dovecot-2.2: lib-fs: Added istream-fs-file to lazily read from f...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/5c72e7d65e6f
changeset: 16943:5c72e7d65e6f
user:      Timo Sirainen <tss at iki.fi>
date:      Wed Nov 06 21:06:15 2013 +0200
description:
lib-fs: Added istream-fs-file to lazily read from fs_file.

diffstat:

 src/lib-fs/Makefile.am       |   2 +
 src/lib-fs/istream-fs-file.c |  61 ++++++++++++++++++++++++++++++++++++++++++++
 src/lib-fs/istream-fs-file.h |  13 +++++++++
 3 files changed, 76 insertions(+), 0 deletions(-)

diffs (101 lines):

diff -r 1c9ecb6bcccc -r 5c72e7d65e6f src/lib-fs/Makefile.am
--- a/src/lib-fs/Makefile.am	Wed Nov 06 21:05:51 2013 +0200
+++ b/src/lib-fs/Makefile.am	Wed Nov 06 21:06:15 2013 +0200
@@ -12,6 +12,7 @@
 	fs-sis.c \
 	fs-sis-common.c \
 	fs-sis-queue.c \
+	istream-fs-file.c \
 	istream-metawrap.c \
 	ostream-metawrap.c \
 	ostream-cmp.c
@@ -20,6 +21,7 @@
 	fs-api.h \
 	fs-api-private.h \
 	fs-sis-common.h \
+	istream-fs-file.h \
 	istream-metawrap.h \
 	ostream-metawrap.h \
 	ostream-cmp.h
diff -r 1c9ecb6bcccc -r 5c72e7d65e6f src/lib-fs/istream-fs-file.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lib-fs/istream-fs-file.c	Wed Nov 06 21:06:15 2013 +0200
@@ -0,0 +1,61 @@
+/* Copyright (c) 2013 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "istream-private.h"
+#include "fs-api-private.h"
+#include "istream-fs-file.h"
+
+struct fs_file_istream {
+	struct istream_private istream;
+	struct fs_file *file;
+};
+
+static void i_stream_fs_file_close(struct iostream_private *stream,
+				   bool close_parent ATTR_UNUSED)
+{
+	struct fs_file_istream *fstream = (struct fs_file_istream *)stream;
+
+	i_stream_destroy(&fstream->istream.parent);
+	fs_file_deinit(&fstream->file);
+}
+
+static ssize_t i_stream_fs_file_read(struct istream_private *stream)
+{
+	struct fs_file_istream *fstream = (struct fs_file_istream *)stream;
+	struct istream *input;
+
+	if (fstream->istream.parent == NULL) {
+		input = fs_read_stream(fstream->file,
+				       fstream->istream.max_buffer_size);
+		i_stream_init_parent(stream, input);
+		i_stream_unref(&input);
+	}
+
+	i_stream_seek(stream->parent, stream->parent_start_offset +
+		      stream->istream.v_offset);
+	return i_stream_read_copy_from_parent(&stream->istream);
+}
+
+struct istream *
+i_stream_create_fs_file(struct fs_file **file, size_t max_buffer_size)
+{
+	struct fs_file_istream *fstream;
+	struct istream *input;
+
+	fstream = i_new(struct fs_file_istream, 1);
+	fstream->file = *file;
+	fstream->istream.iostream.close = i_stream_fs_file_close;
+	fstream->istream.max_buffer_size = max_buffer_size;
+	fstream->istream.read = i_stream_fs_file_read;
+	fstream->istream.stream_size_passthrough = TRUE;
+
+	fstream->istream.istream.blocking =
+		((*file)->flags & FS_OPEN_FLAG_ASYNC) == 0;
+	fstream->istream.istream.seekable =
+		((*file)->flags & FS_OPEN_FLAG_SEEKABLE) != 0;
+
+	input = i_stream_create(&fstream->istream, NULL, -1);
+	i_stream_set_name(input, fs_file_path(*file));
+	*file = NULL;
+	return input;
+}
diff -r 1c9ecb6bcccc -r 5c72e7d65e6f src/lib-fs/istream-fs-file.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/lib-fs/istream-fs-file.h	Wed Nov 06 21:06:15 2013 +0200
@@ -0,0 +1,13 @@
+#ifndef ISTREAM_FS_FILE_H
+#define ISTREAM_FS_FILE_H
+
+struct fs_file;
+
+/* Open the given file only when something is actually tried to be read from
+   the stream. The file is automatically deinitialized when the stream is
+   destroyed (which is why it's also set to NULL so it's not accidentally
+   double-freed). */
+struct istream *
+i_stream_create_fs_file(struct fs_file **file, size_t max_buffer_size);
+
+#endif