1 // Copyright © 2021-present 650 Industries, Inc. (aka Expo)
2 
3 #include "JavaReferencesCache.h"
4 
5 namespace expo {
6 std::shared_ptr<JavaReferencesCache> JavaReferencesCache::instance() {
7   static std::shared_ptr<JavaReferencesCache> singleton{new JavaReferencesCache};
8   return singleton;
9 }
10 
11 void JavaReferencesCache::loadJClasses(JNIEnv *env) {
12   loadJClass(env, "java/lang/Double", {
13     {"<init>", "(D)V"}
14   });
15 
16   loadJClass(env, "java/lang/Boolean", {
17     {"<init>", "(Z)V"}
18   });
19 
20   loadJClass(env, "java/lang/Integer", {
21     {"<init>", "(I)V"}
22   });
23 
24   loadJClass(env, "java/lang/Float", {
25     {"<init>", "(F)V"}
26   });
27 
28   loadJClass(env, "com/facebook/react/bridge/PromiseImpl", {
29     {"<init>", "(Lcom/facebook/react/bridge/Callback;Lcom/facebook/react/bridge/Callback;)V"}
30   });
31 
32   loadJClass(env, "expo/modules/kotlin/jni/PromiseImpl", {
33     {"<init>", "(Lexpo/modules/kotlin/jni/JavaCallback;Lexpo/modules/kotlin/jni/JavaCallback;)V"}
34   });
35 
36   loadJClass(env, "java/lang/Object", {});
37   loadJClass(env, "java/lang/String", {});
38   loadJClass(env, "expo/modules/kotlin/jni/JavaScriptObject", {});
39   loadJClass(env, "expo/modules/kotlin/jni/JavaScriptValue", {});
40   loadJClass(env, "expo/modules/kotlin/jni/JavaScriptTypedArray", {});
41   loadJClass(env, "com/facebook/react/bridge/ReadableNativeArray", {});
42   loadJClass(env, "com/facebook/react/bridge/ReadableNativeMap", {});
43   loadJClass(env, "com/facebook/react/bridge/WritableNativeArray", {});
44   loadJClass(env, "com/facebook/react/bridge/WritableNativeMap", {});
45 }
46 
47 void JavaReferencesCache::loadJClass(
48   JNIEnv *env,
49   const std::string &name,
50   const std::vector<std::pair<std::string, std::string>> &methodsNames
51 ) {
52   // Note this clazz variable points to a leaked global reference.
53   // This is appropriate for classes that are never unloaded which is any class in an Android app.
54   auto clazz = (jclass) env->NewGlobalRef(env->FindClass(name.c_str()));
55 
56   MethodHashMap methods;
57   methods.reserve(methodsNames.size());
58 
59   for (auto &method: methodsNames) {
60     methods.insert(
61       {method, env->GetMethodID(clazz, method.first.c_str(), method.second.c_str())}
62     );
63   }
64 
65   jClassRegistry.insert(
66     {name, CachedJClass(clazz, std::move(methods))}
67   );
68 }
69 
70 JavaReferencesCache::CachedJClass &JavaReferencesCache::getJClass(
71   const std::string &className
72 ) {
73   return jClassRegistry.at(className);
74 }
75 
76 JavaReferencesCache::CachedJClass &JavaReferencesCache::getOrLoadJClass(
77   JNIEnv *env,
78   const std::string &className
79 ) {
80   auto result = jClassRegistry.find(className);
81   if (result == jClassRegistry.end()) {
82     loadJClass(env, className, {});
83     return jClassRegistry.at(className);
84   }
85 
86   return result->second;
87 }
88 
89 jmethodID JavaReferencesCache::CachedJClass::getMethod(
90   const std::string &name,
91   const std::string &signature
92 ) {
93   return methods.at({name, signature});
94 }
95 
96 JavaReferencesCache::CachedJClass::CachedJClass(
97   jclass clazz,
98   MethodHashMap methods
99 ) : clazz(clazz), methods(std::move(methods)) {}
100 } // namespace expo
101