1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_I18N_RTL_H_ 6 #define BASE_I18N_RTL_H_ 7 8 #include <string> 9 10 #include "base/compiler_specific.h" 11 #include "base/i18n/base_i18n_export.h" 12 #include "base/strings/string16.h" 13 #include "build/build_config.h" 14 15 namespace base { 16 17 class FilePath; 18 19 namespace i18n { 20 21 const char16 kRightToLeftMark = 0x200F; 22 const char16 kLeftToRightMark = 0x200E; 23 const char16 kLeftToRightEmbeddingMark = 0x202A; 24 const char16 kRightToLeftEmbeddingMark = 0x202B; 25 const char16 kPopDirectionalFormatting = 0x202C; 26 const char16 kLeftToRightOverride = 0x202D; 27 const char16 kRightToLeftOverride = 0x202E; 28 29 // Locale.java mirrored this enum TextDirection. Please keep in sync. 30 enum TextDirection { 31 UNKNOWN_DIRECTION = 0, 32 RIGHT_TO_LEFT = 1, 33 LEFT_TO_RIGHT = 2, 34 TEXT_DIRECTION_NUM_DIRECTIONS = 3, 35 }; 36 37 // Get the locale that the currently running process has been configured to use. 38 // The return value is of the form language[-country] (e.g., en-US) where the 39 // language is the 2 or 3 letter code from ISO-639. 40 BASE_I18N_EXPORT std::string GetConfiguredLocale(); 41 42 // Canonicalize a string (eg. a POSIX locale string) to a Chrome locale name. 43 BASE_I18N_EXPORT std::string GetCanonicalLocale(const char* locale); 44 45 // Sets the default locale of ICU. 46 // Once the application locale of Chrome in GetApplicationLocale is determined, 47 // the default locale of ICU need to be changed to match the application locale 48 // so that ICU functions work correctly in a locale-dependent manner. 49 // This is handy in that we don't have to call GetApplicationLocale() 50 // everytime we call locale-dependent ICU APIs as long as we make sure 51 // that this is called before any locale-dependent API is called. 52 BASE_I18N_EXPORT void SetICUDefaultLocale(const std::string& locale_string); 53 54 // Returns true if the application text direction is right-to-left. 55 BASE_I18N_EXPORT bool IsRTL(); 56 57 // Returns whether the text direction for the default ICU locale is RTL. This 58 // assumes that SetICUDefaultLocale has been called to set the default locale to 59 // the UI locale of Chrome. 60 // NOTE: Generally, you should call IsRTL() instead of this. 61 BASE_I18N_EXPORT bool ICUIsRTL(); 62 63 // Returns the text direction for |locale_name|. 64 BASE_I18N_EXPORT TextDirection GetTextDirectionForLocale( 65 const char* locale_name); 66 67 // Given the string in |text|, returns the directionality of the first or last 68 // character with strong directionality in the string. If no character in the 69 // text has strong directionality, LEFT_TO_RIGHT is returned. The Bidi 70 // character types L, LRE, LRO, R, AL, RLE, and RLO are considered as strong 71 // directionality characters. Please refer to http://unicode.org/reports/tr9/ 72 // for more information. 73 BASE_I18N_EXPORT TextDirection GetFirstStrongCharacterDirection( 74 const string16& text); 75 BASE_I18N_EXPORT TextDirection GetLastStrongCharacterDirection( 76 const string16& text); 77 78 // Given the string in |text|, returns LEFT_TO_RIGHT or RIGHT_TO_LEFT if all the 79 // strong directionality characters in the string are of the same 80 // directionality. It returns UNKNOWN_DIRECTION if the string contains a mix of 81 // LTR and RTL strong directionality characters. Defaults to LEFT_TO_RIGHT if 82 // the string does not contain directionality characters. Please refer to 83 // http://unicode.org/reports/tr9/ for more information. 84 BASE_I18N_EXPORT TextDirection GetStringDirection(const string16& text); 85 86 // Given the string in |text|, this function modifies the string in place with 87 // the appropriate Unicode formatting marks that mark the string direction 88 // (either left-to-right or right-to-left). The function checks both the current 89 // locale and the contents of the string in order to determine the direction of 90 // the returned string. The function returns true if the string in |text| was 91 // properly adjusted. 92 // 93 // Certain LTR strings are not rendered correctly when the context is RTL. For 94 // example, the string "Foo!" will appear as "!Foo" if it is rendered as is in 95 // an RTL context. Calling this function will make sure the returned localized 96 // string is always treated as a right-to-left string. This is done by 97 // inserting certain Unicode formatting marks into the returned string. 98 // 99 // ** Notes about the Windows version of this function: 100 // TODO(idana) bug 6806: this function adjusts the string in question only 101 // if the current locale is right-to-left. The function does not take care of 102 // the opposite case (an RTL string displayed in an LTR context) since 103 // adjusting the string involves inserting Unicode formatting characters that 104 // Windows does not handle well unless right-to-left language support is 105 // installed. Since the English version of Windows doesn't have right-to-left 106 // language support installed by default, inserting the direction Unicode mark 107 // results in Windows displaying squares. 108 BASE_I18N_EXPORT bool AdjustStringForLocaleDirection(string16* text); 109 110 // Undoes the actions of the above function (AdjustStringForLocaleDirection). 111 BASE_I18N_EXPORT bool UnadjustStringForLocaleDirection(string16* text); 112 113 // Returns true if the string contains at least one character with strong right 114 // to left directionality; that is, a character with either R or AL Unicode 115 // BiDi character type. 116 BASE_I18N_EXPORT bool StringContainsStrongRTLChars(const string16& text); 117 118 // Wraps a string with an LRE-PDF pair which essentialy marks the string as a 119 // Left-To-Right string. Doing this is useful in order to make sure LTR 120 // strings are rendered properly in an RTL context. 121 BASE_I18N_EXPORT void WrapStringWithLTRFormatting(string16* text); 122 123 // Wraps a string with an RLE-PDF pair which essentialy marks the string as a 124 // Right-To-Left string. Doing this is useful in order to make sure RTL 125 // strings are rendered properly in an LTR context. 126 BASE_I18N_EXPORT void WrapStringWithRTLFormatting(string16* text); 127 128 // Wraps file path to get it to display correctly in RTL UI. All filepaths 129 // should be passed through this function before display in UI for RTL locales. 130 BASE_I18N_EXPORT void WrapPathWithLTRFormatting(const FilePath& path, 131 string16* rtl_safe_path); 132 133 // Return the string in |text| wrapped with LRE (Left-To-Right Embedding) and 134 // PDF (Pop Directional Formatting) marks, if needed for UI display purposes. 135 BASE_I18N_EXPORT string16 GetDisplayStringInLTRDirectionality( 136 const string16& text) WARN_UNUSED_RESULT; 137 138 // Strip the beginning (U+202A..U+202B, U+202D..U+202E) and/or ending (U+202C) 139 // explicit bidi control characters from |text|, if there are any. Otherwise, 140 // return the text itself. Explicit bidi control characters display and have 141 // semantic effect. They can be deleted so they might not always appear in a 142 // pair. 143 BASE_I18N_EXPORT string16 StripWrappingBidiControlCharacters( 144 const string16& text) WARN_UNUSED_RESULT; 145 146 } // namespace i18n 147 } // namespace base 148 149 #endif // BASE_I18N_RTL_H_ 150
