Refactor some legacy code and remove unused code (#28622)

1. use slices.Contains, remove Int64sContains
2. use HashEmail, remove base.EncodeMD5
3. remove BasicAuthEncode, IsLetter

4 files changed, 12 insertions, 10 deletions

diff --git a/models/avatars/avatar.go b/models/avatars/avatar.go
index c197a22dc1..bbe16483bf 100644
--- a/models/avatars/avatar.go
+++ b/models/avatars/avatar.go
@@ -5,6 +5,8 @@ package avatars
 
 import (
 	"context"
+	"crypto/md5"
+	"encoding/hex"
 	"fmt"
 	"net/url"
 	"path"
@@ -13,7 +15,6 @@ import (
 	"sync/atomic"
 
 	"code.gitea.io/gitea/models/db"
-	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/cache"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
@@ -90,7 +91,9 @@ func DefaultAvatarLink() string {
 
 // HashEmail hashes email address to MD5 string. https://en.gravatar.com/site/implement/hash/
 func HashEmail(email string) string {
-	return base.EncodeMD5(strings.ToLower(strings.TrimSpace(email)))
+	m := md5.New()
+	_, _ = m.Write([]byte(strings.ToLower(strings.TrimSpace(email))))
+	return hex.EncodeToString(m.Sum(nil))
 }
 
 // GetEmailForHash converts a provided md5sum to the email
diff --git a/models/git/protected_branch.go b/models/git/protected_branch.go
index 528acc175a..66a4b52b17 100644
--- a/models/git/protected_branch.go
+++ b/models/git/protected_branch.go
@@ -17,7 +17,6 @@ import (
 	repo_model "code.gitea.io/gitea/models/repo"
 	"code.gitea.io/gitea/models/unit"
 	user_model "code.gitea.io/gitea/models/user"
-	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/timeutil"
 	"code.gitea.io/gitea/modules/util"
@@ -127,7 +126,7 @@ func (protectBranch *ProtectedBranch) CanUserPush(ctx context.Context, user *use
 		return writeAccess
 	}
 
-	if base.Int64sContains(protectBranch.WhitelistUserIDs, user.ID) {
+	if slices.Contains(protectBranch.WhitelistUserIDs, user.ID) {
 		return true
 	}
 
@@ -150,7 +149,7 @@ func IsUserMergeWhitelisted(ctx context.Context, protectBranch *ProtectedBranch,
 		return permissionInRepo.CanWrite(unit.TypeCode)
 	}
 
-	if base.Int64sContains(protectBranch.MergeWhitelistUserIDs, userID) {
+	if slices.Contains(protectBranch.MergeWhitelistUserIDs, userID) {
 		return true
 	}
 
@@ -182,7 +181,7 @@ func IsUserOfficialReviewer(ctx context.Context, protectBranch *ProtectedBranch,
 		return writeAccess, nil
 	}
 
-	if base.Int64sContains(protectBranch.ApprovalsWhitelistUserIDs, user.ID) {
+	if slices.Contains(protectBranch.ApprovalsWhitelistUserIDs, user.ID) {
 		return true, nil
 	}
 
diff --git a/models/git/protected_tag.go b/models/git/protected_tag.go
index 12e53a3331..8a05045651 100644
--- a/models/git/protected_tag.go
+++ b/models/git/protected_tag.go
@@ -6,11 +6,11 @@ package git
 import (
 	"context"
 	"regexp"
+	"slices"
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/organization"
-	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/timeutil"
 
 	"github.com/gobwas/glob"
@@ -76,7 +76,7 @@ func DeleteProtectedTag(ctx context.Context, pt *ProtectedTag) error {
 
 // IsUserAllowedModifyTag returns true if the user is allowed to modify the tag
 func IsUserAllowedModifyTag(ctx context.Context, pt *ProtectedTag, userID int64) (bool, error) {
-	if base.Int64sContains(pt.AllowlistUserIDs, userID) {
+	if slices.Contains(pt.AllowlistUserIDs, userID) {
 		return true, nil
 	}
 
diff --git a/models/issues/review.go b/models/issues/review.go
index e06670c9a1..4cbfa4f443 100644
--- a/models/issues/review.go
+++ b/models/issues/review.go
@@ -6,6 +6,7 @@ package issues
 import (
 	"context"
 	"fmt"
+	"slices"
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
@@ -15,7 +16,6 @@ import (
 	access_model "code.gitea.io/gitea/models/perm/access"
 	"code.gitea.io/gitea/models/unit"
 	user_model "code.gitea.io/gitea/models/user"
-	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/structs"
 	"code.gitea.io/gitea/modules/timeutil"
 	"code.gitea.io/gitea/modules/util"
@@ -279,7 +279,7 @@ func IsOfficialReviewerTeam(ctx context.Context, issue *Issue, team *organizatio
 		return team.UnitAccessMode(ctx, unit.TypeCode) >= perm.AccessModeWrite, nil
 	}
 
-	return base.Int64sContains(pb.ApprovalsWhitelistTeamIDs, team.ID), nil
+	return slices.Contains(pb.ApprovalsWhitelistTeamIDs, team.ID), nil
 }
 
 // CreateReview creates a new review based on opts