+/*
+*******************************************************************************
+*
+* Copyright (C) 2009-2010, International Business Machines
+* Corporation and others. All Rights Reserved.
+*
+*******************************************************************************
+* file name: errorcode.h
+* encoding: US-ASCII
+* 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"
+#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() {
+ * // 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 // __ERRORCODE_H__
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