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&,
+                            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.

[jungshik at Google, 2011/06/16 18:08:19]

Pls, add a comment that |region| here is actually a full-blown locale id in the
form of 'und_' + region ID. An alternative is: 1) do not prepend 'und_' on the
JavaScript-side 2) add 'und_' at the last moment inside GetCurrencyCode(). 

[Nebojša Ćirić, 2011/06/17 17:48:45]

Done.

+  v8::String::AsciiValue ascii_region(region);
+  icu::Locale icu_region(*ascii_region);
+
+  UChar currency_code[NumberFormat::kCurrencyCodeLength];
+  if (GetCurrencyCode(icu_region, settings, currency_code)) {
+    number_format->setCurrency(currency_code, status);
+  }

[jungshik at Google, 2011/06/16 18:08:19]

What if the locale id (icu_locale) itself has a currency code specified (with
'-u-cu-FOO')? We have to determine the priority order among three possible
sources. 

[Nebojša Ćirić, 2011/06/17 17:48:45]

I made priority:

- specified ISO code in currencyCode
- specified -u-cu- in locale
- infer from region ID

On 2011/06/16 18:08:19, Jungshik Shin wrote:

+
+  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 \x00A4 currency symbol.

[jungshik at Google, 2011/06/16 18:08:19]

nit: \x00A4 => U+00A4

[Nebojša Ćirić, 2011/06/17 17:48:45]

Done.

+  const UChar currency_symbol = 0xA4;

[jungshik at Google, 2011/06/16 18:08:19]

nit: Didn't any complier complain?  Perhaps, it's safer to add 'u'. 

[Nebojša Ćirić, 2011/06/17 17:48:45]

Done.

+
+  int32_t index = skeleton.indexOf(currency_symbol);
+  if (index != -1) {
+    // Find how many 0xA4 are there. There is at least one.

[jungshik at Google, 2011/06/16 18:08:19]

nit: U+00A4

BTW, the code below assumes that a skeleton has one or more U+00A4's in a row.
What if there is an intervening character between them?  Shouldn't we use a
regex matcher (to match 1 to 3 (or 4) U+00A4's in a row? Actually, using regex
seems to be an overkill. Perhaps, after finding |end_index}, you can walk from
index to end_index to make sure there' no other character in-between.  If there
is, you can reject the skeleton as invalid. 

[Nebojša Ćirić, 2011/06/17 17:48:45]

I did this as a regexp in JS code (i18n.js), \u00a4+[^\u00a4]+\u00a4+. If that
matches I convert it to simple \u00A4.

As for more than 3 U+00A4 in a row, C++ code handles it as having 3 in default:
case in switch.

We didn't flesh out the actual error handling. Throwing an exception here would
be too much, but user can examine the skeleton and see what happened.

On 2011/06/16 18:08:19, Jungshik Shin wrote:

+    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));

[jungshik at Google, 2011/06/16 18:08:19]

no support for scientific with a skeleton? 

[Nebojša Ćirić, 2011/06/17 17:48:45]

Not for now. I want to see what Mark has to say about the design doc. I can add
it later on. I'll add todo.

On 2011/06/16 18:08:19, Jungshik Shin wrote:

+  } else {
+    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.

[jungshik at Google, 2011/06/16 18:08:19]

I wonder if there's anything else to pass from skeleton.  e.g. roundingIncrement
(http://goo.gl/RU4qG )? 

roundingMode cannot be set via a pattern. So, we can't support in skeleton, but
roundingIncrement can be set via a pattern....

[Nebojša Ćirić, 2011/06/17 17:48:45]

Added TODO.

On 2011/06/16 18:08:19, Jungshik Shin wrote:

+  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 based on user specified currency code
+// or provided region id.

[jungshik at Google, 2011/06/16 18:08:19]

Here again, it's confusing to say 'region id' because it's more than that.
('und_' + region ID). 

[Nebojša Ćirić, 2011/06/17 17:48:45]

Done.

+// Returns false in case of error.
+static bool GetCurrencyCode(const icu::Locale& icu_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;
+  }
+
+  // Otherwise infer currency code from the region id.
+  const char* region = icu_locale.getName();

[jungshik at Google, 2011/06/16 18:08:19]

wrapping up 'und_' + regionID in Locale class only to get back the raw string
seems a bit roo round-about. I'd just pass around 'region ID' alone. OTOH,
having to prepend 'und_' with char array is not fun...  So, it's up to you.

Anyway, GetCurrencyCode() has to be revised to deal with '-u-cu-FOO' case in
icu_locale. 

[Nebojša Ćirić, 2011/06/17 17:48:45]

Done.

+
+  ucurr_forLocale(region, code, NumberFormat::kCurrencyCodeLength, &status);
+  if (U_FAILURE(status)) {
+    return false;
+  }
+
+  return true;
+}
+
+// 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