[Payment Request] Update the CurrencyStringFormatter to call the native impl.

chrome/android/java/src/org/chromium/chrome/browser/payments/CurrencyStringFormatter.java

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.payments;
 
-import java.text.DecimalFormatSymbols;
-import java.util.Currency;
+import org.chromium.base.annotations.JNINamespace;
+
 import java.util.Locale;
-import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 /**
- * Formatter for currency strings that can be too large to parse into numbers.
+ * Formatter for currency amounts.
  * https://w3c.github.io/browser-payment-api/specs/paymentrequest.html#currencyamount
  */
+@JNINamespace("payments")
 public class CurrencyStringFormatter {
-    // Amount value pattern and capture group numbers.
+    // Amount value pattern.
     private static final String AMOUNT_VALUE_PATTERN = "^(-?)([0-9]+)(\\.([0-9]+))?$";
-    private static final int OPTIONAL_NEGATIVE_GROUP = 1;
-    private static final int DIGITS_BETWEEN_NEGATIVE_AND_PERIOD_GROUP = 2;
-    private static final int DIGITS_AFTER_PERIOD_GROUP = 4;
 
     // Max currency code length. Maximum length of currency code can be at most 2048.
     private static final int MAX_CURRENCY_CODE_LEN = 2048;
 
     // Currency code exceeding 6 chars will be ellipsized during formatting for display.
     private static final int MAX_CURRENCY_CHARS = 6;
 
     // Unicode character for ellipsis.
     private static final String ELLIPSIS = "\u2026";
 
-    // Formatting constants.
-    private static final int DIGIT_GROUPING_SIZE = 3;
-
-    private final Pattern mAmountValuePattern;
-
     /**
      * The currency formatted for display. Currency can be any string of at most
      * 2048 characters.Currency code more than 6 character is formatted to first
      * 5 characters and ellipsis.
      */
     public final String mFormattedCurrencyCode;
 
     /**
-     * The symbol for the currency specified on the bill. For example, the symbol for "USD" is "$".
+     * Pointer to the native implementation.
      */
-    private final String mCurrencySymbol;
+    private final long mCurrencyFormatterAndroid;
 
-    /**
-     * The number of digits after the decimal separator for the currency specified on the bill. For
-     * example, 2 for "USD" and 0 for "JPY".
-     */
-    private final int mDefaultFractionDigits;
-
-    /**
-     * The number grouping separator for the current locale. For example, "," in US. 3-digit groups
-     * are assumed.
-     */
-    private final char mGroupingSeparator;
-
-    /**
-     * The monetary decimal separator for the current locale. For example, "." in US and "," in
-     * France.
-     */
-    private final char mMonetaryDecimalSeparator;
+    private final Pattern mAmountValuePattern;

[please use gerrit instead, 2017/01/13 21:16:25]

No longer used in this file, so can be deleted.

[Mathieu, 2017/01/13 22:27:01]

Done.

 
     /**
      * Builds the formatter for the given currency code and the current user locale.
      *
-     * @param currencyCode The currency code. Most commonly, this follows ISO 4217 format: 3 upper
-     *                     case ASCII letters. For example, "USD". Format is not restricted. Should
-     *                     not be null.
+     * @param currencyCode  The currency code. Most commonly, this follows ISO 4217 format: 3 upper
+     *                      case ASCII letters. For example, "USD". Format is not restricted. Should
+     *                      not be null.
+     * @param currencySystem URI specifying the ISO4217 currency code specification. See for
+     *          details: https://w3c.github.io/browser-payment-api/#paymentcurrencyamount-dictionary
+     *          Can be null, in which case "urn:iso:std:iso:4217" is assumed.
      * @param userLocale User's current locale. Should not be null.
      */
-    public CurrencyStringFormatter(String currencyCode, Locale userLocale) {
+    public CurrencyStringFormatter(String currencyCode, String currencySystem, Locale userLocale) {

[please use gerrit instead, 2017/01/13 21:16:24]

@Nullable String currencySystem.

[Mathieu, 2017/01/13 22:27:01]

Done.

         assert currencyCode != null : "currencyCode should not be null";
         assert userLocale != null : "userLocale should not be null";
 
+        // Note that this technically leaks the native object.

[please use gerrit instead, 2017/01/13 21:16:25]

Is there a remedy for the leak?

[Mathieu, 2017/01/13 22:27:01]

added destroy() (Calling nativeDestroy() which calls "delete this" on the C++
object -- a common pattern in this code). 

Since we don't know when we'll stop using the mFormatter in PaymentRequestImpl,
I've added a finalize() method which is called just before the GC.

+        mCurrencyFormatterAndroid = nativeInitCurrencyFormatterAndroid(
+                currencyCode, currencySystem == null ? "" : currencySystem, userLocale.toString());
+
         mAmountValuePattern = Pattern.compile(AMOUNT_VALUE_PATTERN);
-
         mFormattedCurrencyCode = currencyCode.length() <= MAX_CURRENCY_CHARS

[please use gerrit instead, 2017/01/13 21:16:25]

Can we similarly format the currency code in C++? IMHO this file should be a
thin bridge that always calls into C++ instead of doing anything itself.

