1 files changed, 426 insertions, 0 deletions
diff --git a/intl/components/src/NumberFormat.h b/intl/components/src/NumberFormat.h
new file mode 100644
index 0000000000..684b772e30
--- /dev/null
+++ b/intl/components/src/NumberFormat.h
@@ -0,0 +1,426 @@
+/* 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_NumberFormat_h_
+#define intl_components_NumberFormat_h_
+#include <string_view>
+#include <utility>
+#include <vector>
+
+#include "mozilla/FloatingPoint.h"
+#include "mozilla/intl/ICU4CGlue.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/Result.h"
+#include "mozilla/Utf8.h"
+#include "mozilla/Vector.h"
+#include "mozilla/intl/ICUError.h"
+#include "mozilla/intl/NumberPart.h"
+
+#include "unicode/ustring.h"
+#include "unicode/unum.h"
+#include "unicode/unumberformatter.h"
+
+struct UPluralRules;
+
+namespace mozilla::intl {
+
+struct PluralRulesOptions;
+
+/**
+ * Configure NumberFormat options.
+ * The supported display styles are:
+ *   * Decimal (default)
+ *   * Currency (controlled by mCurrency)
+ *   * Unit (controlled by mUnit)
+ *   * Percent (controlled by mPercent)
+ *
+ * Only one of mCurrency, mUnit or mPercent should be set. If none are set,
+ * the number will formatted as a decimal.
+ *
+ * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#unit
+ */
+struct MOZ_STACK_CLASS NumberFormatOptions {
+  /**
+   * Display a currency amount. |currency| must be a three-letter currency code.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#unit
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#unit-width
+   */
+  enum class CurrencyDisplay {
+    Symbol,
+    Code,
+    Name,
+    NarrowSymbol,
+  };
+  Maybe<std::pair<std::string_view, CurrencyDisplay>> mCurrency;
+
+  /**
+   * Set the fraction digits settings. |min| can be zero, |max| must be
+   * larger-or-equal to |min|.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#fraction-precision
+   */
+  Maybe<std::pair<uint32_t, uint32_t>> mFractionDigits;
+
+  /**
+   * Set the minimum number of integer digits. |min| must be a non-zero
+   * number.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#integer-width
+   */
+  Maybe<uint32_t> mMinIntegerDigits;
+
+  /**
+   * Set the significant digits settings. |min| must be a non-zero number, |max|
+   * must be larger-or-equal to |min|.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#significant-digits-precision
+   */
+  Maybe<std::pair<uint32_t, uint32_t>> mSignificantDigits;
+
+  /**
+   * Display a unit amount. |unit| must be a well-formed unit identifier.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#unit
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#per-unit
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#unit-width
+   */
+  enum class UnitDisplay { Short, Narrow, Long };
+  Maybe<std::pair<std::string_view, UnitDisplay>> mUnit;
+
+  /**
+   * Display a percent number.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#unit
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#scale
+   */
+  bool mPercent = false;
+
+  /**
+   * Set to true to strip trailing zeros after the decimal point for integer
+   * values.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#trailing-zero-display
+   */
+  bool mStripTrailingZero = false;
+
+  /**
+   * Enable or disable grouping.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#grouping
+   */
+  enum class Grouping {
+    Auto,
+    Always,
+    Min2,
+    Never,
+  } mGrouping = Grouping::Auto;
+
+  /**
+   * Set the notation style.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#notation
+   */
+  enum class Notation {
+    Standard,
+    Scientific,
+    Engineering,
+    CompactShort,
+    CompactLong
+  } mNotation = Notation::Standard;
+
+  /**
+   * Set the sign-display.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#sign-display
+   */
+  enum class SignDisplay {
+    Auto,
+    Never,
+    Always,
+    ExceptZero,
+    Negative,
+    Accounting,
+    AccountingAlways,
+    AccountingExceptZero,
+    AccountingNegative,
+  } mSignDisplay = SignDisplay::Auto;
+
+  /**
+   * Set the rounding increment, which must be a non-zero number.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#precision
+   */
+  uint32_t mRoundingIncrement = 1;
+
+  /**
+   * Set the rounding mode.
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#rounding-mode
+   */
+  enum class RoundingMode {
+    Ceil,
+    Floor,
+    Expand,
+    Trunc,
+    HalfCeil,
+    HalfFloor,
+    HalfExpand,
+    HalfTrunc,
+    HalfEven,
+    HalfOdd,
+  } mRoundingMode = RoundingMode::HalfExpand;
+
+  /**
+   * Set the rounding priority. |mFractionDigits| and |mSignificantDigits| must
+   * both be set if the rounding priority isn't equal to "auto".
