utf8: add conversion with size and refactor names

Add functions to use convert a string with length, instead of assuming
NUL termination.

In addition, move the utf8 to 16 conversion routines into the `git_utf8`
namespace instead of using namespaceless `git__` prefixed names.

src/libgit2/streams/schannel.c

@@ -661,7 +661,7 @@ static int schannel_stream_wrap(
 	st->io = in;
 	st->owned = owned;
 
-	if (git__utf8_to_16_alloc(&st->host_w, host) < 0) {
+	if (git_utf8_to_16_alloc(&st->host_w, host) < 0) {
 		git__free(st);
 		return -1;
 	}

src/libgit2/transports/winhttp.c

@@ -158,10 +158,10 @@ static int apply_userpass_credentials(HINTERNET request, DWORD target, int mecha
 		goto done;
 	}
 
-	if ((error = user_len = git__utf8_to_16_alloc(&user, c->username)) < 0)
+	if ((error = user_len = git_utf8_to_16_alloc(&user, c->username)) < 0)
 		goto done;
 
-	if ((error = pass_len = git__utf8_to_16_alloc(&pass, c->password)) < 0)
+	if ((error = pass_len = git_utf8_to_16_alloc(&pass, c->password)) < 0)
 		goto done;
 
 	if (!WinHttpSetCredentials(request, target, native_scheme, user, pass, NULL)) {
@@ -242,7 +242,7 @@ static int acquire_fallback_cred(
 		HRESULT hCoInitResult;
 
 		/* Convert URL to wide characters */
-		if (git__utf8_to_16_alloc(&wide_url, url) < 0) {
+		if (git_utf8_to_16_alloc(&wide_url, url) < 0) {
 			git_error_set(GIT_ERROR_OS, "failed to convert string to wide form");
 			return -1;
 		}
@@ -397,7 +397,7 @@ static int winhttp_stream_connect(winhttp_stream *s)
 		return -1;
 
 	/* Convert URL to wide characters */
-	if (git__utf8_to_16_alloc(&s->request_uri, git_str_cstr(&buf)) < 0) {
+	if (git_utf8_to_16_alloc(&s->request_uri, git_str_cstr(&buf)) < 0) {
 		git_error_set(GIT_ERROR_OS, "failed to convert string to wide form");
 		goto on_error;
 	}
@@ -473,7 +473,7 @@ static int winhttp_stream_connect(winhttp_stream *s)
 		}
 
 		/* Convert URL to wide characters */
-		error = git__utf8_to_16_alloc(&proxy_wide, processed_url.ptr);
+		error = git_utf8_to_16_alloc(&proxy_wide, processed_url.ptr);
 		git_str_dispose(&processed_url);
 		if (error < 0)
 			goto on_error;
@@ -531,7 +531,7 @@ static int winhttp_stream_connect(winhttp_stream *s)
 			s->service) < 0)
 			goto on_error;
 
-		if (git__utf8_to_16(ct, MAX_CONTENT_TYPE_LEN, git_str_cstr(&buf)) < 0) {
+		if (git_utf8_to_16(ct, MAX_CONTENT_TYPE_LEN, git_str_cstr(&buf)) < 0) {
 			git_error_set(GIT_ERROR_OS, "failed to convert content-type to wide characters");
 			goto on_error;
 		}
@@ -548,7 +548,7 @@ static int winhttp_stream_connect(winhttp_stream *s)
 			s->service) < 0)
 			goto on_error;
 
-		if (git__utf8_to_16(ct, MAX_CONTENT_TYPE_LEN, git_str_cstr(&buf)) < 0) {
+		if (git_utf8_to_16(ct, MAX_CONTENT_TYPE_LEN, git_str_cstr(&buf)) < 0) {
 			git_error_set(GIT_ERROR_OS, "failed to convert accept header to wide characters");
 			goto on_error;
 		}
@@ -568,7 +568,7 @@ static int winhttp_stream_connect(winhttp_stream *s)
 			git_str_puts(&buf, t->owner->connect_opts.custom_headers.strings[i]);
 
