!TEMP! driver,protocol: Implement ResetSession

Implementation stolen from the mysql go sql driver. Temporary draft to run tests.
canonical · May 12, 2023 · 25bae79 · 25bae79
1 parent cec175e
commit 25bae79
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Showing 2 changed files with 52 additions and 5 deletions.
diff --git a/driver/driver.go b/driver/driver.go
@@ -335,6 +335,14 @@ type Conn struct {
 	tracing        client.LogLevel
 }
 
+func (c *Conn) ResetSession(ctx context.Context) error {
+	err := c.protocol.ConnCheck()
+	if err != nil {
+		return driver.ErrBadConn
+	}
+	return nil
+}
+
 // PrepareContext returns a prepared statement, bound to this connection.
 // context is for the preparation of the statement, it must not store the
 // context within the statement itself.
@@ -353,7 +361,7 @@ func (c *Conn) PrepareContext(ctx context.Context, query string) (driver.Stmt, e
 	if c.tracing != client.LogNone {
 		start = time.Now()
 	}
-	err := c.protocol.Call(ctx, &c.request, &c.response);
+	err := c.protocol.Call(ctx, &c.request, &c.response)
 	if c.tracing != client.LogNone {
 		c.log(c.tracing, "%.3fs request prepared: %q", time.Since(start).Seconds(), query)
 	}
@@ -392,7 +400,7 @@ func (c *Conn) ExecContext(ctx context.Context, query string, args []driver.Name
 	if c.tracing != client.LogNone {
 		start = time.Now()
 	}
-	err := c.protocol.Call(ctx, &c.request, &c.response);
+	err := c.protocol.Call(ctx, &c.request, &c.response)
 	if c.tracing != client.LogNone {
 		c.log(c.tracing, "%.3fs request exec: %q", time.Since(start).Seconds(), query)
 	}
@@ -428,7 +436,7 @@ func (c *Conn) QueryContext(ctx context.Context, query string, args []driver.Nam
 	if c.tracing != client.LogNone {
 		start = time.Now()
 	}
-	err := c.protocol.Call(ctx, &c.request, &c.response);
+	err := c.protocol.Call(ctx, &c.request, &c.response)
 	if c.tracing != client.LogNone {
 		c.log(c.tracing, "%.3fs request query: %q", time.Since(start).Seconds(), query)
 	}
@@ -588,7 +596,7 @@ func (s *Stmt) ExecContext(ctx context.Context, args []driver.NamedValue) (drive
 	if s.tracing != client.LogNone {
 		start = time.Now()
 	}
-	err := s.protocol.Call(ctx, s.request, s.response);
+	err := s.protocol.Call(ctx, s.request, s.response)
 	if s.tracing != client.LogNone {
 		s.log(s.tracing, "%.3fs request prepared: %q", time.Since(start).Seconds(), s.sql)
 	}
@@ -627,7 +635,7 @@ func (s *Stmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driv
 	if s.tracing != client.LogNone {
 		start = time.Now()
 	}
-	err := s.protocol.Call(ctx, s.request, s.response);
+	err := s.protocol.Call(ctx, s.request, s.response)
 	if s.tracing != client.LogNone {
 		s.log(s.tracing, "%.3fs request prepared: %q", time.Since(start).Seconds(), s.sql)
 	}

diff --git a/internal/protocol/protocol.go b/internal/protocol/protocol.go
@@ -6,6 +6,7 @@ import (
 	"io"
 	"net"
 	"sync"
+	"syscall"
 	"time"
 
 	"github.com/pkg/errors"
@@ -30,6 +31,44 @@ func newProtocol(version uint64, conn net.Conn) *Protocol {
 	return protocol
 }
 
+func connCheck(conn net.Conn) error {
+	var sysErr error
+
+	sysConn, ok := conn.(syscall.Conn)
+	if !ok {
+		return nil
+	}
+	rawConn, err := sysConn.SyscallConn()
+	if err != nil {
+		return err
+	}
+
+	err = rawConn.Read(func(fd uintptr) bool {
+		var buf [1]byte
+		n, err := syscall.Read(int(fd), buf[:])
+		switch {
+		case n == 0 && err == nil:
+			sysErr = io.EOF
+		case n > 0:
+			sysErr = syscall.EBADFD // TODO assign a sensible error here.
+		case err == syscall.EAGAIN || err == syscall.EWOULDBLOCK:
+			sysErr = nil
+		default:
+			sysErr = err
+		}
+		return true
+	})
+	if err != nil {
+		return err
+	}
+
+	return sysErr
+}
+
+func (p *Protocol) ConnCheck() error {
+	return connCheck(p.conn)
+}
+
 // Call invokes a dqlite RPC, sending a request message and receiving a
 // response message.
 func (p *Protocol) Call(ctx context.Context, request, response *Message) (err error) {