// Copyright 2007 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview Utility functions for supporting Bidi issues.
*/
/**
* Namespace for bidi supporting functions.
*/
goog.provide('goog.i18n.bidi');
goog.provide('goog.i18n.bidi.Dir');
goog.provide('goog.i18n.bidi.DirectionalString');
goog.provide('goog.i18n.bidi.Format');
/**
* @define {boolean} FORCE_RTL forces the {@link goog.i18n.bidi.IS_RTL} constant
* to say that the current locale is a RTL locale. This should only be used
* if you want to override the default behavior for deciding whether the
* current locale is RTL or not.
*
* {@see goog.i18n.bidi.IS_RTL}
*/
goog.define('goog.i18n.bidi.FORCE_RTL', false);
/**
* Constant that defines whether or not the current locale is a RTL locale.
* If {@link goog.i18n.bidi.FORCE_RTL} is not true, this constant will default
* to check that {@link goog.LOCALE} is one of a few major RTL locales.
*
* <p>This is designed to be a maximally efficient compile-time constant. For
* example, for the default goog.LOCALE, compiling
* "if (goog.i18n.bidi.IS_RTL) alert('rtl') else {}" should produce no code. It
* is this design consideration that limits the implementation to only
* supporting a few major RTL locales, as opposed to the broader repertoire of
* something like goog.i18n.bidi.isRtlLanguage.
*
* <p>Since this constant refers to the directionality of the locale, it is up
* to the caller to determine if this constant should also be used for the
* direction of the UI.
*
* {@see goog.LOCALE}
*
* @type {boolean}
*
* TODO(user): write a test that checks that this is a compile-time constant.
*/
goog.i18n.bidi.IS_RTL = goog.i18n.bidi.FORCE_RTL ||
(
(goog.LOCALE.substring(0, 2).toLowerCase() == 'ar' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'fa' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'he' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'iw' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'ps' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'sd' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'ug' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'ur' ||
goog.LOCALE.substring(0, 2).toLowerCase() == 'yi') &&
(goog.LOCALE.length == 2 ||
goog.LOCALE.substring(2, 3) == '-' ||
goog.LOCALE.substring(2, 3) == '_')
) || (
goog.LOCALE.length >= 3 &&
goog.LOCALE.substring(0, 3).toLowerCase() == 'ckb' &&
(goog.LOCALE.length == 3 ||
goog.LOCALE.substring(3, 4) == '-' ||
goog.LOCALE.substring(3, 4) == '_')
);
/**
* Unicode formatting characters and directionality string constants.
* @enum {string}
*/
goog.i18n.bidi.Format = {
/** Unicode "Left-To-Right Embedding" (LRE) character. */
LRE: '\u202A',
/** Unicode "Right-To-Left Embedding" (RLE) character. */
RLE: '\u202B',
/** Unicode "Pop Directional Formatting" (PDF) character. */
PDF: '\u202C',
/** Unicode "Left-To-Right Mark" (LRM) character. */
LRM: '\u200E',
/** Unicode "Right-To-Left Mark" (RLM) character. */
RLM: '\u200F'
};
/**
* Directionality enum.
* @enum {number}
*/
goog.i18n.bidi.Dir = {
/**
* Left-to-right.
*/
LTR: 1,
/**
* Right-to-left.
*/
RTL: -1,
/**
* Neither left-to-right nor right-to-left.
*/
NEUTRAL: 0
};
/**
* 'right' string constant.
* @type {string}
*/
goog.i18n.bidi.RIGHT = 'right';
/**
* 'left' string constant.
* @type {string}
*/
goog.i18n.bidi.LEFT = 'left';
/**
* 'left' if locale is RTL, 'right' if not.
* @type {string}
*/
goog.i18n.bidi.I18N_RIGHT = goog.i18n.bidi.IS_RTL ? goog.i18n.bidi.LEFT :
goog.i18n.bidi.RIGHT;
/**
* 'right' if locale is RTL, 'left' if not.
* @type {string}
*/
goog.i18n.bidi.I18N_LEFT = goog.i18n.bidi.IS_RTL ? goog.i18n.bidi.RIGHT :
goog.i18n.bidi.LEFT;
/**
* Convert a directionality given in various formats to a goog.i18n.bidi.Dir
* constant. Useful for interaction with different standards of directionality
* representation.
