From 6ea4d2c82de80efc87708e5e182034b7c6c2019e Mon Sep 17 00:00:00 2001 From: Gibheer Date: Thu, 5 Sep 2024 19:38:25 +0200 Subject: switch from github.com/lib/pq to github.com/jackc/pgx/v5 lib/pq is out of maintenance for some time now, so switch to the newer more active library. Looks like it finally stabilized after a long time. --- vendor/github.com/jackc/pgx/v5/large_objects.go | 161 ++++++++++++++++++++++++ 1 file changed, 161 insertions(+) create mode 100644 vendor/github.com/jackc/pgx/v5/large_objects.go (limited to 'vendor/github.com/jackc/pgx/v5/large_objects.go') diff --git a/vendor/github.com/jackc/pgx/v5/large_objects.go b/vendor/github.com/jackc/pgx/v5/large_objects.go new file mode 100644 index 0000000..9d21afd --- /dev/null +++ b/vendor/github.com/jackc/pgx/v5/large_objects.go @@ -0,0 +1,161 @@ +package pgx + +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. +// +// For more details see: http://www.postgresql.org/docs/current/static/largeobjects.html +type LargeObjects struct { + tx Tx +} + +type LargeObjectMode int32 + +const ( + LargeObjectModeWrite LargeObjectMode = 0x20000 + LargeObjectModeRead LargeObjectMode = 0x40000 +) + +// Create creates a new large object. If oid is zero, the server assigns an unused OID. +func (o *LargeObjects) Create(ctx context.Context, oid uint32) (uint32, error) { + err := o.tx.QueryRow(ctx, "select lo_create($1)", oid).Scan(&oid) + return oid, err +} + +// Open opens an existing large object with the given mode. ctx will also be used for all operations on the opened large +// object. +func (o *LargeObjects) Open(ctx context.Context, oid uint32, mode LargeObjectMode) (*LargeObject, error) { + var fd int32 + err := o.tx.QueryRow(ctx, "select lo_open($1, $2)", oid, mode).Scan(&fd) + if err != nil { + return nil, err + } + return &LargeObject{fd: fd, tx: o.tx, ctx: ctx}, nil +} + +// Unlink removes a large object from the database. +func (o *LargeObjects) Unlink(ctx context.Context, oid uint32) error { + var result int32 + err := o.tx.QueryRow(ctx, "select lo_unlink($1)", oid).Scan(&result) + if err != nil { + return err + } + + if result != 1 { + return errors.New("failed to remove large object") + } + + return nil +} + +// A LargeObject is a large object stored on the server. It is only valid within the transaction that it was initialized +// in. It uses the context it was initialized with for all operations. It implements these interfaces: +// +// io.Writer +// io.Reader +// io.Seeker +// io.Closer +type LargeObject struct { + ctx context.Context + tx Tx + fd int32 +} + +// 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") + } + } + + return nTotal, 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") + } + } + + return nTotal, nil +} + +// Seek moves the current location pointer to the new location specified by offset. +func (o *LargeObject) Seek(offset int64, whence int) (n int64, err error) { + err = o.tx.QueryRow(o.ctx, "select lo_lseek64($1, $2, $3)", o.fd, offset, whence).Scan(&n) + return n, err +} + +// Tell returns the current read or write location of the large object descriptor. +func (o *LargeObject) Tell() (n int64, err error) { + err = o.tx.QueryRow(o.ctx, "select lo_tell64($1)", o.fd).Scan(&n) + return n, err +} + +// Truncate the large object to size. +func (o *LargeObject) Truncate(size int64) (err error) { + _, err = o.tx.Exec(o.ctx, "select lo_truncate64($1, $2)", o.fd, size) + return err +} + +// Close the large object descriptor. +func (o *LargeObject) Close() error { + _, err := o.tx.Exec(o.ctx, "select lo_close($1)", o.fd) + return err +} -- cgit v1.2.3-70-g09d2