First commit

.gitignore

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+/.idea

LICENSE

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+Copyright (c) 2022 Frédéric G. MARAND <[email protected]>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

go.mod

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+module code.osinet.fr/fgm/izidic
+
+go 1.19

izidic.go

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+// Package izidic defines a tiny dependency injection container,
+// loosely inspired by a subset of silexphp/pimple.
+//
+// Like Pimple, the basic feature is that storing service definitions does not
+// create instances, allowing users to store definitions of services requiring
+// other services before those are actually defined.
+package izidic
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+)
+
+// Service is the type used to define container serviceDefs accessors.
+//
+// It takes an instance of the container and returns an instance of the desired service,
+// which should then be type-asserted before use.
+//
+// Any access to a service from the container returns the same instance.
+type Service func(dic *Container) (any, error)
+
+// Container is the container, holding both parameters and services
+type Container struct {
+	sync.Mutex
+	parameters  map[string]any
+	serviceDefs map[string]Service
+	services    map[string]any
+}
+
+// Register registers a service with the container.
+func (dic *Container) Register(name string, fn Service) {
+	dic.Lock()
+	defer dic.Unlock()
+	dic.serviceDefs[name] = fn
+}
+
+// Store stores a parameter in the container.
+func (dic *Container) Store(name string, param any) {
+	dic.Lock()
+	defer dic.Unlock()
+	dic.parameters[name] = param
+}
+
+// Service returns the single instance of the requested service on success.
+func (dic *Container) Service(name string) (any, error) {
+	dic.Lock()
+	defer dic.Unlock()
+
+	// Reuse existing instance if any.
+	instance, found := dic.services[name]
+	if found {
+		return instance, nil
+	}
+
+	// Otherwise instantiate.
+	service, found := dic.serviceDefs[name]
+	if !found {
+		return nil, fmt.Errorf("service %s not found", name)
+	}
+	instance, err := service(dic)
+	if err != nil {
+		return nil, fmt.Errorf("failed instantiating service %s: %w", name, err)
+	}
+	dic.services[name] = instance
+
+	return instance, nil
+}
+
+func (dic *Container) MustService(name string) any {
+	instance, err := dic.Service(name)
+	if err != nil {
+		panic(err)
+	}
+	return instance
+}
+
+func (dic *Container) Param(name string) (any, error) {
+	dic.Lock()
+	defer dic.Unlock()
+	p, found := dic.parameters[name]
+	if !found {
+		return nil, errors.New("parameter not found")
+	}
+	return p, nil
+}
+
+func (dic *Container) MustParam(name string) any {
+	p, err := dic.Param(name)
+	if err != nil {
+		panic(err)
+	}
+	return p
+}