[PATCH v6 03/10] kunit: string-stream: Add option to make all lines end with newline

Richard Fitzgerald
2023-08-28T10:42:42Z

Add an optional feature to string_stream that will append a newline to
any added string that does not already end with a newline. The purpose
of this is so that string_stream can be used to collect log lines.

This is enabled/disabled by calling string_stream_set_append_newlines().

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Reviewed-by: David Gow <davidgow@google.com>
---
lib/kunit/string-stream.c | 28 +++++++++++++++++++++-------
lib/kunit/string-stream.h | 7 +++++++
2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/lib/kunit/string-stream.c b/lib/kunit/string-stream.c
index ed24d86af9f5..1dcf6513b692 100644
--- a/lib/kunit/string-stream.c
+++ b/lib/kunit/string-stream.c
@@ -44,32 +44,46 @@ int string_stream_vadd(struct string_stream *stream,
va_list args)
{
struct string_stream_fragment *frag_container;
- int len;
+ int buf_len, result_len;
va_list args_for_counting;

/* Make a copy because `vsnprintf` could change it */
va_copy(args_for_counting, args);

/* Evaluate length of formatted string */
- len = vsnprintf(NULL, 0, fmt, args_for_counting);
+ buf_len = vsnprintf(NULL, 0, fmt, args_for_counting);

va_end(args_for_counting);

- if (len == 0)
+ if (buf_len == 0)
return 0;

+ /* Reserve one extra for possible appended newline. */
+ if (stream->append_newlines)
+ buf_len++;
+
/* Need space for null byte. */
- len++;
+ buf_len++;

frag_container = alloc_string_stream_fragment(stream->test,
- len,
+ buf_len,
stream->gfp);
if (IS_ERR(frag_container))
return PTR_ERR(frag_container);

- len = vsnprintf(frag_container->fragment, len, fmt, args);
+ if (stream->append_newlines) {
+ /* Don't include reserved newline byte in writeable length. */
+ result_len = vsnprintf(frag_container->fragment, buf_len - 1, fmt, args);
+
+ /* Append newline if necessary. */
+ if (frag_container->fragment[result_len - 1] != '\n')
+ result_len = strlcat(frag_container->fragment, "\n", buf_len);
+ } else {
+ result_len = vsnprintf(frag_container->fragment, buf_len, fmt, args);
+ }
+
spin_lock(&stream->lock);
- stream->length += len;
+ stream->length += result_len;
list_add_tail(&frag_container->node, &stream->fragments);
spin_unlock(&stream->lock);

diff --git a/lib/kunit/string-stream.h b/lib/kunit/string-stream.h
index b669f9a75a94..048930bf97f0 100644
--- a/lib/kunit/string-stream.h
+++ b/lib/kunit/string-stream.h
@@ -25,6 +25,7 @@ struct string_stream {
spinlock_t lock;
struct kunit *test;
gfp_t gfp;
+ bool append_newlines;
};

struct kunit;
@@ -47,4 +48,10 @@ bool string_stream_is_empty(struct string_stream *stream);

void string_stream_destroy(struct string_stream *stream);

+static inline void string_stream_set_append_newlines(struct string_stream *stream,
+ bool append_newlines)
+{
+ stream->append_newlines = append_newlines;
+}
+
#endif /* _KUNIT_STRING_STREAM_H */
--
2.30.2