*
* @param {goog.i18n.bidi.Dir|number|boolean|null} givenDir Directionality given
* in one of the following formats:
* 1. A goog.i18n.bidi.Dir constant.
* 2. A number (positive = LTR, negative = RTL, 0 = neutral).
* 3. A boolean (true = RTL, false = LTR).
* 4. A null for unknown directionality.
* @param {boolean=} opt_noNeutral Whether a givenDir of zero or
* goog.i18n.bidi.Dir.NEUTRAL should be treated as null, i.e. unknown, in
* order to preserve legacy behavior.
* @return {?goog.i18n.bidi.Dir} A goog.i18n.bidi.Dir constant matching the
* given directionality. If given null, returns null (i.e. unknown).
*/
goog.i18n.bidi.toDir = function(givenDir, opt_noNeutral) {
if (typeof givenDir == 'number') {
// This includes the non-null goog.i18n.bidi.Dir case.
return givenDir > 0 ? goog.i18n.bidi.Dir.LTR :
givenDir < 0 ? goog.i18n.bidi.Dir.RTL :
opt_noNeutral ? null : goog.i18n.bidi.Dir.NEUTRAL;
} else if (givenDir == null) {
return null;
} else {
// Must be typeof givenDir == 'boolean'.
return givenDir ? goog.i18n.bidi.Dir.RTL : goog.i18n.bidi.Dir.LTR;
}
};
/**
* A practical pattern to identify strong LTR characters. This pattern is not
* theoretically correct according to the Unicode standard. It is simplified for
* performance and small code size.
* @type {string}
* @private
*/
goog.i18n.bidi.ltrChars_ =
'A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02B8\u0300-\u0590\u0800-\u1FFF' +
'\u200E\u2C00-\uFB1C\uFE00-\uFE6F\uFEFD-\uFFFF';
/**
* A practical pattern to identify strong RTL character. This pattern is not
* theoretically correct according to the Unicode standard. It is simplified
* for performance and small code size.
* @type {string}
* @private
*/
goog.i18n.bidi.rtlChars_ =
'\u0591-\u06EF\u06FA-\u07FF\u200F\uFB1D-\uFDFF\uFE70-\uFEFC';
/**
* Simplified regular expression for an HTML tag (opening or closing) or an HTML
* escape. We might want to skip over such expressions when estimating the text
* directionality.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.htmlSkipReg_ = /<[^>]*>|&[^;]+;/g;
/**
* Returns the input text with spaces instead of HTML tags or HTML escapes, if
* opt_isStripNeeded is true. Else returns the input as is.
* Useful for text directionality estimation.
* Note: the function should not be used in other contexts; it is not 100%
* correct, but rather a good-enough implementation for directionality
* estimation purposes.
* @param {string} str The given string.
* @param {boolean=} opt_isStripNeeded Whether to perform the stripping.
* Default: false (to retain consistency with calling functions).
* @return {string} The given string cleaned of HTML tags / escapes.
* @private
*/
goog.i18n.bidi.stripHtmlIfNeeded_ = function(str, opt_isStripNeeded) {
return opt_isStripNeeded ? str.replace(goog.i18n.bidi.htmlSkipReg_, '') :
str;
};
/**
* Regular expression to check for RTL characters.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.rtlCharReg_ = new RegExp('[' + goog.i18n.bidi.rtlChars_ + ']');
/**
* Regular expression to check for LTR characters.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.ltrCharReg_ = new RegExp('[' + goog.i18n.bidi.ltrChars_ + ']');
/**
* Test whether the given string has any RTL characters in it.
* @param {string} str The given string that need to be tested.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether the string contains RTL characters.
*/
goog.i18n.bidi.hasAnyRtl = function(str, opt_isHtml) {
return goog.i18n.bidi.rtlCharReg_.test(goog.i18n.bidi.stripHtmlIfNeeded_(
str, opt_isHtml));
};
/**
* Test whether the given string has any RTL characters in it.
* @param {string} str The given string that need to be tested.
* @return {boolean} Whether the string contains RTL characters.
