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fp-go/v2/context/readerioresult/resource.go
Dr. Carsten Leue 600521b220 fix: refactor
Signed-off-by: Dr. Carsten Leue <carsten.leue@de.ibm.com>
2025-11-11 11:01:49 +01:00

58 lines
2.1 KiB
Go

// Copyright (c) 2023 - 2025 IBM Corp.
// 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 readerioresult
import (
RIOR "github.com/IBM/fp-go/v2/readerioresult"
)
// WithResource constructs a function that creates a resource, then operates on it and then releases the resource.
// This implements the RAII (Resource Acquisition Is Initialization) pattern, ensuring that resources are
// properly released even if the operation fails or the context is canceled.
//
// The resource is created, used, and released in a safe manner:
// - onCreate: Creates the resource
// - The provided function uses the resource
// - onRelease: Releases the resource (always called, even on error)
//
// Parameters:
// - onCreate: ReaderIOResult that creates the resource
// - onRelease: Function to release the resource
//
// Returns a function that takes a resource-using function and returns a ReaderIOResult.
//
// Example:
//
// file := WithResource(
// openFile("data.txt"),
// func(f *os.File) ReaderIOResult[any] {
// return TryCatch(func(ctx context.Context) func() (any, error) {
// return func() (any, error) { return nil, f.Close() }
// })
// },
// )
// result := file(func(f *os.File) ReaderIOResult[string] {
// return TryCatch(func(ctx context.Context) func() (string, error) {
// return func() (string, error) {
// data, err := io.ReadAll(f)
// return string(data), err
// }
// })
// })
func WithResource[A, R, ANY any](onCreate ReaderIOResult[R], onRelease Kleisli[R, ANY]) Kleisli[Kleisli[R, A], A] {
return RIOR.WithResource[A](onCreate, onRelease)
}