mirror of https://github.com/grpc/grpc-go.git
119 lines
3.0 KiB
Go
119 lines
3.0 KiB
Go
/*
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*
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* Copyright 2020 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package testutils
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import (
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"context"
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)
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// DefaultChanBufferSize is the default buffer size of the underlying channel.
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const DefaultChanBufferSize = 1
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// Channel wraps a generic channel and provides a timed receive operation.
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type Channel struct {
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// C is the underlying channel on which values sent using the SendXxx()
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// methods are delivered. Tests which cannot use ReceiveXxx() for whatever
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// reasons can use C to read the values.
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C chan any
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}
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// Send sends value on the underlying channel.
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func (c *Channel) Send(value any) {
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c.C <- value
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}
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// SendContext sends value on the underlying channel, or returns an error if
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// the context expires.
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func (c *Channel) SendContext(ctx context.Context, value any) error {
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select {
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case c.C <- value:
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return nil
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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// SendOrFail attempts to send value on the underlying channel. Returns true
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// if successful or false if the channel was full.
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func (c *Channel) SendOrFail(value any) bool {
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select {
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case c.C <- value:
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return true
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default:
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return false
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}
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}
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// ReceiveOrFail returns the value on the underlying channel and true, or nil
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// and false if the channel was empty.
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func (c *Channel) ReceiveOrFail() (any, bool) {
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select {
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case got := <-c.C:
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return got, true
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default:
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return nil, false
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}
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}
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// Drain drains the channel by repeatedly reading from it until it is empty.
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func (c *Channel) Drain() {
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for {
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select {
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case <-c.C:
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default:
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return
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}
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}
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}
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// Receive returns the value received on the underlying channel, or the error
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// returned by ctx if it is closed or cancelled.
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func (c *Channel) Receive(ctx context.Context) (any, error) {
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select {
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case <-ctx.Done():
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return nil, ctx.Err()
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case got := <-c.C:
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return got, nil
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}
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}
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// Replace clears the value on the underlying channel, and sends the new value.
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//
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// It's expected to be used with a size-1 channel, to only keep the most
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// up-to-date item. This method is inherently racy when invoked concurrently
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// from multiple goroutines.
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func (c *Channel) Replace(value any) {
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for {
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select {
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case c.C <- value:
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return
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case <-c.C:
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}
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}
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}
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// NewChannel returns a new Channel.
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func NewChannel() *Channel {
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return NewChannelWithSize(DefaultChanBufferSize)
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}
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// NewChannelWithSize returns a new Channel with a buffer of bufSize.
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func NewChannelWithSize(bufSize int) *Channel {
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return &Channel{C: make(chan any, bufSize)}
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}
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