* @deprecated Use hasAnyRtl.
*/
goog.i18n.bidi.hasRtlChar = goog.i18n.bidi.hasAnyRtl;
/**
* Test whether the given string has any LTR characters in it.
* @param {string} str The given string that need to be tested.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether the string contains LTR characters.
*/
goog.i18n.bidi.hasAnyLtr = function(str, opt_isHtml) {
return goog.i18n.bidi.ltrCharReg_.test(goog.i18n.bidi.stripHtmlIfNeeded_(
str, opt_isHtml));
};
/**
* Regular expression pattern to check if the first character in the string
* is LTR.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.ltrRe_ = new RegExp('^[' + goog.i18n.bidi.ltrChars_ + ']');
/**
* Regular expression pattern to check if the first character in the string
* is RTL.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.rtlRe_ = new RegExp('^[' + goog.i18n.bidi.rtlChars_ + ']');
/**
* Check if the first character in the string is RTL or not.
* @param {string} str The given string that need to be tested.
* @return {boolean} Whether the first character in str is an RTL char.
*/
goog.i18n.bidi.isRtlChar = function(str) {
return goog.i18n.bidi.rtlRe_.test(str);
};
/**
* Check if the first character in the string is LTR or not.
* @param {string} str The given string that need to be tested.
* @return {boolean} Whether the first character in str is an LTR char.
*/
goog.i18n.bidi.isLtrChar = function(str) {
return goog.i18n.bidi.ltrRe_.test(str);
};
/**
* Check if the first character in the string is neutral or not.
* @param {string} str The given string that need to be tested.
* @return {boolean} Whether the first character in str is a neutral char.
*/
goog.i18n.bidi.isNeutralChar = function(str) {
return !goog.i18n.bidi.isLtrChar(str) && !goog.i18n.bidi.isRtlChar(str);
};
/**
* Regular expressions to check if a piece of text is of LTR directionality
* on first character with strong directionality.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.ltrDirCheckRe_ = new RegExp(
'^[^' + goog.i18n.bidi.rtlChars_ + ']*[' + goog.i18n.bidi.ltrChars_ + ']');
/**
* Regular expressions to check if a piece of text is of RTL directionality
* on first character with strong directionality.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.rtlDirCheckRe_ = new RegExp(
'^[^' + goog.i18n.bidi.ltrChars_ + ']*[' + goog.i18n.bidi.rtlChars_ + ']');
/**
* Check whether the first strongly directional character (if any) is RTL.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether RTL directionality is detected using the first
* strongly-directional character method.
*/
goog.i18n.bidi.startsWithRtl = function(str, opt_isHtml) {
return goog.i18n.bidi.rtlDirCheckRe_.test(goog.i18n.bidi.stripHtmlIfNeeded_(
str, opt_isHtml));
};
/**
* Check whether the first strongly directional character (if any) is RTL.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether RTL directionality is detected using the first
* strongly-directional character method.
* @deprecated Use startsWithRtl.
*/
goog.i18n.bidi.isRtlText = goog.i18n.bidi.startsWithRtl;
/**
* Check whether the first strongly directional character (if any) is LTR.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether LTR directionality is detected using the first
* strongly-directional character method.
*/
goog.i18n.bidi.startsWithLtr = function(str, opt_isHtml) {
return goog.i18n.bidi.ltrDirCheckRe_.test(goog.i18n.bidi.stripHtmlIfNeeded_(
str, opt_isHtml));
};
/**
* Check whether the first strongly directional character (if any) is LTR.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether LTR directionality is detected using the first
* strongly-directional character method.
* @deprecated Use startsWithLtr.
*/
goog.i18n.bidi.isLtrText = goog.i18n.bidi.startsWithLtr;
/**
* Regular expression to check if a string looks like something that must
* always be LTR even in RTL text, e.g. a URL. When estimating the
* directionality of text containing these, we treat these as weakly LTR,
* like numbers.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.isRequiredLtrRe_ = /^http:\/\/.*/;
/**
* Check whether the input string either contains no strongly directional
* characters or looks like a url.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether neutral directionality is detected.
