Bug 1493955 - Store floating-point preferences in a locale-independent way r=njn

Differential Revision: https://phabricator.services.mozilla.com/D6796

--HG--
extra : moz-landing-system : lando

modules/libpref/Preferences.cpp

@@ -2394,6 +2394,7 @@ nsPrefBranch::GetFloatPref(const char* aPrefName, float* aRetVal)
   nsAutoCString stringVal;
   nsresult rv = GetCharPref(aPrefName, stringVal);
   if (NS_SUCCEEDED(rv)) {
+    // ToFloat() does a locale-independent conversion.
     *aRetVal = stringVal.ToFloat(&rv);
   }
 
@@ -5035,6 +5036,7 @@ Preferences::GetFloat(const char* aPrefName,
   nsAutoCString result;
   nsresult rv = Preferences::GetCString(aPrefName, result, aKind);
   if (NS_SUCCEEDED(rv)) {
+    // ToFloat() does a locale-independent conversion.
     *aResult = result.ToFloat(&rv);
   }
   return rv;
@@ -5845,7 +5847,9 @@ static void
 SetPref_float(const char* aName, float aDefaultValue)
 {
   PrefValue value;
-  nsPrintfCString defaultValue("%f", aDefaultValue);
+  // Convert the value in a locale-independent way.
+  nsAutoCString defaultValue;
+  defaultValue.AppendFloat(aDefaultValue);
   value.mStringVal = defaultValue.get();
   pref_SetPref(aName,
                PrefType::String,
@@ -5973,8 +5977,7 @@ InitVarCachePref(const nsACString& aName,
   }
 }
 
-// XXX: this will eventually become used
-MOZ_MAYBE_UNUSED static void
+static void
 InitVarCachePref(const nsACString& aName,
                  float* aCache,
                  float aDefaultValue,

modules/libpref/Preferences.h

@@ -19,7 +19,6 @@
 #include "nsIObserver.h"
 #include "nsIPrefBranch.h"
 #include "nsIPrefService.h"
-#include "nsPrintfCString.h"
 #include "nsString.h"
 #include "nsTArray.h"
 #include "nsWeakReference.h"
@@ -309,7 +308,9 @@ public:
                            float aValue,
                            PrefValueKind aKind = PrefValueKind::User)
   {
-    return SetCString(aPrefName, nsPrintfCString("%f", aValue), aKind);
+    nsAutoCString value;
+    value.AppendFloat(aValue);
+    return SetCString(aPrefName, value, aKind);
   }
 
   static nsresult SetCString(const char* aPrefName,

modules/libpref/test/gtest/Basics.cpp

@@ -4,6 +4,8 @@
  * 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/. */
 
+#include <locale.h>
+
 #include "gtest/gtest.h"
 #include "mozilla/Preferences.h"
 
@@ -34,3 +36,22 @@ TEST(PrefsBasics, Errors)
   ASSERT_FLOAT_EQ(Preferences::GetFloat("foo.float", 1.0f, PrefValueKind::User),
                   4.44f);
 }
+
+TEST(PrefsBasics, FloatConversions)
+{
+  // Set a global locale that uses the comma as the decimal separator. Since
+  // we can't tell which locales will be available on a machine the tests are
+  // executed only if the locale was set correctly.
+  const char* oldLocale = setlocale(LC_NUMERIC, "nl_NL");
+  if (oldLocale != nullptr) {
+    Preferences::SetFloat("foo.float", 3.33f, PrefValueKind::Default);
+    Preferences::SetFloat("foo.float", 4.44f, PrefValueKind::User);
+    ASSERT_FLOAT_EQ(
+      Preferences::GetFloat("foo.float", 1.0f, PrefValueKind::Default), 3.33f);
+    ASSERT_FLOAT_EQ(
+      Preferences::GetFloat("foo.float", 1.0f, PrefValueKind::User), 4.44f);
+
+    // Restore the original locale
+    setlocale(LC_NUMERIC, oldLocale);
+  }
+}

toolkit/components/antitracking/AntiTrackingCommon.cpp

@@ -30,6 +30,7 @@
 #include "nsIWebProgressListener.h"
 #include "nsNetUtil.h"
 #include "nsPIDOMWindow.h"
+#include "nsPrintfCString.h"
 #include "nsScriptSecurityManager.h"
 #include "nsSandboxFlags.h"
 #include "prtime.h"

toolkit/components/extensions/ExtensionPolicyService.cpp

@@ -29,6 +29,7 @@
 #include "nsILoadInfo.h"
 #include "nsIXULRuntime.h"
 #include "nsNetUtil.h"
+#include "nsPrintfCString.h"
 #include "nsPIDOMWindow.h"
 #include "nsXULAppAPI.h"
 #include "nsQueryObject.h"

toolkit/components/telemetry/tests/gtest/TestCombinedStacks.cpp

@@ -4,6 +4,8 @@
 
 #include "other/CombinedStacks.h"
 #include "other/ProcessedStack.h"
+#include "nsPrintfCString.h"
+
 using namespace mozilla::Telemetry;
 using namespace TelemetryTestHelpers;
 

toolkit/recordreplay/ipc/ChildIPC.cpp

@@ -23,6 +23,7 @@
 
 #include "InfallibleVector.h"
 #include "MemorySnapshot.h"
+#include "nsPrintfCString.h"
 #include "ParentInternal.h"
 #include "ProcessRecordReplay.h"
 #include "ProcessRedirect.h"

xpcom/threads/Scheduler.cpp

@@ -16,7 +16,6 @@
 #include "mozilla/SchedulerGroup.h"
 #include "nsCycleCollector.h"
 #include "nsIThread.h"
-#include "nsPrintfCString.h"
 #include "nsThread.h"
 #include "nsThreadManager.h"
 #include "PrioritizedEventQueue.h"

xpcom/threads/Scheduler.h

@@ -14,6 +14,7 @@
 #include "mozilla/UniquePtr.h"
 #include "nsTArray.h"
 #include "nsILabelableRunnable.h"
+#include "nsPrintfCString.h"
 
 // Windows silliness. winbase.h defines an empty no-argument Yield macro.
 #undef Yield