util: provide helper function to copy strings

Provide a helper function to copy a number of strings from the source to
the target.

2 files changed, 59 insertions, 0 deletions

diff --git a/src/util/util.c b/src/util/util.c
index e37f26fcb..f4a6709e5 100644
--- a/src/util/util.c
+++ b/src/util/util.c
@@ -21,6 +21,43 @@
 # include <Shlwapi.h>
 #endif
 
+void git_strings_free_deep(char **strings, size_t n)
+{
+	size_t i;
+
+	for (i = 0; i < n; i++)
+		git__free(strings[i]);
+
+	git__free(strings);
+}
+
+int git_strings_copy_deep(char **tgt, char *const *const src, size_t n)
+{
+	size_t i;
+
+	assert(tgt && src);
+
+	if (!n) {
+		*tgt = NULL;
+		return 0;
+	}
+
+	*tgt = git__calloc(n, sizeof(char *));
+	GIT_ERROR_CHECK_ALLOC(tgt);
+
+	for (i = 0; i < n; i++) {
+		if (!src[i])
+			continue;
+
+		if (!(tgt[i] = git__strdup(src[i]))) {
+			git_strings_free_deep(tgt, n);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
 int git__strntol64(int64_t *result, const char *nptr, size_t nptr_len, const char **endptr, int base)
 {
 	const char *p;
diff --git a/src/util/util.h b/src/util/util.h
index cdfc9c239..aa4123bf2 100644
--- a/src/util/util.h
+++ b/src/util/util.h
@@ -13,6 +13,8 @@
 # include <ctype.h>
 #endif
 
+#include "git2/strarray.h"
+
 #include "buffer.h"
 #include "strnlen.h"
 #include "thread-utils.h"
@@ -334,6 +336,26 @@ extern int git__utf8_iterate(const uint8_t *str, int str_len, int32_t *dst);
  */
 extern size_t git__utf8_valid_buf_length(const uint8_t *str, size_t str_len);
 
+/**
+ * Free the given array and the strings contained therein.
+ *
+ * @param strings The string array to free
+ * @param n The number of strings to free
+ */
+extern void git_strings_free_deep(char **strings, size_t n);
+
+/**
+ * Copy the strings from one array to another.  The target array will be
+ * created and the strings will be duplicated into it.  Any NULL pointers
+ * in the source will be preserved.
+ *
+ * @param tgt The destination string array
+ * @param src The source string array
+ * @param n The number of strings to copy
+ */
+extern int git_strings_copy_deep(
+	char **tgt, char *const *const src, size_t n);
+
 /*
  * Safely zero-out memory, making sure that the compiler
  * doesn't optimize away the operation.