Update ICU to 54.1 step 1

source/common/unifiedcache.h

+/*
+******************************************************************************
+* Copyright (C) 2014, International Business Machines Corporation and
+* others. All Rights Reserved.
+******************************************************************************
+*
+* File UNIFIEDCACHE.H - The ICU Unified cache.
+******************************************************************************
+*/
+
+#ifndef __UNIFIED_CACHE_H__
+#define __UNIFIED_CACHE_H__
+
+#include "utypeinfo.h"  // for 'typeid' to work
+
+#include "unicode/uobject.h"
+#include "unicode/locid.h"
+#include "sharedobject.h"
+#include "unicode/unistr.h"
+#include "cstring.h"
+#include "ustr_imp.h"
+
+struct UHashtable;
+struct UHashElement;
+
+U_NAMESPACE_BEGIN
+
+class UnifiedCache;
+
+/**
+ * A base class for all cache keys
+ */
+class U_COMMON_API CacheKeyBase : public UObject {
+ public:
+   CacheKeyBase() : creationStatus(U_ZERO_ERROR) {}
+
+   /**
+    * Copy constructor. Needed to support cloning.
+    */
+   CacheKeyBase(const CacheKeyBase &other) 
+           : UObject(other), creationStatus(other.creationStatus) { }
+   virtual ~CacheKeyBase();
+
+   /**
+    * Returns the hash code for this object.
+    */
+   virtual int32_t hashCode() const = 0;
+
+   /**
+    * Clones this object polymorphically. Caller owns returned value.
+    */
+   virtual CacheKeyBase *clone() const = 0;
+
+   /**
+    * Equality operator.
+    */
+   virtual UBool operator == (const CacheKeyBase &other) const = 0;
+
+   /**
+    * Create a new object for this key. Called by cache on cache miss.
+    * createObject must add a reference to the object it returns. Note
+    * that getting an object from the cache and returning it without calling
+    * removeRef on it satisfies this requirement. It can also return NULL
+    * and set status to an error.
+    *
+    * @param creationContext the context in which the object is being
+    *                        created. May be NULL.
+    * @param status          Implementations can return a failure here.
+    *                        In addition, implementations may return a
+    *                        non NULL object and set a warning status.
+    */
+   virtual const SharedObject *createObject(
+           const void *creationContext, UErrorCode &status) const = 0;
+
+   /**
+    * Writes a description of this key to buffer and returns buffer. Written
+    * description is NULL terminated.
+    */
+   virtual char *writeDescription(char *buffer, int32_t bufSize) const = 0;
+
+   /**
+    * Inequality operator.
+    */
+   UBool operator != (const CacheKeyBase &other) const {
+       return !(*this == other);
+   }
+ private:
+   mutable UErrorCode creationStatus;
+   friend class UnifiedCache;
+};
+
+
+
+/**
+ * Templated version of CacheKeyBase. 
+ * A key of type LocaleCacheKey<T> maps to a value of type T.
+ */
+template<typename T>
+class CacheKey : public CacheKeyBase {
+ public:
+   virtual ~CacheKey() { }
+   /**
+    * The template parameter, T, determines the hash code returned.
+    */
+   virtual int32_t hashCode() const {
+       const char *s = typeid(T).name();
+       return ustr_hashCharsN(s, uprv_strlen(s));
+   }
+
+   /**
+    * Use the value type, T,  as the description.
+    */
+   virtual char *writeDescription(char *buffer, int32_t bufLen) const {
+       const char *s = typeid(T).name();
+       uprv_strncpy(buffer, s, bufLen);
+       buffer[bufLen - 1] = 0;
+       return buffer;
+   }
+
+   /**
+    * Two objects are equal if they are of the same type.
+    */
+   virtual UBool operator == (const CacheKeyBase &other) const {
+       return typeid(*this) == typeid(other);
+   }
+};
+
+/**
+ * Cache key based on locale.
+ * A key of type LocaleCacheKey<T> maps to a value of type T.
+ */
+template<typename T>
+class LocaleCacheKey : public CacheKey<T> {
+ protected:
+   Locale   fLoc;
+ public:
+   LocaleCacheKey(const Locale &loc) : fLoc(loc) {};
+   LocaleCacheKey(const LocaleCacheKey<T> &other)
+           : CacheKey<T>(other), fLoc(other.fLoc) { }
+   virtual ~LocaleCacheKey() { }
+   virtual int32_t hashCode() const {
+       return 37 *CacheKey<T>::hashCode() + fLoc.hashCode();
+   }
+   virtual UBool operator == (const CacheKeyBase &other) const {
+       // reflexive
+       if (this == &other) {
+           return TRUE;
+       }
+       if (!CacheKey<T>::operator == (other)) {
+           return FALSE;
+       }
+       // We know this and other are of same class because operator== on
+       // CacheKey returned true.
+       const LocaleCacheKey<T> *fOther =
+               static_cast<const LocaleCacheKey<T> *>(&other);
+       return fLoc == fOther->fLoc;
+   }
+   virtual CacheKeyBase *clone() const {
+       return new LocaleCacheKey<T>(*this);
+   }
+   virtual const T *createObject(
+           const void *creationContext, UErrorCode &status) const;
+   /**
+    * Use the locale id as the description.
