From 76afc495feccd060663dc0e502670eb949a8793a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Flc=E3=82=9B?= <four_leaf_clover@foxmail.com>
Date: Thu, 14 Mar 2024 22:47:19 +0800
Subject: [PATCH] refactor(context): Rename `Chain` to `Pipe` and add `Chain`
 (#153)
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* refactor(context): Rename `Chain` to `Pipe` and add `Chain`

Signed-off-by: Flc゛ <four_leaf_clover@foxmail.com>

* refactor(context): Rename `Chain` to `Pipe` and add `Chain`

Signed-off-by: Flc゛ <four_leaf_clover@foxmail.com>

---------

Signed-off-by: Flc゛ <four_leaf_clover@foxmail.com>
---
 context/context.go      | 16 +++++++++-
 context/context_test.go | 68 +++++++++++++++++++++++++++++------------
 2 files changed, 64 insertions(+), 20 deletions(-)

diff --git a/context/context.go b/context/context.go
index 088fc33d..08c67934 100644
--- a/context/context.go
+++ b/context/context.go
@@ -6,7 +6,8 @@ import (
 
 type Provider func(ctx context.Context) (context.Context, error)
 
-func Chain(ctx context.Context, providers ...Provider) (context.Context, error) {
+// Pipe returns a Provider that chains the provided Providers.
+func Pipe(ctx context.Context, providers ...Provider) (context.Context, error) {
 	var err error
 	for _, provider := range providers {
 		if provider != nil {
@@ -17,3 +18,16 @@ func Chain(ctx context.Context, providers ...Provider) (context.Context, error)
 	}
 	return ctx, nil
 }
+
+// Chain is a reverse Pipe.
+func Chain(ctx context.Context, providers ...Provider) (context.Context, error) {
+	var err error
+	for i := len(providers) - 1; i >= 0; i-- {
+		if providers[i] != nil {
+			if ctx, err = providers[i](ctx); err != nil {
+				return ctx, err
+			}
+		}
+	}
+	return ctx, nil
+}
diff --git a/context/context_test.go b/context/context_test.go
index 733debc5..8df367e8 100644
--- a/context/context_test.go
+++ b/context/context_test.go
@@ -8,36 +8,44 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestContext(t *testing.T) {
-	type (
-		mockProviderStruct1 struct{}
-		mockProviderStruct2 struct{}
-		mockProviderStruct3 struct{}
-	)
+type (
+	mockProviderStruct1 struct{}
+	mockProviderStruct2 struct{}
+	mockProviderStruct3 struct{}
+)
 
-	var (
-		mockProvider1 = func(ctx context.Context) (context.Context, error) {
-			return context.WithValue(ctx, mockProviderStruct1{}, "mockProvider1"), nil
-		}
+var result chan string
 
-		mockProvider2 = func(ctx context.Context) (context.Context, error) {
-			return context.WithValue(ctx, mockProviderStruct2{}, "mockProvider2"), nil
-		}
+var (
+	mockProvider1 = func(ctx context.Context) (context.Context, error) {
+		result <- "mockProvider1"
+		return context.WithValue(ctx, mockProviderStruct1{}, "mockProvider1"), nil
+	}
 
-		mockProvider3 = func(ctx context.Context) (context.Context, error) {
-			return ctx, errors.New("mockProvider3")
-		}
-	)
+	mockProvider2 = func(ctx context.Context) (context.Context, error) {
+		result <- "mockProvider2"
+		return context.WithValue(ctx, mockProviderStruct2{}, "mockProvider2"), nil
+	}
 
-	ctx1, err1 := Chain(
+	mockProvider3 = func(ctx context.Context) (context.Context, error) {
+		result <- "mockProvider3"
+		return ctx, errors.New("mockProvider3")
+	}
+)
+
+func TestPipe(t *testing.T) {
+	result = make(chan string, 2)
+	ctx1, err1 := Pipe(
 		context.Background(),
 		mockProvider1, mockProvider2,
 	)
 	assert.NoError(t, err1)
 	assert.Equal(t, "mockProvider1", ctx1.Value(mockProviderStruct1{}))
 	assert.Equal(t, "mockProvider2", ctx1.Value(mockProviderStruct2{}))
+	assert.Equal(t, "mockProvider1", <-result)
+	assert.Equal(t, "mockProvider2", <-result)
 
-	ctx2, err2 := Chain(
+	ctx2, err2 := Pipe(
 		context.Background(),
 		mockProvider1, mockProvider3,
 	)
@@ -45,4 +53,26 @@ func TestContext(t *testing.T) {
 	assert.NotNil(t, ctx2)
 	assert.Equal(t, "mockProvider1", ctx2.Value(mockProviderStruct1{}))
 	assert.Nil(t, ctx2.Value(mockProviderStruct3{}))
+	assert.Equal(t, "mockProvider1", <-result)
+}
+
+func TestChain(t *testing.T) {
+	result = make(chan string, 2)
+	ctx1, err1 := Chain(
+		context.Background(),
+		mockProvider1, mockProvider2,
+	)
+	assert.NoError(t, err1)
+	assert.Equal(t, "mockProvider1", ctx1.Value(mockProviderStruct1{}))
+	assert.Equal(t, "mockProvider2", ctx1.Value(mockProviderStruct2{}))
+	assert.Equal(t, "mockProvider2", <-result)
+	assert.Equal(t, "mockProvider1", <-result)
+
+	ctx2, err2 := Chain(
+		context.Background(),
+		mockProvider3, mockProvider1,
+	)
+	assert.Error(t, err2)
+	assert.Equal(t, "mockProvider1", ctx2.Value(mockProviderStruct1{}))
+	assert.Equal(t, "mockProvider1", <-result)
 }