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34 lines
936 B
Go
34 lines
936 B
Go
// Copyright (c) 2022 Shivaram Lingamneni
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// released under the MIT license
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package utils
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import (
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"sync/atomic"
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"unsafe"
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)
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/*
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This can be used to implement the following pattern:
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1. Prepare a config object (this can be arbitrarily expensive)
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2. Take a pointer to the config object and use Set() to install it
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3. Use Get() to access the config from any goroutine
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4. To update the config, call Set() again with a new prepared config object
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5. As long as any individual config object is not modified (by any goroutine)
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after it is installed with Set(), this is free of data races, and Get()
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is extremely cheap (on amd64 it compiles down to plain MOV instructions).
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*/
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type ConfigStore[Config any] struct {
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ptr unsafe.Pointer
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}
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func (c *ConfigStore[Config]) Get() *Config {
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return (*Config)(atomic.LoadPointer(&c.ptr))
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}
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func (c *ConfigStore[Config]) Set(ptr *Config) {
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atomic.StorePointer(&c.ptr, unsafe.Pointer(ptr))
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}
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