* On Android, use pthread_setspecific to automatically detach native …

…threads on exit
bytedeco · Jul 11, 2018 · 198d2d6 · 198d2d6
1 parent b53117a
commit 198d2d6
Showing 1 changed file with 36 additions and 3 deletions.
diff --git a/src/main/java/org/bytedeco/javacpp/tools/Generator.java b/src/main/java/org/bytedeco/javacpp/tools/Generator.java
@@ -280,6 +280,7 @@ boolean classes(boolean handleExceptions, boolean defineAdapters, boolean conver
         out.println();
         out.println("#ifdef __ANDROID__");
         out.println("    #include <android/log.h>");
+        out.println("    #include <pthread.h>");
         out.println("#elif defined(__APPLE__) && defined(__OBJC__)");
         out.println("    #include <TargetConditionals.h>");
         out.println("    #include <Foundation/Foundation.h>");
@@ -466,6 +467,20 @@ boolean classes(boolean handleExceptions, boolean defineAdapters, boolean conver
         out.println("    va_end(ap);");
         out.println("}");
         out.println();
+        out.println("#ifdef __ANDROID__");
+        out.println("    static pthread_key_t current_env;");
+        out.println("    static JavaCPP_noinline void JavaCPP_detach_env(void *data)");
+        out.println("    {");
+        out.println("        if (JavaCPP_vm) {");
+        out.println("            JavaCPP_vm->DetachCurrentThread();");
+        out.println("        }");
+        out.println("    }");
+        out.println("    static JavaCPP_noinline void JavaCPP_create_pthread_key(void)");
+        out.println("    {");
+        out.println("        pthread_key_create(&current_env, JavaCPP_detach_env);");
+        out.println("    }");
+        out.println("#endif");
+        out.println();
         if (baseLoadSuffix == null || baseLoadSuffix.isEmpty()) {
             out.println("static inline jboolean JavaCPP_trimMemory() {");
             out.println("#if defined(__linux__) && !defined(__ANDROID__)");
@@ -1156,8 +1171,11 @@ boolean classes(boolean handleExceptions, boolean defineAdapters, boolean conver
             out.println();
         }
         if (!functions.isEmpty() || !virtualFunctions.isEmpty()) {
+            out.println("static pthread_once_t once = PTHREAD_ONCE_INIT;");
+            out.println("static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;");
+            out.println();
             out.println("static JavaCPP_noinline void JavaCPP_detach(bool detach) {");
-            out.println("#ifndef NO_JNI_DETACH_THREAD");
+            out.println("#if !defined(NO_JNI_DETACH_THREAD) && !defined(__ANDROID__)");
             out.println("    if (detach && JavaCPP_vm->DetachCurrentThread() != JNI_OK) {");
             out.println("        JavaCPP_log(\"Could not detach the JavaVM from the current thread.\");");
             out.println("    }");
@@ -1188,6 +1206,14 @@ boolean classes(boolean handleExceptions, boolean defineAdapters, boolean conver
                 out.println("#endif");
             }
             out.println("    }");
+            out.println("#ifdef __ANDROID__");
+            out.println("    pthread_mutex_lock(&lock);");
+            out.println("    pthread_once(&once, JavaCPP_create_pthread_key);");
+            out.println("    if ((*env = (JNIEnv *)pthread_getspecific(current_env)) != NULL) {");
+            out.println("        attached = true;");
+            out.println("        goto done;");
+            out.println("    }");
+            out.println("#endif");
             out.println("    if (vm->GetEnv((void**)env, " + JNI_VERSION + ") != JNI_OK) {");
             out.println("        struct {");
             out.println("            JNIEnv **env;");
@@ -1197,17 +1223,24 @@ boolean classes(boolean handleExceptions, boolean defineAdapters, boolean conver
             out.println("        if (vm->AttachCurrentThread(env2, NULL) != JNI_OK) {");
             out.println("            JavaCPP_log(\"Could not attach the JavaVM to the current thread.\");");
             out.println("            *env = NULL;");
-            out.println("            return false;");
+            out.println("            goto done;");
             out.println("        }");
+            out.println("#ifdef __ANDROID__");
+            out.println("        pthread_setspecific(current_env, *env);");
+            out.println("#endif");
             out.println("        attached = true;");
             out.println("    }");
             out.println("    if (JavaCPP_vm == NULL) {");
             out.println("        if (JNI_OnLoad" + loadSuffix + "(vm, NULL) < 0) {");
             out.println("            JavaCPP_detach(attached);");
             out.println("            *env = NULL;");
-            out.println("            return false;");
+            out.println("            goto done;");
             out.println("        }");
             out.println("    }");
+            out.println("done:");
+            out.println("#ifdef __ANDROID__");
+            out.println("    pthread_mutex_unlock(&lock);");
+            out.println("#endif");
             out.println("    return attached;");
             out.println("}");
             out.println();