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Diffstat (limited to 'deps/node/deps/icu-small/source/common/unifiedcache.h')
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diff --git a/deps/node/deps/icu-small/source/common/unifiedcache.h b/deps/node/deps/icu-small/source/common/unifiedcache.h deleted file mode 100644 index b3ccd60d..00000000 --- a/deps/node/deps/icu-small/source/common/unifiedcache.h +++ /dev/null @@ -1,556 +0,0 @@ -// © 2016 and later: Unicode, Inc. and others. -// License & terms of use: http://www.unicode.org/copyright.html -/* -****************************************************************************** -* Copyright (C) 2015, 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() : fCreationStatus(U_ZERO_ERROR), fIsMaster(FALSE) {} - - /** - * Copy constructor. Needed to support cloning. - */ - CacheKeyBase(const CacheKeyBase &other) - : UObject(other), fCreationStatus(other.fCreationStatus), fIsMaster(FALSE) { } - 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 fCreationStatus; - mutable UBool fIsMaster; - 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, static_cast<int32_t>(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 (int32_t)(37u * (uint32_t)CacheKey<T>::hashCode() + (uint32_t)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. - * Design doc here: - * https://docs.google.com/document/d/1RwGQJs4N4tawNbf809iYDRCvXoMKqDJihxzYt1ysmd8/edit?usp=sharing - */ -class U_COMMON_API UnifiedCache : public UnifiedCacheBase { - public: - /** - * @internal - * Do not call directly. Instead use UnifiedCache::getInstance() as - * there should be only one UnifiedCache in an application. - */ - UnifiedCache(UErrorCode &status); - - /** - * Return a pointer to the global cache instance. - */ - static 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; - - /** - * Configures at what point evcition of unused entries will begin. - * Eviction is triggered whenever the number of evictable keys exeeds - * BOTH count AND (number of in-use items) * (percentageOfInUseItems / 100). - * Once the number of unused entries drops below one of these, - * eviction ceases. Because eviction happens incrementally, - * the actual unused entry count may exceed both these numbers - * from time to time. - * - * A cache entry is defined as unused if it is not essential to guarantee - * that for a given key X, the cache returns the same reference to the - * same value as long as the client already holds a reference to that - * value. - * - * If this method is never called, the default settings are 1000 and 100%. - * - * Although this method is thread-safe, it is designed to be called at - * application startup. If it is called in the middle of execution, it - * will have no immediate effect on the cache. However over time, the - * cache will perform eviction slices in an attempt to honor the new - * settings. - * - * If a client already holds references to many different unique values - * in the cache such that the number of those unique values far exeeds - * "count" then the cache may not be able to maintain this maximum. - * However, if this happens, the cache still guarantees that the number of - * unused entries will remain only a small percentage of the total cache - * size. - * - * If the parameters passed are negative, setEvctionPolicy sets status to - * U_ILLEGAL_ARGUMENT_ERROR. - */ - void setEvictionPolicy( - int32_t count, int32_t percentageOfInUseItems, UErrorCode &status); - - - /** - * Returns how many entries have been auto evicted during the lifetime - * of this cache. This only includes auto evicted entries, not - * entries evicted because of a call to flush(). - */ - int64_t autoEvictedCount() const; - - /** - * Returns the unused entry count in this cache. For testing only, - * Regular clients will not need this. - */ - int32_t unusedCount() const; - - virtual void handleUnreferencedObject() const; - virtual ~UnifiedCache(); - - private: - UHashtable *fHashtable; - mutable int32_t fEvictPos; - mutable int32_t fNumValuesTotal; - mutable int32_t fNumValuesInUse; - int32_t fMaxUnused; - int32_t fMaxPercentageOfInUse; - mutable int64_t fAutoEvictedCount; - SharedObject *fNoValue; - - UnifiedCache(const UnifiedCache &other); - UnifiedCache &operator=(const UnifiedCache &other); - - /** - * Flushes the contents of the cache. If cache values hold references to other - * cache values then _flush should be called in a loop until it returns FALSE. - * - * On entry, gCacheMutex must be held. - * On exit, those values with are evictable are flushed. - * - * @param all if false flush evictable items only, which are those with no external - * references, plus those that can be safely recreated.<br> - * if true, flush all elements. Any values (sharedObjects) with remaining - * hard (external) references are not deleted, but are detached from - * the cache, so that a subsequent removeRefs can delete them. - * _flush is not thread safe when all is true. - * @return TRUE if any value in cache was flushed or FALSE otherwise. - */ - UBool _flush(UBool all) const; - - /** - * Gets value out of cache. - * On entry. gCacheMutex must not be held. value must be NULL. status - * must be U_ZERO_ERROR. - * On exit. value and status set to what is in cache at key or on cache - * miss the key's createObject() is called and value and status are set to - * the result of that. In this latter case, best effort is made to add the - * value and status to the cache. If createObject() fails to create a value, - * fNoValue is stored in cache, and value is set to NULL. Caller must call - * removeRef on value if non NULL. - */ - void _get( - const CacheKeyBase &key, - const SharedObject *&value, - const void *creationContext, - UErrorCode &status) const; - - /** - * Attempts to fetch value and status for key from