+   *
+   * https://github.com/unicode-org/icu/blob/master/docs/userguide/format_parse/numbers/skeletons.md#fraction-precision
+   */
+  enum class RoundingPriority {
+    Auto,
+    MorePrecision,
+    LessPrecision,
+  } mRoundingPriority = RoundingPriority::Auto;
+};
+
+/**
+ * According to http://userguide.icu-project.org/design, as long as we constrain
+ * ourselves to const APIs ICU is const-correct.
+ */
+
+/**
+ * A NumberFormat implementation that roughly mirrors the API provided by
+ * the ECMA-402 Intl.NumberFormat object.
+ *
+ * https://tc39.es/ecma402/#numberformat-objects
+ */
+class NumberFormat final {
+ public:
+  /**
+   * Initialize a new NumberFormat for the provided locale and using the
+   * provided options.
+   *
+   * https://tc39.es/ecma402/#sec-initializenumberformat
+   */
+  static Result<UniquePtr<NumberFormat>, ICUError> TryCreate(
+      std::string_view aLocale, const NumberFormatOptions& aOptions);
+
+  NumberFormat() = default;
+  NumberFormat(const NumberFormat&) = delete;
+  NumberFormat& operator=(const NumberFormat&) = delete;
+  ~NumberFormat();
+
+  /**
+   * Formats a double to a utf-16 string. The string view is valid until
+   * another number is formatted. Accessing the string view after this event
+   * is undefined behavior.
+   *
+   * https://tc39.es/ecma402/#sec-formatnumberstring
+   */
+  Result<std::u16string_view, ICUError> format(double number) const {
+    if (!formatInternal(number)) {
+      return Err(ICUError::InternalError);
+    }
+
+    return formatResult();
+  }
+
+  /**
+   * Formats a double to a utf-16 string, and fills the provided parts vector.
+   * The string view is valid until another number is formatted. Accessing the
+   * string view after this event is undefined behavior.
+   *
+   * This is utf-16 only because the only current use case is in
+   * SpiderMonkey. Supporting utf-8 would require recalculating the offsets
+   * in NumberPartVector from fixed width to variable width, which might be
+   * tricky to get right and is work that won't be necessary if we switch to
+   * ICU4X (see Bug 1707035).
+   *
+   * https://tc39.es/ecma402/#sec-partitionnumberpattern
+   */
+  Result<std::u16string_view, ICUError> formatToParts(
+      double number, NumberPartVector& parts) const;
+
+  /**
+   * Formats a double to the provider buffer (either utf-8 or utf-16)
+   *
+   * https://tc39.es/ecma402/#sec-formatnumberstring
+   */
+  template <typename B>
+  Result<Ok, ICUError> format(double number, B& buffer) const {
+    if (!formatInternal(number)) {
+      return Err(ICUError::InternalError);
+    }
+
+    return formatResult<typename B::CharType, B>(buffer);
+  }
+
+  /**
+   * Formats an int64_t to a utf-16 string. The string view is valid until
+   * another number is formatted. Accessing the string view after this event is
+   * undefined behavior.
+   *
+   * https://tc39.es/ecma402/#sec-formatnumberstring
+   */
+  Result<std::u16string_view, ICUError> format(int64_t number) const {
+    if (!formatInternal(number)) {
+      return Err(ICUError::InternalError);
+    }
+
+    return formatResult();
+  }
+
+  /**
+   * Formats a int64_t to a utf-16 string, and fills the provided parts vector.
+   * The string view is valid until another number is formatted. Accessing the
+   * string view after this event is undefined behavior.
+   *
+   * This is utf-16 only because the only current use case is in
+   * SpiderMonkey. Supporting utf-8 would require recalculating the offsets
+   * in NumberPartVector from fixed width to variable width, which might be
+   * tricky to get right and is work that won't be necessary if we switch to
+   * ICU4X (see Bug 1707035).
+   *
+   * https://tc39.es/ecma402/#sec-partitionnumberpattern
+   */
+  Result<std::u16string_view, ICUError> formatToParts(
+      int64_t number, NumberPartVector& parts) const;
+
+  /**
+   * Formats an int64_t to the provider buffer (either utf-8 or utf-16).
+   *
+   * https://tc39.es/ecma402/#sec-formatnumberstring
+   */
+  template <typename B>
+  Result<Ok, ICUError> format(int64_t number, B& buffer) const {
+    if (!formatInternal(number)) {
+      return Err(ICUError::InternalError);
+    }
+
+    return formatResult<typename B::CharType, B>(buffer);
+  }
+
+  /**
+   * Formats a string encoded decimal number to a utf-16 string. The string view
+   * is valid until another number is formatted. Accessing the string view
+   * after this event is undefined behavior.
