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      1 
      2 /*
      3  * Copyright 2014 Google Inc.
      4  *
      5  * Use of this source code is governed by a BSD-style license that can be
      6  * found in the LICENSE file.
      7  */
      8 
      9 #ifndef GrResourceKey_DEFINED
     10 #define GrResourceKey_DEFINED
     11 
     12 #include "GrTypes.h"
     13 #include "GrBinHashKey.h"
     14 
     15 class GrResourceKey {
     16 public:
     17     static GrCacheID::Domain ScratchDomain() {
     18         static const GrCacheID::Domain gDomain = GrCacheID::GenerateDomain();
     19         return gDomain;
     20     }
     21 
     22     /** Uniquely identifies the GrGpuResource subclass in the key to avoid collisions
     23         across resource types. */
     24     typedef uint8_t ResourceType;
     25 
     26     /** Flags set by the GrGpuResource subclass. */
     27     typedef uint8_t ResourceFlags;
     28 
     29     /** Generate a unique ResourceType */
     30     static ResourceType GenerateResourceType();
     31 
     32     /** Creates a key for resource */
     33     GrResourceKey(const GrCacheID& id, ResourceType type, ResourceFlags flags) {
     34         this->init(id.getDomain(), id.getKey(), type, flags);
     35     };
     36 
     37     GrResourceKey(const GrResourceKey& src) { fKey = src.fKey; }
     38 
     39     GrResourceKey() { fKey.reset(); }
     40 
     41     void reset(const GrCacheID& id, ResourceType type, ResourceFlags flags) {
     42         this->init(id.getDomain(), id.getKey(), type, flags);
     43     }
     44 
     45     uint32_t getHash() const { return fKey.getHash(); }
     46 
     47     bool isScratch() const {
     48         return ScratchDomain() ==
     49             *reinterpret_cast<const GrCacheID::Domain*>(fKey.getData() +
     50                                                         kCacheIDDomainOffset);
     51     }
     52 
     53     ResourceType getResourceType() const {
     54         return *reinterpret_cast<const ResourceType*>(fKey.getData() +
     55                                                       kResourceTypeOffset);
     56     }
     57 
     58     ResourceFlags getResourceFlags() const {
     59         return *reinterpret_cast<const ResourceFlags*>(fKey.getData() +
     60                                                        kResourceFlagsOffset);
     61     }
     62 
     63     bool operator==(const GrResourceKey& other) const { return fKey == other.fKey; }
     64 
     65     // A key indicating that the resource is not usable as a scratch resource.
     66     static GrResourceKey& NullScratchKey() {
     67         static const GrCacheID::Key kBogusKey = { { {0} } };
     68         static GrCacheID kBogusID(ScratchDomain(), kBogusKey);
     69         static GrResourceKey kNullScratchKey(kBogusID, NoneResourceType(), 0);
     70         return kNullScratchKey;
     71     }
     72 
     73     bool isNullScratch() const {
     74         return this->isScratch() && NoneResourceType() == this->getResourceType();
     75     }
     76 
     77 private:
     78     enum {
     79         kCacheIDKeyOffset = 0,
     80         kCacheIDDomainOffset = kCacheIDKeyOffset + sizeof(GrCacheID::Key),
     81         kResourceTypeOffset = kCacheIDDomainOffset + sizeof(GrCacheID::Domain),
     82         kResourceFlagsOffset = kResourceTypeOffset + sizeof(ResourceType),
     83         kPadOffset = kResourceFlagsOffset + sizeof(ResourceFlags),
     84         kKeySize = SkAlign4(kPadOffset),
     85         kPadSize = kKeySize - kPadOffset
     86     };
     87 
     88     static ResourceType NoneResourceType() {
     89         static const ResourceType gNoneResourceType = GenerateResourceType();
     90         return gNoneResourceType;
     91     }
     92 
     93     void init(const GrCacheID::Domain domain,
     94               const GrCacheID::Key& key,
     95               ResourceType type,
     96               ResourceFlags flags) {
     97         union {
     98             uint8_t  fKey8[kKeySize];
     99             uint32_t fKey32[kKeySize / 4];
    100         } keyData;
    101 
    102         uint8_t* k = keyData.fKey8;
    103         memcpy(k + kCacheIDKeyOffset, key.fData8, sizeof(GrCacheID::Key));
    104         memcpy(k + kCacheIDDomainOffset, &domain, sizeof(GrCacheID::Domain));
    105         memcpy(k + kResourceTypeOffset, &type, sizeof(ResourceType));
    106         memcpy(k + kResourceFlagsOffset, &flags, sizeof(ResourceFlags));
    107         memset(k + kPadOffset, 0, kPadSize);
    108         fKey.setKeyData(keyData.fKey32);
    109     }
    110     GrBinHashKey<kKeySize> fKey;
    111 };
    112 
    113 #endif
    114