A number of test features need to do pretty complicated string printing
where it may not be possible to rely on a single preallocated string
with parameters.
So provide a library for constructing the string as you go similar to
C++'s std::string. string_stream is really just a string builder,
nothing more.
Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
include/kunit/string-stream.h | 51 ++++++++
lib/kunit/Makefile | 3 +-
lib/kunit/string-stream.c | 217 ++++++++++++++++++++++++++++++++++
3 files changed, 270 insertions(+), 1 deletion(-)
create mode 100644 include/kunit/string-stream.h
create mode 100644 lib/kunit/string-stream.c
diff --git a/include/kunit/string-stream.h b/include/kunit/string-stream.h
new file mode 100644
index 000000000000..fe98a00b75a9
--- /dev/null
+++ b/include/kunit/string-stream.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * C++ stream style string builder used in KUnit for building messages.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
+ */
+
+#ifndef _KUNIT_STRING_STREAM_H
+#define _KUNIT_STRING_STREAM_H
+
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <stdarg.h>
+
+struct string_stream_fragment {
+ struct kunit *test;
+ struct list_head node;
+ char *fragment;
+};
+
+struct string_stream {
+ size_t length;
+ struct list_head fragments;
+ /* length and fragments are protected by this lock */
+ spinlock_t lock;
+ struct kunit *test;
+ gfp_t gfp;
+};
+
+struct kunit;
+
+struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp);
+
+int __printf(2, 3) string_stream_add(struct string_stream *stream,
+ const char *fmt, ...);
+
+int string_stream_vadd(struct string_stream *stream,
+ const char *fmt,
+ va_list args);
+
+char *string_stream_get_string(struct string_stream *stream);
+
+int string_stream_append(struct string_stream *stream,
+ struct string_stream *other);
+
+bool string_stream_is_empty(struct string_stream *stream);
+
+int string_stream_destroy(struct string_stream *stream);
+
+#endif /* _KUNIT_STRING_STREAM_H */
diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile
index 5efdc4dea2c0..275b565a0e81 100644
--- a/lib/kunit/Makefile
+++ b/lib/kunit/Makefile
@@ -1 +1,2 @@
-obj-$(CONFIG_KUNIT) += test.o
+obj-$(CONFIG_KUNIT) += test.o \
+ string-stream.o
diff --git a/lib/kunit/string-stream.c b/lib/kunit/string-stream.c
new file mode 100644
index 000000000000..e6d17aacca30
--- /dev/null
+++ b/lib/kunit/string-stream.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * C++ stream style string builder used in KUnit for building messages.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
+ */
+
+#include <kunit/string-stream.h>
+#include <kunit/test.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+struct string_stream_fragment_alloc_context {
+ struct kunit *test;
+ int len;
+ gfp_t gfp;
+};
+
+static int string_stream_fragment_init(struct kunit_resource *res,
+ void *context)
+{
+ struct string_stream_fragment_alloc_context *ctx = context;
+ struct string_stream_fragment *frag;
+
+ frag = kunit_kzalloc(ctx->test, sizeof(*frag), ctx->gfp);
+ if (!frag)
+ return -ENOMEM;
+
+ frag->test = ctx->test;
+ frag->fragment = kunit_kmalloc(ctx->test, ctx->len, ctx->gfp);
+ if (!frag->fragment)
+ return -ENOMEM;
+
+ res->allocation = frag;
+
+ return 0;
+}
+
+static void string_stream_fragment_free(struct kunit_resource *res)
+{
+ struct string_stream_fragment *frag = res->allocation;
+
+ list_del(&frag->node);
+ kunit_kfree(frag->test, frag->fragment);
+ kunit_kfree(frag->test, frag);
+}
+
+static struct string_stream_fragment *alloc_string_stream_fragment(
+ struct kunit *test, int len, gfp_t gfp)
+{
+ struct string_stream_fragment_alloc_context context = {
+ .test = test,
+ .len = len,
+ .gfp = gfp
+ };
+
+ return kunit_alloc_resource(test,
+ string_stream_fragment_init,
+ string_stream_fragment_free,
+ gfp,
+ &context);
+}
+
+static int string_stream_fragment_destroy(struct string_stream_fragment *frag)
+{
+ return kunit_resource_destroy(frag->test,
+ kunit_resource_instance_match,
+ string_stream_fragment_free,
+ frag);
+}
+
+int string_stream_vadd(struct string_stream *stream,
+ const char *fmt,
+ va_list args)
+{
+ struct string_stream_fragment *frag_container;
+ int len;
+ va_list args_for_counting;
+
+ /* Make a copy because `vsnprintf` could change it */
+ va_copy(args_for_counting, args);
+
+ /* Need space for null byte. */
+ len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1;
+
+ va_end(args_for_counting);
+
+ frag_container = alloc_string_stream_fragment(stream->test,
+ len,
+ stream->gfp);
+ if (!frag_container)
+ return -ENOMEM;
+
+ len = vsnprintf(frag_container->fragment, len, fmt, args);
+ spin_lock(&stream->lock);
+ stream->length += len;
+ list_add_tail(&frag_container->node, &stream->fragments);
+ spin_unlock(&stream->lock);
+
+ return 0;
+}
+
+int string_stream_add(struct string_stream *stream, const char *fmt, ...)
