6 files changed, 975 insertions, 0 deletions
diff --git a/modules/cache/cache.go b/modules/cache/cache.go
new file mode 100644
index 00000000..546c54df
--- /dev/null
+++ b/modules/cache/cache.go
@@ -0,0 +1,184 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cache
+
+import (
+	"fmt"
+	"strconv"
+	"time"
+
+	"code.gitea.io/gitea/modules/setting"
+
+	mc "gitea.com/go-chi/cache"
+
+	_ "gitea.com/go-chi/cache/memcache" // memcache plugin for cache
+)
+
+var conn mc.Cache
+
+func newCache(cacheConfig setting.Cache) (mc.Cache, error) {
+	return mc.NewCacher(mc.Options{
+		Adapter:       cacheConfig.Adapter,
+		AdapterConfig: cacheConfig.Conn,
+		Interval:      cacheConfig.Interval,
+	})
+}
+
+// Init start cache service
+func Init() error {
+	var err error
+
+	if conn == nil {
+		if conn, err = newCache(setting.CacheService.Cache); err != nil {
+			return err
+		}
+		if err = conn.Ping(); err != nil {
+			return err
+		}
+	}
+
+	return err
+}
+
+const (
+	testCacheKey       = "DefaultCache.TestKey"
+	SlowCacheThreshold = 100 * time.Microsecond
+)
+
+func Test() (time.Duration, error) {
+	if conn == nil {
+		return 0, fmt.Errorf("default cache not initialized")
+	}
+
+	testData := fmt.Sprintf("%x", make([]byte, 500))
+
+	start := time.Now()
+
+	if err := conn.Delete(testCacheKey); err != nil {
+		return 0, fmt.Errorf("expect cache to delete data based on key if exist but got: %w", err)
+	}
+	if err := conn.Put(testCacheKey, testData, 10); err != nil {
+		return 0, fmt.Errorf("expect cache to store data but got: %w", err)
+	}
+	testVal := conn.Get(testCacheKey)
+	if testVal == nil {
+		return 0, fmt.Errorf("expect cache hit but got none")
+	}
+	if testVal != testData {
+		return 0, fmt.Errorf("expect cache to return same value as stored but got other")
+	}
+
+	return time.Since(start), nil
+}
+
+// GetCache returns the currently configured cache
+func GetCache() mc.Cache {
+	return conn
+}
+
+// GetString returns the key value from cache with callback when no key exists in cache
+func GetString(key string, getFunc func() (string, error)) (string, error) {
+	if conn == nil || setting.CacheService.TTL == 0 {
+		return getFunc()
+	}
+
+	cached := conn.Get(key)
+
+	if cached == nil {
+		value, err := getFunc()
+		if err != nil {
+			return value, err
+		}
+		return value, conn.Put(key, value, setting.CacheService.TTLSeconds())
+	}
+
+	if value, ok := cached.(string); ok {
+		return value, nil
+	}
+
+	if stringer, ok := cached.(fmt.Stringer); ok {
+		return stringer.String(), nil
+	}
+
+	return fmt.Sprintf("%s", cached), nil
+}
+
+// GetInt returns key value from cache with callback when no key exists in cache
+func GetInt(key string, getFunc func() (int, error)) (int, error) {
+	if conn == nil || setting.CacheService.TTL == 0 {
+		return getFunc()
+	}
+
+	cached := conn.Get(key)
+
+	if cached == nil {
+		value, err := getFunc()
+		if err != nil {
+			return value, err
+		}
+
+		return value, conn.Put(key, value, setting.CacheService.TTLSeconds())
+	}
+
+	switch v := cached.(type) {
+	case int:
+		return v, nil
+	case string:
+		value, err := strconv.Atoi(v)
+		if err != nil {
+			return 0, err
+		}
+		return value, nil
+	default:
+		value, err := getFunc()
+		if err != nil {
+			return value, err
+		}
+		return value, conn.Put(key, value, setting.CacheService.TTLSeconds())
+	}
+}
+
+// GetInt64 returns key value from cache with callback when no key exists in cache
+func GetInt64(key string, getFunc func() (int64, error)) (int64, error) {
