Avoid MAX_PATH limitation in launcher

... and drop some manual memory management.

Change-Id: I4c60ce559ff185d4685a6b9799a97651438115b1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/162502
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

1 files changed, 18 insertions, 41 deletions

diff --git a/tools/source/misc/pathutils.cxx b/tools/source/misc/pathutils.cxx
index 706740a320f9..30bdbde8f013 100644
--- a/tools/source/misc/pathutils.cxx
+++ b/tools/source/misc/pathutils.cxx
@@ -43,63 +43,40 @@ WCHAR * filename(WCHAR * path) {
     }
 }
 
-WCHAR * buildPath(
-    WCHAR * path, WCHAR const * frontBegin, WCHAR const * frontEnd,
-    WCHAR const * backBegin, std::size_t backLength)
+std::wstring buildPath(std::wstring_view front, std::wstring_view back)
 {
     // Remove leading ".." segments in the second path together with matching
     // segments in the first path that are neither empty nor "." nor ".." nor
     // end in ":" (which is not foolproof, as it can erroneously erase the start
     // of a UNC path, but only if the input is bad data):
-    while (backLength >= 2 && backBegin[0] == L'.' && backBegin[1] == L'.' &&
-           (backLength == 2 || backBegin[2] == L'\\'))
+    while (back.starts_with(L"..") &&
+           (back.size() == 2 || back[2] == L'\\'))
     {
-        if (frontEnd - frontBegin < 2 || frontEnd[-1] != L'\\' ||
-            frontEnd[-2] == L'\\' || frontEnd[-2] == L':' ||
-            (frontEnd[-2] == L'.' &&
-             (frontEnd - frontBegin < 3 || frontEnd[-3] == L'\\' ||
-              (frontEnd[-3] == L'.' &&
-               (frontEnd - frontBegin < 4 || frontEnd[-4] == L'\\')))))
+        if (front.size() < 2 || front.back() != L'\\' ||
+            front[front.size() - 2] == L'\\' || front[front.size() - 2] == L':' ||
+            (front[front.size() - 2] == L'.' &&
+             (front.size() < 3 || front[front.size() - 3] == L'\\' ||
+              (front[front.size() - 3] == L'.' &&
+               (front.size() < 4 || front[front.size() - 4] == L'\\')))))
         {
             break;
         }
-        WCHAR const * p = frontEnd - 1;
-        while (p != frontBegin && p[-1] != L'\\') {
+        auto p = front.end() - 1;
+        while (p != front.begin() && p[-1] != L'\\') {
             --p;
         }
-        if (p == frontBegin) {
+        if (p == front.begin()) {
             break;
         }
-        frontEnd = p;
-        if (backLength == 2) {
-            backBegin += 2;
-            backLength -= 2;
+        front.remove_suffix(front.end() - p);
+        if (back.size() == 2) {
+            back = {};
         } else {
-            backBegin += 3;
-            backLength -= 3;
+            back.remove_prefix(3);
         }
     }
-    if (backLength <
-        o3tl::make_unsigned(MAX_PATH - (frontEnd - frontBegin)))
-    {
-        WCHAR * p;
-        if (frontBegin == path) {
-            p = const_cast< WCHAR * >(frontEnd);
-        } else {
-            p = path;
-            while (frontBegin != frontEnd) {
-                *p++ = *frontBegin++;
-            }
-        }
-        for (; backLength > 0; --backLength) {
-            *p++ = *backBegin++;
-        }
-        *p = L'\0';
-        return p;
-    } else {
-        SetLastError(ERROR_FILENAME_EXCED_RANGE);
-        return nullptr;
-    }
+
+    return std::wstring(front) + std::wstring(back);
 }
 
 }