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authorGibheer <gibheer+git@zero-knowledge.org>2024-09-05 19:38:25 +0200
committerGibheer <gibheer+git@zero-knowledge.org>2024-09-05 19:38:25 +0200
commit6ea4d2c82de80efc87708e5e182034b7c6c2019e (patch)
tree35c0856a929040216c82153ca62d43b27530a887 /vendor/github.com/jackc/pgx/v5/large_objects.go
parent6f64eeace1b66639b9380b44e88a8d54850a4306 (diff)
switch from github.com/lib/pq to github.com/jackc/pgx/v5HEAD20240905master
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.
Diffstat (limited to 'vendor/github.com/jackc/pgx/v5/large_objects.go')
-rw-r--r--vendor/github.com/jackc/pgx/v5/large_objects.go161
1 files changed, 161 insertions, 0 deletions
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
+}