1
0
mirror of https://github.com/open-telemetry/opentelemetry-go.git synced 2024-12-10 09:50:58 +02:00
opentelemetry-go/sdk/metric/cache.go
Charlie Le 1b55281859
docs(typos): Run codespell to fix typos (#3980)
* docs(typos): Run codespell to fix typos

There were a lot of typos through the repository, so I ran
[codespell][], a tool for automatically fixing typos, to fix them.

```console
make codespell
```

There's already a tool called [misspell][] that's supposed to take care
of this, but misspell hasn't been updated for 6 years, and it doesn't
seem to be catching any of the typos that codespell can.

[codespell]: https://github.com/codespell-project/codespell
[misspell]: https://github.com/client9/misspell

* Revert and ignore spelling for Consequentially

* Add GH workflow for codespell

* Revert GH Workflow and Makefile for codespell

Per @pellared, since there's no instructions for setting up codespell,
it was suggested that the changes for setting up a workflow and section
in Makefile include instructions for setting up codespell as well.

* Revert spelling on consequently

---------

Co-authored-by: Chester Cheung <cheung.zhy.csu@gmail.com>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
2023-04-11 17:28:13 -07:00

55 lines
1.5 KiB
Go

// Copyright The OpenTelemetry 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 metric // import "go.opentelemetry.io/otel/sdk/metric"
import (
"sync"
)
// cache is a locking storage used to quickly return already computed values.
//
// The zero value of a cache is empty and ready to use.
//
// A cache must not be copied after first use.
//
// All methods of a cache are safe to call concurrently.
type cache[K comparable, V any] struct {
sync.Mutex
data map[K]V
}
// Lookup returns the value stored in the cache with the associated key if it
// exists. Otherwise, f is called and its returned value is set in the cache
// for key and returned.
//
// Lookup is safe to call concurrently. It will hold the cache lock, so f
// should not block excessively.
func (c *cache[K, V]) Lookup(key K, f func() V) V {
c.Lock()
defer c.Unlock()
if c.data == nil {
val := f()
c.data = map[K]V{key: val}
return val
}
if v, ok := c.data[key]; ok {
return v
}
val := f()
c.data[key] = val
return val
}