From: Lucas De Marchi <lucas.de.marchi@gmail.com>
Date: Thu, 14 Nov 2024 04:49:52 +0000 (-0600)
Subject: strbuf: Add strbuf_used()
X-Git-Tag: v34~86
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5706fb7d61d25255eab589b3533182b8e98378c8;p=thirdparty%2Fkmod.git

strbuf: Add strbuf_used()

So users don't feel tempted to look at inside the strbuf. Just add a
function for it and proper tests.

Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/239
---

diff --git a/libkmod/libkmod-builtin.c b/libkmod/libkmod-builtin.c
index dad82bb4..293ea894 100644
--- a/libkmod/libkmod-builtin.c
+++ b/libkmod/libkmod-builtin.c
@@ -139,10 +139,10 @@ static char **strbuf_to_vector(struct strbuf *buf, size_t count)
 	char *s;
 	size_t n;
 
-	/* (string vector + NULL) * sizeof(char *) + buf->used */
+	/* (string vector + NULL) * sizeof(char *) + strbuf_used() */
 	if (uaddsz_overflow(count, 1, &n) ||
 	    umulsz_overflow(sizeof(char *), n, &vec_size) ||
-	    uaddsz_overflow(buf->used, vec_size, &total_size)) {
+	    uaddsz_overflow(strbuf_used(buf), vec_size, &total_size)) {
 		errno = ENOMEM;
 		return NULL;
 	}
@@ -151,7 +151,7 @@ static char **strbuf_to_vector(struct strbuf *buf, size_t count)
 	if (vector == NULL)
 		return NULL;
 	buf->bytes = NULL;
-	memmove(vector + count + 1, vector, buf->used);
+	memmove(vector + count + 1, vector, strbuf_used(buf));
 	s = (char *)(vector + count + 1);
 
 	for (n = 0; n < count; n++) {
diff --git a/libkmod/libkmod-index.c b/libkmod/libkmod-index.c
index 7909c774..4046977c 100644
--- a/libkmod/libkmod-index.c
+++ b/libkmod/libkmod-index.c
@@ -369,7 +369,7 @@ static void index_dump_node(struct index_node_f *node, struct strbuf *buf, int f
 	pushed = strbuf_pushchars(buf, node->prefix);
 
 	for (v = node->values; v != NULL; v = v->next) {
-		write_str_safe(fd, buf->bytes, buf->used);
+		write_str_safe(fd, buf->bytes, strbuf_used(buf));
 		write_str_safe(fd, " ", 1);
 		write_str_safe(fd, v->value, strlen(v->value));
 		write_str_safe(fd, "\n", 1);
@@ -833,7 +833,7 @@ static void index_mm_dump_node(struct index_mm_node *node, struct strbuf *buf, i
 		struct index_mm_value v;
 
 		read_value_mm(&p, &v);
-		write_str_safe(fd, buf->bytes, buf->used);
+		write_str_safe(fd, buf->bytes, strbuf_used(buf));
 		write_str_safe(fd, " ", 1);
 		write_str_safe(fd, v.value, v.len);
 		write_str_safe(fd, "\n", 1);
diff --git a/shared/strbuf.h b/shared/strbuf.h
index 538f199e..96e6ed24 100644
--- a/shared/strbuf.h
+++ b/shared/strbuf.h
@@ -101,3 +101,16 @@ void strbuf_popchar(struct strbuf *buf);
  * guaranteed to have (at least) 5 chars available without needing to reallocate.
  */
 void strbuf_popchars(struct strbuf *buf, size_t n);
+
+/*
+ * Return number of used chars. This may different than calling strlen() in a C string
+ * since '\0' is considered a valid char - this only keeps track of how many slots are
+ * used in the underlying storage.
+ *
+ * If used knows '\0' has not been added (e.g. when calling just strbuf_pushchars() and
+ * similar), then the result matches the output of strlen().
+ */
+static inline size_t strbuf_used(struct strbuf *buf)
+{
+	return buf->used;
+}
diff --git a/testsuite/test-strbuf.c b/testsuite/test-strbuf.c
index a9da0ec4..859f9b26 100644
--- a/testsuite/test-strbuf.c
+++ b/testsuite/test-strbuf.c
@@ -203,4 +203,28 @@ static int test_strbuf_pushmem(const struct test *t)
 }
 DEFINE_TEST(test_strbuf_pushmem, .description = "test strbuf_reserve");
 
+static int test_strbuf_used(const struct test *t)
+{
+	_cleanup_strbuf_ struct strbuf buf;
+
+	strbuf_init(&buf);
+	assert_return(strbuf_used(&buf) == 0, EXIT_FAILURE);
+
+	strbuf_pushchars(&buf, TEXT);
+	assert_return(strbuf_used(&buf) == strlen(TEXT), EXIT_FAILURE);
+
+	strbuf_reserve_extra(&buf, 1);
+	assert_return(strbuf_used(&buf) == strlen(TEXT), EXIT_FAILURE);
+
+	assert_return(streq(TEXT, strbuf_str(&buf)), EXIT_FAILURE);
+	assert_return(strbuf_used(&buf) == strlen(TEXT), EXIT_FAILURE);
+
+	strbuf_pushchar(&buf, '\0');
+	assert_return(streq(TEXT, strbuf_str(&buf)), EXIT_FAILURE);
+	assert_return(strbuf_used(&buf) == strlen(TEXT) + 1, EXIT_FAILURE);
+
+	return 0;
+}
+DEFINE_TEST(test_strbuf_used, .description = "test strbuf_used");
+
 TESTSUITE_MAIN();