MediaUtils: Use delayed / lazy library loading
Postpone loading libutilscallstack until needed
to save memory.
Test: atest library_tests
Test: adb shell 'showmap $(pgrep mediametrics)'
Bug: 227536784
Change-Id: I3d4c9e9b6d854b013185e18fc20d4bec320df14e
diff --git a/media/utils/MediaUtilsDelayed.cpp b/media/utils/MediaUtilsDelayed.cpp
new file mode 100644
index 0000000..c6c092d
--- /dev/null
+++ b/media/utils/MediaUtilsDelayed.cpp
@@ -0,0 +1,55 @@
+/*
+ * 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.
+ */
+
+#include <mediautils/Library.h>
+#include <mediautils/MediaUtilsDelayed.h>
+#include "MediaUtilsDelayedLibrary.h"
+
+#define LOG_TAG "MediaUtilsDelayed"
+#include <utils/Log.h>
+#include <memory>
+
+namespace android::mediautils {
+
+namespace {
+// Specific implementation details for MediaUtils Delayed Library.
+
+// The following use static Meyer's singleton caches instead of letting
+// refcounted management as provided above. This is for speed.
+std::shared_ptr<void> getDelayedLibrary() {
+ static std::shared_ptr<void> library = loadLibrary(MEDIAUTILS_DELAYED_LIBRARY_NAME);
+ return library;
+}
+
+// Get the delayed dispatch table. This is refcounted and keeps the underlying library alive.
+std::shared_ptr<delayed_library::DelayedDispatchTable> getDelayedDispatchTable() {
+ static auto delayedDispatchTable =
+ getObjectFromLibrary<delayed_library::DelayedDispatchTable>(
+ MEDIAUTILS_DELAYED_DISPATCH_TABLE_SYMBOL_NAME, getDelayedLibrary());
+ return delayedDispatchTable;
+}
+
+} // namespace
+
+// Public implementations of methods here.
+
+std::string getCallStackStringForTid(pid_t tid) {
+ auto delayedDispatchTable = getDelayedDispatchTable();
+ if (!delayedDispatchTable) return {}; // on failure, return empty string
+ return delayedDispatchTable->getCallStackStringForTid(tid);
+}
+
+} // android::mediautils