+{
+ va_list args;
+ int result;
+
+ va_start(args, fmt);
+ result = string_stream_vadd(stream, fmt, args);
+ va_end(args);
+
+ return result;
+}
+
+static void string_stream_clear(struct string_stream *stream)
+{
+ struct string_stream_fragment *frag_container, *frag_container_safe;
+
+ spin_lock(&stream->lock);
+ list_for_each_entry_safe(frag_container,
+ frag_container_safe,
+ &stream->fragments,
+ node) {
+ string_stream_fragment_destroy(frag_container);
+ }
+ stream->length = 0;
+ spin_unlock(&stream->lock);
+}
+
+char *string_stream_get_string(struct string_stream *stream)
+{
+ struct string_stream_fragment *frag_container;
+ size_t buf_len = stream->length + 1; /* +1 for null byte. */
+ char *buf;
+
+ buf = kunit_kzalloc(stream->test, buf_len, stream->gfp);
+ if (!buf)
+ return NULL;
+
+ spin_lock(&stream->lock);
+ list_for_each_entry(frag_container, &stream->fragments, node)
+ strlcat(buf, frag_container->fragment, buf_len);
+ spin_unlock(&stream->lock);
+
+ return buf;
+}
+
+int string_stream_append(struct string_stream *stream,
+ struct string_stream *other)
+{
+ const char *other_content;
+
+ other_content = string_stream_get_string(other);
+
+ if (!other_content)
+ return -ENOMEM;
+
+ return string_stream_add(stream, other_content);
+}
+
+bool string_stream_is_empty(struct string_stream *stream)
+{
+ return list_empty(&stream->fragments);
+}
+
+struct string_stream_alloc_context {
+ struct kunit *test;
+ gfp_t gfp;
+};
+
+static int string_stream_init(struct kunit_resource *res, void *context)
+{
+ struct string_stream *stream;
+ struct string_stream_alloc_context *ctx = context;
+
+ stream = kunit_kzalloc(ctx->test, sizeof(*stream), ctx->gfp);
+ if (!stream)
+ return -ENOMEM;
+
+ res->allocation = stream;
+ stream->gfp = ctx->gfp;
+ stream->test = ctx->test;
+ INIT_LIST_HEAD(&stream->fragments);
+ spin_lock_init(&stream->lock);
+
+ return 0;
+}
+
+static void string_stream_free(struct kunit_resource *res)
+{
+ struct string_stream *stream = res->allocation;
+
+ string_stream_clear(stream);
+}
+
+struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp)
+{
+ struct string_stream_alloc_context context = {
+ .test = test,
+ .gfp = gfp
+ };
+
+ return kunit_alloc_resource(test,
+ string_stream_init,
+ string_stream_free,
+ gfp,
+ &context);
+}
+
+int string_stream_destroy(struct string_stream *stream)
+{
+ return kunit_resource_destroy(stream->test,
+ kunit_resource_instance_match,
+ string_stream_free,
+ stream);
+}
--
2.23.0.351.gc4317032e6-goog
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