1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SkUrlDataManager_DEFINED
9 #define SkUrlDataManager_DEFINED
10 
11 #include "SkChecksum.h"
12 #include "SkData.h"
13 #include "SkString.h"
14 #include "SkTDynamicHash.h"
15 
16 /*
17  * A simple class which allows clients to add opaque data types, and returns a url where this data
18  * will be hosted.  Its up to the owner of this class to actually serve the data.
19  */
20 bool operator==(const SkData& a, const SkData& b);
21 
22 class UrlDataManager {
23 public:
24     UrlDataManager(SkString rootUrl);
~UrlDataManager()25     ~UrlDataManager() { this->reset(); }
26 
27     /*
28      * Adds a data blob to the cache with a particular content type.  UrlDataManager will hash
29      * the blob data to ensure uniqueness
30      */
31     SkString addData(SkData*, const char* contentType);
32 
33     struct UrlData : public SkRefCnt {
34         SkString fUrl;
35         SkString fContentType;
36         SkAutoTUnref<SkData> fData;
37     };
38 
39     /*
40      * returns the UrlData object which should be hosted at 'url'
41      */
getDataFromUrl(SkString url)42     UrlData* getDataFromUrl(SkString url) {
43         return fUrlLookup.find(url);
44     }
45     void reset();
46 
47 private:
48     struct LookupTrait {
49         // We use the data as a hash, this is not really optimal but is fine until proven otherwise
GetKeyLookupTrait50         static const SkData& GetKey(const UrlData& data) {
51             return *data.fData.get();
52         }
53 
HashLookupTrait54         static uint32_t Hash(const SkData& key) {
55             return SkChecksum::Murmur3(key.bytes(), key.size());
56         }
57     };
58 
59     struct ReverseLookupTrait {
GetKeyReverseLookupTrait60         static const SkString& GetKey(const UrlData& data) {
61             return data.fUrl;
62         }
63 
HashReverseLookupTrait64         static uint32_t Hash(const SkString& key) {
65             return SkChecksum::Murmur3(key.c_str(), strlen(key.c_str()));
66         }
67     };
68 
69 
70     SkString fRootUrl;
71     SkTDynamicHash<UrlData, SkData, LookupTrait> fCache;
72     SkTDynamicHash<UrlData, SkString, ReverseLookupTrait> fUrlLookup;
73     uint32_t fDataId;
74 };
75 
76 #endif
77