+	if conn == nil || setting.CacheService.TTL == 0 {
+		return getFunc()
+	}
+
+	cached := conn.Get(key)
+
+	if cached == nil {
+		value, err := getFunc()
+		if err != nil {
+			return value, err
+		}
+
+		return value, conn.Put(key, value, setting.CacheService.TTLSeconds())
+	}
+
+	switch v := conn.Get(key).(type) {
+	case int64:
+		return v, nil
+	case string:
+		value, err := strconv.ParseInt(v, 10, 64)
+		if err != nil {
+			return 0, err
+		}
+		return value, nil
+	default:
+		value, err := getFunc()
+		if err != nil {
+			return value, err
+		}
+
+		return value, conn.Put(key, value, setting.CacheService.TTLSeconds())
+	}
+}
+
+// Remove key from cache
+func Remove(key string) {
+	if conn == nil {
+		return
+	}
+	_ = conn.Delete(key)
+}
diff --git a/modules/cache/cache_redis.go b/modules/cache/cache_redis.go
new file mode 100644
index 00000000..6c358b0a
--- /dev/null
+++ b/modules/cache/cache_redis.go
@@ -0,0 +1,162 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cache
+
+import (
+	"fmt"
+	"strconv"
+	"time"
+
+	"code.gitea.io/gitea/modules/graceful"
+	"code.gitea.io/gitea/modules/nosql"
+
+	"gitea.com/go-chi/cache"
+	"github.com/redis/go-redis/v9"
+)
+
+// RedisCacher represents a redis cache adapter implementation.
+type RedisCacher struct {
+	c          redis.UniversalClient
+	prefix     string
+	hsetName   string
+	occupyMode bool
+}
+
+// toStr convert string/int/int64 interface to string. it's only used by the RedisCacher.Put internally
+func toStr(v any) string {
+	if v == nil {
+		return ""
+	}
+	switch v := v.(type) {
+	case string:
+		return v
+	case []byte:
+		return string(v)
+	case int:
+		return strconv.FormatInt(int64(v), 10)
+	case int64:
+		return strconv.FormatInt(v, 10)
+	default:
+		return fmt.Sprint(v) // as what the old com.ToStr does in most cases
+	}
+}
+
+// Put puts value (string type) into cache with key and expire time.
+// If expired is 0, it lives forever.
+func (c *RedisCacher) Put(key string, val any, expire int64) error {
+	// this function is not well-designed, it only puts string values into cache
+	key = c.prefix + key
+	if expire == 0 {
+		if err := c.c.Set(graceful.GetManager().HammerContext(), key, toStr(val), 0).Err(); err != nil {
+			return err
+		}
+	} else {
+		dur := time.Duration(expire) * time.Second
+		if err := c.c.Set(graceful.GetManager().HammerContext(), key, toStr(val), dur).Err(); err != nil {
+			return err
+		}
+	}
+
+	if c.occupyMode {
+		return nil
+	}
+	return c.c.HSet(graceful.GetManager().HammerContext(), c.hsetName, key, "0").Err()
+}
+
+// Get gets cached value by given key.
+func (c *RedisCacher) Get(key string) any {
+	val, err := c.c.Get(graceful.GetManager().HammerContext(), c.prefix+key).Result()
+	if err != nil {
+		return nil
+	}
+	return val
+}
+
+// Delete deletes cached value by given key.
+func (c *RedisCacher) Delete(key string) error {
+	key = c.prefix + key
+	if err := c.c.Del(graceful.GetManager().HammerContext(), key).Err(); err != nil {
+		return err
+	}
+
+	if c.occupyMode {
+		return nil
+	}
+	return c.c.HDel(graceful.GetManager().HammerContext(), c.hsetName, key).Err()
+}
+
+// Incr increases cached int-type value by given key as a counter.
+func (c *RedisCacher) Incr(key string) error {
+	if !c.IsExist(key) {
+		return fmt.Errorf("key '%s' not exist", key)
+	}
+	return c.c.Incr(graceful.GetManager().HammerContext(), c.prefix+key).Err()
+}
+
+// Decr decreases cached int-type value by given key as a counter.
