1 files changed, 89 insertions, 0 deletions
diff --git a/adb/daemon/logging.cpp b/adb/daemon/logging.cpp
new file mode 100644
index 000000000..203c6c73d
--- /dev/null
+++ b/adb/daemon/logging.cpp
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2020 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 "daemon/logging.h"
+
+#include <mutex>
+#include <optional>
+#include <string_view>
+
+#include <android-base/no_destructor.h>
+#include <android-base/properties.h>
+#include <android-base/strings.h>
+#include <android-base/thread_annotations.h>
+
+#if defined(__ANDROID__)
+struct LogStatus {
+    bool enabled[static_cast<size_t>(adb::LogType::COUNT)];
+
+    bool& operator[](adb::LogType type) { return enabled[static_cast<size_t>(type)]; }
+};
+
+using android::base::CachedProperty;
+using android::base::NoDestructor;
+
+static NoDestructor<std::mutex> log_mutex;
+static NoDestructor<CachedProperty> log_property GUARDED_BY(log_mutex)("debug.adbd.logging");
+static std::optional<LogStatus> cached_log_status GUARDED_BY(log_mutex);
+
+static NoDestructor<CachedProperty> persist_log_property
+        GUARDED_BY(log_mutex)("persist.debug.adbd.logging");
+static std::optional<LogStatus> cached_persist_log_status GUARDED_BY(log_mutex);
+
+static LogStatus ParseLogStatus(std::string_view str) {
+    LogStatus result = {};
+    for (const auto& part : android::base::Split(std::string(str), ",")) {
+        if (part == "cnxn") {
+            result[adb::LogType::Connection] = true;
+        } else if (part == "service") {
+            result[adb::LogType::Service] = true;
+        } else if (part == "shell") {
+            result[adb::LogType::Shell] = true;
+        } else if (part == "all") {
+            result[adb::LogType::Connection] = true;
+            result[adb::LogType::Service] = true;
+            result[adb::LogType::Shell] = true;
+        }
+    }
+    return result;
+}
+
+static LogStatus GetLogStatus(android::base::CachedProperty* property,
+                              std::optional<LogStatus>* cached_status) REQUIRES(log_mutex) {
+    bool changed;
+    const char* value = property->Get(&changed);
+    if (changed || !*cached_status) {
+        **cached_status = ParseLogStatus(value);
+    }
+    return **cached_status;
+}
+
+namespace adb {
+bool is_logging_enabled(LogType type) {
+    std::lock_guard<std::mutex> lock(*log_mutex);
+    return GetLogStatus(log_property.get(), &cached_log_status)[type] ||
+           GetLogStatus(persist_log_property.get(), &cached_persist_log_status)[type];
+}
+}  // namespace adb
+
+#else
+
+namespace adb {
+bool is_logging_enabled(LogType type) {
+    return false;
+}
+}  // namespace adb
+#endif