 			/* Convert header to wide characters */
-			if ((error = git__utf8_to_16_alloc(&custom_header_wide, git_str_cstr(&buf))) < 0)
+			if ((error = git_utf8_to_16_alloc(&custom_header_wide, git_str_cstr(&buf))) < 0)
 				goto on_error;
 
 			if (!WinHttpAddRequestHeaders(s->request, custom_header_wide, (ULONG)-1L,
@@ -783,7 +783,7 @@ static int winhttp_connect(
 	}
 
 	/* Prepare host */
-	if (git__utf8_to_16_alloc(&wide_host, host) < 0) {
+	if (git_utf8_to_16_alloc(&wide_host, host) < 0) {
 		git_error_set(GIT_ERROR_OS, "unable to convert host to wide characters");
 		goto on_error;
 	}
@@ -792,7 +792,7 @@ static int winhttp_connect(
 	if (git_http__user_agent(&ua) < 0)
 		goto on_error;
 
-	if (git__utf8_to_16_alloc(&wide_ua, git_str_cstr(&ua)) < 0) {
+	if (git_utf8_to_16_alloc(&wide_ua, git_str_cstr(&ua)) < 0) {
 		git_error_set(GIT_ERROR_OS, "unable to convert host to wide characters");
 		goto on_error;
 	}
@@ -1182,7 +1182,7 @@ replay:
 			}
 
 			/* Convert the Location header to UTF-8 */
-			if (git__utf16_to_8_alloc(&location8, location) < 0) {
+			if (git_utf8_from_16_alloc(&location8, location) < 0) {
 				git_error_set(GIT_ERROR_OS, "failed to convert Location header to UTF-8");
 				git__free(location);
 				return -1;
@@ -1254,7 +1254,7 @@ replay:
 		else
 			p_snprintf(expected_content_type_8, MAX_CONTENT_TYPE_LEN, "application/x-git-%s-advertisement", s->service);
 
-		if (git__utf8_to_16(expected_content_type, MAX_CONTENT_TYPE_LEN, expected_content_type_8) < 0) {
+		if (git_utf8_to_16(expected_content_type, MAX_CONTENT_TYPE_LEN, expected_content_type_8) < 0) {
 			git_error_set(GIT_ERROR_OS, "failed to convert expected content-type to wide characters");
 			return -1;
 		}

src/util/fs_path.c

@@ -2015,7 +2015,7 @@ int git_fs_path_find_executable(git_str *fullpath, const char *executable)
 	git_win32_path fullpath_w, executable_w;
 	int error;
 
-	if (git__utf8_to_16(executable_w, GIT_WIN_PATH_MAX, executable) < 0)
+	if (git_utf8_to_16(executable_w, GIT_WIN_PATH_MAX, executable) < 0)
 		return -1;
 
 	error = git_win32_path_find_executable(fullpath_w, executable_w);

src/util/util.c

@@ -743,7 +743,7 @@ int git__getenv(git_str *out, const char *name)
 
 	git_str_clear(out);
 
-	if (git__utf8_to_16_alloc(&wide_name, name) < 0)
+	if (git_utf8_to_16_alloc(&wide_name, name) < 0)
 		return -1;
 
 	if ((value_len = GetEnvironmentVariableW(wide_name, NULL, 0)) > 0) {

src/util/win32/error.c

@@ -43,7 +43,7 @@ char *git_win32_get_error_message(DWORD error_code)
 		(LPWSTR)&lpMsgBuf, 0, NULL)) {
 		/* Convert the message to UTF-8. If this fails, we will
 		 * return NULL, which is a condition expected by the caller */
-		if (git__utf16_to_8_alloc(&utf8_msg, lpMsgBuf) < 0)
+		if (git_utf8_from_16_alloc(&utf8_msg, lpMsgBuf) < 0)
 			utf8_msg = NULL;
 
 		LocalFree(lpMsgBuf);

src/util/win32/path_w32.c

@@ -336,13 +336,13 @@ int git_win32_path_from_utf8(git_win32_path out, const char *src)
 
