Add default implementation for CAS AIDL

Bug: 230377377, 227673974
Test: manual
Change-Id: I85015dd6e1a69ff9b57f832f5b1cd01fb65dda25
diff --git a/cas/aidl/default/SharedLibrary.cpp b/cas/aidl/default/SharedLibrary.cpp
new file mode 100755
index 0000000..e79f383
--- /dev/null
+++ b/cas/aidl/default/SharedLibrary.cpp
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "android.hardware.cas-SharedLibrary"
+
+#include "SharedLibrary.h"
+#include <dlfcn.h>
+#include <utils/Log.h>
+
+namespace aidl {
+namespace android {
+namespace hardware {
+namespace cas {
+
+SharedLibrary::SharedLibrary(const String8& path) {
+    mLibHandle = dlopen(path.string(), RTLD_NOW);
+}
+
+SharedLibrary::~SharedLibrary() {
+    if (mLibHandle != NULL) {
+        dlclose(mLibHandle);
+        mLibHandle = NULL;
+    }
+}
+
+bool SharedLibrary::operator!() const {
+    return mLibHandle == NULL;
+}
+
+void* SharedLibrary::lookup(const char* symbol) const {
+    if (!mLibHandle) {
+        return NULL;
+    }
+    // Clear last error before we load the symbol again,
+    // in case the caller didn't retrieve it.
+    (void)dlerror();
+    return dlsym(mLibHandle, symbol);
+}
+
+const char* SharedLibrary::lastError() const {
+    const char* error = dlerror();
+    return error ? error : "No errors or unknown error";
+}
+
+}  // namespace cas
+}  // namespace hardware
+}  // namespace android
+}  // namespace aidl