Adding support for number formating to the JS i18n API.

src/extensions/experimental/number-format.cc

+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "src/extensions/experimental/number-format.h"
+
+#include <string.h>
+
+#include "src/extensions/experimental/i18n-utils.h"
+#include "unicode/dcfmtsym.h"
+#include "unicode/decimfmt.h"
+#include "unicode/locid.h"
+#include "unicode/numfmt.h"
+#include "unicode/uchar.h"
+#include "unicode/ucurr.h"
+
+namespace v8 {
+namespace internal {
+
+const int NumberFormat::kCurrencyCodeLength = 4;
+
+v8::Persistent<v8::FunctionTemplate> NumberFormat::number_format_template_;
+
+static icu::DecimalFormat* CreateNumberFormat(v8::Handle<v8::String>,
+                                              v8::Handle<v8::String>,
+                                              v8::Handle<v8::Object>);
+static icu::DecimalFormat* CreateFormatterFromSkeleton(
+    const icu::Locale&, const icu::UnicodeString&, UErrorCode*);
+static icu::DecimalFormatSymbols* GetFormatSymbols(const icu::Locale&);
+static bool GetCurrencyCode(const icu::Locale&,
+                            const char* const,
+                            v8::Handle<v8::Object>,
+                            UChar*);
+static v8::Handle<v8::Value> ThrowUnexpectedObjectError();
+
+icu::DecimalFormat* NumberFormat::UnpackNumberFormat(
+    v8::Handle<v8::Object> obj) {
+  if (number_format_template_->HasInstance(obj)) {
+    return static_cast<icu::DecimalFormat*>(
+        obj->GetPointerFromInternalField(0));
+  }
+
+  return NULL;
+}
+
+void NumberFormat::DeleteNumberFormat(v8::Persistent<v8::Value> object,
+                                      void* param) {
+  v8::Persistent<v8::Object> persistent_object =
+      v8::Persistent<v8::Object>::Cast(object);
+
+  // First delete the hidden C++ object.
+  // Unpacking should never return NULL here. That would only happen if
+  // this method is used as the weak callback for persistent handles not
+  // pointing to a number formatter.
+  delete UnpackNumberFormat(persistent_object);
+
+  // Then dispose of the persistent handle to JS object.
+  persistent_object.Dispose();
+}
+
+v8::Handle<v8::Value> NumberFormat::Format(const v8::Arguments& args) {
+  v8::HandleScope handle_scope;
+
+  if (args.Length() != 1 || !args[0]->IsNumber()) {
+    // Just return NaN on invalid input.
+    return v8::String::New("NaN");
+  }
+
+  icu::DecimalFormat* number_format = UnpackNumberFormat(args.Holder());
+  if (!number_format) {
+    return ThrowUnexpectedObjectError();
+  }
+
+  // ICU will handle actual NaN value properly and return NaN string.
+  icu::UnicodeString result;
+  number_format->format(args[0]->NumberValue(), result);
+
+  return v8::String::New(
+      reinterpret_cast<const uint16_t*>(result.getBuffer()), result.length());
+}
+
+v8::Handle<v8::Value> NumberFormat::JSNumberFormat(const v8::Arguments& args) {
+  v8::HandleScope handle_scope;
+
+  // Expect locale id, region id and settings.
+  if (args.Length() != 3 ||
+      !args[0]->IsString() || !args[1]->IsString() || !args[2]->IsObject()) {
+    return v8::ThrowException(v8::Exception::SyntaxError(
+        v8::String::New("Locale, region and number settings are required.")));
+  }
+
+  icu::DecimalFormat* number_format = CreateNumberFormat(
+      args[0]->ToString(), args[1]->ToString(), args[2]->ToObject());
+
+  if (number_format_template_.IsEmpty()) {
+    v8::Local<v8::FunctionTemplate> raw_template(v8::FunctionTemplate::New());
+
+    raw_template->SetClassName(v8::String::New("v8Locale.NumberFormat"));
+
+    // Define internal field count on instance template.
+    v8::Local<v8::ObjectTemplate> object_template =
+        raw_template->InstanceTemplate();
+
+    // Set aside internal field for icu number formatter.
+    object_template->SetInternalFieldCount(1);
+
+    // Define all of the prototype methods on prototype template.
+    v8::Local<v8::ObjectTemplate> proto = raw_template->PrototypeTemplate();
+    proto->Set(v8::String::New("format"),
+               v8::FunctionTemplate::New(Format));
+
+    number_format_template_ =
+        v8::Persistent<v8::FunctionTemplate>::New(raw_template);
+  }
+
+  // Create an empty object wrapper.
+  v8::Local<v8::Object> local_object =
+      number_format_template_->GetFunction()->NewInstance();
+  v8::Persistent<v8::Object> wrapper =