+func (c *RedisCacher) Decr(key string) error {
+	if !c.IsExist(key) {
+		return fmt.Errorf("key '%s' not exist", key)
+	}
+	return c.c.Decr(graceful.GetManager().HammerContext(), c.prefix+key).Err()
+}
+
+// IsExist returns true if cached value exists.
+func (c *RedisCacher) IsExist(key string) bool {
+	if c.c.Exists(graceful.GetManager().HammerContext(), c.prefix+key).Val() == 1 {
+		return true
+	}
+
+	if !c.occupyMode {
+		c.c.HDel(graceful.GetManager().HammerContext(), c.hsetName, c.prefix+key)
+	}
+	return false
+}
+
+// Flush deletes all cached data.
+func (c *RedisCacher) Flush() error {
+	if c.occupyMode {
+		return c.c.FlushDB(graceful.GetManager().HammerContext()).Err()
+	}
+
+	keys, err := c.c.HKeys(graceful.GetManager().HammerContext(), c.hsetName).Result()
+	if err != nil {
+		return err
+	}
+	if err = c.c.Del(graceful.GetManager().HammerContext(), keys...).Err(); err != nil {
+		return err
+	}
+	return c.c.Del(graceful.GetManager().HammerContext(), c.hsetName).Err()
+}
+
+// StartAndGC starts GC routine based on config string settings.
+// AdapterConfig: network=tcp,addr=:6379,password=macaron,db=0,pool_size=100,idle_timeout=180,hset_name=MacaronCache,prefix=cache:
+func (c *RedisCacher) StartAndGC(opts cache.Options) error {
+	c.hsetName = "MacaronCache"
+	c.occupyMode = opts.OccupyMode
+
+	uri := nosql.ToRedisURI(opts.AdapterConfig)
+
+	c.c = nosql.GetManager().GetRedisClient(uri.String())
+
+	for k, v := range uri.Query() {
+		switch k {
+		case "hset_name":
+			c.hsetName = v[0]
+		case "prefix":
+			c.prefix = v[0]
+		}
+	}
+
+	return c.c.Ping(graceful.GetManager().HammerContext()).Err()
+}
+
+// Ping tests if the cache is alive.
+func (c *RedisCacher) Ping() error {
+	return c.c.Ping(graceful.GetManager().HammerContext()).Err()
+}
+
+func init() {
+	cache.Register("redis", &RedisCacher{})
+}
diff --git a/modules/cache/cache_test.go b/modules/cache/cache_test.go
new file mode 100644
index 00000000..0b031814
--- /dev/null
+++ b/modules/cache/cache_test.go
@@ -0,0 +1,163 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cache
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func createTestCache() {
+	conn, _ = newCache(setting.Cache{
+		Adapter: "memory",
+		TTL:     time.Minute,
+	})
+	setting.CacheService.TTL = 24 * time.Hour
+}
+
+func TestNewContext(t *testing.T) {
+	require.NoError(t, Init())
+
+	setting.CacheService.Cache = setting.Cache{Adapter: "redis", Conn: "some random string"}
+	con, err := newCache(setting.Cache{
+		Adapter:  "rand",
+		Conn:     "false conf",
+		Interval: 100,
+	})
+	require.Error(t, err)
+	assert.Nil(t, con)
+}
+
+func TestTest(t *testing.T) {
+	defer test.MockVariableValue(&conn, nil)()
+	_, err := Test()
+	require.Error(t, err)
+
+	createTestCache()
+	elapsed, err := Test()
+	require.NoError(t, err)
+	// mem cache should take from 300ns up to 1ms on modern hardware ...