*/
goog.i18n.bidi.isNeutralText = function(str, opt_isHtml) {
str = goog.i18n.bidi.stripHtmlIfNeeded_(str, opt_isHtml);
return goog.i18n.bidi.isRequiredLtrRe_.test(str) ||
!goog.i18n.bidi.hasAnyLtr(str) && !goog.i18n.bidi.hasAnyRtl(str);
};
/**
* Regular expressions to check if the last strongly-directional character in a
* piece of text is LTR.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.ltrExitDirCheckRe_ = new RegExp(
'[' + goog.i18n.bidi.ltrChars_ + '][^' + goog.i18n.bidi.rtlChars_ + ']*$');
/**
* Regular expressions to check if the last strongly-directional character in a
* piece of text is RTL.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.rtlExitDirCheckRe_ = new RegExp(
'[' + goog.i18n.bidi.rtlChars_ + '][^' + goog.i18n.bidi.ltrChars_ + ']*$');
/**
* Check if the exit directionality a piece of text is LTR, i.e. if the last
* strongly-directional character in the string is LTR.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether LTR exit directionality was detected.
*/
goog.i18n.bidi.endsWithLtr = function(str, opt_isHtml) {
return goog.i18n.bidi.ltrExitDirCheckRe_.test(
goog.i18n.bidi.stripHtmlIfNeeded_(str, opt_isHtml));
};
/**
* Check if the exit directionality a piece of text is LTR, i.e. if the last
* strongly-directional character in the string is LTR.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether LTR exit directionality was detected.
* @deprecated Use endsWithLtr.
*/
goog.i18n.bidi.isLtrExitText = goog.i18n.bidi.endsWithLtr;
/**
* Check if the exit directionality a piece of text is RTL, i.e. if the last
* strongly-directional character in the string is RTL.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether RTL exit directionality was detected.
*/
goog.i18n.bidi.endsWithRtl = function(str, opt_isHtml) {
return goog.i18n.bidi.rtlExitDirCheckRe_.test(
goog.i18n.bidi.stripHtmlIfNeeded_(str, opt_isHtml));
};
/**
* Check if the exit directionality a piece of text is RTL, i.e. if the last
* strongly-directional character in the string is RTL.
* @param {string} str String being checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether RTL exit directionality was detected.
* @deprecated Use endsWithRtl.
*/
goog.i18n.bidi.isRtlExitText = goog.i18n.bidi.endsWithRtl;
/**
* A regular expression for matching right-to-left language codes.
* See {@link #isRtlLanguage} for the design.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.rtlLocalesRe_ = new RegExp(
'^(ar|ckb|dv|he|iw|fa|nqo|ps|sd|ug|ur|yi|' +
'.*[-_](Arab|Hebr|Thaa|Nkoo|Tfng))' +
'(?!.*[-_](Latn|Cyrl)($|-|_))($|-|_)',
'i');
/**
* Check if a BCP 47 / III language code indicates an RTL language, i.e. either:
* - a language code explicitly specifying one of the right-to-left scripts,
* e.g. "az-Arab", or<p>
* - a language code specifying one of the languages normally written in a
* right-to-left script, e.g. "fa" (Farsi), except ones explicitly specifying
* Latin or Cyrillic script (which are the usual LTR alternatives).<p>
* The list of right-to-left scripts appears in the 100-199 range in
* http://www.unicode.org/iso15924/iso15924-num.html, of which Arabic and
* Hebrew are by far the most widely used. We also recognize Thaana, N'Ko, and
* Tifinagh, which also have significant modern usage. The rest (Syriac,
* Samaritan, Mandaic, etc.) seem to have extremely limited or no modern usage
* and are not recognized to save on code size.
* The languages usually written in a right-to-left script are taken as those
* with Suppress-Script: Hebr|Arab|Thaa|Nkoo|Tfng in
* http://www.iana.org/assignments/language-subtag-registry,
* as well as Central (or Sorani) Kurdish (ckb), Sindhi (sd) and Uyghur (ug).
* Other subtags of the language code, e.g. regions like EG (Egypt), are
* ignored.
* @param {string} lang BCP 47 (a.k.a III) language code.
* @return {boolean} Whether the language code is an RTL language.
