/* Copyright (c) 2011-2018 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "ostream.h"
#include "iostream-rawlog-private.h"
#include "istream-private.h"
#include "istream-rawlog.h"

struct rawlog_istream {
	struct istream_private istream;
	struct rawlog_iostream riostream;
};

static void i_stream_rawlog_close(struct iostream_private *stream,
				  bool close_parent)
{
	struct rawlog_istream *rstream =
		container_of(stream, struct rawlog_istream, istream.iostream);

	iostream_rawlog_close(&rstream->riostream);
	if (close_parent)
		i_stream_close(rstream->istream.parent);
}

static void i_stream_rawlog_destroy(struct iostream_private *stream)
{
	struct rawlog_istream *rstream =
		container_of(stream, struct rawlog_istream, istream.iostream);
       uoff_t v_offset;

       v_offset = rstream->istream.parent_start_offset +
               rstream->istream.istream.v_offset;
       if (rstream->istream.parent->seekable ||
           v_offset > rstream->istream.parent->v_offset) {
               /* get to same position in parent stream */
               i_stream_seek(rstream->istream.parent, v_offset);
       }
}

static ssize_t i_stream_rawlog_read(struct istream_private *stream)
{
	struct rawlog_istream *rstream =
		container_of(stream, struct rawlog_istream, istream);
	ssize_t ret;
	size_t pos;

	i_stream_seek(stream->parent, rstream->istream.parent_start_offset +
		      stream->istream.v_offset);

	stream->pos -= stream->skip;
	stream->skip = 0;

	stream->buffer = i_stream_get_data(stream->parent, &pos);
	if (pos > stream->pos)
		ret = 0;
	else do {
		ret = i_stream_read_memarea(stream->parent);
		stream->istream.stream_errno = stream->parent->stream_errno;
		stream->istream.eof = stream->parent->eof;
		stream->buffer = i_stream_get_data(stream->parent, &pos);
	} while (pos <= stream->pos && ret > 0);
	if (ret == -2)
		return -2;
	if (ret == -1)
		iostream_rawlog_flush(&rstream->riostream);

	if (pos <= stream->pos)
		ret = ret == 0 ? 0 : -1;
	else {
		ret = (ssize_t)(pos - stream->pos);
		iostream_rawlog_write(&rstream->riostream,
				      stream->buffer + stream->pos, ret);
	}
	stream->pos = pos;
	i_assert(ret != -1 || stream->istream.eof ||
		 stream->istream.stream_errno != 0);
	return ret;
}

struct istream *
i_stream_create_rawlog(struct istream *input, const char *rawlog_path,
		       int rawlog_fd, enum iostream_rawlog_flags flags)
{
	struct ostream *rawlog_output;
	bool autoclose_fd = (flags & IOSTREAM_RAWLOG_FLAG_AUTOCLOSE) != 0;

	i_assert(rawlog_path != NULL);
	i_assert(rawlog_fd != -1);

	rawlog_output = autoclose_fd ?
		o_stream_create_fd_autoclose(&rawlog_fd, 0) :
		o_stream_create_fd(rawlog_fd, 0);
	o_stream_set_name(rawlog_output,
			  t_strdup_printf("rawlog(%s)", rawlog_path));
	return i_stream_create_rawlog_from_stream(input, rawlog_output, flags);
}

struct istream *
i_stream_create_rawlog_from_stream(struct istream *input,
				   struct ostream *rawlog_output,
				   enum iostream_rawlog_flags flags)
{
	struct rawlog_istream *rstream;

	rstream = i_new(struct rawlog_istream, 1);
	rstream->istream.max_buffer_size = input->real_stream->max_buffer_size;
	rstream->istream.stream_size_passthrough = TRUE;

	rstream->riostream.rawlog_output = rawlog_output;
	iostream_rawlog_init(&rstream->riostream, flags, TRUE);

	rstream->istream.read = i_stream_rawlog_read;
	rstream->istream.iostream.close = i_stream_rawlog_close;
	rstream->istream.iostream.destroy = i_stream_rawlog_destroy;

	rstream->istream.istream.readable_fd = input->readable_fd;
	rstream->istream.istream.blocking = input->blocking;
	rstream->istream.istream.seekable = input->seekable;
	return i_stream_create(&rstream->istream, input,
			       i_stream_get_fd(input), 0);
}