+	assert.Less(t, elapsed, SlowCacheThreshold)
+}
+
+func TestGetCache(t *testing.T) {
+	createTestCache()
+
+	assert.NotNil(t, GetCache())
+}
+
+func TestGetString(t *testing.T) {
+	createTestCache()
+
+	data, err := GetString("key", func() (string, error) {
+		return "", fmt.Errorf("some error")
+	})
+	require.Error(t, err)
+	assert.Equal(t, "", data)
+
+	data, err = GetString("key", func() (string, error) {
+		return "", nil
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "", data)
+
+	data, err = GetString("key", func() (string, error) {
+		return "some data", nil
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "", data)
+	Remove("key")
+
+	data, err = GetString("key", func() (string, error) {
+		return "some data", nil
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "some data", data)
+
+	data, err = GetString("key", func() (string, error) {
+		return "", fmt.Errorf("some error")
+	})
+	require.NoError(t, err)
+	assert.Equal(t, "some data", data)
+	Remove("key")
+}
+
+func TestGetInt(t *testing.T) {
+	createTestCache()
+
+	data, err := GetInt("key", func() (int, error) {
+		return 0, fmt.Errorf("some error")
+	})
+	require.Error(t, err)
+	assert.Equal(t, 0, data)
+
+	data, err = GetInt("key", func() (int, error) {
+		return 0, nil
+	})
+	require.NoError(t, err)
+	assert.Equal(t, 0, data)
+
+	data, err = GetInt("key", func() (int, error) {
+		return 100, nil
+	})
+	require.NoError(t, err)
+	assert.Equal(t, 0, data)
+	Remove("key")
+
+	data, err = GetInt("key", func() (int, error) {
+		return 100, nil
+	})
+	require.NoError(t, err)
+	assert.Equal(t, 100, data)
+
+	data, err = GetInt("key", func() (int, error) {
+		return 0, fmt.Errorf("some error")
+	})
+	require.NoError(t, err)
+	assert.Equal(t, 100, data)
+	Remove("key")
+}
+
+func TestGetInt64(t *testing.T) {
+	createTestCache()
+
+	data, err := GetInt64("key", func() (int64, error) {
+		return 0, fmt.Errorf("some error")
+	})
+	require.Error(t, err)
+	assert.EqualValues(t, 0, data)
+
+	data, err = GetInt64("key", func() (int64, error) {
+		return 0, nil
+	})
+	require.NoError(t, err)
+	assert.EqualValues(t, 0, data)
+
+	data, err = GetInt64("key", func() (int64, error) {
+		return 100, nil
+	})
+	require.NoError(t, err)
+	assert.EqualValues(t, 0, data)
+	Remove("key")
+
+	data, err = GetInt64("key", func() (int64, error) {
+		return 100, nil
+	})
+	require.NoError(t, err)
+	assert.EqualValues(t, 100, data)
+
+	data, err = GetInt64("key", func() (int64, error) {
+		return 0, fmt.Errorf("some error")
+	})
+	require.NoError(t, err)
+	assert.EqualValues(t, 100, data)
+	Remove("key")
+}
diff --git a/modules/cache/cache_twoqueue.go b/modules/cache/cache_twoqueue.go
new file mode 100644
index 00000000..f9de2563
--- /dev/null
+++ b/modules/cache/cache_twoqueue.go
@@ -0,0 +1,208 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cache
+
+import (
+	"strconv"
+	"sync"
+	"time"
+
+	"code.gitea.io/gitea/modules/json"
+
+	mc "gitea.com/go-chi/cache"
+	lru "github.com/hashicorp/golang-lru/v2"
+)
+
+// TwoQueueCache represents a LRU 2Q cache adapter implementation
+type TwoQueueCache struct {
+	lock     sync.Mutex
+	cache    *lru.TwoQueueCache[string, any]
+	interval int
+}
+
+// TwoQueueCacheConfig describes the configuration for TwoQueueCache
+type TwoQueueCacheConfig struct {
+	Size        int     `ini:"SIZE" json:"size"`
+	RecentRatio float64 `ini:"RECENT_RATIO" json:"recent_ratio"`
+	GhostRatio  float64 `ini:"GHOST_RATIO" json:"ghost_ratio"`
+}
+
+// MemoryItem represents a memory cache item.
+type MemoryItem struct {
+	Val     any
+	Created int64
+	Timeout int64
+}
+
+func (item *MemoryItem) hasExpired() bool {
+	return item.Timeout > 0 &&
+		(time.Now().Unix()-item.Created) >= item.Timeout
+}
+
+var _ mc.Cache = &TwoQueueCache{}
+
+// Put puts value into cache with key and expire time.