+   *
+   * https://tc39.es/ecma402/#sec-formatnumberstring
+   */
+  Result<std::u16string_view, ICUError> format(std::string_view number) const {
+    if (!formatInternal(number)) {
+      return Err(ICUError::InternalError);
+    }
+
+    return formatResult();
+  }
+
+  /**
+   * Formats a string encoded decimal number to a utf-16 string, and fills the
+   * provided parts vector. The string view is valid until another number is
+   * formatted. Accessing the string view after this event is undefined
+   * behavior.
+   *
+   * This is utf-16 only because the only current use case is in
+   * SpiderMonkey. Supporting utf-8 would require recalculating the offsets
+   * in NumberPartVector from fixed width to variable width, which might be
+   * tricky to get right and is work that won't be necessary if we switch to
+   * ICU4X (see Bug 1707035).
+   *
+   * https://tc39.es/ecma402/#sec-partitionnumberpattern
+   */
+  Result<std::u16string_view, ICUError> formatToParts(
+      std::string_view number, NumberPartVector& parts) const;
+
+  /**
+   * Formats a string encoded decimal number to the provider buffer
+   * (either utf-8 or utf-16).
+   *
+   * https://tc39.es/ecma402/#sec-formatnumberstring
+   */
+  template <typename B>
+  Result<Ok, ICUError> format(std::string_view number, B& buffer) const {
+    if (!formatInternal(number)) {
+      return Err(ICUError::InternalError);
+    }
+
+    return formatResult<typename B::CharType, B>(buffer);
+  }
+
+  /**
+   * Formats the number and selects the keyword by using a provided
+   * UPluralRules object.
+   *
+   * https://tc39.es/ecma402/#sec-intl.pluralrules.prototype.select
+   *
+   * TODO(1713917) This is necessary because both PluralRules and
+   * NumberFormat have a shared dependency on the raw UFormattedNumber
+   * type. Once we transition to using ICU4X, the FFI calls should no
+   * longer require such shared dependencies. At that time, this
+   * functionality should be removed from NumberFormat and invoked
+   * solely from PluralRules.
+   */
+  Result<int32_t, ICUError> selectFormatted(double number, char16_t* keyword,
+                                            int32_t keywordSize,
+                                            UPluralRules* pluralRules) const;
+
+  /**
+   * Returns an iterator over all supported number formatter locales.
+   *
+   * The returned strings are ICU locale identifiers and NOT BCP 47 language
+   * tags.
+   *
+   * Also see <https://unicode-org.github.io/icu/userguide/locale>.
+   */
+  static auto GetAvailableLocales() {
+    return AvailableLocalesEnumeration<unum_countAvailable,
+                                       unum_getAvailable>();
+  }
+
+ private:
+  UNumberFormatter* mNumberFormatter = nullptr;
+  UFormattedNumber* mFormattedNumber = nullptr;
+  bool mFormatForUnit = false;
+
+  Result<Ok, ICUError> initialize(std::string_view aLocale,
+                                  const NumberFormatOptions& aOptions);
+
+  [[nodiscard]] bool formatInternal(double number) const;
+  [[nodiscard]] bool formatInternal(int64_t number) const;
+  [[nodiscard]] bool formatInternal(std::string_view number) const;
+
+  Result<std::u16string_view, ICUError> formatResult() const;
+
+  template <typename C, typename B>
+  Result<Ok, ICUError> formatResult(B& buffer) const {
+    // We only support buffers with char or char16_t.
+    static_assert(std::is_same_v<C, char> || std::is_same_v<C, char16_t>);
+
+    return formatResult().andThen(
+        [&buffer](std::u16string_view result) -> Result<Ok, ICUError> {
+          if constexpr (std::is_same_v<C, char>) {
+            if (!FillBuffer(Span(result.data(), result.size()), buffer)) {
+              return Err(ICUError::OutOfMemory);
+            }
+            return Ok();
+          } else {
+            // ICU provides APIs which accept a buffer, but they just copy from
+            // an internal buffer behind the scenes anyway.
+            if (!buffer.reserve(result.size())) {
+              return Err(ICUError::OutOfMemory);
+            }
+            PodCopy(static_cast<char16_t*>(buffer.data()), result.data(),
+                    result.size());
+            buffer.written(result.size());
+
+            return Ok();
+          }
+        });
+  }
+};
+
+}  // namespace mozilla::intl
+
+#endif