Move basebackup code to new directory src/backend/backup

Reviewed by David Steele and Justin Pryzby

Discussion: http://postgr.es/m/CA+TgmoafqboATDSoXHz8VLrSwK_MDhjthK4hEpYjqf9_1Fmczw%40mail.gmail.com

src/backend/backup/basebackup_sink.c

@@ -0,0 +1,125 @@
+/*-------------------------------------------------------------------------
+ *
+ * basebackup_sink.c
+ *	  Default implementations for bbsink (basebackup sink) callbacks.
+ *
+ * Portions Copyright (c) 2010-2022, PostgreSQL Global Development Group
+ *
+ * src/backend/backup/basebackup_sink.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres.h"
+
+#include "backup/basebackup_sink.h"
+
+/*
+ * Forward begin_backup callback.
+ *
+ * Only use this implementation if you want the bbsink you're implementing to
+ * share a buffer with the successor bbsink.
+ */
+void
+bbsink_forward_begin_backup(bbsink *sink)
+{
+	Assert(sink->bbs_next != NULL);
+	Assert(sink->bbs_state != NULL);
+	bbsink_begin_backup(sink->bbs_next, sink->bbs_state,
+						sink->bbs_buffer_length);
+	sink->bbs_buffer = sink->bbs_next->bbs_buffer;
+}
+
+/*
+ * Forward begin_archive callback.
+ */
+void
+bbsink_forward_begin_archive(bbsink *sink, const char *archive_name)
+{
+	Assert(sink->bbs_next != NULL);
+	bbsink_begin_archive(sink->bbs_next, archive_name);
+}
+
+/*
+ * Forward archive_contents callback.
+ *
+ * Code that wants to use this should initialize its own bbs_buffer and
+ * bbs_buffer_length fields to the values from the successor sink. In cases
+ * where the buffer isn't shared, the data needs to be copied before forwarding
+ * the callback. We don't do try to do that here, because there's really no
+ * reason to have separately allocated buffers containing the same identical
+ * data.
+ */
+void
+bbsink_forward_archive_contents(bbsink *sink, size_t len)
+{
+	Assert(sink->bbs_next != NULL);
+	Assert(sink->bbs_buffer == sink->bbs_next->bbs_buffer);
+	Assert(sink->bbs_buffer_length == sink->bbs_next->bbs_buffer_length);
+	bbsink_archive_contents(sink->bbs_next, len);
+}
+
+/*
+ * Forward end_archive callback.
+ */
+void
+bbsink_forward_end_archive(bbsink *sink)
+{
+	Assert(sink->bbs_next != NULL);
+	bbsink_end_archive(sink->bbs_next);
+}
+
+/*
+ * Forward begin_manifest callback.
+ */
+void
+bbsink_forward_begin_manifest(bbsink *sink)
+{
+	Assert(sink->bbs_next != NULL);
+	bbsink_begin_manifest(sink->bbs_next);
+}
+
+/*
+ * Forward manifest_contents callback.
+ *
+ * As with the archive_contents callback, it's expected that the buffer is
+ * shared.
+ */
+void
+bbsink_forward_manifest_contents(bbsink *sink, size_t len)
+{
+	Assert(sink->bbs_next != NULL);
+	Assert(sink->bbs_buffer == sink->bbs_next->bbs_buffer);
+	Assert(sink->bbs_buffer_length == sink->bbs_next->bbs_buffer_length);
+	bbsink_manifest_contents(sink->bbs_next, len);
+}
+
+/*
+ * Forward end_manifest callback.
+ */
+void
+bbsink_forward_end_manifest(bbsink *sink)
+{
+	Assert(sink->bbs_next != NULL);
+	bbsink_end_manifest(sink->bbs_next);
+}
+
+/*
+ * Forward end_backup callback.
+ */
+void
+bbsink_forward_end_backup(bbsink *sink, XLogRecPtr endptr, TimeLineID endtli)
+{
+	Assert(sink->bbs_next != NULL);
+	bbsink_end_backup(sink->bbs_next, endptr, endtli);
+}
+
+/*
+ * Forward cleanup callback.
+ */
+void
+bbsink_forward_cleanup(bbsink *sink)
+{
+	Assert(sink->bbs_next != NULL);
+	bbsink_cleanup(sink->bbs_next);
+}