From bf46501a1049667338295ff74df82b6d32bbffab Mon Sep 17 00:00:00 2001
From: dragon <explodingfkl@gmail.com>
Date: Fri, 27 Dec 2024 17:32:02 +0800
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9E=20cache?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 README.md              |  2 +
 pkg/server.go          |  8 ++++
 pkg/services/cache.go  | 96 ++++++++++++++++++++++++++++++++++++++++--
 pkg/services/config.go | 58 +++++++++++++++++++++++++
 4 files changed, 161 insertions(+), 3 deletions(-)
 create mode 100644 pkg/services/config.go

diff --git a/README.md b/README.md
index 134c8ac..642049a 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,8 @@
 
 > 新一代 Gitea Pages，替换之前的 caddy-gitea-proxy
 
+注意，默认实现未考虑高并发高负载环境，
+
 ## TODO
 
 - [ ] CNAME 自定义域名
diff --git a/pkg/server.go b/pkg/server.go
index d092a8d..992391e 100644
--- a/pkg/server.go
+++ b/pkg/server.go
@@ -6,6 +6,14 @@ import (
 
 type ServerOptions struct {
 	Domain string
+	Cache  services.Config
+}
+
+func DefaultOptions(domain string) *ServerOptions {
+	return &ServerOptions{
+		Domain: domain,
+		Cache:  services.NewConfigMemory(),
+	}
 }
 
 type Server struct {
diff --git a/pkg/services/cache.go b/pkg/services/cache.go
index 6525513..cb82be4 100644
--- a/pkg/services/cache.go
+++ b/pkg/services/cache.go
@@ -1,7 +1,97 @@
 package services
 
+import (
+	"errors"
+	"io"
+	"sync"
+	"time"
+)
+
 type Cache interface {
-	Put(key string, value []byte) error
-	Get(key string) ([]byte, error)
-	Delete(key string) error
+	Put(key string, reader io.Reader) error
+	Get(key string) (io.ReadSeekCloser, error)
+	Delete(pattern string) error
+	io.Closer
+}
+
+var ErrCacheOutOfMemory = errors.New("内容无法被缓存，超过最大限定值")
+
+type CacheMemory struct {
+	l       sync.RWMutex
+	data    map[string][]byte
+	maxAge  time.Duration
+	sizeGl  int
+	sizeOne int
+
+	current int
+	cache   []byte
+	ordered []string
+}
+
+func NewCacheMemory(maxUsage, maxGlobalUsage int) *CacheMemory {
+	return &CacheMemory{
+		data:    make(map[string][]byte),
+		l:       sync.RWMutex{},
+		sizeGl:  maxGlobalUsage,
+		sizeOne: maxUsage,
+
+		cache:   make([]byte, maxUsage+1),
+		ordered: make([]string, 0),
+	}
+}
+
+func (c *CacheMemory) Put(key string, reader io.Reader) error {
+	c.l.Lock()
+	defer c.l.Unlock()
+	size, err := io.ReadAtLeast(reader, c.cache, 0)
+	if err != nil {
+		return err
+	}
+	if size == len(c.cache) {
+		return ErrCacheOutOfMemory
+	}
+	needed := c.sizeGl - c.current + size
+	if needed < 0 {
+		// 清理旧的内容
+		count := 0
+		for i, k := range c.ordered {
+			needed += len(c.data[k])
+			if needed > 0 {
+				break
+			}
+			count = i + 1
+		}
+
+		if needed < 0 {
+			// 清理全部内容也无法留出空间
+			return ErrCacheOutOfMemory
+		}
+		for _, s := range c.ordered[:count] {
+			delete(c.data, s)
+			c.current -= len(c.data)
+		}
+		c.ordered = c.ordered[count:]
+	}
+
+	dest := make([]byte, size)
+	copy(dest, c.cache[:size])
+	c.data[key] = dest
+	c.ordered = append(c.ordered, key)
+	c.current += len(dest)
+	return nil
+}
+
+func (c *CacheMemory) Get(key string) (io.ReadSeekCloser, error) {
+	//TODO implement me
+	panic("implement me")
+}
+
+func (c *CacheMemory) Delete(key string) error {
+	//TODO implement me
+	panic("implement me")
+}
+
+func (c *CacheMemory) Close() error {
+	//TODO implement me
+	panic("implement me")
 }
diff --git a/pkg/services/config.go b/pkg/services/config.go
new file mode 100644
index 0000000..c96db81
--- /dev/null
+++ b/pkg/services/config.go
@@ -0,0 +1,58 @@
+package services
+
+import (
+	"io"
+	"os"
+	"sync"
+)
+
+type Config interface {
+	Put(key string, value string) error
+	Get(key string) (string, error)
+	Delete(key string) error
+	io.Closer
+}
+
+func NewConfigMemory() Config {
+	return &ConfigMemory{
+		data: make(map[string]string),
+		lock: sync.RWMutex{},
+	}
+}
+
+// ConfigMemory 一个简单的内存配置归档，仅用于测试
+type ConfigMemory struct {
+	data map[string]string
+	lock sync.RWMutex
+}
+
+func (m *ConfigMemory) Put(key string, value string) error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	m.data[key] = value
+	return nil
+}
+
+func (m *ConfigMemory) Get(key string) (string, error) {
+	m.lock.RLock()
+	defer m.lock.RUnlock()
+	v, ok := m.data[key]
+	if !ok {
+		return "", os.ErrNotExist
+	}
+	return v, nil
+}
+
+func (m *ConfigMemory) Delete(key string) error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	delete(m.data, key)
+	return nil
+}
+
+func (m *ConfigMemory) Close() error {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+	clear(m.data)
+	return nil
+}