*/
goog.i18n.bidi.isRtlLanguage = function(lang) {
return goog.i18n.bidi.rtlLocalesRe_.test(lang);
};
/**
* Regular expression for bracket guard replacement in html.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.bracketGuardHtmlRe_ =
/(\(.*?\)+)|(\[.*?\]+)|(\{.*?\}+)|(<.*?(>)+)/g;
/**
* Regular expression for bracket guard replacement in text.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.bracketGuardTextRe_ =
/(\(.*?\)+)|(\[.*?\]+)|(\{.*?\}+)|(<.*?>+)/g;
/**
* Apply bracket guard using html span tag. This is to address the problem of
* messy bracket display frequently happens in RTL layout.
* @param {string} s The string that need to be processed.
* @param {boolean=} opt_isRtlContext specifies default direction (usually
* direction of the UI).
* @return {string} The processed string, with all bracket guarded.
*/
goog.i18n.bidi.guardBracketInHtml = function(s, opt_isRtlContext) {
var useRtl = opt_isRtlContext === undefined ?
goog.i18n.bidi.hasAnyRtl(s) : opt_isRtlContext;
if (useRtl) {
return s.replace(goog.i18n.bidi.bracketGuardHtmlRe_,
'<span dir=rtl>$&</span>');
}
return s.replace(goog.i18n.bidi.bracketGuardHtmlRe_,
'<span dir=ltr>$&</span>');
};
/**
* Apply bracket guard using LRM and RLM. This is to address the problem of
* messy bracket display frequently happens in RTL layout.
* This version works for both plain text and html. But it does not work as
* good as guardBracketInHtml in some cases.
* @param {string} s The string that need to be processed.
* @param {boolean=} opt_isRtlContext specifies default direction (usually
* direction of the UI).
* @return {string} The processed string, with all bracket guarded.
*/
goog.i18n.bidi.guardBracketInText = function(s, opt_isRtlContext) {
var useRtl = opt_isRtlContext === undefined ?
goog.i18n.bidi.hasAnyRtl(s) : opt_isRtlContext;
var mark = useRtl ? goog.i18n.bidi.Format.RLM : goog.i18n.bidi.Format.LRM;
return s.replace(goog.i18n.bidi.bracketGuardTextRe_, mark + '$&' + mark);
};
/**
* Enforce the html snippet in RTL directionality regardless overall context.
* If the html piece was enclosed by tag, dir will be applied to existing
* tag, otherwise a span tag will be added as wrapper. For this reason, if
* html snippet start with with tag, this tag must enclose the whole piece. If
* the tag already has a dir specified, this new one will override existing
* one in behavior (tested on FF and IE).
* @param {string} html The string that need to be processed.
* @return {string} The processed string, with directionality enforced to RTL.
*/
goog.i18n.bidi.enforceRtlInHtml = function(html) {
if (html.charAt(0) == '<') {
return html.replace(/<\w+/, '$& dir=rtl');
}
// '\n' is important for FF so that it won't incorrectly merge span groups
return '\n<span dir=rtl>' + html + '</span>';
};
/**
* Enforce RTL on both end of the given text piece using unicode BiDi formatting
* characters RLE and PDF.
* @param {string} text The piece of text that need to be wrapped.
* @return {string} The wrapped string after process.
*/
goog.i18n.bidi.enforceRtlInText = function(text) {
return goog.i18n.bidi.Format.RLE + text + goog.i18n.bidi.Format.PDF;
};
/**
* Enforce the html snippet in RTL directionality regardless overall context.
* If the html piece was enclosed by tag, dir will be applied to existing
* tag, otherwise a span tag will be added as wrapper. For this reason, if
* html snippet start with with tag, this tag must enclose the whole piece. If
* the tag already has a dir specified, this new one will override existing
* one in behavior (tested on FF and IE).
* @param {string} html The string that need to be processed.
* @return {string} The processed string, with directionality enforced to RTL.
*/
goog.i18n.bidi.enforceLtrInHtml = function(html) {
if (html.charAt(0) == '<') {
return html.replace(/<\w+/, '$& dir=ltr');
}
// '\n' is important for FF so that it won't incorrectly merge span groups
return '\n<span dir=ltr>' + html + '</span>';
};
/**
* Enforce LTR on both end of the given text piece using unicode BiDi formatting
* characters LRE and PDF.
