[Lldb-commits] [lldb] [lldb][windows] refactor CreateProcessW setup (PR #168733)

[Charles Zablit via lldb-commits]

================
@@ -21,42 +21,41 @@
 using namespace lldb;
 using namespace lldb_private;
 
-static void CreateEnvironmentBuffer(const Environment &env,
-                                    std::vector<char> &buffer) {
-  // The buffer is a list of null-terminated UTF-16 strings, followed by an
-  // extra L'\0' (two bytes of 0).  An empty environment must have one
-  // empty string, followed by an extra L'\0'.
+std::vector<wchar_t>
+ProcessLauncherWindows::CreateEnvironmentBufferW(const Environment &env) {
+  std::vector<std::wstring> env_entries;
   for (const auto &KV : env) {
-    std::wstring warg;
-    if (llvm::ConvertUTF8toWide(Environment::compose(KV), warg)) {
-      buffer.insert(
-          buffer.end(), reinterpret_cast<const char *>(warg.c_str()),
-          reinterpret_cast<const char *>(warg.c_str() + warg.size() + 1));
+    std::wstring wentry;
+    if (llvm::ConvertUTF8toWide(Environment::compose(KV), wentry)) {
+      env_entries.push_back(std::move(wentry));
     }
   }
-  // One null wchar_t (to end the block) is two null bytes
-  buffer.push_back(0);
-  buffer.push_back(0);
-  // Insert extra two bytes, just in case the environment was empty.
-  buffer.push_back(0);
-  buffer.push_back(0);
+  std::sort(env_entries.begin(), env_entries.end(),
+            [](const std::wstring &a, const std::wstring &b) {
+              return _wcsicmp(a.c_str(), b.c_str()) < 0;
+            });
----------------
charles-zablit wrote:

As I understand it from [the `CreateProcess` documentation](https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessw), we have to sort the env variables before calling `CreateProcessW`:
> An application must manually pass the current directory information to the new process. To do so, the application must explicitly create these environment variable strings, sort them alphabetically (because the system uses a sorted environment), and put them into the environment block. Typically, they will go at the front of the environment block, due to the environment block sort order.

https://github.com/llvm/llvm-project/pull/168733