1 files changed, 61 insertions, 0 deletions
diff --git a/mozglue/misc/WindowsEnumProcessModules.h b/mozglue/misc/WindowsEnumProcessModules.h
new file mode 100644
index 0000000000..573b0dbdfa
--- /dev/null
+++ b/mozglue/misc/WindowsEnumProcessModules.h
@@ -0,0 +1,61 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_WindowsEnumProcessModules_h
+#define mozilla_WindowsEnumProcessModules_h
+
+#include <windows.h>
+#include <psapi.h>
+
+#include "mozilla/FunctionRef.h"
+#include "mozilla/NativeNt.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WinHeaderOnlyUtils.h"
+
+namespace mozilla {
+
+// Why don't we use CreateToolhelp32Snapshot instead of EnumProcessModules?
+// CreateToolhelp32Snapshot gets the ANSI versions of module path strings
+// via ntdll!RtlQueryProcessDebugInformation and stores them into a snapshot.
+// Module32FirstW/Module32NextW re-converts ANSI into Unicode, but it cannot
+// restore lost information.   This means we still need GetModuleFileNameEx
+// even when we use CreateToolhelp32Snapshot, but EnumProcessModules is faster.
+inline bool EnumerateProcessModules(
+    const FunctionRef<void(const wchar_t*, HMODULE)>& aCallback) {
+  DWORD modulesSize;
+  if (!::EnumProcessModules(nt::kCurrentProcess, nullptr, 0, &modulesSize)) {
+    return false;
+  }
+
+  DWORD modulesNum = modulesSize / sizeof(HMODULE);
+  UniquePtr<HMODULE[]> modules = MakeUnique<HMODULE[]>(modulesNum);
+  if (!::EnumProcessModules(nt::kCurrentProcess, modules.get(),
+                            modulesNum * sizeof(HMODULE), &modulesSize)) {
+    return false;
+  }
+
+  // The list may have shrunk between calls
+  if (modulesSize / sizeof(HMODULE) < modulesNum) {
+    modulesNum = modulesSize / sizeof(HMODULE);
+  }
+
+  for (DWORD i = 0; i < modulesNum; ++i) {
+    UniquePtr<wchar_t[]> modulePath = GetFullModulePath(modules[i]);
+    if (!modulePath) {
+      continue;
+    }
+
+    // Please note that modules[i] could be invalid if the module
+    // was unloaded after GetFullModulePath succeeded.
+    aCallback(modulePath.get(), modules[i]);
+  }
+
+  return true;
+}
+
+}  // namespace mozilla
+
+#endif  // mozilla_WindowsEnumProcessModules_h