+      v8::Persistent<v8::Object>::New(local_object);
+
+  // Set number formatter as internal field of the resulting JS object.
+  wrapper->SetPointerInInternalField(0, number_format);
+
+  // Create options key.
+  v8::Local<v8::Object> options = v8::Object::New();
+
+  // Show what ICU decided to use for easier problem tracking.
+  // Keep it as v8 specific extension.
+  icu::UnicodeString pattern;
+  number_format->toPattern(pattern);
+  options->Set(v8::String::New("v8ResolvedPattern"),
+               v8::String::New(reinterpret_cast<const uint16_t*>(
+                   pattern.getBuffer()), pattern.length()));
+
+  // Set resolved currency code in options.currency if not empty.
+  icu::UnicodeString currency(number_format->getCurrency());
+  if (!currency.isEmpty()) {
+    options->Set(v8::String::New("currencyCode"),
+                 v8::String::New(reinterpret_cast<const uint16_t*>(
+                     currency.getBuffer()), currency.length()));
+  }
+
+  wrapper->Set(v8::String::New("options"), options);
+
+  // Make object handle weak so we can delete iterator once GC kicks in.
+  wrapper.MakeWeak(NULL, DeleteNumberFormat);
+
+  return wrapper;
+}
+
+// Returns DecimalFormat.
+static icu::DecimalFormat* CreateNumberFormat(v8::Handle<v8::String> locale,
+                                              v8::Handle<v8::String> region,
+                                              v8::Handle<v8::Object> settings) {
+  v8::HandleScope handle_scope;
+
+  v8::String::AsciiValue ascii_locale(locale);
+  icu::Locale icu_locale(*ascii_locale);
+
+  // Make formatter from skeleton.
+  icu::DecimalFormat* number_format = NULL;
+  UErrorCode status = U_ZERO_ERROR;
+  icu::UnicodeString setting;
+
+  if (I18NUtils::ExtractStringSetting(settings, "skeleton", &setting)) {
+    // TODO(cira): Use ICU skeleton once
+    // http://bugs.icu-project.org/trac/ticket/8610 is resolved.
+    number_format = CreateFormatterFromSkeleton(icu_locale, setting, &status);
+  } else if (I18NUtils::ExtractStringSetting(settings, "pattern", &setting)) {
+    number_format =
+        new icu::DecimalFormat(setting, GetFormatSymbols(icu_locale), status);
+  } else if (I18NUtils::ExtractStringSetting(settings, "style", &setting)) {
+    if (setting == UNICODE_STRING_SIMPLE("currency")) {
+      number_format = static_cast<icu::DecimalFormat*>(
+          icu::NumberFormat::createCurrencyInstance(icu_locale, status));
+    } else if (setting == UNICODE_STRING_SIMPLE("percent")) {
+      number_format = static_cast<icu::DecimalFormat*>(
+          icu::NumberFormat::createPercentInstance(icu_locale, status));
+    } else if (setting == UNICODE_STRING_SIMPLE("scientific")) {
+      number_format = static_cast<icu::DecimalFormat*>(
+          icu::NumberFormat::createScientificInstance(icu_locale, status));
+    } else {
+      // Make it decimal in any other case.
+      number_format = static_cast<icu::DecimalFormat*>(
+          icu::NumberFormat::createInstance(icu_locale, status));
+    }
+  }
+
+  if (U_FAILURE(status)) {
+    delete number_format;
+    status = U_ZERO_ERROR;
+    number_format = static_cast<icu::DecimalFormat*>(
+        icu::NumberFormat::createInstance(icu_locale, status));
+  }
+
+  // Attach appropriate currency code to the formatter.
+  // It affects currency formatters only.
+  // Region is full language identifier in form 'und_' + region id.
+  v8::String::AsciiValue ascii_region(region);
+
+  UChar currency_code[NumberFormat::kCurrencyCodeLength];
+  if (GetCurrencyCode(icu_locale, *ascii_region, settings, currency_code)) {
+    number_format->setCurrency(currency_code, status);
+  }
+
+  return number_format;
+}
+
+// Generates ICU number format pattern from given skeleton.
+static icu::DecimalFormat* CreateFormatterFromSkeleton(
+    const icu::Locale& icu_locale,
+    const icu::UnicodeString& skeleton,
+    UErrorCode* status) {
+  icu::DecimalFormat skeleton_format(
+      skeleton, GetFormatSymbols(icu_locale), *status);
+
+  // Find out if skeleton contains currency or percent symbol and create
+  // proper instance to tweak.
+  icu::DecimalFormat* base_format = NULL;
+
+  // UChar representation of U+00A4 currency symbol.
+  const UChar currency_symbol = 0xA4u;
+
+  int32_t index = skeleton.indexOf(currency_symbol);
+  if (index != -1) {
+    // Find how many U+00A4 are there. There is at least one.