 	/* See if this is an absolute path (beginning with a drive letter) */
 	if (git_fs_path_is_absolute(src)) {
-		if (git__utf8_to_16(dest, GIT_WIN_PATH_MAX, src) < 0)
+		if (git_utf8_to_16(dest, GIT_WIN_PATH_MAX, src) < 0)
 			goto on_error;
 	}
 	/* File-prefixed NT-style paths beginning with \\?\ */
 	else if (path__is_nt_namespace(src)) {
 		/* Skip the NT prefix, the destination already contains it */
-		if (git__utf8_to_16(dest, GIT_WIN_PATH_MAX, src + PATH__NT_NAMESPACE_LEN) < 0)
+		if (git_utf8_to_16(dest, GIT_WIN_PATH_MAX, src + PATH__NT_NAMESPACE_LEN) < 0)
 			goto on_error;
 	}
 	/* UNC paths */
@@ -351,7 +351,7 @@ int git_win32_path_from_utf8(git_win32_path out, const char *src)
 		dest += 4;
 
 		/* Skip the leading "\\" */
-		if (git__utf8_to_16(dest, GIT_WIN_PATH_MAX - 2, src + 2) < 0)
+		if (git_utf8_to_16(dest, GIT_WIN_PATH_MAX - 2, src + 2) < 0)
 			goto on_error;
 	}
 	/* Absolute paths omitting the drive letter */
@@ -365,7 +365,7 @@ int git_win32_path_from_utf8(git_win32_path out, const char *src)
 		}
 
 		/* Skip the drive letter specification ("C:") */
-		if (git__utf8_to_16(dest + 2, GIT_WIN_PATH_MAX - 2, src) < 0)
+		if (git_utf8_to_16(dest + 2, GIT_WIN_PATH_MAX - 2, src) < 0)
 			goto on_error;
 	}
 	/* Relative paths */
@@ -377,7 +377,7 @@ int git_win32_path_from_utf8(git_win32_path out, const char *src)
 
 		dest[cwd_len++] = L'\\';
 
-		if (git__utf8_to_16(dest + cwd_len, GIT_WIN_PATH_MAX - cwd_len, src) < 0)
+		if (git_utf8_to_16(dest + cwd_len, GIT_WIN_PATH_MAX - cwd_len, src) < 0)
 			goto on_error;
 	}
 
@@ -404,7 +404,7 @@ int git_win32_path_relative_from_utf8(git_win32_path out, const char *src)
 		return git_win32_path_from_utf8(out, src);
 	}
 
-	if ((len = git__utf8_to_16(dest, GIT_WIN_PATH_MAX, src)) < 0)
+	if ((len = git_utf8_to_16(dest, GIT_WIN_PATH_MAX, src)) < 0)
 		return -1;
 
 	for (p = dest; p < (dest + len); p++) {
@@ -433,7 +433,7 @@ int git_win32_path_to_utf8(git_win32_utf8_path dest, const wchar_t *src)
 		}
 	}
 
-	if ((len = git__utf16_to_8(out, GIT_WIN_PATH_UTF8, src)) < 0)
+	if ((len = git_utf8_from_16(out, GIT_WIN_PATH_UTF8, src)) < 0)
 		return len;
 
 	git_fs_path_mkposix(dest);
@@ -471,7 +471,7 @@ char *git_win32_path_8dot3_name(const char *path)
 	if (namelen > 12 || (shortname = git__malloc(namelen + 1)) == NULL)
 		return NULL;
 
-	if ((len = git__utf16_to_8(shortname, namelen + 1, start)) < 0)
+	if ((len = git_utf8_from_16(shortname, namelen + 1, start)) < 0)
 		return NULL;
 
 	return shortname;

src/util/win32/posix_w32.c

@@ -649,7 +649,7 @@ int p_getcwd(char *buffer_out, size_t size)
 	git_win32_path_remove_namespace(cwd, wcslen(cwd));
 