* @param {string} text The piece of text that need to be wrapped.
* @return {string} The wrapped string after process.
*/
goog.i18n.bidi.enforceLtrInText = function(text) {
return goog.i18n.bidi.Format.LRE + text + goog.i18n.bidi.Format.PDF;
};
/**
* Regular expression to find dimensions such as "padding: .3 0.4ex 5px 6;"
* @type {RegExp}
* @private
*/
goog.i18n.bidi.dimensionsRe_ =
/:\s*([.\d][.\w]*)\s+([.\d][.\w]*)\s+([.\d][.\w]*)\s+([.\d][.\w]*)/g;
/**
* Regular expression for left.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.leftRe_ = /left/gi;
/**
* Regular expression for right.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.rightRe_ = /right/gi;
/**
* Placeholder regular expression for swapping.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.tempRe_ = /%%%%/g;
/**
* Swap location parameters and 'left'/'right' in CSS specification. The
* processed string will be suited for RTL layout. Though this function can
* cover most cases, there are always exceptions. It is suggested to put
* those exceptions in separate group of CSS string.
* @param {string} cssStr CSS spefication string.
* @return {string} Processed CSS specification string.
*/
goog.i18n.bidi.mirrorCSS = function(cssStr) {
return cssStr.
// reverse dimensions
replace(goog.i18n.bidi.dimensionsRe_, ':$1 $4 $3 $2').
replace(goog.i18n.bidi.leftRe_, '%%%%'). // swap left and right
replace(goog.i18n.bidi.rightRe_, goog.i18n.bidi.LEFT).
replace(goog.i18n.bidi.tempRe_, goog.i18n.bidi.RIGHT);
};
/**
* Regular expression for hebrew double quote substitution, finding quote
* directly after hebrew characters.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.doubleQuoteSubstituteRe_ = /([\u0591-\u05f2])"/g;
/**
* Regular expression for hebrew single quote substitution, finding quote
* directly after hebrew characters.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.singleQuoteSubstituteRe_ = /([\u0591-\u05f2])'/g;
/**
* Replace the double and single quote directly after a Hebrew character with
* GERESH and GERSHAYIM. In such case, most likely that's user intention.
* @param {string} str String that need to be processed.
* @return {string} Processed string with double/single quote replaced.
*/
goog.i18n.bidi.normalizeHebrewQuote = function(str) {
return str.
replace(goog.i18n.bidi.doubleQuoteSubstituteRe_, '$1\u05f4').
replace(goog.i18n.bidi.singleQuoteSubstituteRe_, '$1\u05f3');
};
/**
* Regular expression to split a string into "words" for directionality
* estimation based on relative word counts.
* @type {RegExp}
* @private
*/
goog.i18n.bidi.wordSeparatorRe_ = /\s+/;
/**
* Regular expression to check if a string contains any numerals. Used to
* differentiate between completely neutral strings and those containing
* numbers, which are weakly LTR.
*
* Native Arabic digits (\u0660 - \u0669) are not included because although they
* do flow left-to-right inside a number, this is the case even if the overall
* directionality is RTL, and a mathematical expression using these digits is
* supposed to flow right-to-left overall, including unary plus and minus
* appearing to the right of a number, and this does depend on the overall
* directionality being RTL. The digits used in Farsi (\u06F0 - \u06F9), on the
* other hand, are included, since Farsi math (including unary plus and minus)
* does flow left-to-right.
*
* @type {RegExp}
* @private
*/
goog.i18n.bidi.hasNumeralsRe_ = /[\d\u06f0-\u06f9]/;
/**
* This constant controls threshold of RTL directionality.
* @type {number}
* @private
*/
goog.i18n.bidi.rtlDetectionThreshold_ = 0.40;
/**
* Estimates the directionality of a string based on relative word counts.
* If the number of RTL words is above a certain percentage of the total number
* of strongly directional words, returns RTL.
* Otherwise, if any words are strongly or weakly LTR, returns LTR.
* Otherwise, returns UNKNOWN, which is used to mean "neutral".
* Numbers are counted as weakly LTR.
