Merge pull request swiftlang#21365 from compnerd/your-command

stdlib: make CommandLine inspection work

Author: compnerd

stdlib/public/stubs/CommandLine.cpp

@@ -29,6 +29,12 @@
 #include "../SwiftShims/RuntimeStubs.h"
 #include "../SwiftShims/GlobalObjects.h"
 
+#if defined(_WIN32)
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+#include <shellapi.h>
+#endif
+
 // Backing storage for overrides of `Swift.CommandLine.arguments`.
 static char **_swift_stdlib_ProcessOverrideUnsafeArgv = nullptr;
 static int _swift_stdlib_ProcessOverrideUnsafeArgc = 0;
@@ -101,8 +107,53 @@ char ** _swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
     return _swift_stdlib_ProcessOverrideUnsafeArgv;
   }
 
-  *outArgLen = __argc;
-  return __argv;
+  *outArgLen = 0;
+
+
+  LPWSTR *szArgList;
+  int nArgs;
+  szArgList = CommandLineToArgvW(GetCommandLineW(), &nArgs);
+  if (szArgList == nullptr)
+    return nullptr;
+
+  std::vector<char *> argv;
+  for (int i = 0; i < nArgs; ++i) {
+    int szBufferSize = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS,
+                                           szArgList[i], -1, nullptr, 0,
+                                           nullptr, nullptr);
+    if (szBufferSize == 0) {
+      for (char *arg : argv)
+        free(arg);
+      return nullptr;
+    }
+
+    char *buffer = static_cast<char *>(calloc(static_cast<size_t>(szBufferSize),
+                                              sizeof(char)));
+    if (buffer == nullptr) {
+      for (char *arg : argv)
+        free(arg);
+      return nullptr;
+    }
+
+    if (!WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, szArgList[i], -1,
+                             buffer, szBufferSize, nullptr, nullptr)) {
+      for (char *arg : argv)
+        free(arg);
+      return nullptr;
+    }
+
+    argv.push_back(buffer);
+  }
+
+  LocalFree(szArgList);
+
+  char **args = static_cast<char **>(calloc(argv.size() + 1, sizeof(char *)));
+  std::copy(argv.begin(), argv.end(), args);
+  args[argv.size()] = nullptr;
+
+  assert(argv.size() < INT_MAX && "overflow");
+  *outArgLen = static_cast<int>(argv.size());
+  return args;
 }
 #elif defined(__FreeBSD__)
 #include <errno.h>