/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrResourceCache_DEFINED
#define GrResourceCache_DEFINED
#include "GrConfig.h"
#include "GrTypes.h"
#include "GrTHashCache.h"
#include "GrBinHashKey.h"
#include "SkTInternalLList.h"
class GrResource;
class GrResourceEntry;
class GrResourceKey {
public:
enum {
kHashBits = 7,
kHashCount = 1 << kHashBits,
kHashMask = kHashCount - 1
};
static GrCacheID::Domain ScratchDomain() {
static const GrCacheID::Domain gDomain = GrCacheID::GenerateDomain();
return gDomain;
}
/** Uniquely identifies the GrResource subclass in the key to avoid collisions
across resource types. */
typedef uint8_t ResourceType;
/** Flags set by the GrResource subclass. */
typedef uint8_t ResourceFlags;
/** Generate a unique ResourceType */
static ResourceType GenerateResourceType();
/** Creates a key for resource */
GrResourceKey(const GrCacheID& id, ResourceType type, ResourceFlags flags) {
this->init(id.getDomain(), id.getKey(), type, flags);
};
GrResourceKey(const GrResourceKey& src) {
fKey = src.fKey;
}
GrResourceKey() {
fKey.fHashedKey.reset();
}
void reset(const GrCacheID& id, ResourceType type, ResourceFlags flags) {
this->init(id.getDomain(), id.getKey(), type, flags);
}
//!< returns hash value [0..kHashMask] for the key
int getHash() const {
return fKey.fHashedKey.getHash() & kHashMask;
}
bool isScratch() const {
return ScratchDomain() ==
*reinterpret_cast<const GrCacheID::Domain*>(fKey.fHashedKey.getData() +
kCacheIDDomainOffset);
}
ResourceType getResourceType() const {
return *reinterpret_cast<const ResourceType*>(fKey.fHashedKey.getData() +
kResourceTypeOffset);
}
ResourceFlags getResourceFlags() const {
return *reinterpret_cast<const ResourceFlags*>(fKey.fHashedKey.getData() +
kResourceFlagsOffset);
}
int compare(const GrResourceKey& other) const {
return fKey.fHashedKey.compare(other.fKey.fHashedKey);
}
static bool LT(const GrResourceKey& a, const GrResourceKey& b) {
return a.compare(b) < 0;
}
static bool EQ(const GrResourceKey& a, const GrResourceKey& b) {
return 0 == a.compare(b);
}
inline static bool LT(const GrResourceEntry& entry, const GrResourceKey& key);
inline static bool EQ(const GrResourceEntry& entry, const GrResourceKey& key);
inline static bool LT(const GrResourceEntry& a, const GrResourceEntry& b);
inline static bool EQ(const GrResourceEntry& a, const GrResourceEntry& b);
private:
enum {
kCacheIDKeyOffset = 0,
kCacheIDDomainOffset = kCacheIDKeyOffset + sizeof(GrCacheID::Key),
kResourceTypeOffset = kCacheIDDomainOffset + sizeof(GrCacheID::Domain),
kResourceFlagsOffset = kResourceTypeOffset + sizeof(ResourceType),
kPadOffset = kResourceFlagsOffset + sizeof(ResourceFlags),
kKeySize = SkAlign4(kPadOffset),
kPadSize = kKeySize - kPadOffset
};
void init(const GrCacheID::Domain domain,
const GrCacheID::Key& key,
ResourceType type,
ResourceFlags flags) {
union {
uint8_t fKey8[kKeySize];
uint32_t fKey32[kKeySize / 4];
} keyData;
uint8_t* k = keyData.fKey8;
memcpy(k + kCacheIDKeyOffset, key.fData8, sizeof(GrCacheID::Key));
memcpy(k + kCacheIDDomainOffset, &domain, sizeof(GrCacheID::Domain));
memcpy(k + kResourceTypeOffset, &type, sizeof(ResourceType));
memcpy(k + kResourceFlagsOffset, &flags, sizeof(ResourceFlags));
memset(k + kPadOffset, 0, kPadSize);
fKey.fHashedKey.setKeyData(keyData.fKey32);
}
struct Key;
typedef GrTBinHashKey<Key, kKeySize> HashedKey;
struct Key {
int compare(const HashedKey& hashedKey) const {
return fHashedKey.compare(fHashedKey);
}
HashedKey fHashedKey;
};
Key fKey;
};
///////////////////////////////////////////////////////////////////////////////
class GrResourceEntry {
public:
GrResource* resource() const { return fResource; }
const GrResourceKey& key() const { return fKey; }
#if GR_DEBUG
void validate() const;
#else
void validate() const {}
#endif
private:
GrResourceEntry(const GrResourceKey& key, GrResource* resource);
~GrResourceEntry();
GrResourceKey fKey;
GrResource* fResource;
// we're a linked list
SK_DECLARE_INTERNAL_LLIST_INTERFACE(GrResourceEntry);
friend class GrResourceCache;
friend class GrDLinkedList;
};
bool GrResourceKey::LT(const GrResourceEntry& entry, const GrResourceKey& key) {
return LT(entry.key(), key);
}
bool GrResourceKey::EQ(const GrResourceEntry& entry, const GrResourceKey& key) {
return EQ(entry.key(), key);
}
bool GrResourceKey::LT(const GrResourceEntry& a, const GrResourceEntry& b) {
return LT(a.key(), b.key());
}
bool GrResourceKey::EQ(const GrResourceEntry& a, const GrResourceEntry& b) {
return EQ(a.key(), b.key());
}
///////////////////////////////////////////////////////////////////////////////
#include "GrTHashCache.h"
/**
* Cache of GrResource objects.
*
* These have a corresponding GrResourceKey, built from 128bits identifying the
* resource.