[Mathieu, 2017/01/13 22:27:01]

Sure thing, done

                 ? currencyCode
                 : currencyCode.substring(0, MAX_CURRENCY_CHARS - 1) + ELLIPSIS;
-
-        String currencySymbol;
-        int defaultFractionDigits;
-        try {
-            Currency currency = Currency.getInstance(currencyCode);
-            currencySymbol = currency.getSymbol();
-            defaultFractionDigits = currency.getDefaultFractionDigits();
-        } catch (IllegalArgumentException e) {
-            // The spec does not limit the currencies to official ISO 4217 currency code list, which
-            // is used by java.util.Currency. For example, "BTX" (bitcoin) is not an official ISO
-            // 4217 currency code, but is allowed by the spec.
-            currencySymbol = "";
-            defaultFractionDigits = 0;
-        }
-
-        // If the prefix of the currency symbol matches the prefix of the currency code, remove the
-        // matching prefix from the symbol. The UI already shows the currency code, so there's no
-        // need to show duplicate information.
-        String symbol = "";
-        for (int i = 0; i < currencySymbol.length(); i++) {
-            if (i >= currencyCode.length() || currencySymbol.charAt(i) != currencyCode.charAt(i)) {
-                symbol = currencySymbol.substring(i);
-                break;
-            }
-        }
-        mCurrencySymbol = symbol;
-
-        mDefaultFractionDigits = defaultFractionDigits;
-
-        // Use the symbols from user's current locale. For example, use "," for decimal separator in
-        // France, even if paying in "USD".
-        DecimalFormatSymbols symbols = new DecimalFormatSymbols(userLocale);
-        mGroupingSeparator = symbols.getGroupingSeparator();
-        mMonetaryDecimalSeparator = symbols.getMonetaryDecimalSeparator();
     }
 
     /**
      * Returns true if the amount value string is in valid format.
      *
      * @param amountValue The number to check for validity.
      * @return Whether the number is in valid format.
      */
     public boolean isValidAmountValue(String amountValue) {

[please use gerrit instead, 2017/01/13 21:16:25]

No longer used in production code. Can be deleted.

[Mathieu, 2017/01/13 22:27:01]

Done.

         return amountValue != null && mAmountValuePattern.matcher(amountValue).matches();
     }
 
     /**
      * Returns true if the currency code string is in valid format.
      *
      * @param amountCurrencyCode The currency code to check for validity.
      * @return Whether the currency code is in valid format.
      */
     public boolean isValidAmountCurrencyCode(String amountCurrencyCode) {
         return amountCurrencyCode != null && amountCurrencyCode.length() <= MAX_CURRENCY_CODE_LEN;
     }
 
     /** @return The currency code formatted for display. */
     public String getFormattedCurrencyCode() {
         return mFormattedCurrencyCode;
     }
 
     /**
      * Formats the currency string for display. Does not parse the string into a number, because it
-     * might be too large. The number is formatted for the current locale and follows the symbol of
-     * the currency code.
+     * might be too large. The number is formatted for the current locale and can include a
+     * currency symbol (e.g. $) anywhere in the string, but will not contain the currency code
+     * (e.g. USD/US). All spaces in the currency are unicode non-breaking space.
      *
      * @param amountValue The number to format. Should be in "^-?[0-9]+(\.[0-9]+)?$" format. Should
      *                    not be null.
-     * @return The currency symbol followed by a space and the formatted number.
+     * @return The amount formatted with the specified currency. See description for details.
      */
     public String format(String amountValue) {
         assert amountValue != null : "amountValue should not be null";
 
-        Matcher m = mAmountValuePattern.matcher(amountValue);
+        return nativeFormat(mCurrencyFormatterAndroid, amountValue);
+    }
 
-        // Required to capture the groups.
-        boolean matches = m.matches();
-        assert matches;
-
-        StringBuilder result = new StringBuilder(m.group(OPTIONAL_NEGATIVE_GROUP));
-        result.append(mCurrencySymbol);
-        int digitStart = result.length();
-
-        result.append(m.group(DIGITS_BETWEEN_NEGATIVE_AND_PERIOD_GROUP));
-        for (int i = result.length() - DIGIT_GROUPING_SIZE; i > digitStart;
-                i -= DIGIT_GROUPING_SIZE) {
-            result.insert(i, mGroupingSeparator);
-        }
-
-        String decimals = m.group(DIGITS_AFTER_PERIOD_GROUP);
-        int numberOfDecimals = decimals == null ? 0 : decimals.length();
-
-        if (numberOfDecimals > 0 || mDefaultFractionDigits > 0) {
-            result.append(mMonetaryDecimalSeparator);
-            if (null != decimals) result.append(decimals);
-
-            for (int i = numberOfDecimals; i < mDefaultFractionDigits; i++) {
-                result.append("0");
-            }
-        }
-
-        return result.toString();
-    }
+    private native long nativeInitCurrencyFormatterAndroid(
+            String currencyCode, String currencySystem, String localeName);
+    private native String nativeFormat(
+            long nativeCurrencyFormatterAndroid, String amountValue);
 }