+func (c *TwoQueueCache) Put(key string, val any, timeout int64) error {
+	item := &MemoryItem{
+		Val:     val,
+		Created: time.Now().Unix(),
+		Timeout: timeout,
+	}
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Add(key, item)
+	return nil
+}
+
+// Get gets cached value by given key.
+func (c *TwoQueueCache) Get(key string) any {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	cached, ok := c.cache.Get(key)
+	if !ok {
+		return nil
+	}
+	item, ok := cached.(*MemoryItem)
+
+	if !ok || item.hasExpired() {
+		c.cache.Remove(key)
+		return nil
+	}
+
+	return item.Val
+}
+
+// Delete deletes cached value by given key.
+func (c *TwoQueueCache) Delete(key string) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Remove(key)
+	return nil
+}
+
+// Incr increases cached int-type value by given key as a counter.
+func (c *TwoQueueCache) Incr(key string) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	cached, ok := c.cache.Get(key)
+	if !ok {
+		return nil
+	}
+	item, ok := cached.(*MemoryItem)
+
+	if !ok || item.hasExpired() {
+		c.cache.Remove(key)
+		return nil
+	}
+
+	var err error
+	item.Val, err = mc.Incr(item.Val)
+	return err
+}
+
+// Decr decreases cached int-type value by given key as a counter.
+func (c *TwoQueueCache) Decr(key string) error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	cached, ok := c.cache.Get(key)
+	if !ok {
+		return nil
+	}
+	item, ok := cached.(*MemoryItem)
+
+	if !ok || item.hasExpired() {
+		c.cache.Remove(key)
+		return nil
+	}
+
+	var err error
+	item.Val, err = mc.Decr(item.Val)
+	return err
+}
+
+// IsExist returns true if cached value exists.
+func (c *TwoQueueCache) IsExist(key string) bool {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	cached, ok := c.cache.Peek(key)
+	if !ok {
+		return false
+	}
+	item, ok := cached.(*MemoryItem)
+	if !ok || item.hasExpired() {
+		c.cache.Remove(key)
+		return false
+	}
+
+	return true
+}
+
+// Flush deletes all cached data.
+func (c *TwoQueueCache) Flush() error {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.cache.Purge()
+	return nil
+}
+
+func (c *TwoQueueCache) checkAndInvalidate(key string) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	cached, ok := c.cache.Peek(key)
+	if !ok {
+		return
+	}
+	item, ok := cached.(*MemoryItem)
+	if !ok || item.hasExpired() {
+		c.cache.Remove(key)
+	}
+}
+
+func (c *TwoQueueCache) startGC() {
+	if c.interval < 0 {
+		return
+	}
+	for _, key := range c.cache.Keys() {
+		c.checkAndInvalidate(key)
+	}
+	time.AfterFunc(time.Duration(c.interval)*time.Second, c.startGC)
+}
+
+// StartAndGC starts GC routine based on config string settings.
+func (c *TwoQueueCache) StartAndGC(opts mc.Options) error {
+	var err error
+	size := 50000
+	if opts.AdapterConfig != "" {
+		size, err = strconv.Atoi(opts.AdapterConfig)
+	}
+	if err != nil {
+		if !json.Valid([]byte(opts.AdapterConfig)) {
+			return err
+		}
+
+		cfg := &TwoQueueCacheConfig{
+			Size:        50000,
+			RecentRatio: lru.Default2QRecentRatio,
+			GhostRatio:  lru.Default2QGhostEntries,
+		}
+		_ = json.Unmarshal([]byte(opts.AdapterConfig), cfg)
+		c.cache, err = lru.New2QParams[string, any](cfg.Size, cfg.RecentRatio, cfg.GhostRatio)
+	} else {
+		c.cache, err = lru.New2Q[string, any](size)
+	}
+	c.interval = opts.Interval
+	if c.interval > 0 {
+		go c.startGC()
+	}
+	return err
+}
+
+// Ping tests if the cache is alive.
