1 files changed, 49 insertions, 0 deletions
diff --git a/src/lib/buffer-istream.c b/src/lib/buffer-istream.c
new file mode 100644
index 0000000..3898fd0
--- /dev/null
+++ b/src/lib/buffer-istream.c
@@ -0,0 +1,49 @@
+/* Copyright (c) 2020 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "buffer.h"
+#include "eacces-error.h"
+#include "istream.h"
+
+enum buffer_append_result
+buffer_append_full_istream(buffer_t *buf, struct istream *is, size_t max_read_size,
+			   const char **error_r)
+{
+	const unsigned char *data;
+	size_t size;
+	ssize_t ret;
+
+	while ((ret = i_stream_read_more(is, &data, &size)) > 0) {
+		if (max_read_size == 0)
+			return BUFFER_APPEND_READ_MAX_SIZE;
+		size = I_MIN(max_read_size, size);
+		buffer_append(buf, data, size);
+		i_stream_skip(is, size);
+		max_read_size -= size;
+	}
+
+	if (ret == 0)
+		return BUFFER_APPEND_READ_MORE;
+
+	i_assert(is->eof);
+
+	if (is->stream_errno != 0) {
+		*error_r = i_stream_get_error(is);
+		return BUFFER_APPEND_READ_ERROR;
+	}
+	return BUFFER_APPEND_OK;
+}
+
+enum buffer_append_result
+buffer_append_full_file(buffer_t *buf, const char *file, size_t max_read_size,
+			const char **error_r)
+{
+	struct istream *is = i_stream_create_file(file, IO_BLOCK_SIZE);
+	enum buffer_append_result res =
+		buffer_append_full_istream(buf, is, max_read_size, error_r);
+	if (is->stream_errno == EACCES)
+		*error_r = eacces_error_get("open", file);
+	i_stream_unref(&is);
+	i_assert(res != BUFFER_APPEND_READ_MORE);
+	return res;
+}