Commit a34f5b0db55ba2bd0080ccd8f08db157a76168a9
2018-10-18T08:57:27
win32: refactor `git_win32_path_remove_namespace` Update `git_win32_path_remove_namespace` to disambiguate the prefix being removed versus the prefix being added. Now we remove the "namespace", and (may) add a "prefix" in its place. Eg, we remove the `\\?\` namespace. We remove the `\\?\UNC\` namespace, and replace it with the `\\` prefix. This aids readability somewhat. Additionally, use pointer arithmetic instead of offsets, which seems to also help readability.
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diff --git a/src/win32/path_w32.c b/src/win32/path_w32.c
index 18dc81a..b955b02 100644
--- a/src/win32/path_w32.c
+++ b/src/win32/path_w32.c
@@ -418,46 +418,57 @@ size_t git_win32_path_trim_end(wchar_t *str, size_t len)
*/
size_t git_win32_path_remove_namespace(wchar_t *str, size_t len)
{
- static const wchar_t dosdevices_prefix[] = L"\\\?\?\\";
- static const wchar_t nt_prefix[] = L"\\\\?\\";
- static const wchar_t unc_prefix[] = L"UNC\\";
- static const wchar_t unc_canonicalized_prefix[] = L"\\\\";
+ static const wchar_t dosdevices_namespace[] = L"\\\?\?\\";
+ static const wchar_t nt_namespace[] = L"\\\\?\\";
+ static const wchar_t unc_namespace_remainder[] = L"UNC\\";
+ static const wchar_t unc_prefix[] = L"\\\\";
- size_t to_advance = 0;
+ const wchar_t *prefix = NULL, *remainder = NULL;
+ size_t prefix_len = 0, remainder_len = 0;
/* "\??\" -- DOS Devices prefix */
- if (len >= CONST_STRLEN(dosdevices_prefix) &&
- !wcsncmp(str, dosdevices_prefix, CONST_STRLEN(dosdevices_prefix))) {
- to_advance += CONST_STRLEN(dosdevices_prefix);
- len -= CONST_STRLEN(dosdevices_prefix);
+ if (len >= CONST_STRLEN(dosdevices_namespace) &&
+ !wcsncmp(str, dosdevices_namespace, CONST_STRLEN(dosdevices_namespace))) {
+ remainder = str + CONST_STRLEN(dosdevices_namespace);
+ remainder_len = len - CONST_STRLEN(dosdevices_namespace);
}
/* "\\?\" -- NT namespace prefix */
- else if (len >= CONST_STRLEN(nt_prefix) &&
- !wcsncmp(str, nt_prefix, CONST_STRLEN(nt_prefix))) {
- to_advance += CONST_STRLEN(nt_prefix);
- len -= CONST_STRLEN(nt_prefix);
+ else if (len >= CONST_STRLEN(nt_namespace) &&
+ !wcsncmp(str, nt_namespace, CONST_STRLEN(nt_namespace))) {
+ remainder = str + CONST_STRLEN(nt_namespace);
+ remainder_len = len - CONST_STRLEN(nt_namespace);
}
/* "\??\UNC\", "\\?\UNC\" -- UNC prefix */
- if (to_advance && len >= CONST_STRLEN(unc_prefix) &&
- !wcsncmp(str + to_advance, unc_prefix, CONST_STRLEN(unc_prefix))) {
+ if (remainder_len >= CONST_STRLEN(unc_namespace_remainder) &&
+ !wcsncmp(remainder, unc_namespace_remainder, CONST_STRLEN(unc_namespace_remainder))) {
/*
* The proper Win32 path for a UNC share has "\\" at beginning of it
- * and looks like "\\server\share\<folderStructure>".
- * So, remove the UNC prefix, but leave room for a "\\"
+ * and looks like "\\server\share\<folderStructure>". So remove the
+ * UNC namespace and add a prefix of "\\" in its place.
*/
- to_advance += (CONST_STRLEN(unc_prefix) - CONST_STRLEN(unc_canonicalized_prefix));
- len -= (CONST_STRLEN(unc_prefix) - CONST_STRLEN(unc_canonicalized_prefix));
+ remainder += CONST_STRLEN(unc_namespace_remainder);
+ remainder_len -= CONST_STRLEN(unc_namespace_remainder);
- /**
- * Place a "\\" in the string so the result is "\\server\\share\<folderStructure>"
- */
- memmove(str + to_advance, unc_canonicalized_prefix, CONST_STRLEN(unc_canonicalized_prefix) * sizeof(wchar_t));
+ prefix = unc_prefix;
+ prefix_len = CONST_STRLEN(unc_prefix);
}
- if (to_advance) {
- memmove(str, str + to_advance, len * sizeof(wchar_t));
+ if (remainder) {
+ /*
+ * Sanity check that the new string isn't longer than the old one.
+ * (This could only happen due to programmer error introducing a
+ * prefix longer than the namespace it replaces.)
+ */
+ assert(len >= remainder_len + prefix_len);
+
+ if (prefix)
+ memmove(str, prefix, prefix_len * sizeof(wchar_t));
+
+ memmove(str + prefix_len, remainder, remainder_len * sizeof(wchar_t));
+
+ len = remainder_len + prefix_len;
str[len] = L'\0';
}