 	/* Convert the working directory back to UTF-8 */
-	if (git__utf16_to_8(buffer_out, size, cwd) < 0) {
+	if (git_utf8_from_16(buffer_out, size, cwd) < 0) {
 		DWORD code = GetLastError();
 
 		if (code == ERROR_INSUFFICIENT_BUFFER)

src/util/win32/utf-conv.c

@@ -15,108 +15,114 @@ GIT_INLINE(void) git__set_errno(void)
 		errno = EINVAL;
 }
 
-/**
- * Converts a UTF-8 string to wide characters.
- *
- * @param dest The buffer to receive the wide string.
- * @param dest_size The size of the buffer, in characters.
- * @param src The UTF-8 string to convert.
- * @return The length of the wide string, in characters (not counting the NULL terminator), or < 0 for failure
- */
-int git__utf8_to_16(wchar_t *dest, size_t dest_size, const char *src)
+int git_utf8_to_16(wchar_t *dest, size_t dest_size, const char *src)
+{
+	/* Length of -1 indicates NULL termination of the input string. */
+	return git_utf8_to_16_with_len(dest, dest_size, src, -1);
+}
+
+int git_utf8_to_16_with_len(
+	wchar_t *dest,
+	size_t _dest_size,
+	const char *src,
+	int src_len)
 {
+	int dest_size = (int)min(_dest_size, INT_MAX);
 	int len;
 
-	/* Length of -1 indicates NULL termination of the input string. Subtract 1 from the result to
-	* turn 0 into -1 (an error code) and to not count the NULL terminator as part of the string's
-	* length. MultiByteToWideChar never returns int's minvalue, so underflow is not possible */
-	if ((len = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, src, -1, dest, (int)dest_size) - 1) < 0)
+	/*
+	 * Subtract 1 from the result to turn 0 into -1 (an error code) and
+	 * to not count the NULL terminator as part of the string's length.
+	 * MultiByteToWideChar never returns int's minvalue, so underflow
+	 * is not possible.
+	 */
+	len = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS,
+		src, src_len, dest, dest_size) - 1;
+
+	if (len < 0)
 		git__set_errno();
 
 	return len;
 }
 
-/**
- * Converts a wide string to UTF-8.
- *
- * @param dest The buffer to receive the UTF-8 string.
- * @param dest_size The size of the buffer, in bytes.
- * @param src The wide string to convert.
- * @return The length of the UTF-8 string, in bytes (not counting the NULL terminator), or < 0 for failure
- */
-int git__utf16_to_8(char *dest, size_t dest_size, const wchar_t *src)
+int git_utf8_from_16(char *dest, size_t dest_size, const wchar_t *src)
 {
+	/* Length of -1 indicates NULL termination of the input string. */
+	return git_utf8_from_16_with_len(dest, dest_size, src, -1);
+}
+
+int git_utf8_from_16_with_len(
+	char *dest,
+	size_t _dest_size,
+	const wchar_t *src,
+	int src_len)
+{
+	int dest_size = (int)min(_dest_size, INT_MAX);
 	int len;
 
-	/* Length of -1 indicates NULL termination of the input string. Subtract 1 from the result to
-	 * turn 0 into -1 (an error code) and to not count the NULL terminator as part of the string's
-	 * length. WideCharToMultiByte never returns int's minvalue, so underflow is not possible */
-	if ((len = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, src, -1, dest, (int)dest_size, NULL, NULL) - 1) < 0)
+	/*
+	 * Subtract 1 from the result to turn 0 into -1 (an error code) and
+	 * to not count the NULL terminator as part of the string's length.
+	 * WideCharToMultiByte never returns int's minvalue, so underflow
+	 * is not possible.
+	 */
+	len = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS,
+		src, src_len, dest, dest_size, NULL, NULL) - 1;
+
+	if (len < 0)
 		git__set_errno();
 
 	return len;
 }
 
-/**
- * Converts a UTF-8 string to wide characters.
- * Memory is allocated to hold the converted string.
- * The caller is responsible for freeing the string with git__free.
- *
- * @param dest Receives a pointer to the wide string.
- * @param src The UTF-8 string to convert.
- * @return The length of the wide string, in characters (not counting the NULL terminator), or < 0 for failure
- */
-int git__utf8_to_16_alloc(wchar_t **dest, const char *src)
+int git_utf8_to_16_alloc(wchar_t **dest, const char *src)
+{
+	/* Length of -1 indicates NULL termination of the input string. */
+	return git_utf8_to_16_alloc_with_len(dest, src, -1);
+}
+
+int git_utf8_to_16_alloc_with_len(wchar_t **dest, const char *src, int src_len)
 {
 	int utf16_size;
 
