1// Copyright 2013 The Flutter Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include <fstream>
6#include <iterator>
7
8#include "flutter/fml/build_config.h"
9#include "flutter/fml/logging.h"
10#include "flutter/fml/paths.h"
11#include "flutter/lib/ui/plugins/callback_cache.h"
12#include "rapidjson/document.h"
13#include "rapidjson/stringbuffer.h"
14#include "rapidjson/writer.h"
15#include "third_party/tonic/converter/dart_converter.h"
16
17using rapidjson::Document;
18using rapidjson::StringBuffer;
19using rapidjson::Writer;
20using tonic::ToDart;
21
22namespace flutter {
23
24static const char* kHandleKey = "handle";
25static const char* kRepresentationKey = "representation";
26static const char* kNameKey = "name";
27static const char* kClassNameKey = "class_name";
28static const char* kLibraryPathKey = "library_path";
29static const char* kCacheName = "flutter_callback_cache.json";
30std::mutex DartCallbackCache::mutex_;
31std::string DartCallbackCache::cache_path_;
32std::map<int64_t, DartCallbackRepresentation> DartCallbackCache::cache_;
33
34void DartCallbackCache::SetCachePath(const std::string& path) {
35 cache_path_ = fml::paths::JoinPaths({path, kCacheName});
36}
37
38Dart_Handle DartCallbackCache::GetCallback(int64_t handle) {
39 std::scoped_lock lock(mutex_);
40 auto iterator = cache_.find(handle);
41 if (iterator != cache_.end()) {
42 DartCallbackRepresentation cb = iterator->second;
43 return LookupDartClosure(cb.name, cb.class_name, cb.library_path);
44 }
45 return Dart_Null();
46}
47
48int64_t DartCallbackCache::GetCallbackHandle(const std::string& name,
49 const std::string& class_name,
50 const std::string& library_path) {
51 std::scoped_lock lock(mutex_);
52 std::hash<std::string> hasher;
53 int64_t hash = hasher(name);
54 hash += hasher(class_name);
55 hash += hasher(library_path);
56
57 if (cache_.find(hash) == cache_.end()) {
58 cache_[hash] = {name, class_name, library_path};
59 SaveCacheToDisk();
60 }
61 return hash;
62}
63
64std::unique_ptr<DartCallbackRepresentation>
65DartCallbackCache::GetCallbackInformation(int64_t handle) {
66 std::scoped_lock lock(mutex_);
67 auto iterator = cache_.find(handle);
68 if (iterator != cache_.end()) {
69 return std::make_unique<DartCallbackRepresentation>(iterator->second);
70 }
71 return nullptr;
72}
73
74void DartCallbackCache::SaveCacheToDisk() {
75 // Cache JSON format
76 // [
77 // {
78 // "hash": 42,
79 // "representation": {
80 // "name": "...",
81 // "class_name": "...",
82 // "library_path": "..."
83 // }
84 // },
85 // {
86 // ...
87 // }
88 // ]
89 StringBuffer s;
90 Writer<StringBuffer> writer(s);
91 writer.StartArray();
92 for (auto iterator = cache_.begin(); iterator != cache_.end(); ++iterator) {
93 int64_t hash = iterator->first;
94 DartCallbackRepresentation cb = iterator->second;
95 writer.StartObject();
96 writer.Key(kHandleKey);
97 writer.Int64(hash);
98 writer.Key(kRepresentationKey);
99 writer.StartObject();
100 writer.Key(kNameKey);
101 writer.String(cb.name.c_str());
102 writer.Key(kClassNameKey);
103 writer.String(cb.class_name.c_str());
104 writer.Key(kLibraryPathKey);
105 writer.String(cb.library_path.c_str());
106 writer.EndObject();
107 writer.EndObject();
108 }
109 writer.EndArray();
110
111 std::ofstream output(cache_path_);
112 output << s.GetString();
113 output.close();
114}
115
116void DartCallbackCache::LoadCacheFromDisk() {
117 std::scoped_lock lock(mutex_);
118
119 // Don't reload the cache if it's already populated.
120 if (!cache_.empty()) {
121 return;
122 }
123 std::ifstream input(cache_path_);
124 if (!input) {
125 return;
126 }
127 std::string cache_contents{std::istreambuf_iterator<char>(input),
128 std::istreambuf_iterator<char>()};
129 Document d;
130 d.Parse(cache_contents.c_str());
131 if (d.HasParseError() || !d.IsArray()) {
132 FML_LOG(WARNING) << "Could not parse callback cache, aborting restore";
133 // TODO(bkonyi): log and bail (delete cache?)
134 return;
135 }
136 const auto entries = d.GetArray();
137 for (auto* it = entries.begin(); it != entries.end(); ++it) {
138 const auto root_obj = it->GetObject();
139 const auto representation = root_obj[kRepresentationKey].GetObject();
140
141 const int64_t hash = root_obj[kHandleKey].GetInt64();
142 DartCallbackRepresentation cb;
143 cb.name = representation[kNameKey].GetString();
144 cb.class_name = representation[kClassNameKey].GetString();
145 cb.library_path = representation[kLibraryPathKey].GetString();
146 cache_[hash] = cb;
147 }
148}
149
150Dart_Handle DartCallbackCache::LookupDartClosure(
151 const std::string& name,
152 const std::string& class_name,
153 const std::string& library_path) {
154 Dart_Handle closure_name = ToDart(name);
155 if (Dart_IsError(closure_name)) {
156 return closure_name;
157 }
158 Dart_Handle library_name =
159 library_path.empty() ? Dart_Null() : ToDart(library_path);
160 if (Dart_IsError(library_name)) {
161 return library_name;
162 }
163 Dart_Handle cls_name = class_name.empty() ? Dart_Null() : ToDart(class_name);
164 if (Dart_IsError(cls_name)) {
165 return cls_name;
166 }
167
168 Dart_Handle library;
169 if (library_name == Dart_Null()) {
170 library = Dart_RootLibrary();
171 } else {
172 library = Dart_LookupLibrary(library_name);
173 }
174 if (Dart_IsError(library)) {
175 return library;
176 }
177
178 Dart_Handle closure;
179 if (Dart_IsNull(cls_name)) {
180 closure = Dart_GetField(library, closure_name);
181 } else {
182 Dart_Handle cls = Dart_GetClass(library, cls_name);
183 if (Dart_IsError(cls)) {
184 return cls;
185 }
186 if (Dart_IsNull(cls)) {
187 closure = Dart_Null();
188 } else {
189 closure = Dart_GetStaticMethodClosure(library, cls, closure_name);
190 }
191 }
192 return closure;
193}
194
195} // namespace flutter
196