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Diffstat (limited to 'common/hcontext/context.go')
-rw-r--r-- | common/hcontext/context.go | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/common/hcontext/context.go b/common/hcontext/context.go new file mode 100644 index 000000000..9524ef284 --- /dev/null +++ b/common/hcontext/context.go @@ -0,0 +1,46 @@ +// Copyright 2024 The Hugo Authors. All rights reserved. +// +// 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 hcontext + +import "context" + +// ContextDispatcher is a generic interface for setting and getting values from a context. +type ContextDispatcher[T any] interface { + Set(ctx context.Context, value T) context.Context + Get(ctx context.Context) T +} + +// NewContextDispatcher creates a new ContextDispatcher with the given key. +func NewContextDispatcher[T any, R comparable](key R) ContextDispatcher[T] { + return keyInContext[T, R]{ + id: key, + } +} + +type keyInContext[T any, R comparable] struct { + zero T + id R +} + +func (f keyInContext[T, R]) Get(ctx context.Context) T { + v := ctx.Value(f.id) + if v == nil { + return f.zero + } + return v.(T) +} + +func (f keyInContext[T, R]) Set(ctx context.Context, value T) context.Context { + return context.WithValue(ctx, f.id, value) +} |