On Wed, Nov 28, 2018 at 11:36:20AM -0800, Brendan Higgins wrote:
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.
Hrm, what's the potential for such thing actually being eventually generically useful for printk folks, I wonder? Petr?
Luis
Signed-off-by: Brendan Higgins brendanhiggins@google.com
include/kunit/string-stream.h | 44 ++++++++++ kunit/Makefile | 3 +- kunit/string-stream.c | 149 ++++++++++++++++++++++++++++++++++ 3 files changed, 195 insertions(+), 1 deletion(-) create mode 100644 include/kunit/string-stream.h create mode 100644 kunit/string-stream.c
diff --git a/include/kunit/string-stream.h b/include/kunit/string-stream.h new file mode 100644 index 0000000000000..933ed5740cf07 --- /dev/null +++ b/include/kunit/string-stream.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*
- C++ stream style string builder used in KUnit for building messages.
- Copyright (C) 2018, Google LLC.
- Author: Brendan Higgins brendanhiggins@google.com
- */
+#ifndef _KUNIT_STRING_STREAM_H +#define _KUNIT_STRING_STREAM_H
+#include <linux/types.h> +#include <linux/spinlock.h> +#include <linux/kref.h> +#include <stdarg.h>
+struct string_stream_fragment {
- 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 kref refcount;
- int (*add)(struct string_stream *this, const char *fmt, ...);
- int (*vadd)(struct string_stream *this, const char *fmt, va_list args);
- char *(*get_string)(struct string_stream *this);
- void (*clear)(struct string_stream *this);
- bool (*is_empty)(struct string_stream *this);
+};
+struct string_stream *new_string_stream(void);
+void destroy_string_stream(struct string_stream *stream);
+void string_stream_get(struct string_stream *stream);
+int string_stream_put(struct string_stream *stream);
+#endif /* _KUNIT_STRING_STREAM_H */ diff --git a/kunit/Makefile b/kunit/Makefile index 5efdc4dea2c08..275b565a0e81f 100644 --- a/kunit/Makefile +++ b/kunit/Makefile @@ -1 +1,2 @@ -obj-$(CONFIG_KUNIT) += test.o +obj-$(CONFIG_KUNIT) += test.o \
string-stream.odiff --git a/kunit/string-stream.c b/kunit/string-stream.c new file mode 100644 index 0000000000000..1e7efa630cc35 --- /dev/null +++ b/kunit/string-stream.c @@ -0,0 +1,149 @@ +// SPDX-License-Identifier: GPL-2.0 +/*
- C++ stream style string builder used in KUnit for building messages.
- Copyright (C) 2018, Google LLC.
- Author: Brendan Higgins brendanhiggins@google.com
- */
+#include <linux/list.h> +#include <linux/slab.h> +#include <kunit/string-stream.h>
+static int string_stream_vadd(struct string_stream *this,
const char *fmt,va_list args)+{
- struct string_stream_fragment *fragment;
- int len;
- va_list args_for_counting;
- unsigned long flags;
- /* 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);
- fragment = kmalloc(sizeof(*fragment), GFP_KERNEL);
- if (!fragment)
return -ENOMEM;- fragment->fragment = kmalloc(len, GFP_KERNEL);
- if (!fragment->fragment) {
kfree(fragment);return -ENOMEM;- }
- len = vsnprintf(fragment->fragment, len, fmt, args);
- spin_lock_irqsave(&this->lock, flags);
- this->length += len;
- list_add_tail(&fragment->node, &this->fragments);
- spin_unlock_irqrestore(&this->lock, flags);
- return 0;
+}
+static int string_stream_add(struct string_stream *this, const char *fmt, ...) +{
- va_list args;
- int result;
- va_start(args, fmt);
- result = string_stream_vadd(this, fmt, args);
- va_end(args);
- return result;
+}
+static void string_stream_clear(struct string_stream *this) +{
- struct string_stream_fragment *fragment, *fragment_safe;
- unsigned long flags;
- spin_lock_irqsave(&this->lock, flags);
- list_for_each_entry_safe(fragment,
fragment_safe,&this->fragments,node) {list_del(&fragment->node);kfree(fragment->fragment);kfree(fragment);- }
- this->length = 0;
- spin_unlock_irqrestore(&this->lock, flags);
+}
+static char *string_stream_get_string(struct string_stream *this) +{
- struct string_stream_fragment *fragment;
- size_t buf_len = this->length + 1; /* +1 for null byte. */
- char *buf;
- unsigned long flags;
- buf = kzalloc(buf_len, GFP_KERNEL);
- if (!buf)
return NULL;- spin_lock_irqsave(&this->lock, flags);
- list_for_each_entry(fragment, &this->fragments, node)
strlcat(buf, fragment->fragment, buf_len);- spin_unlock_irqrestore(&this->lock, flags);
- return buf;
+}
+static bool string_stream_is_empty(struct string_stream *this) +{
- bool is_empty;
- unsigned long flags;
- spin_lock_irqsave(&this->lock, flags);
- is_empty = list_empty(&this->fragments);
- spin_unlock_irqrestore(&this->lock, flags);
- return is_empty;
+}
+void destroy_string_stream(struct string_stream *stream) +{
- stream->clear(stream);
- kfree(stream);
+}
+static void string_stream_destroy(struct kref *kref) +{
- struct string_stream *stream = container_of(kref,
struct string_stream,refcount);- destroy_string_stream(stream);
+}
+struct string_stream *new_string_stream(void) +{
- struct string_stream *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
- if (!stream)
return NULL;- INIT_LIST_HEAD(&stream->fragments);
- spin_lock_init(&stream->lock);
- kref_init(&stream->refcount);
- stream->add = string_stream_add;
- stream->vadd = string_stream_vadd;
- stream->get_string = string_stream_get_string;
- stream->clear = string_stream_clear;
- stream->is_empty = string_stream_is_empty;
- return stream;
+}
+void string_stream_get(struct string_stream *stream) +{
- kref_get(&stream->refcount);
+}
+int string_stream_put(struct string_stream *stream) +{
- return kref_put(&stream->refcount, &string_stream_destroy);
+}
-- 2.20.0.rc0.387.gc7a69e6b6c-goog