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Diffstat (limited to 'intl/icu/source/common/unicode/errorcode.h')
-rw-r--r-- | intl/icu/source/common/unicode/errorcode.h | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/intl/icu/source/common/unicode/errorcode.h b/intl/icu/source/common/unicode/errorcode.h new file mode 100644 index 0000000000..fe7b518323 --- /dev/null +++ b/intl/icu/source/common/unicode/errorcode.h @@ -0,0 +1,144 @@ +// © 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +******************************************************************************* +* +* Copyright (C) 2009-2011, International Business Machines +* Corporation and others. All Rights Reserved. +* +******************************************************************************* +* file name: errorcode.h +* encoding: UTF-8 +* tab size: 8 (not used) +* indentation:4 +* +* created on: 2009mar10 +* created by: Markus W. Scherer +*/ + +#ifndef __ERRORCODE_H__ +#define __ERRORCODE_H__ + +/** + * \file + * \brief C++ API: ErrorCode class intended to make it easier to use + * ICU C and C++ APIs from C++ user code. + */ + +#include "unicode/utypes.h" + +#if U_SHOW_CPLUSPLUS_API + +#include "unicode/uobject.h" + +U_NAMESPACE_BEGIN + +/** + * Wrapper class for UErrorCode, with conversion operators for direct use + * in ICU C and C++ APIs. + * Intended to be used as a base class, where a subclass overrides + * the handleFailure() function so that it throws an exception, + * does an assert(), logs an error, etc. + * This is not an abstract base class. This class can be used and instantiated + * by itself, although it will be more useful when subclassed. + * + * Features: + * - The constructor initializes the internal UErrorCode to U_ZERO_ERROR, + * removing one common source of errors. + * - Same use in C APIs taking a UErrorCode * (pointer) + * and C++ taking UErrorCode & (reference) via conversion operators. + * - Possible automatic checking for success when it goes out of scope. + * + * Note: For automatic checking for success in the destructor, a subclass + * must implement such logic in its own destructor because the base class + * destructor cannot call a subclass function (like handleFailure()). + * The ErrorCode base class destructor does nothing. + * + * Note also: While it is possible for a destructor to throw an exception, + * it is generally unsafe to do so. This means that in a subclass the destructor + * and the handleFailure() function may need to take different actions. + * + * Sample code: + * \code + * class IcuErrorCode: public icu::ErrorCode { + * public: + * virtual ~IcuErrorCode() { // should be defined in .cpp as "key function" + * // Safe because our handleFailure() does not throw exceptions. + * if(isFailure()) { handleFailure(); } + * } + * protected: + * virtual void handleFailure() const { + * log_failure(u_errorName(errorCode)); + * exit(errorCode); + * } + * }; + * IcuErrorCode error_code; + * UConverter *cnv = ucnv_open("Shift-JIS", error_code); + * length = ucnv_fromUChars(dest, capacity, src, length, error_code); + * ucnv_close(cnv); + * // IcuErrorCode destructor checks for success. + * \endcode + * + * @stable ICU 4.2 + */ +class U_COMMON_API ErrorCode: public UMemory { +public: + /** + * Default constructor. Initializes its UErrorCode to U_ZERO_ERROR. + * @stable ICU 4.2 + */ + ErrorCode() : errorCode(U_ZERO_ERROR) {} + /** Destructor, does nothing. See class documentation for details. @stable ICU 4.2 */ + virtual ~ErrorCode(); + /** Conversion operator, returns a reference. @stable ICU 4.2 */ + operator UErrorCode & () { return errorCode; } + /** Conversion operator, returns a pointer. @stable ICU 4.2 */ + operator UErrorCode * () { return &errorCode; } + /** Tests for U_SUCCESS(). @stable ICU 4.2 */ + UBool isSuccess() const { return U_SUCCESS(errorCode); } + /** Tests for U_FAILURE(). @stable ICU 4.2 */ + UBool isFailure() const { return U_FAILURE(errorCode); } + /** Returns the UErrorCode value. @stable ICU 4.2 */ + UErrorCode get() const { return errorCode; } + /** Sets the UErrorCode value. @stable ICU 4.2 */ + void set(UErrorCode value) { errorCode=value; } + /** Returns the UErrorCode value and resets it to U_ZERO_ERROR. @stable ICU 4.2 */ + UErrorCode reset(); + /** + * Asserts isSuccess(). + * In other words, this method checks for a failure code, + * and the base class handles it like this: + * \code + * if(isFailure()) { handleFailure(); } + * \endcode + * @stable ICU 4.4 + */ + void assertSuccess() const; + /** + * Return a string for the UErrorCode value. + * The string will be the same as the name of the error code constant + * in the UErrorCode enum. + * @stable ICU 4.4 + */ + const char* errorName() const; + +protected: + /** + * Internal UErrorCode, accessible to subclasses. + * @stable ICU 4.2 + */ + UErrorCode errorCode; + /** + * Called by assertSuccess() if isFailure() is true. + * A subclass should override this function to deal with a failure code: + * Throw an exception, log an error, terminate the program, or similar. + * @stable ICU 4.2 + */ + virtual void handleFailure() const {} +}; + +U_NAMESPACE_END + +#endif /* U_SHOW_CPLUSPLUS_API */ + +#endif // __ERRORCODE_H__ |