Bug 1735352 - Part 3: Add wrapper for ICU4C specific library functions. r=platform-i18n-reviewers,gregtatum

Adds abstractions for `u_init()`, `u_cleanup()`, and `u_setMemoryFunctions()`,
and additionally a method to retrieve `U_ICU_VERSION`.

Because these methods are unlikely to replaceable with ICU4X, the class was
named "ICU4CLibrary" to make clear that the functionality is specific to ICU4C.

Differential Revision: https://phabricator.services.mozilla.com/D128228

intl/components/moz.build

@@ -10,6 +10,7 @@ EXPORTS.mozilla.intl = [
     "src/DateTimeFormat.h",
     "src/DateTimePatternGenerator.h",
     "src/ICU4CGlue.h",
+    "src/ICU4CLibrary.h",
     "src/ICUError.h",
     "src/ListFormat.h",
     "src/Locale.h",
@@ -32,6 +33,7 @@ UNIFIED_SOURCES += [
     "src/DateTimeFormat.cpp",
     "src/DateTimePatternGenerator.cpp",
     "src/ICU4CGlue.cpp",
+    "src/ICU4CLibrary.cpp",
     "src/ListFormat.cpp",
     "src/LocaleCanonicalizer.cpp",
     "src/MeasureUnit.cpp",

intl/components/src/ICU4CLibrary.cpp

@@ -0,0 +1,41 @@
+/* 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/. */
+
+#include "mozilla/intl/ICU4CLibrary.h"
+
+#include "unicode/putil.h"
+#include "unicode/uclean.h"
+#include "unicode/utypes.h"
+#include "unicode/uversion.h"
+
+namespace mozilla::intl {
+
+ICUResult ICU4CLibrary::Initialize() {
+#if !MOZ_SYSTEM_ICU
+  // Explicitly set the data directory to its default value, but only when we're
+  // sure that we use our in-tree ICU copy. See bug 1527879 and ICU bug
+  // report <https://unicode-org.atlassian.net/browse/ICU-20491>.
+  u_setDataDirectory("");
+#endif
+
+  UErrorCode status = U_ZERO_ERROR;
+  u_init(&status);
+  return ToICUResult(status);
+}
+
+void ICU4CLibrary::Cleanup() { u_cleanup(); }
+
+ICUResult ICU4CLibrary::SetMemoryFunctions(MemoryFunctions aMemoryFunctions) {
+  UErrorCode status = U_ZERO_ERROR;
+  u_setMemoryFunctions(/* context = */ nullptr, aMemoryFunctions.mAllocFn,
+                       aMemoryFunctions.mReallocFn, aMemoryFunctions.mFreeFn,
+                       &status);
+  return ToICUResult(status);
+}
+
+Span<const char> ICU4CLibrary::GetVersion() {
+  return MakeStringSpan(U_ICU_VERSION);
+}
+
+}  // namespace mozilla::intl

intl/components/src/ICU4CLibrary.h

@@ -0,0 +1,74 @@
+/* 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 intl_components_ICU4CLibrary_h
+#define intl_components_ICU4CLibrary_h
+
+#include "mozilla/intl/ICU4CGlue.h"
+#include "mozilla/Span.h"
+
+#include <stddef.h>
+
+namespace mozilla::intl {
+/**
+ * Wrapper around non-portable, ICU4C specific functions.
+ */
+class ICU4CLibrary final {
+ public:
+  ICU4CLibrary() = delete;
+
+  /**
+   * Initializes the ICU4C library.
+   *
+   * Note: This function should only be called once.
+   */
+  static ICUResult Initialize();
+
+  /**
+   * Releases any memory held by ICU. Any open ICU objects and resources are
+   * left in an undefined state after this operation.
+   *
+   * NOTE: This function is not thread-safe.
+   */
+  static void Cleanup();
+
+  struct MemoryFunctions {
+    // These are equivalent to ICU's |UMemAllocFn|, |UMemReallocFn|, and
+    // |UMemFreeFn| types. The first argument (called |context| in the ICU
+    // docs) will always be nullptr and should be ignored.
+    using AllocFn = void* (*)(const void*, size_t);
+    using ReallocFn = void* (*)(const void*, void*, size_t);
+    using FreeFn = void (*)(const void*, void*);
+
+    /**
+     * Function called when allocating memory.
+     */
+    AllocFn mAllocFn = nullptr;
+
+    /**
+     * Function called when reallocating memory.
+     */
+    ReallocFn mReallocFn = nullptr;
+
+    /**
+     * Function called when freeing memory.
+     */
+    FreeFn mFreeFn = nullptr;
+  };
+
+  /**
+   * Sets the ICU memory functions.
+   *
+   * This function can only be called before the initial call to Initialize()!
+   */
+  static ICUResult SetMemoryFunctions(MemoryFunctions aMemoryFunctions);
+
+  /**
+   * Return the ICU version number.
+   */
+  static Span<const char> GetVersion();
+};
+}  // namespace mozilla::intl
+
+#endif