*
* The cache stores the entries in a double-linked list, which is its LRU.
* When an entry is "locked" (i.e. given to the caller), it is moved to the
* head of the list. If/when we must purge some of the entries, we walk the
* list backwards from the tail, since those are the least recently used.
*
* For fast searches, we maintain a sorted array (based on the GrResourceKey)
* which we can bsearch. When a new entry is added, it is inserted into this
* array.
*
* For even faster searches, a hash is computed from the Key. If there is
* a collision between two keys with the same hash, we fall back on the
* bsearch, and update the hash to reflect the most recent Key requested.
*/
class GrResourceCache {
public:
GrResourceCache(int maxCount, size_t maxBytes);
~GrResourceCache();
/**
* Return the current resource cache limits.
*
* @param maxResource If non-null, returns maximum number of resources
* that can be held in the cache.
* @param maxBytes If non-null, returns maximum number of bytes of
* gpu memory that can be held in the cache.
*/
void getLimits(int* maxResources, size_t* maxBytes) const;
/**
* Specify the resource cache limits. If the current cache exceeds either
* of these, it will be purged (LRU) to keep the cache within these limits.
*
* @param maxResources The maximum number of resources that can be held in
* the cache.
* @param maxBytes The maximum number of bytes of resource memory that
* can be held in the cache.
*/
void setLimits(int maxResource, size_t maxResourceBytes);
/**
* Returns the number of bytes consumed by cached resources.
*/
size_t getCachedResourceBytes() const { return fEntryBytes; }
// For a found or added resource to be completely exclusive to the caller
// both the kNoOtherOwners and kHide flags need to be specified
enum OwnershipFlags {
kNoOtherOwners_OwnershipFlag = 0x1, // found/added resource has no other owners
kHide_OwnershipFlag = 0x2 // found/added resource is hidden from future 'find's
};
/**
* Search for an entry with the same Key. If found, return it.
* If not found, return null.
* If ownershipFlags includes kNoOtherOwners and a resource is returned
* then that resource has no other refs to it.
* If ownershipFlags includes kHide and a resource is returned then that
* resource will not be returned from future 'find' calls until it is
* 'freed' (and recycled) or makeNonExclusive is called.
* For a resource to be completely exclusive to a caller both kNoOtherOwners
* and kHide must be specified.
*/
GrResource* find(const GrResourceKey& key,
uint32_t ownershipFlags = 0);
/**
* Add the new resource to the cache (by creating a new cache entry based
* on the provided key and resource).
*
* Ownership of the resource is transferred to the resource cache,
* which will unref() it when it is purged or deleted.
*
* If ownershipFlags includes kHide, subsequent calls to 'find' will not
* return 'resource' until it is 'freed' (and recycled) or makeNonExclusive
* is called.
*/
void addResource(const GrResourceKey& key,
GrResource* resource,
uint32_t ownershipFlags = 0);
/**
* Determines if the cache contains an entry matching a key. If a matching
* entry exists but was detached then it will not be found.
*/
bool hasKey(const GrResourceKey& key) const;
/**
* Hide 'entry' so that future searches will not find it. Such
* hidden entries will not be purged. The entry still counts against
* the cache's budget and should be made non-exclusive when exclusive access
* is no longer needed.
*/
void makeExclusive(GrResourceEntry* entry);
/**
* Restore 'entry' so that it can be found by future searches. 'entry'
* will also be purgeable (provided its lock count is now 0.)
*/
void makeNonExclusive(GrResourceEntry* entry);
/**
* Removes every resource in the cache that isn't locked.
*/
void purgeAllUnlocked();
/**
* Allow cache to purge unused resources to obey resource limitations
* Note: this entry point will be hidden (again) once totally ref-driven
* cache maintenance is implemented
*/
void purgeAsNeeded();
#if GR_DEBUG
void validate() const;
#else
void validate() const {}
#endif
#if GR_CACHE_STATS
void printStats();
#endif
private:
enum BudgetBehaviors {
kAccountFor_BudgetBehavior,
kIgnore_BudgetBehavior
};
void internalDetach(GrResourceEntry*, BudgetBehaviors behavior = kAccountFor_BudgetBehavior);
void attachToHead(GrResourceEntry*, BudgetBehaviors behavior = kAccountFor_BudgetBehavior);
void removeInvalidResource(GrResourceEntry* entry);
GrTHashTable<GrResourceEntry, GrResourceKey, 8> fCache;
// We're an internal doubly linked list
typedef SkTInternalLList<GrResourceEntry> EntryList;
EntryList fList;
#if GR_DEBUG
// These objects cannot be returned by a search
EntryList fExclusiveList;
#endif
// our budget, used in purgeAsNeeded()
int fMaxCount;
size_t fMaxBytes;
// our current stats, related to our budget
#if GR_CACHE_STATS
int fHighWaterEntryCount;
size_t fHighWaterEntryBytes;
int fHighWaterClientDetachedCount;
size_t fHighWaterClientDetachedBytes;
#endif
int fEntryCount;
size_t fEntryBytes;
int fClientDetachedCount;
size_t fClientDetachedBytes;
// prevents recursive purging
bool fPurging;
#if GR_DEBUG
static size_t countBytes(const SkTInternalLList<GrResourceEntry>& list);
#endif
};
///////////////////////////////////////////////////////////////////////////////
#if GR_DEBUG
class GrAutoResourceCacheValidate {
public:
GrAutoResourceCacheValidate(GrResourceCache* cache) : fCache(cache) {
cache->validate();
}
~GrAutoResourceCacheValidate() {
fCache->validate();
}
private:
GrResourceCache* fCache;
};
#else
class GrAutoResourceCacheValidate {
public:
GrAutoResourceCacheValidate(GrResourceCache*) {}
};
#endif
#endif