+func (c *TwoQueueCache) Ping() error {
+	return mc.GenericPing(c)
+}
+
+func init() {
+	mc.Register("twoqueue", &TwoQueueCache{})
+}
diff --git a/modules/cache/context.go b/modules/cache/context.go
new file mode 100644
index 00000000..62bbf5dc
--- /dev/null
+++ b/modules/cache/context.go
@@ -0,0 +1,179 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cache
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"code.gitea.io/gitea/modules/log"
+)
+
+// cacheContext is a context that can be used to cache data in a request level context
+// This is useful for caching data that is expensive to calculate and is likely to be
+// used multiple times in a request.
+type cacheContext struct {
+	data    map[any]map[any]any
+	lock    sync.RWMutex
+	created time.Time
+	discard bool
+}
+
+func (cc *cacheContext) Get(tp, key any) any {
+	cc.lock.RLock()
+	defer cc.lock.RUnlock()
+	return cc.data[tp][key]
+}
+
+func (cc *cacheContext) Put(tp, key, value any) {
+	cc.lock.Lock()
+	defer cc.lock.Unlock()
+
+	if cc.discard {
+		return
+	}
+
+	d := cc.data[tp]
+	if d == nil {
+		d = make(map[any]any)
+		cc.data[tp] = d
+	}
+	d[key] = value
+}
+
+func (cc *cacheContext) Delete(tp, key any) {
+	cc.lock.Lock()
+	defer cc.lock.Unlock()
+	delete(cc.data[tp], key)
+}
+
+func (cc *cacheContext) Discard() {
+	cc.lock.Lock()
+	defer cc.lock.Unlock()
+	cc.data = nil
+	cc.discard = true
+}
+
+func (cc *cacheContext) isDiscard() bool {
+	cc.lock.RLock()
+	defer cc.lock.RUnlock()
+	return cc.discard
+}
+
+// cacheContextLifetime is the max lifetime of cacheContext.
+// Since cacheContext is used to cache data in a request level context, 10s is enough.
+// If a cacheContext is used more than 10s, it's probably misuse.
+const cacheContextLifetime = 10 * time.Second
+
+var timeNow = time.Now
+
+func (cc *cacheContext) Expired() bool {
+	return timeNow().Sub(cc.created) > cacheContextLifetime
+}
+
+var cacheContextKey = struct{}{}
+
+/*
+Since there are both WithCacheContext and WithNoCacheContext,
+it may be confusing when there is nesting.
+
+Some cases to explain the design:
+
+When:
+- A, B or C means a cache context.
+- A', B' or C' means a discard cache context.
+- ctx means context.Backgrand().
+- A(ctx) means a cache context with ctx as the parent context.
+- B(A(ctx)) means a cache context with A(ctx) as the parent context.
+- With is alias of WithCacheContext.
+- WithNo is alias of WithNoCacheContext.
+
+So:
+- With(ctx) -> A(ctx)
+- With(With(ctx)) -> A(ctx), not B(A(ctx)), always reuse parent cache context if possible.
+- With(With(With(ctx))) -> A(ctx), not C(B(A(ctx))), ditto.
+- WithNo(ctx) -> ctx, not A'(ctx), don't create new cache context if we don't have to.
+- WithNo(With(ctx)) -> A'(ctx)
+- WithNo(WithNo(With(ctx))) -> A'(ctx), not B'(A'(ctx)), don't create new cache context if we don't have to.
+- With(WithNo(With(ctx))) -> B(A'(ctx)), not A(ctx), never reuse a discard cache context.
+- WithNo(With(WithNo(With(ctx)))) -> B'(A'(ctx))
+- With(WithNo(With(WithNo(With(ctx))))) -> C(B'(A'(ctx))), so there's always only one not-discard cache context.
+*/
+
+func WithCacheContext(ctx context.Context) context.Context {
+	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
+		if !c.isDiscard() {
+			// reuse parent context
+			return ctx
+		}
+	}
+	return context.WithValue(ctx, cacheContextKey, &cacheContext{
+		data:    make(map[any]map[any]any),
+		created: timeNow(),
+	})
+}
+
+func WithNoCacheContext(ctx context.Context) context.Context {
+	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
+		// The caller want to run long-life tasks, but the parent context is a cache context.