[jungshik at Google, 2011/06/21 23:28:41]

nit: Add a comment that non-consecutive U+00A4's have been taken care of in
i18n.js

[Nebojša Ćirić, 2011/06/22 16:50:41]

Done.

+    int32_t end_index = skeleton.lastIndexOf(currency_symbol, index);
+
+    icu::NumberFormat::EStyles style;
+    switch (end_index - index) {
+      case 0:
+        style = icu::NumberFormat::kCurrencyStyle;
+        break;
+      case 1:
+        style = icu::NumberFormat::kIsoCurrencyStyle;
+        break;
+      default:
+        style = icu::NumberFormat::kPluralCurrencyStyle;
+    }
+
+    base_format = static_cast<icu::DecimalFormat*>(
+        icu::NumberFormat::createInstance(icu_locale, style, *status));
+  } else if (skeleton.indexOf('%') != -1) {
+    base_format = static_cast<icu::DecimalFormat*>(
+        icu::NumberFormat::createPercentInstance(icu_locale, *status));
+  } else {
+    // TODO(cira): Handle scientific skeleton.
+    base_format = static_cast<icu::DecimalFormat*>(
+        icu::NumberFormat::createInstance(icu_locale, *status));
+  }
+
+  if (U_FAILURE(*status)) {
+    delete base_format;
+    return NULL;
+  }
+
+  // Copy important information from skeleton to the new formatter.
+  // TODO(cira): copy rounding information from skeleton?
+  base_format->setGroupingUsed(skeleton_format.isGroupingUsed());
+
+  base_format->setMinimumIntegerDigits(
+      skeleton_format.getMinimumIntegerDigits());
+
+  base_format->setMinimumFractionDigits(
+      skeleton_format.getMinimumFractionDigits());
+
+  base_format->setMaximumFractionDigits(
+      skeleton_format.getMaximumFractionDigits());
+
+  return base_format;
+}
+
+// Gets decimal symbols for a locale.
+static icu::DecimalFormatSymbols* GetFormatSymbols(
+    const icu::Locale& icu_locale) {
+  UErrorCode status = U_ZERO_ERROR;
+  icu::DecimalFormatSymbols* symbols =
+      new icu::DecimalFormatSymbols(icu_locale, status);
+
+  if (U_FAILURE(status)) {
+    delete symbols;
+    // Use symbols from default locale.
+    symbols = new icu::DecimalFormatSymbols(status);
+  }
+
+  return symbols;
+}
+
+// Gets currency ISO 4217 3-letter code.
+// Check currencyCode setting first, then @currency=code and in the end
+// try to infer currency code from locale in the form 'und_' + region id.
+// Returns false in case of error.
+static bool GetCurrencyCode(const icu::Locale& icu_locale,
+                            const char* const und_region_locale,
+                            v8::Handle<v8::Object> settings,
+                            UChar* code) {
+  UErrorCode status = U_ZERO_ERROR;
+
+  // If there is user specified currency code, use it.
+  icu::UnicodeString currency;
+  if (I18NUtils::ExtractStringSetting(settings, "currencyCode", &currency)) {
+    currency.extract(code, NumberFormat::kCurrencyCodeLength, status);
+    return true;
+  }
+
+  // If ICU locale has -cu- currency code use it.
+  char currency_code[NumberFormat::kCurrencyCodeLength];
+  int32_t length = icu_locale.getKeywordValue(
+      "currency", currency_code, NumberFormat::kCurrencyCodeLength, status);
+  if (length != 0) {
+    I18NUtils::AsciiToUChar(currency_code, length + 1,
+                            code, NumberFormat::kCurrencyCodeLength);
+    return true;
+  }
+
+  // Otherwise infer currency code from the region id.
+  ucurr_forLocale(
+      und_region_locale, code, NumberFormat::kCurrencyCodeLength, &status);
+  if (U_FAILURE(status)) {
+    return false;
+  }
+
+  return true;

[jungshik at Google, 2011/06/21 23:28:41]

nit: You can combine the above 4 lines to "return !!U_SUCCESS(status);" 

[Nebojša Ćirić, 2011/06/22 16:50:41]

Done.

+}
+
+// Throws a JavaScript exception.
+static v8::Handle<v8::Value> ThrowUnexpectedObjectError() {
+  // Returns undefined, and schedules an exception to be thrown.
+  return v8::ThrowException(v8::Exception::Error(
+      v8::String::New("NumberFormat method called on an object "
+                      "that is not a NumberFormat.")));
+}
+
+} }  // namespace v8::internal