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0d9010e150
pbkdf2 is too expensive to run in init, so this change makes it load
lazily. I introduced a lazy package that I hope to use more in my
`GODEBUG=inittrace=1` adventure.
Benchmark results:
```
$ hyperfine "coder --help" "coder-new --help"
Benchmark 1: coder --help
Time (mean ± σ): 82.1 ms ± 3.8 ms [User: 93.3 ms, System: 30.4 ms]
Range (min … max): 72.2 ms … 90.7 ms 35 runs
Benchmark 2: coder-new --help
Time (mean ± σ): 52.0 ms ± 4.3 ms [User: 62.4 ms, System: 30.8 ms]
Range (min … max): 41.9 ms … 62.2 ms 52 runs
Summary
coder-new --help ran
1.58 ± 0.15 times faster than coder --help
```
29 lines
555 B
Go
29 lines
555 B
Go
// Package lazy provides a lazy value implementation.
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// It's useful especially in global variable initialization to avoid
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// slowing down the program startup time.
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package lazy
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import (
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"sync"
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"sync/atomic"
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)
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type Value[T any] struct {
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once sync.Once
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fn func() T
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cached atomic.Pointer[T]
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}
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func (v *Value[T]) Load() T {
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v.once.Do(func() {
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vv := v.fn()
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v.cached.Store(&vv)
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})
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return *v.cached.Load()
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}
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// New creates a new lazy value with the given load function.
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func New[T any](fn func() T) *Value[T] {
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return &Value[T]{fn: fn}
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}
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