 	*dest = NULL;
 
-	/* Length of -1 indicates NULL termination of the input string */
-	utf16_size = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, src, -1, NULL, 0);
+	utf16_size = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS,
+		src, src_len, NULL, 0);
 
 	if (!utf16_size) {
 		git__set_errno();
 		return -1;
 	}
 
-	if (!(*dest = git__mallocarray(utf16_size, sizeof(wchar_t)))) {
-		errno = ENOMEM;
-		return -1;
-	}
+	*dest = git__mallocarray(utf16_size, sizeof(wchar_t));
+	GIT_ERROR_CHECK_ALLOC(*dest);
 
-	utf16_size = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, src, -1, *dest, utf16_size);
-
-	if (!utf16_size) {
-		git__set_errno();
+	utf16_size = git_utf8_to_16_with_len(*dest, (size_t)utf16_size,
+		src, src_len);
 
+	if (utf16_size < 0) {
 		git__free(*dest);
 		*dest = NULL;
 	}
 
-	/* Subtract 1 from the result to turn 0 into -1 (an error code) and to not count the NULL
-	 * terminator as part of the string's length. MultiByteToWideChar never returns int's minvalue,
-	 * so underflow is not possible */
-	return utf16_size - 1;
+	return utf16_size;
 }
 
-/**
- * Converts a wide string to UTF-8.
- * Memory is allocated to hold the converted string.
- * The caller is responsible for freeing the string with git__free.
- *
- * @param dest Receives a pointer to the UTF-8 string.
- * @param src The wide string to convert.
- * @return The length of the UTF-8 string, in bytes (not counting the NULL terminator), or < 0 for failure
- */
-int git__utf16_to_8_alloc(char **dest, const wchar_t *src)
+int git_utf8_from_16_alloc(char **dest, const wchar_t *src)
+{
+	/* Length of -1 indicates NULL termination of the input string. */
+	return git_utf8_from_16_alloc_with_len(dest, src, -1);
+}
+
+int git_utf8_from_16_alloc_with_len(char **dest, const wchar_t *src, int src_len)
 {
 	int utf8_size;
 
 	*dest = NULL;
 
-	/* Length of -1 indicates NULL termination of the input string */
-	utf8_size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, src, -1, NULL, 0, NULL, NULL);
+	utf8_size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS,
+		src, src_len, NULL, 0, NULL, NULL);
 
 	if (!utf8_size) {
 		git__set_errno();
@@ -124,23 +130,15 @@ int git__utf16_to_8_alloc(char **dest, const wchar_t *src)
 	}
 
 	*dest = git__malloc(utf8_size);
+	GIT_ERROR_CHECK_ALLOC(*dest);
 
-	if (!*dest) {
-		errno = ENOMEM;
-		return -1;
-	}
-
-	utf8_size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, src, -1, *dest, utf8_size, NULL, NULL);
-
-	if (!utf8_size) {
-		git__set_errno();
+	utf8_size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS,
+		src, src_len, *dest, utf8_size, NULL, NULL);
 
