}
+
+var defaultBufferPoolSizes = []int{
+	256,
+	4 << 10,  // 4KB (go page size)
+	16 << 10, // 16KB (max HTTP/2 frame size used by gRPC)
+	32 << 10, // 32KB (default buffer size for io.Copy)
+	1 << 20,  // 1MB
+}
+
+var defaultBufferPool BufferPool
+
+func init() {
+	defaultBufferPool = NewTieredBufferPool(defaultBufferPoolSizes...)
+
+	internal.SetDefaultBufferPoolForTesting = func(pool BufferPool) {
+		defaultBufferPool = pool
+	}
+
+	internal.SetBufferPoolingThresholdForTesting = func(threshold int) {
+		bufferPoolingThreshold = threshold
+	}
+}
+
+// DefaultBufferPool returns the current default buffer pool. It is a BufferPool
+// created with NewBufferPool that uses a set of default sizes optimized for
+// expected workflows.
+func DefaultBufferPool() BufferPool {
+	return defaultBufferPool
+}
+
+// NewTieredBufferPool returns a BufferPool implementation that uses multiple
+// underlying pools of the given pool sizes.
+func NewTieredBufferPool(poolSizes ...int) BufferPool {
+	sort.Ints(poolSizes)
+	pools := make([]*sizedBufferPool, len(poolSizes))
+	for i, s := range poolSizes {
+		pools[i] = newSizedBufferPool(s)
+	}
+	return &tieredBufferPool{
+		sizedPools: pools,
+	}
+}
+
+// tieredBufferPool implements the BufferPool interface with multiple tiers of
+// buffer pools for different sizes of buffers.
+type tieredBufferPool struct {
+	sizedPools   []*sizedBufferPool
+	fallbackPool simpleBufferPool
+}
+
+func (p *tieredBufferPool) Get(size int) *[]byte {
+	return p.getPool(size).Get(size)
+}
+
+func (p *tieredBufferPool) Put(buf *[]byte) {
+	p.getPool(cap(*buf)).Put(buf)
+}
+
+func (p *tieredBufferPool) getPool(size int) BufferPool {
+	poolIdx := sort.Search(len(p.sizedPools), func(i int) bool {
+		return p.sizedPools[i].defaultSize >= size
+	})
+
+	if poolIdx == len(p.sizedPools) {
+		return &p.fallbackPool
+	}
+
+	return p.sizedPools[poolIdx]
+}
+
+// sizedBufferPool is a BufferPool implementation that is optimized for specific
+// buffer sizes. For example, HTTP/2 frames within gRPC have a default max size
+// of 16kb and a sizedBufferPool can be configured to only return buffers with a
+// capacity of 16kb. Note that however it does not support returning larger
+// buffers and in fact panics if such a buffer is requested. Because of this,
+// this BufferPool implementation is not meant to be used on its own and rather
+// is intended to be embedded in a tieredBufferPool such that Get is only
+// invoked when the required size is smaller than or equal to defaultSize.
+type sizedBufferPool struct {
+	pool        sync.Pool
+	defaultSize int
+}
+
+func (p *sizedBufferPool) Get(size int) *[]byte {
+	buf := p.pool.Get().(*[]byte)
+	b := *buf
+	clear(b[:cap(b)])
+	*buf = b[:size]
+	return buf
+}
+
+func (p *sizedBufferPool) Put(buf *[]byte) {
+	if cap(*buf) < p.defaultSize {
+		// Ignore buffers that are too small to fit in the pool. Otherwise, when
+		// Get is called it will panic as it tries to index outside the bounds
+		// of the buffer.
+		return
+	}
+	p.pool.Put(buf)
+}
+
+func newSizedBufferPool(size int) *sizedBufferPool {
+	return &sizedBufferPool{
+		pool: sync.Pool{
+			New: func() any {
+				buf := make([]byte, size)
+				return &buf
+			},
+		},
+		defaultSize: size,
+	}
+}
+
+var _ BufferPool = (*simpleBufferPool)(nil)
+
+// simpleBufferPool is an implementation of the BufferPool interface that
+// attempts to pool buffers with a sync.Pool. When Get is invoked, it tries to
+// acquire a buffer from the pool but if that buffer is too small, it returns it
+// to the pool and creates a new one.
+type simpleBufferPool struct {
+	pool sync.Pool
+}
+
+func (p *simpleBufferPool) Get(size int) *[]byte {
+	bs, ok := p.pool.Get().(*[]byte)
+	if ok && cap(*bs) >= size {
+		*bs = (*bs)[:size]
+		return bs
+	}
+
+	// A buffer was pulled from the pool, but it is too small. Put it back in
+	// the pool and create one large enough.
+	if ok {
+		p.pool.Put(bs)
+	}
+
+	b := make([]byte, size)
+	return &b
+}
+
+func (p *simpleBufferPool) Put(buf *[]byte) {
+	p.pool.Put(buf)
+}
+
+var _ BufferPool = NopBufferPool{}
+
+// NopBufferPool is a buffer pool that returns new buffers without pooling.
+type NopBufferPool struct{}
+
+// Get returns a buffer with specified length from the pool.
+func (NopBufferPool) Get(length int) *[]byte {
+	b := make([]byte, length)
+	return &b
+}
+
+// Put returns a buffer to the pool.
+func (NopBufferPool) Put(*[]byte) {
+}