+    */
+   virtual char *writeDescription(char *buffer, int32_t bufLen) const {
+       const char *s = fLoc.getName();
+       uprv_strncpy(buffer, s, bufLen);
+       buffer[bufLen - 1] = 0;
+       return buffer;
+   }
+
+};
+
+/**
+ * The unified cache. A singleton type.
+ */
+class U_COMMON_API UnifiedCache : public UObject {
+ public:
+   /**
+    * @internal
+    */
+   UnifiedCache(UErrorCode &status);
+
+   /**
+    * Returns the cache instance.
+    */
+   static const UnifiedCache *getInstance(UErrorCode &status);
+
+   /**
+    * Fetches a value from the cache by key. Equivalent to
+    * get(key, NULL, ptr, status);
+    */
+   template<typename T>
+   void get(
+           const CacheKey<T>& key,
+           const T *&ptr,
+           UErrorCode &status) const {
+       get(key, NULL, ptr, status);
+   }
+
+   /**
+    * Fetches value from the cache by key.
+    *
+    * @param key             the cache key.
+    * @param creationContext passed verbatim to createObject method of key
+    * @param ptr             On entry, ptr must be NULL or be included if
+    *                        the reference count of the object it points
+    *                        to. On exit, ptr points to the fetched object
+    *                        from the cache or is left unchanged on
+    *                        failure. Caller must call removeRef on ptr
+    *                        if set to a non NULL value.
+    * @param status          Any error returned here. May be set to a
+    *                        warning value even if ptr is set.
+    */
+   template<typename T>
+   void get(
+           const CacheKey<T>& key,
+           const void *creationContext,
+           const T *&ptr,
+           UErrorCode &status) const {
+       if (U_FAILURE(status)) {
+           return;
+       }
+       UErrorCode creationStatus = U_ZERO_ERROR;
+       const SharedObject *value = NULL;
+       _get(key, value, creationContext, creationStatus);
+       const T *tvalue = (const T *) value;
+       if (U_SUCCESS(creationStatus)) {
+           SharedObject::copyPtr(tvalue, ptr);
+       }
+       SharedObject::clearPtr(tvalue);
+       // Take care not to overwrite a warning status passed in with
+       // another warning or U_ZERO_ERROR.
+       if (status == U_ZERO_ERROR || U_FAILURE(creationStatus)) {
+           status = creationStatus;
+       }
+   }
+
+#ifdef UNIFIED_CACHE_DEBUG
+   /**
+    * Dumps the contents of this cache to standard error. Used for testing of
+    * cache only.
+    */
+   void dumpContents() const;
+#endif
+
+   /**
+    * Convenience method to get a value of type T from cache for a
+    * particular locale with creationContext == NULL.
+    * @param loc    the locale
+    * @param ptr    On entry, must be NULL or included in the ref count
+    *               of the object to which it points.
+    *               On exit, fetched value stored here or is left
+    *               unchanged on failure. Caller must call removeRef on
+    *               ptr if set to a non NULL value.
+    * @param status Any error returned here. May be set to a
+    *               warning value even if ptr is set.
+    */
+   template<typename T>
+   static void getByLocale(
+           const Locale &loc, const T *&ptr, UErrorCode &status) {
+       const UnifiedCache *cache = getInstance(status);
+       if (U_FAILURE(status)) {
+           return;
+       }
+       cache->get(LocaleCacheKey<T>(loc), ptr, status);
+   }
+
+#ifdef UNIFIED_CACHE_DEBUG
+   /**
+    * Dumps the cache contents to stderr. For testing only.
+    */
+   static void dump();
+#endif
+
+   /**
+    * Returns the number of keys in this cache. For testing only.
+    */
+   int32_t keyCount() const;
+
+   /**
+    * Removes any values from cache that are not referenced outside
+    * the cache.
+    */
+   void flush() const;
+
+   virtual ~UnifiedCache();
+ private:
+   UHashtable *fHashtable;
+   UnifiedCache(const UnifiedCache &other);
+   UnifiedCache &operator=(const UnifiedCache &other);
+   UBool _flush(UBool all) const;
+   void _get(
+           const CacheKeyBase &key,
+           const SharedObject *&value,
+           const void *creationContext,
+           UErrorCode &status) const;
+   UBool _poll(
+           const CacheKeyBase &key,
+           const SharedObject *&value,
+           UErrorCode &status) const;
+   void _putNew(
+           const CacheKeyBase &key,
+           const SharedObject *value,
+           const UErrorCode creationStatus,
+           UErrorCode &status) const;
+   void _putIfAbsentAndGet(
+           const CacheKeyBase &key,
+           const SharedObject *&value,
+           UErrorCode &status) const;
+#ifdef UNIFIED_CACHE_DEBUG
+   void _dumpContents() const;
+#endif
+   static void _put(
+           const UHashElement *element,
+           const SharedObject *value,
+           const UErrorCode status);
+   static void _fetch(
+           const UHashElement *element,
+           const SharedObject *&value,
+           UErrorCode &status);
+   static UBool _inProgress(const UHashElement *element);
+};
+
+U_NAMESPACE_END
+
+#endif