增加websocket支持

vendor/github.com/jackc/pgx/v5/large_objects.go

@@ -4,15 +4,8 @@ import (
 	"context"
 	"errors"
 	"io"
-
-	"github.com/jackc/pgx/v5/pgtype"
 )
 
-// The PostgreSQL wire protocol has a limit of 1 GB - 1 per message. See definition of
-// PQ_LARGE_MESSAGE_LIMIT in the PostgreSQL source code. To allow for the other data
-// in the message,maxLargeObjectMessageLength should be no larger than 1 GB - 1 KB.
-var maxLargeObjectMessageLength = 1024*1024*1024 - 1024
-
 // LargeObjects is a structure used to access the large objects API. It is only valid within the transaction where it
 // was created.
 //
@@ -75,65 +68,32 @@ type LargeObject struct {
 
 // Write writes p to the large object and returns the number of bytes written and an error if not all of p was written.
 func (o *LargeObject) Write(p []byte) (int, error) {
-	nTotal := 0
-	for {
-		expected := len(p) - nTotal
-		if expected == 0 {
-			break
-		} else if expected > maxLargeObjectMessageLength {
-			expected = maxLargeObjectMessageLength
-		}
-
-		var n int
-		err := o.tx.QueryRow(o.ctx, "select lowrite($1, $2)", o.fd, p[nTotal:nTotal+expected]).Scan(&n)
-		if err != nil {
-			return nTotal, err
-		}
-
-		if n < 0 {
-			return nTotal, errors.New("failed to write to large object")
-		}
-
-		nTotal += n
-
-		if n < expected {
-			return nTotal, errors.New("short write to large object")
-		} else if n > expected {
-			return nTotal, errors.New("invalid write to large object")
-		}
+	var n int
+	err := o.tx.QueryRow(o.ctx, "select lowrite($1, $2)", o.fd, p).Scan(&n)
+	if err != nil {
+		return n, err
 	}
 
-	return nTotal, nil
+	if n < 0 {
+		return 0, errors.New("failed to write to large object")
+	}
+
+	return n, nil
 }
 
 // Read reads up to len(p) bytes into p returning the number of bytes read.
 func (o *LargeObject) Read(p []byte) (int, error) {
-	nTotal := 0
-	for {
-		expected := len(p) - nTotal
-		if expected == 0 {
-			break
-		} else if expected > maxLargeObjectMessageLength {
-			expected = maxLargeObjectMessageLength
-		}
-
-		res := pgtype.PreallocBytes(p[nTotal:])
-		err := o.tx.QueryRow(o.ctx, "select loread($1, $2)", o.fd, expected).Scan(&res)
-		// We compute expected so that it always fits into p, so it should never happen
-		// that PreallocBytes's ScanBytes had to allocate a new slice.
-		nTotal += len(res)
-		if err != nil {
-			return nTotal, err
-		}
-
-		if len(res) < expected {
-			return nTotal, io.EOF
-		} else if len(res) > expected {
-			return nTotal, errors.New("invalid read of large object")
-		}
+	var res []byte
+	err := o.tx.QueryRow(o.ctx, "select loread($1, $2)", o.fd, len(p)).Scan(&res)
+	copy(p, res)
+	if err != nil {
+		return len(res), err
 	}
 
-	return nTotal, nil
+	if len(res) < len(p) {
+		err = io.EOF
+	}
+	return len(res), err
 }
 
 // Seek moves the current location pointer to the new location specified by offset.