Bug 1549578: Cache most recently used UDateTimePatternGenerator in SharedIntlData. r=jwalden

Differential Revision: https://phabricator.services.mozilla.com/D30114

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

js/src/builtin/intl/DateTimeFormat.cpp

@@ -548,14 +548,12 @@ bool js::intl_patternForSkeleton(JSContext* cx, unsigned argc, Value* vp) {
 
   mozilla::Range<const char16_t> skelChars = skeleton.twoByteRange();
 
-  UErrorCode status = U_ZERO_ERROR;
+  SharedIntlData& sharedIntlData = cx->runtime()->sharedIntlData.ref();
   UDateTimePatternGenerator* gen =
-      udatpg_open(IcuLocale(locale.get()), &status);
-  if (U_FAILURE(status)) {
-    intl::ReportInternalError(cx);
+      sharedIntlData.getDateTimePatternGenerator(cx, locale.get());
+  if (!gen) {
     return false;
   }
-  ScopedICUObject<UDateTimePatternGenerator, udatpg_close> toClose(gen);
 
   JSString* str = CallICU(
       cx, [gen, &skelChars](UChar* chars, uint32_t size, UErrorCode* status) {

js/src/builtin/intl/SharedIntlData.cpp

@@ -13,6 +13,7 @@
 #include "mozilla/TextUtils.h"
 
 #include <stdint.h>
+#include <utility>
 
 #include "builtin/intl/CommonFunctions.h"
 #include "builtin/intl/ICUStubs.h"
@@ -395,6 +396,39 @@ bool js::intl::SharedIntlData::isUpperCaseFirst(JSContext* cx,
   return true;
 }
 
+void js::intl::DateTimePatternGeneratorDeleter::operator()(
+    UDateTimePatternGenerator* ptr) {
+  udatpg_close(ptr);
+}
+
+UDateTimePatternGenerator*
+js::intl::SharedIntlData::getDateTimePatternGenerator(JSContext* cx,
+                                                      const char* locale) {
+  // Return the cached instance if the requested locale matches the locale
+  // of the cached generator.
+  if (dateTimePatternGeneratorLocale &&
+      StringsAreEqual(dateTimePatternGeneratorLocale.get(), locale)) {
+    return dateTimePatternGenerator.get();
+  }
+
+  UErrorCode status = U_ZERO_ERROR;
+  UniqueUDateTimePatternGenerator gen(udatpg_open(IcuLocale(locale), &status));
+  if (U_FAILURE(status)) {
+    intl::ReportInternalError(cx);
+    return nullptr;
+  }
+
+  JS::UniqueChars localeCopy = js::DuplicateString(cx, locale);
+  if (!localeCopy) {
+    return nullptr;
+  }
+
+  dateTimePatternGenerator = std::move(gen);
+  dateTimePatternGeneratorLocale = std::move(localeCopy);
+
+  return dateTimePatternGenerator.get();
+}
+
 void js::intl::SharedIntlData::destroyInstance() {
   availableTimeZones.clearAndCompact();
   ianaZonesTreatedAsLinksByICU.clearAndCompact();
@@ -418,5 +452,6 @@ size_t js::intl::SharedIntlData::sizeOfExcludingThis(
          ianaZonesTreatedAsLinksByICU.shallowSizeOfExcludingThis(mallocSizeOf) +
          ianaLinksCanonicalizedDifferentlyByICU.shallowSizeOfExcludingThis(
              mallocSizeOf) +
-         upperCaseFirstLocales.shallowSizeOfExcludingThis(mallocSizeOf);
+         upperCaseFirstLocales.shallowSizeOfExcludingThis(mallocSizeOf) +
+         mallocSizeOf(dateTimePatternGeneratorLocale.get());
 }

js/src/builtin/intl/SharedIntlData.h

@@ -8,6 +8,7 @@
 #define builtin_intl_SharedIntlData_h
 
 #include "mozilla/MemoryReporting.h"
+#include "mozilla/UniquePtr.h"
 
 #include <stddef.h>
 
@@ -19,10 +20,17 @@
 #include "js/Utility.h"
 #include "vm/StringType.h"
 
+using UDateTimePatternGenerator = void*;
+
 namespace js {
 
 namespace intl {
 
+class DateTimePatternGeneratorDeleter {
+ public:
+  void operator()(UDateTimePatternGenerator* ptr);
+};
+
 /**
  * Stores Intl data which can be shared across compartments (but not contexts).
  *
@@ -203,6 +211,22 @@ class SharedIntlData {
   bool isUpperCaseFirst(JSContext* cx, JS::Handle<JSString*> locale,
                         bool* isUpperFirst);
 
+ private:
+  using UniqueUDateTimePatternGenerator =
+      mozilla::UniquePtr<UDateTimePatternGenerator,
+                         DateTimePatternGeneratorDeleter>;
+
+  UniqueUDateTimePatternGenerator dateTimePatternGenerator;
+  JS::UniqueChars dateTimePatternGeneratorLocale;
+
+ public:
+  /**
+   * Wrapper around |udatpg_open| to return a possibly cached generator
+   * instance. The returned pointer must not be closed via |udatpg_close|.
+   */
+  UDateTimePatternGenerator* getDateTimePatternGenerator(JSContext* cx,
+                                                         const char* locale);
+
  public:
   void destroyInstance();