+	if (utf8_size < 0) {
 		git__free(*dest);
 		*dest = NULL;
 	}
 
-	/* Subtract 1 from the result to turn 0 into -1 (an error code) and to not count the NULL
-	 * terminator as part of the string's length. MultiByteToWideChar never returns int's minvalue,
-	 * so underflow is not possible */
-	return utf8_size - 1;
+	return utf8_size;
 }

src/util/win32/utf-conv.h

@@ -16,14 +16,45 @@
 #endif
 
 /**
+ * Converts a NUL-terminated UTF-8 string to wide characters. This is a
+ * convenience function for `git_utf8_to_16_with_len`.
+ *
+ * @param dest The buffer to receive the wide string.
+ * @param dest_size The size of the buffer, in characters.
+ * @param src The UTF-8 string to convert.
+ * @return The length of the wide string, in characters
+ *         (not counting the NULL terminator), or < 0 for failure
+ */
+int git_utf8_to_16(wchar_t *dest, size_t dest_size, const char *src);
+
+/**
  * Converts a UTF-8 string to wide characters.
  *
  * @param dest The buffer to receive the wide string.
  * @param dest_size The size of the buffer, in characters.
  * @param src The UTF-8 string to convert.
- * @return The length of the wide string, in characters (not counting the NULL terminator), or < 0 for failure
+ * @param src_len The length of the string to convert.
+ * @return The length of the wide string, in characters
+ *         (not counting the NULL terminator), or < 0 for failure
+ */
+int git_utf8_to_16_with_len(
+	wchar_t *dest,
+	size_t dest_size,
+	const char *src,
+	int src_len);
+
+/**
+ * Converts a NUL-terminated wide string to UTF-8. This is a convenience
+ * function for `git_utf8_from_16_with_len`.
+ *
+ * @param dest The buffer to receive the UTF-8 string.
+ * @param dest_size The size of the buffer, in bytes.
+ * @param src The wide string to convert.
+ * @param src_len The length of the string to convert.
+ * @return The length of the UTF-8 string, in bytes
+ *         (not counting the NULL terminator), or < 0 for failure
  */
-int git__utf8_to_16(wchar_t *dest, size_t dest_size, const char *src);
+int git_utf8_from_16(char *dest, size_t dest_size, const wchar_t *src);
 
 /**
  * Converts a wide string to UTF-8.
@@ -31,30 +62,66 @@ int git__utf8_to_16(wchar_t *dest, size_t dest_size, const char *src);
  * @param dest The buffer to receive the UTF-8 string.
  * @param dest_size The size of the buffer, in bytes.
  * @param src The wide string to convert.
- * @return The length of the UTF-8 string, in bytes (not counting the NULL terminator), or < 0 for failure
+ * @param src_len The length of the string to convert.
+ * @return The length of the UTF-8 string, in bytes
+ *         (not counting the NULL terminator), or < 0 for failure
  */
-int git__utf16_to_8(char *dest, size_t dest_size, const wchar_t *src);
+int git_utf8_from_16_with_len(char *dest, size_t dest_size, const wchar_t *src, int src_len);
 
 /**
- * Converts a UTF-8 string to wide characters.
- * Memory is allocated to hold the converted string.
- * The caller is responsible for freeing the string with git__free.
+ * Converts a UTF-8 string to wide characters. Memory is allocated to hold
+ * the converted string. The caller is responsible for freeing the string
+ * with git__free.
  *
  * @param dest Receives a pointer to the wide string.
  * @param src The UTF-8 string to convert.
- * @return The length of the wide string, in characters (not counting the NULL terminator), or < 0 for failure
+ * @return The length of the wide string, in characters
+ *         (not counting the NULL terminator), or < 0 for failure
  */
-int git__utf8_to_16_alloc(wchar_t **dest, const char *src);
+int git_utf8_to_16_alloc(wchar_t **dest, const char *src);
 
