Bug 1768758 - Add Windows-specific function getW() for getting wchar_t r=xpcom-reviewers,win-reviewers,gstoll,nika

`char16_t` and `wchar_t` are functionally the same on Windows. But logging statements do not handle `char16_t` very well, resulting in the need to static cast to `wchar_t`. For more info, see [[ https://bugzilla.mozilla.org/show_bug.cgi?id=1768758 | bug task ]]:

This diff introduces a Windows-specific function for getting strings as `wchar_t` and replaces previous workaround usages.

Differential Revision: https://phabricator.services.mozilla.com/D215869

security/sandbox/win/src/sandboxbroker/sandboxBroker.cpp

@@ -453,7 +453,7 @@ static void AddCachedDirRule(sandbox::TargetPolicy* aPolicy,
   if (sandbox::SBOX_ALL_OK != result) {
     NS_ERROR("Failed to add file policy rule.");
     LOG_E("Failed (ResultCode %d) to add %d access to: %S", result, aAccess,
-          static_cast<const wchar_t*>(rulePath.get()));
+          rulePath.getW());
   }
 }
 

toolkit/components/contentanalysis/ContentAnalysis.cpp

@@ -246,7 +246,7 @@ nsresult ContentAnalysis::CreateContentAnalysisClient(
     if (orgName) {
       auto dependentOrgName = nsDependentString(orgName.get());
       LOGD("Content analysis client signed with organization name \"%S\"",
-           static_cast<const wchar_t*>(dependentOrgName.get()));
+           dependentOrgName.getW());
       signatureMatches = aClientSignatureSetting.Equals(dependentOrgName);
     } else {
       LOGD("Content analysis client has no signature");

toolkit/components/remote/RemoteUtils.h

@@ -18,7 +18,7 @@ static void BuildClassName(const char* aProgram, const char* aProfile,
 #  if defined XP_WIN
   nsString pfn = mozilla::widget::WinUtils::GetPackageFamilyName();
   if (!pfn.IsEmpty()) {
-    aClassName.AppendPrintf("_%S", static_cast<const wchar_t*>(pfn.get()));
+    aClassName.AppendPrintf("_%S", pfn.getW());
   }
 #  endif
   aClassName.AppendPrintf("_%s_RemoteWindow", aProfile);

toolkit/xre/dllservices/tests/gtest/TestUntrustedModules.cpp

@@ -42,14 +42,12 @@ class ModuleLoadCounter final {
     for (size_t i = 0; i < N; ++i) {
       auto entry = mCounters.Lookup(aNames[i]);
       if (!entry) {
-        wprintf(L"%s is not registered.\n",
-                static_cast<const wchar_t*>(aNames[i].get()));
+        wprintf(L"%s is not registered.\n", aNames[i].getW());
         result = false;
       } else if (*entry != aCounts[i]) {
         // We can return false, but let's print out all unmet modules
         // which may be helpful to investigate test failures.
-        wprintf(L"%s:%4d\n", static_cast<const wchar_t*>(aNames[i].get()),
-                *entry);
+        wprintf(L"%s:%4d\n", aNames[i].getW(), *entry);
         result = false;
       }
     }
@@ -253,7 +251,7 @@ class UntrustedModulesFixture : public TelemetryTestFixture {
     EXPECT_TRUE(matchResult.isBoolean() && matchResult.toBoolean());
     if (!matchResult.isBoolean() || !matchResult.toBoolean()) {
       // If match failed, print out the actual JSON kindly.
-      wprintf(L"JSON: %s\n", static_cast<const wchar_t*>(json.get()));
+      wprintf(L"JSON: %s\n", json.getW());
       wprintf(L"RE: %s\n", aPattern);
     }
     wprintf(L"ValidateJSValue bottom\n");

uriloader/exthandler/win/nsOSHelperAppService.cpp

@@ -454,9 +454,8 @@ nsOSHelperAppService::GetMIMEInfoFromOS(const nsACString& aMIMEType,
   bool haveMeaningfulMimeType =
       !aMIMEType.IsEmpty() &&
       !aMIMEType.LowerCaseEqualsLiteral(APPLICATION_OCTET_STREAM);
-  LOG("Extension lookup on '%S' with mimetype '%s'%s\n",
-      static_cast<const wchar_t*>(fileExtension.get()), flatType.get(),
-      haveMeaningfulMimeType ? " (treated as meaningful)" : "");
+  LOG("Extension lookup on '%S' with mimetype '%s'%s\n", fileExtension.getW(),
+      flatType.get(), haveMeaningfulMimeType ? " (treated as meaningful)" : "");
 
   RefPtr<nsMIMEInfoWin> mi;
 
@@ -488,13 +487,12 @@ nsOSHelperAppService::GetMIMEInfoFromOS(const nsACString& aMIMEType,
     usedMimeTypeExtensionForLookup = true;
     fileExtension = extensionFromMimeType;
     LOG("Now using '%s' mimetype's default file extension '%S' for lookup\n",
-        flatType.get(), static_cast<const wchar_t*>(fileExtension.get()));
+        flatType.get(), fileExtension.getW());
   }
 