cache. - * On entry, gCacheMutex must not be held value must be NULL and status must - * be U_ZERO_ERROR. - * On exit, either returns FALSE (In this - * case caller should try to create the object) or returns TRUE with value - * pointing to the fetched value and status set to fetched status. When - * FALSE is returned status may be set to failure if an in progress hash - * entry could not be made but value will remain unchanged. When TRUE is - * returned, caller must call removeRef() on value. - */ - UBool _poll( - const CacheKeyBase &key, - const SharedObject *&value, - UErrorCode &status) const; - - /** - * Places a new value and creationStatus in the cache for the given key. - * On entry, gCacheMutex must be held. key must not exist in the cache. - * On exit, value and creation status placed under key. Soft reference added - * to value on successful add. On error sets status. - */ - void _putNew( - const CacheKeyBase &key, - const SharedObject *value, - const UErrorCode creationStatus, - UErrorCode &status) const; - - /** - * Places value and status at key if there is no value at key or if cache - * entry for key is in progress. Otherwise, it leaves the current value and - * status there. - * - * On entry. gCacheMutex must not be held. Value must be - * included in the reference count of the object to which it points. - * - * On exit, value and status are changed to what was already in the cache if - * something was there and not in progress. Otherwise, value and status are left - * unchanged in which case they are placed in the cache on a best-effort basis. - * Caller must call removeRef() on value. - */ - void _putIfAbsentAndGet( - const CacheKeyBase &key, - const SharedObject *&value, - UErrorCode &status) const; - - /** - * Returns the next element in the cache round robin style. - * Returns nullptr if the cache is empty. - * On entry, gCacheMutex must be held. - */ - const UHashElement *_nextElement() const; - - /** - * Return the number of cache items that would need to be evicted - * to bring usage into conformance with eviction policy. - * - * An item corresponds to an entry in the hash table, a hash table element. - * - * On entry, gCacheMutex must be held. - */ - int32_t _computeCountOfItemsToEvict() const; - - /** - * Run an eviction slice. - * On entry, gCacheMutex must be held. - * _runEvictionSlice runs a slice of the evict pipeline by examining the next - * 10 entries in the cache round robin style evicting them if they are eligible. - */ - void _runEvictionSlice() const; - - /** - * Register a master cache entry. A master key is the first key to create - * a given SharedObject value. Subsequent keys whose create function - * produce referneces to an already existing SharedObject are not masters - - * they can be evicted and subsequently recreated. - * - * On entry, gCacheMutex must be held. - * On exit, items in use count incremented, entry is marked as a master - * entry, and value registered with cache so that subsequent calls to - * addRef() and removeRef() on it correctly interact with the cache. - */ - void _registerMaster(const CacheKeyBase *theKey, const SharedObject *value) const; - - /** - * Store a value and creation error status in given hash entry. - * On entry, gCacheMutex must be held. Hash entry element must be in progress. - * value must be non NULL. - * On Exit, soft reference added to value. value and status stored in hash - * entry. Soft reference removed from previous stored value. Waiting - * threads notified. - */ - void _put( - const UHashElement *element, - const SharedObject *value, - const UErrorCode status) const; - /** - * Remove a soft reference, and delete the SharedObject if no references remain. - * To be used from within the UnifiedCache implementation only. - * gCacheMutex must be held by caller. - * @param value the SharedObject to be acted on. - */ - void removeSoftRef(const SharedObject *value) const; - - /** - * Increment the hard reference count of the given SharedObject. - * gCacheMutex must be held by the caller. - * Update numValuesEvictable on transitions between zero and one reference. - * - * @param value The SharedObject to be referenced. - * @return the hard reference count after the addition. - */ - int32_t addHardRef(const SharedObject *value) const; - - /** - * Decrement the hard reference count of the given SharedObject. - * gCacheMutex must be held by the caller. - * Update numValuesEvictable on transitions between one and zero reference. - * - * @param value The SharedObject to be referenced. - * @return the hard reference count after the removal. - */ - int32_t removeHardRef(const SharedObject *value) const; - - -#ifdef UNIFIED_CACHE_DEBUG - void _dumpContents() const; -#endif - - /** - * Fetch value and error code from a particular hash entry. - * On entry, gCacheMutex must be held. value must be either NULL or must be - * included in the ref count of the object to which it points. - * On exit, value and status set to what is in the hash entry. Caller must - * eventually call removeRef on value. - * If hash entry is in progress, value will be set to gNoValue and status will - * be set to U_ZERO_ERROR. - */ - void _fetch(const UHashElement *element, const SharedObject *&value, - UErrorCode &status) const; - - /** - * Determine if given hash entry is in progress. - * On entry, gCacheMutex must be held. - */ - UBool _inProgress(const UHashElement *element) const; - - /** - * Determine if given hash entry is in progress. - * On entry, gCacheMutex must be held. - */ - UBool _inProgress(const SharedObject *theValue, UErrorCode creationStatus) const; - - /** - * Determine if given hash entry is eligible for eviction. - * On entry, gCacheMutex must be held. - */ - UBool _isEvictable(const UHashElement *element) const; -}; - -U_NAMESPACE_END - -#endif |