 /**
- * Converts a wide string to UTF-8.
- * Memory is allocated to hold the converted string.
- * The caller is responsible for freeing the string with git__free.
+ * Converts a UTF-8 string to wide characters. Memory is allocated to hold
+ * the converted string. The caller is responsible for freeing the string
+ * with git__free.
+ *
+ * @param dest Receives a pointer to the wide string.
+ * @param src The UTF-8 string to convert.
+ * @param src_len The length of the string.
+ * @return The length of the wide string, in characters
+ *         (not counting the NULL terminator), or < 0 for failure
+ */
+int git_utf8_to_16_alloc_with_len(
+	wchar_t **dest,
+	const char *src,
+	int src_len);
+
+/**
+ * Converts a wide string to UTF-8. Memory is allocated to hold the
+ * converted string. The caller is responsible for freeing the string
+ * with git__free.
+ *
+ * @param dest Receives a pointer to the UTF-8 string.
+ * @param src The wide string to convert.
+ * @return The length of the UTF-8 string, in bytes
+ *         (not counting the NULL terminator), or < 0 for failure
+ */
+int git_utf8_from_16_alloc(char **dest, const wchar_t *src);
+
+/**
+ * Converts a wide string to UTF-8. Memory is allocated to hold the
+ * converted string. The caller is responsible for freeing the string
+ * with git__free.
  *
  * @param dest Receives a pointer to the UTF-8 string.
  * @param src The wide string to convert.
- * @return The length of the UTF-8 string, in bytes (not counting the NULL terminator), or < 0 for failure
+ * @param src_len The length of the wide string.
+ * @return The length of the UTF-8 string, in bytes
+ *         (not counting the NULL terminator), or < 0 for failure
  */
-int git__utf16_to_8_alloc(char **dest, const wchar_t *src);
+int git_utf8_from_16_alloc_with_len(
+	char **dest,
+	const wchar_t *src,
+	int src_len);
 
 #endif

src/util/win32/w32_util.c

@@ -115,7 +115,7 @@ int git_win32__file_attribute_to_stat(
 
 			/* st_size gets the UTF-8 length of the target name, in bytes,
 			 * not counting the NULL terminator */
-			if ((st->st_size = git__utf16_to_8(NULL, 0, target)) < 0) {
+			if ((st->st_size = git_utf8_from_16(NULL, 0, target)) < 0) {
 				git_error_set(GIT_ERROR_OS, "could not convert reparse point name for '%ls'", path);
 				return -1;
 			}

tests/clar/clar_libgit2.c

@@ -103,10 +103,10 @@ int cl_setenv(const char *name, const char *value)
 {
 	wchar_t *wide_name, *wide_value = NULL;
 
-	cl_assert(git__utf8_to_16_alloc(&wide_name, name) >= 0);
+	cl_assert(git_utf8_to_16_alloc(&wide_name, name) >= 0);
 
 	if (value) {
-		cl_assert(git__utf8_to_16_alloc(&wide_value, value) >= 0);
+		cl_assert(git_utf8_to_16_alloc(&wide_value, value) >= 0);
 		cl_assert(SetEnvironmentVariableW(wide_name, wide_value));
 	} else {
 		/* Windows XP returns 0 (failed) when passing NULL for lpValue when

tests/util/link.c

@@ -98,7 +98,7 @@ static void do_junction(const char *old, const char *new)
 
 	git_str_putc(&unparsed_buf, '\\');
 
-	subst_utf16_len = git__utf8_to_16(NULL, 0, git_str_cstr(&unparsed_buf));
+	subst_utf16_len = git_utf8_to_16(NULL, 0, git_str_cstr(&unparsed_buf));
 	subst_byte_len = subst_utf16_len * sizeof(WCHAR);
 
 	print_utf16_len = subst_utf16_len - 4;
@@ -124,11 +124,11 @@ static void do_junction(const char *old, const char *new)
 	subst_utf16 = reparse_buf->ReparseBuffer.MountPoint.PathBuffer;
 	print_utf16 = subst_utf16 + subst_utf16_len + 1;
 
-	ret = git__utf8_to_16(subst_utf16, subst_utf16_len + 1,
+	ret = git_utf8_to_16(subst_utf16, subst_utf16_len + 1,
 		git_str_cstr(&unparsed_buf));
 	cl_assert_equal_i(subst_utf16_len, ret);
 
-	ret = git__utf8_to_16(print_utf16,
+	ret = git_utf8_to_16(print_utf16,
 		print_utf16_len + 1, git_str_cstr(&unparsed_buf) + 4);
 	cl_assert_equal_i(print_utf16_len, ret);