OP#792 initial commit after fork

internal/deadlineconn/deadlineconn.go

@@ -0,0 +1,176 @@
+// Copyright (c) 2015-2022 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 deadlineconn implements net.Conn wrapper with configured deadlines.
+package deadlineconn
+
+import (
+	"context"
+	"net"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// updateInterval is the minimum time between deadline updates.
+const updateInterval = 250 * time.Millisecond
+
+// DeadlineConn - is a generic stream-oriented network connection supporting buffered reader and read/write timeout.
+type DeadlineConn struct {
+	net.Conn
+	readDeadline            time.Duration // sets the read deadline on a connection.
+	readSetAt               time.Time
+	writeDeadline           time.Duration // sets the write deadline on a connection.
+	writeSetAt              time.Time
+	abortReads, abortWrites atomic.Bool // A deadline was set to indicate caller wanted the conn to time out.
+	infReads, infWrites     atomic.Bool
+	mu                      sync.Mutex
+}
+
+// Unwrap will unwrap the connection and remove the deadline if applied.
+// If not a *DeadlineConn, the unmodified net.Conn is returned.
+func Unwrap(c net.Conn) net.Conn {
+	if dc, ok := c.(*DeadlineConn); ok {
+		return dc.Conn
+	}
+	return c
+}
+
+// Sets read deadline
+func (c *DeadlineConn) setReadDeadline() {
+	// Do not set a Read deadline, if upstream wants to cancel all reads.
+	if c.readDeadline <= 0 || c.abortReads.Load() || c.infReads.Load() {
+		return
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.abortReads.Load() {
+		return
+	}
+
+	now := time.Now()
+	if now.Sub(c.readSetAt) > updateInterval {
+		c.Conn.SetReadDeadline(now.Add(c.readDeadline + updateInterval))
+		c.readSetAt = now
+	}
+}
+
+func (c *DeadlineConn) setWriteDeadline() {
+	// Do not set a Write deadline, if upstream wants to cancel all reads.
+	if c.writeDeadline <= 0 || c.abortWrites.Load() || c.infWrites.Load() {
+		return
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.abortWrites.Load() {
+		return
+	}
+	now := time.Now()
+	if now.Sub(c.writeSetAt) > updateInterval {
+		c.Conn.SetWriteDeadline(now.Add(c.writeDeadline + updateInterval))
+		c.writeSetAt = now
+	}
+}
+
+// Read - reads data from the connection using wrapped buffered reader.
+func (c *DeadlineConn) Read(b []byte) (n int, err error) {
+	if c.abortReads.Load() {
+		return 0, context.DeadlineExceeded
+	}
+	c.setReadDeadline()
+	n, err = c.Conn.Read(b)
+	return n, err
+}
+
+// Write - writes data to the connection.
+func (c *DeadlineConn) Write(b []byte) (n int, err error) {
+	if c.abortWrites.Load() {
+		return 0, context.DeadlineExceeded
+	}
+	c.setWriteDeadline()
+	n, err = c.Conn.Write(b)
+	return n, err
+}
+
+// SetDeadline will set the deadline for reads and writes.
+// A zero value for t means I/O operations will not time out.
+func (c *DeadlineConn) SetDeadline(t time.Time) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.readSetAt = time.Time{}
+	c.writeSetAt = time.Time{}
+	c.abortReads.Store(!t.IsZero() && time.Until(t) < 0)
+	c.abortWrites.Store(!t.IsZero() && time.Until(t) < 0)
+	c.infReads.Store(t.IsZero())
+	c.infWrites.Store(t.IsZero())
+	return c.Conn.SetDeadline(t)
+}
+
+// SetReadDeadline sets the deadline for future Read calls
+// and any currently-blocked Read call.
+// A zero value for t means Read will not time out.
+func (c *DeadlineConn) SetReadDeadline(t time.Time) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.abortReads.Store(!t.IsZero() && time.Until(t) < 0)
+	c.infReads.Store(t.IsZero())
+	c.readSetAt = time.Time{}
+	return c.Conn.SetReadDeadline(t)
+}
+
+// SetWriteDeadline sets the deadline for future Write calls
+// and any currently-blocked Write call.
+// Even if write times out, it may return n > 0, indicating that
+// some of the data was successfully written.
+// A zero value for t means Write will not time out.
+func (c *DeadlineConn) SetWriteDeadline(t time.Time) error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.abortWrites.Store(!t.IsZero() && time.Until(t) < 0)
+	c.infWrites.Store(t.IsZero())
+	c.writeSetAt = time.Time{}
+	return c.Conn.SetWriteDeadline(t)
+}
+
+// Close wraps conn.Close and stops sending deadline updates.
+func (c *DeadlineConn) Close() error {
+	c.abortReads.Store(true)
+	c.abortWrites.Store(true)
+	return c.Conn.Close()
+}
+
+// WithReadDeadline sets a new read side net.Conn deadline.
+func (c *DeadlineConn) WithReadDeadline(d time.Duration) *DeadlineConn {
+	c.readDeadline = d
+	return c
+}
+
+// WithWriteDeadline sets a new write side net.Conn deadline.
+func (c *DeadlineConn) WithWriteDeadline(d time.Duration) *DeadlineConn {
+	c.writeDeadline = d
+	return c
+}
+
+// New - creates a new connection object wrapping net.Conn with deadlines.
+func New(c net.Conn) *DeadlineConn {
+	return &DeadlineConn{
+		Conn: c,
+	}
+}