* @param {string} str The string to be checked.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {goog.i18n.bidi.Dir} Estimated overall directionality of {@code str}.
*/
goog.i18n.bidi.estimateDirection = function(str, opt_isHtml) {
var rtlCount = 0;
var totalCount = 0;
var hasWeaklyLtr = false;
var tokens = goog.i18n.bidi.stripHtmlIfNeeded_(str, opt_isHtml).
split(goog.i18n.bidi.wordSeparatorRe_);
for (var i = 0; i < tokens.length; i++) {
var token = tokens[i];
if (goog.i18n.bidi.startsWithRtl(token)) {
rtlCount++;
totalCount++;
} else if (goog.i18n.bidi.isRequiredLtrRe_.test(token)) {
hasWeaklyLtr = true;
} else if (goog.i18n.bidi.hasAnyLtr(token)) {
totalCount++;
} else if (goog.i18n.bidi.hasNumeralsRe_.test(token)) {
hasWeaklyLtr = true;
}
}
return totalCount == 0 ?
(hasWeaklyLtr ? goog.i18n.bidi.Dir.LTR : goog.i18n.bidi.Dir.NEUTRAL) :
(rtlCount / totalCount > goog.i18n.bidi.rtlDetectionThreshold_ ?
goog.i18n.bidi.Dir.RTL : goog.i18n.bidi.Dir.LTR);
};
/**
* Check the directionality of a piece of text, return true if the piece of
* text should be laid out in RTL direction.
* @param {string} str The piece of text that need to be detected.
* @param {boolean=} opt_isHtml Whether str is HTML / HTML-escaped.
* Default: false.
* @return {boolean} Whether this piece of text should be laid out in RTL.
*/
goog.i18n.bidi.detectRtlDirectionality = function(str, opt_isHtml) {
return goog.i18n.bidi.estimateDirection(str, opt_isHtml) ==
goog.i18n.bidi.Dir.RTL;
};
/**
* Sets text input element's directionality and text alignment based on a
* given directionality. Does nothing if the given directionality is unknown or
* neutral.
* @param {Element} element Input field element to set directionality to.
* @param {goog.i18n.bidi.Dir|number|boolean|null} dir Desired directionality,
* given in one of the following formats:
* 1. A goog.i18n.bidi.Dir constant.
* 2. A number (positive = LRT, negative = RTL, 0 = neutral).
* 3. A boolean (true = RTL, false = LTR).
* 4. A null for unknown directionality.
*/
goog.i18n.bidi.setElementDirAndAlign = function(element, dir) {
if (element) {
dir = goog.i18n.bidi.toDir(dir);
if (dir) {
element.style.textAlign =
dir == goog.i18n.bidi.Dir.RTL ?
goog.i18n.bidi.RIGHT : goog.i18n.bidi.LEFT;
element.dir = dir == goog.i18n.bidi.Dir.RTL ? 'rtl' : 'ltr';
}
}
};
/**
* Sets element dir based on estimated directionality of the given text.
* @param {!Element} element
* @param {string} text
*/
goog.i18n.bidi.setElementDirByTextDirectionality = function(element, text) {
switch (goog.i18n.bidi.estimateDirection(text)) {
case (goog.i18n.bidi.Dir.LTR):
element.dir = 'ltr';
break;
case (goog.i18n.bidi.Dir.RTL):
element.dir = 'rtl';
break;
default:
// Default for no direction, inherit from document.
element.removeAttribute('dir');
}
};
/**
* Strings that have an (optional) known direction.
*
* Implementations of this interface are string-like objects that carry an
* attached direction, if known.
* @interface
*/
goog.i18n.bidi.DirectionalString = function() {};
/**
* Interface marker of the DirectionalString interface.
*
* This property can be used to determine at runtime whether or not an object
* implements this interface. All implementations of this interface set this
* property to {@code true}.
* @type {boolean}
*/
goog.i18n.bidi.DirectionalString.prototype.
implementsGoogI18nBidiDirectionalString;
/**
* Retrieves this object's known direction (if any).
* @return {?goog.i18n.bidi.Dir} The known direction. Null if unknown.
*/
goog.i18n.bidi.DirectionalString.prototype.getDirection;
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