js/src/builtin/TestingFunctions.cpp

@@ -10,6 +10,7 @@
 #include "mozilla/Casting.h"
 #include "mozilla/FloatingPoint.h"
 #ifdef JS_HAS_INTL_API
+#  include "mozilla/intl/ICU4CLibrary.h"
 #  include "mozilla/intl/Locale.h"
 #  include "mozilla/intl/String.h"
 #  include "mozilla/intl/TimeZone.h"
@@ -103,9 +104,6 @@
 #include "js/Vector.h"
 #include "js/Wrapper.h"
 #include "threading/CpuCount.h"
-#ifdef JS_HAS_INTL_API
-#  include "unicode/uversion.h"
-#endif
 #include "util/DifferentialTesting.h"
 #include "util/StringBuffer.h"
 #include "util/Text.h"
@@ -7321,7 +7319,7 @@ static bool GetICUOptions(JSContext* cx, unsigned argc, Value* vp) {
 #ifdef JS_HAS_INTL_API
   RootedString str(cx);
 
-  str = NewStringCopyZ<CanGC>(cx, U_ICU_VERSION);
+  str = NewStringCopy<CanGC>(cx, mozilla::intl::ICU4CLibrary::GetVersion());
   if (!str || !JS_DefineProperty(cx, info, "version", str, JSPROP_ENUMERATE)) {
     return false;
   }

js/src/vm/Initialization.cpp

@@ -9,6 +9,9 @@
 #include "js/Initialization.h"
 
 #include "mozilla/Assertions.h"
+#if JS_HAS_INTL_API
+#  include "mozilla/intl/ICU4CLibrary.h"
+#endif
 #include "mozilla/TextUtils.h"
 
 #include "jstypes.h"
@@ -22,13 +25,6 @@
 #include "jit/JitCommon.h"
 #include "jit/ProcessExecutableMemory.h"
 #include "js/Utility.h"
-
-#if JS_HAS_INTL_API
-#  include "unicode/putil.h"
-#  include "unicode/uclean.h"
-#  include "unicode/utypes.h"
-#endif  // JS_HAS_INTL_API
-
 #include "threading/ProtectedData.h"  // js::AutoNoteSingleThreadedRegion
 #include "util/Poison.h"
 #include "vm/ArrayBufferObject.h"
@@ -193,17 +189,8 @@ JS_PUBLIC_API const char* JS::detail::InitWithFailureDiagnostic(
   RETURN_IF_FAIL(js::jit::AtomicOperations::Initialize());
 
 #if JS_HAS_INTL_API
-#  if !MOZ_SYSTEM_ICU
-  // Explicitly set the data directory to its default value, but only when we're
-  // sure that we use our in-tree ICU copy. See bug 1527879 and ICU bug
-  // report <https://unicode-org.atlassian.net/browse/ICU-20491>.
-  u_setDataDirectory("");
-#  endif
-
-  UErrorCode err = U_ZERO_ERROR;
-  u_init(&err);
-  if (U_FAILURE(err)) {
-    return "u_init() failed";
+  if (mozilla::intl::ICU4CLibrary::Initialize().isErr()) {
+    return "ICU4CLibrary::Initialize() failed";
   }
 #endif  // JS_HAS_INTL_API
 
@@ -310,7 +297,7 @@ JS_PUBLIC_API void JS_ShutDown(void) {
   PRMJ_NowShutdown();
 
 #if JS_HAS_INTL_API
-  u_cleanup();
+  mozilla::intl::ICU4CLibrary::Cleanup();
 #endif  // JS_HAS_INTL_API
 
 #ifdef MOZ_VTUNE
@@ -337,10 +324,9 @@ JS_PUBLIC_API bool JS_SetICUMemoryFunctions(JS_ICUAllocFn allocFn,
              "operation (including JS_Init)");
 
 #if JS_HAS_INTL_API
-  UErrorCode status = U_ZERO_ERROR;
-  u_setMemoryFunctions(/* context = */ nullptr, allocFn, reallocFn, freeFn,
-                       &status);
-  return U_SUCCESS(status);
+  return mozilla::intl::ICU4CLibrary::SetMemoryFunctions(
+             {allocFn, reallocFn, freeFn})
+      .isOk();
 #else
   return true;
 #endif