rename all remaining packages to internal/ (#12418)

This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`

internal/dsync/dsync-server_test.go

@@ -0,0 +1,151 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package dsync
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+const WriteLock = -1
+
+type lockServer struct {
+	mutex sync.Mutex
+	// Map of locks, with negative value indicating (exclusive) write lock
+	// and positive values indicating number of read locks
+	lockMap map[string]int64
+
+	// Refresh returns lock not found if set to true
+	lockNotFound bool
+
+	// Set to true if you want peers servers to do not respond
+	responseDelay int64
+}
+
+func (l *lockServer) setRefreshReply(refreshed bool) {
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+	l.lockNotFound = !refreshed
+}
+
+func (l *lockServer) setResponseDelay(responseDelay time.Duration) {
+	atomic.StoreInt64(&l.responseDelay, int64(responseDelay))
+}
+
+func (l *lockServer) Lock(args *LockArgs, reply *bool) error {
+	if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
+		time.Sleep(time.Duration(d))
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+	if _, *reply = l.lockMap[args.Resources[0]]; !*reply {
+		l.lockMap[args.Resources[0]] = WriteLock // No locks held on the given name, so claim write lock
+	}
+	*reply = !*reply // Negate *reply to return true when lock is granted or false otherwise
+	return nil
+}
+
+func (l *lockServer) Unlock(args *LockArgs, reply *bool) error {
+	if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
+		time.Sleep(time.Duration(d))
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+	var locksHeld int64
+	if locksHeld, *reply = l.lockMap[args.Resources[0]]; !*reply { // No lock is held on the given name
+		return fmt.Errorf("Unlock attempted on an unlocked entity: %s", args.Resources[0])
+	}
+	if *reply = locksHeld == WriteLock; !*reply { // Unless it is a write lock
+		return fmt.Errorf("Unlock attempted on a read locked entity: %s (%d read locks active)", args.Resources[0], locksHeld)
+	}
+	delete(l.lockMap, args.Resources[0]) // Remove the write lock
+	return nil
+}
+
+const ReadLock = 1
+
+func (l *lockServer) RLock(args *LockArgs, reply *bool) error {
+	if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
+		time.Sleep(time.Duration(d))
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+	var locksHeld int64
+	if locksHeld, *reply = l.lockMap[args.Resources[0]]; !*reply {
+		l.lockMap[args.Resources[0]] = ReadLock // No locks held on the given name, so claim (first) read lock
+		*reply = true
+	} else {
+		if *reply = locksHeld != WriteLock; *reply { // Unless there is a write lock
+			l.lockMap[args.Resources[0]] = locksHeld + ReadLock // Grant another read lock
+		}
+	}
+	return nil
+}
+
+func (l *lockServer) RUnlock(args *LockArgs, reply *bool) error {
+	if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
+		time.Sleep(time.Duration(d))
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+	var locksHeld int64
+	if locksHeld, *reply = l.lockMap[args.Resources[0]]; !*reply { // No lock is held on the given name
+		return fmt.Errorf("RUnlock attempted on an unlocked entity: %s", args.Resources[0])
+	}
+	if *reply = locksHeld != WriteLock; !*reply { // A write-lock is held, cannot release a read lock
+		return fmt.Errorf("RUnlock attempted on a write locked entity: %s", args.Resources[0])
+	}
+	if locksHeld > ReadLock {
+		l.lockMap[args.Resources[0]] = locksHeld - ReadLock // Remove one of the read locks held
+	} else {
+		delete(l.lockMap, args.Resources[0]) // Remove the (last) read lock
+	}
+	return nil
+}
+
+func (l *lockServer) Refresh(args *LockArgs, reply *bool) error {
+	if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
+		time.Sleep(time.Duration(d))
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+	*reply = !l.lockNotFound
+	return nil
+}
+
+func (l *lockServer) ForceUnlock(args *LockArgs, reply *bool) error {
+	if d := atomic.LoadInt64(&l.responseDelay); d != 0 {
+		time.Sleep(time.Duration(d))
+	}
+
+	l.mutex.Lock()
+	defer l.mutex.Unlock()
+	if len(args.UID) != 0 {
+		return fmt.Errorf("ForceUnlock called with non-empty UID: %s", args.UID)
+	}
+	delete(l.lockMap, args.Resources[0]) // Remove the lock (irrespective of write or read lock)
+	*reply = true
+	return nil
+}