Use a LRUCache rather than an Unbounded one

go.mod

@@ -4,6 +4,7 @@ go 1.19
 
 require (
 	github.com/ALTree/bigfloat v0.0.0-20220102081255-38c8b72a9924
+	github.com/gammazero/deque v0.2.0
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/google/uuid v1.3.0
 	github.com/jamesruan/go-rfc1924 v0.0.0-20170108144916-2767ca7c638f
@@ -11,7 +12,7 @@ require (
 	github.com/spf13/cobra v1.5.0
 	github.com/spf13/pflag v1.0.5
 	golang.org/x/crypto v0.0.0-20220919173607-35f4265a4bc0
-	golang.org/x/exp v0.0.0-20220921023135-46d9e7742f1e
+	golang.org/x/exp v0.0.0-20220921164117-439092de6870
 	golang.org/x/image v0.0.0-20220902085622-e7cb96979f69
 	golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8
 )

go.sum

@@ -1,6 +1,8 @@
 github.com/ALTree/bigfloat v0.0.0-20220102081255-38c8b72a9924 h1:DG4UyTVIujioxwJc8Zj8Nabz1L1wTgQ/xNBSQDfdP3I=
 github.com/ALTree/bigfloat v0.0.0-20220102081255-38c8b72a9924/go.mod h1:+NaH2gLeY6RPBPPQf4aRotPPStg+eXc8f9ZaE4vRfD4=
 github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/gammazero/deque v0.2.0 h1:SkieyNB4bg2/uZZLxvya0Pq6diUlwx7m2TeT7GAIWaA=
+github.com/gammazero/deque v0.2.0/go.mod h1:LFroj8x4cMYCukHJDbxFCkT+r9AndaJnFMuZDV34tuU=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
@@ -21,8 +23,8 @@ github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 golang.org/x/crypto v0.0.0-20220919173607-35f4265a4bc0 h1:a5Yg6ylndHHYJqIPrdq0AhvR6KTvDTAvgBtaidhEevY=
 golang.org/x/crypto v0.0.0-20220919173607-35f4265a4bc0/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
-golang.org/x/exp v0.0.0-20220921023135-46d9e7742f1e h1:Ctm9yurWsg7aWwIpH9Bnap/IdSVxixymIb3MhiMEQQA=
+golang.org/x/exp v0.0.0-20220921164117-439092de6870 h1:j8b6j9gzSigH28O5SjSpQSSh9lFd6f5D/q0aHjNTulc=
-golang.org/x/exp v0.0.0-20220921023135-46d9e7742f1e/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
+golang.org/x/exp v0.0.0-20220921164117-439092de6870/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
 golang.org/x/image v0.0.0-20220902085622-e7cb96979f69 h1:Lj6HJGCSn5AjxRAH2+r35Mir4icalbqku+CLUtjnvXY=
 golang.org/x/image v0.0.0-20220902085622-e7cb96979f69/go.mod h1:doUCurBvlfPMKfmIpRIywoHmhN3VyhnoFDbvIEWF4hY=
 golang.org/x/sys v0.0.0-20220919091848-fb04ddd9f9c8 h1:h+EGohizhe9XlX18rfpa8k8RAc5XyaeamM+0VHRd4lc=

tools/utils/cache.go

@@ -0,0 +1,59 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package utils
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/gammazero/deque"
+)
+
+var _ = fmt.Print
+
+type LRUCache[K comparable, V any] struct {
+	data     map[K]V
+	lock     sync.RWMutex
+	max_size int
+	lru      deque.Deque[K]
+}
+
+func NewLRUCache[K comparable, V any](max_size int) *LRUCache[K, V] {
+	ans := LRUCache[K, V]{data: map[K]V{}, max_size: max_size}
+	return &ans
+}
+
+func (self *LRUCache[K, V]) GetOrCreate(key K, create func(key K) (V, error)) (V, error) {
+	self.lock.RLock()
+	ans, found := self.data[key]
+	self.lock.RUnlock()
+	if found {
+		return ans, nil
+	}
+	ans, err := create(key)
+	if err == nil {
+		self.lock.Lock()
+		self.data[key] = ans
+		self.lru.PushFront(key)
+		if self.max_size > 0 && self.lru.Len() > self.max_size {
+			k := self.lru.PopBack()
+			delete(self.data, k)
+		}
+		self.lock.Unlock()
+	}
+	return ans, err
+}
+
+func (self *LRUCache[K, V]) MustGetOrCreate(key K, create func(key K) V) V {
+	self.lock.RLock()
+	ans, found := self.data[key]
+	self.lock.RUnlock()
+	if found {
+		return ans
+	}
+	ans = create(key)
+	self.lock.Lock()
+	self.data[key] = ans
+	self.lock.Unlock()
+	return ans
+}

tools/utils/regexp.go

@@ -6,52 +6,11 @@ import (
 	"fmt"
 	"regexp"
 	"strings"
-	"sync"
 )
 
 var _ = fmt.Print
 
-type UnboundedCache[K comparable, V any] struct {
+var pat_cache = NewLRUCache[string, *regexp.Regexp](128)
-	data map[K]V
-	lock sync.RWMutex
-}
-
-func NewUnboundedCache[K comparable, V any]() *UnboundedCache[K, V] {
-	ans := UnboundedCache[K, V]{data: map[K]V{}}
-	return &ans
-}
-
-func (self *UnboundedCache[K, V]) GetOrCreate(key K, create func(key K) (V, error)) (V, error) {
-	self.lock.RLock()
-	ans, found := self.data[key]
-	self.lock.RUnlock()
-	if found {
-		return ans, nil
-	}
-	ans, err := create(key)
-	if err == nil {
-		self.lock.Lock()
-		self.data[key] = ans
-		self.lock.Unlock()
-	}
-	return ans, err
-}
-
-func (self *UnboundedCache[K, V]) MustGetOrCreate(key K, create func(key K) V) V {
-	self.lock.RLock()
-	ans, found := self.data[key]
-	self.lock.RUnlock()
-	if found {
-		return ans
-	}
-	ans = create(key)
-	self.lock.Lock()
-	self.data[key] = ans
-	self.lock.Unlock()
-	return ans
-}
-
-var pat_cache = NewUnboundedCache[string, *regexp.Regexp]()
 
 type SubMatch struct {
 	Text       string