   // If we have an extension, use it for lookup:
   mi = GetByExtension(fileExtension, flatType.get());
-  LOG("Extension lookup on '%S' found: 0x%p\n",
-      static_cast<const wchar_t*>(fileExtension.get()), mi.get());
+  LOG("Extension lookup on '%S' found: 0x%p\n", fileExtension.getW(), mi.get());
 
   if (mi) {
     bool hasDefault = false;
@@ -505,8 +503,7 @@ nsOSHelperAppService::GetMIMEInfoFromOS(const nsACString& aMIMEType,
       RefPtr<nsMIMEInfoWin> miFromMimeType =
           GetByExtension(extensionFromMimeType, flatType.get());
       LOG("Mime-based ext. lookup for '%S' found 0x%p\n",
-          static_cast<const wchar_t*>(extensionFromMimeType.get()),
-          miFromMimeType.get());
+          extensionFromMimeType.getW(), miFromMimeType.get());
       if (miFromMimeType) {
         nsAutoString desc;
         miFromMimeType->GetDefaultDescription(desc);
@@ -522,7 +519,7 @@ nsOSHelperAppService::GetMIMEInfoFromOS(const nsACString& aMIMEType,
   if (!extensionFromMimeType.IsEmpty() && !usedMimeTypeExtensionForLookup) {
     mi = GetByExtension(extensionFromMimeType, flatType.get());
     LOG("Mime-based ext. lookup for '%S' found 0x%p\n",
-        static_cast<const wchar_t*>(extensionFromMimeType.get()), mi.get());
+        extensionFromMimeType.getW(), mi.get());
   }
   if (mi) {
     mi.forget(aMIMEInfo);

widget/windows/GfxInfo.cpp

@@ -107,8 +107,7 @@ GfxInfo::GetCleartypeParameters(nsAString& aCleartypeParams) {
     ClearTypeParameterInfo& params = clearTypeParams[d];
 
     if (displayNames) {
-      outStr.AppendPrintf(
-          "%S [ ", static_cast<const wchar_t*>(params.displayName.get()));
+      outStr.AppendPrintf("%S [ ", params.displayName.getW());
     }
 
     if (params.gamma >= 0) {

widget/windows/OSKTabTipManager.cpp

@@ -82,8 +82,7 @@ void OSKTabTipManager::ShowOnScreenKeyboard() {
         if (FAILED(hres) || !path) {
           return;
         }
-        commonProgramFilesPath =
-            static_cast<const wchar_t*>(nsDependentString(path).get());
+        commonProgramFilesPath = nsDependentString(path).getW();
         ::CoTaskMemFree(path);
       }
       wstrpath.replace(commonProgramFilesOffset,

widget/windows/nsPrintDialogUtil.cpp

@@ -73,8 +73,7 @@ static nsReturnRef<nsHGLOBAL> CreateGlobalDevModeAndInit(
     const nsString& aPrintName, nsIPrintSettings* aPS) {
   nsHPRINTER hPrinter = nullptr;
   // const cast kludge for silly Win32 api's
-  LPWSTR printName =
-      const_cast<wchar_t*>(static_cast<const wchar_t*>(aPrintName.get()));
+  LPWSTR printName = const_cast<wchar_t*>(aPrintName.getW());
   BOOL status = ::OpenPrinterW(printName, &hPrinter, nullptr);
   if (!status) {
     return nsReturnRef<nsHGLOBAL>();
@@ -165,9 +164,8 @@ nsresult NativeShowPrintDialog(HWND aHWnd, bool aHaveSelection,
     GetDefaultPrinterNameFromGlobalPrinters(printerName);
   } else {
     HANDLE hPrinter = nullptr;
-    if (!::OpenPrinterW(const_cast<wchar_t*>(
-                            static_cast<const wchar_t*>(printerName.get())),
-                        &hPrinter, nullptr)) {
+    if (!::OpenPrinterW(const_cast<wchar_t*>(printerName.getW()), &hPrinter,
+                        nullptr)) {
       // If the last used printer is not found, we should use default printer.
       GetDefaultPrinterNameFromGlobalPrinters(printerName);
     } else {

xpcom/string/nsTString.h

@@ -166,6 +166,18 @@ class nsTString : public nsTSubstring<T> {
     return this->mData;
   }
 
+#ifdef XP_WIN
+  /**
+   * Returns the string as a wchar_t
+   */
+  template <typename U = T>
+  typename std::enable_if<std::is_same<U, char16_t>::value,
+                          const wchar_t*>::type
+  getW() const {
+    return reinterpret_cast<const wchar_t*>(this->mData);
+  }
+#endif
+
   /**
    * returns character at specified index.
    *