mirror of
https://github.com/foxcpp/maddy.git
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bf188e454f
The intention is to keep to repo root clean while the list of packages is slowly growing. Additionally, a bunch of small (~30 LoC) files in the repo root is merged into a single maddy.go file, for the same reason. Most of the internal code is moved into the internal/ directory. Go toolchain will make it impossible to import these packages from external applications. Some packages are renamed and moved into the pkg/ directory in the root. According to https://github.com/golang-standards/project-layout this is the de-facto standard to place "library code that's ok to use by external applications" in. To clearly define the purpose of top-level directories, README.md files are added to each.
61 lines
870 B
Go
61 lines
870 B
Go
package future
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import (
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"context"
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"sync"
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)
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type Future struct {
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mu sync.RWMutex
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set bool
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val interface{}
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notify chan struct{}
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}
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func New() *Future {
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return &Future{notify: make(chan struct{})}
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}
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func (f *Future) Set(val interface{}) {
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f.mu.Lock()
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defer f.mu.Unlock()
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if f.set {
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panic("Future.Set called multiple times")
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}
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f.set = true
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f.val = val
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close(f.notify)
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}
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func (f *Future) Get() interface{} {
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val, _ := f.GetContext(context.Background())
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return val
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}
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func (f *Future) GetContext(ctx context.Context) (interface{}, error) {
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f.mu.RLock()
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if f.set {
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val := f.val
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f.mu.RUnlock()
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return val, nil
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}
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f.mu.RUnlock()
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select {
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case <-f.notify:
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case <-ctx.Done():
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return nil, ctx.Err()
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}
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f.mu.RLock()
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defer f.mu.RUnlock()
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if !f.set {
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panic("future: Notification received, but value is not set")
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}
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return f.val, nil
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}
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