+		// So we should disable and clean the cache data, or it will be kept in memory for a long time.
+		c.Discard()
+		return ctx
+	}
+
+	return ctx
+}
+
+func GetContextData(ctx context.Context, tp, key any) any {
+	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
+		if c.Expired() {
+			// The warning means that the cache context is misused for long-life task,
+			// it can be resolved with WithNoCacheContext(ctx).
+			log.Warn("cache context is expired, may be misused for long-life tasks: %v", c)
+			return nil
+		}
+		return c.Get(tp, key)
+	}
+	return nil
+}
+
+func SetContextData(ctx context.Context, tp, key, value any) {
+	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
+		if c.Expired() {
+			// The warning means that the cache context is misused for long-life task,
+			// it can be resolved with WithNoCacheContext(ctx).
+			log.Warn("cache context is expired, may be misused for long-life tasks: %v", c)
+			return
+		}
+		c.Put(tp, key, value)
+		return
+	}
+}
+
+func RemoveContextData(ctx context.Context, tp, key any) {
+	if c, ok := ctx.Value(cacheContextKey).(*cacheContext); ok {
+		if c.Expired() {
+			// The warning means that the cache context is misused for long-life task,
+			// it can be resolved with WithNoCacheContext(ctx).
+			log.Warn("cache context is expired, may be misused for long-life tasks: %v", c)
+			return
+		}
+		c.Delete(tp, key)
+	}
+}
+
+// GetWithContextCache returns the cache value of the given key in the given context.
+func GetWithContextCache[T any](ctx context.Context, cacheGroupKey string, cacheTargetID any, f func() (T, error)) (T, error) {
+	v := GetContextData(ctx, cacheGroupKey, cacheTargetID)
+	if vv, ok := v.(T); ok {
+		return vv, nil
+	}
+	t, err := f()
+	if err != nil {
+		return t, err
+	}
+	SetContextData(ctx, cacheGroupKey, cacheTargetID, t)
+	return t, nil
+}
diff --git a/modules/cache/context_test.go b/modules/cache/context_test.go
new file mode 100644
index 00000000..1ee3d2dd
--- /dev/null
+++ b/modules/cache/context_test.go
@@ -0,0 +1,79 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cache
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestWithCacheContext(t *testing.T) {
+	ctx := WithCacheContext(context.Background())
+
+	v := GetContextData(ctx, "empty_field", "my_config1")
+	assert.Nil(t, v)
+
+	const field = "system_setting"
+	v = GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v)
+	SetContextData(ctx, field, "my_config1", 1)
+	v = GetContextData(ctx, field, "my_config1")
+	assert.NotNil(t, v)
+	assert.EqualValues(t, 1, v.(int))
+
+	RemoveContextData(ctx, field, "my_config1")
+	RemoveContextData(ctx, field, "my_config2") // remove a non-exist key
+
+	v = GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v)
+
+	vInt, err := GetWithContextCache(ctx, field, "my_config1", func() (int, error) {
+		return 1, nil
+	})
+	require.NoError(t, err)
+	assert.EqualValues(t, 1, vInt)
+
+	v = GetContextData(ctx, field, "my_config1")
+	assert.EqualValues(t, 1, v)
+
+	now := timeNow
+	defer func() {
+		timeNow = now
+	}()
+	timeNow = func() time.Time {
+		return now().Add(10 * time.Second)
+	}
+	v = GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v)
+}
+
+func TestWithNoCacheContext(t *testing.T) {
+	ctx := context.Background()
+
+	const field = "system_setting"
+
+	v := GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v)
+	SetContextData(ctx, field, "my_config1", 1)
+	v = GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v) // still no cache
+
+	ctx = WithCacheContext(ctx)
+	v = GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v)
+	SetContextData(ctx, field, "my_config1", 1)
+	v = GetContextData(ctx, field, "my_config1")
+	assert.NotNil(t, v)
+
+	ctx = WithNoCacheContext(ctx)
+	v = GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v)
+	SetContextData(ctx, field, "my_config1", 1)
+	v = GetContextData(ctx, field, "my_config1")
+	assert.Nil(t, v) // still no cache
+}