libpower: RAII wake lock implementation

Bug: 133175847
Test: boot blueline
Test: device suspends if left alone
Change-Id: I5a63fedabb18a9dcd510ca76303f54ec6c0b7f8c

Android.bp

@@ -35,7 +35,10 @@ cc_test {
     defaults: ["libpower_defaults"],
     srcs: ["power_test.cpp"],
     static_libs: ["libpower"],
-    shared_libs: ["android.system.suspend@1.0"],
+    shared_libs: [
+        "android.system.suspend@1.0",
+        "suspend_control_aidl_interface-cpp",
+    ],
     test_suites: ["device-tests"],
     require_root: true,
 }

include/hardware_legacy/power.h

@@ -17,6 +17,10 @@
 #ifndef _HARDWARE_POWER_H
 #define _HARDWARE_POWER_H
 
+#if __cplusplus
+#include <memory>
+#include <string>
+#endif
 #include <stdint.h>
 
 #if __cplusplus
@@ -33,9 +37,27 @@ enum {
 int acquire_wake_lock(int lock, const char* id);
 int release_wake_lock(const char* id);
 
-
 #if __cplusplus
-} // extern "C"
+}  // extern "C"
 #endif
 
-#endif // _HARDWARE_POWER_H
+#if __cplusplus
+// RAII way to acquire wake locks.
+namespace android {
+namespace power {
+
+class WakeLock {
+   public:
+    WakeLock(const std::string& name);
+    ~WakeLock();
+
+   private:
+    class WakeLockImpl;
+    std::unique_ptr<WakeLockImpl> mImpl;
+};
+
+}  // namespace power
+}  // namespace android
+#endif
+
+#endif  // _HARDWARE_POWER_H

power.cpp

@@ -78,3 +78,28 @@ int release_wake_lock(const char* id) {
     }
     return -1;
 }
+
+namespace android::power {
+
+WakeLock::WakeLock(const std::string& name) : mImpl(std::make_unique<WakeLockImpl>(name)) {}
+
+WakeLock::~WakeLock() = default;
+
+class WakeLock::WakeLockImpl {
+   public:
+    WakeLockImpl(const std::string& name) : mWakeLock(nullptr) {
+        static sp<ISystemSuspend> suspendService = ISystemSuspend::getService();
+        mWakeLock = suspendService->acquireWakeLock(WakeLockType::PARTIAL, name);
+    }
+    ~WakeLockImpl() {
+        auto ret = mWakeLock->release();
+        if (!ret.isOk()) {
+            LOG(ERROR) << "IWakeLock::release() call failed: " << ret.description();
+        }
+    }
+
+   private:
+    sp<IWakeLock> mWakeLock;
+};
+
+}  // namespace android::power

power_test.cpp

@@ -14,6 +14,9 @@
  * limitations under the License.
  */
 
+#include <android/system/suspend/ISuspendControlService.h>
+#include <binder/IServiceManager.h>
+#include <gtest/gtest.h>
 #include <hardware_legacy/power.h>
 
 #include <csignal>
@@ -22,8 +25,9 @@
 #include <thread>
 #include <vector>
 
-#include <gtest/gtest.h>
-
+using android::sp;
+using android::system::suspend::ISuspendControlService;
+using android::system::suspend::WakeLockInfo;
 using namespace std::chrono_literals;
 
 namespace android {
@@ -73,10 +77,8 @@ TEST(LibpowerTest, WakeLockStressTest) {
             for (int j = 0; j < numLocks; j++) {
                 // We want ids to be unique.
                 std::string id = std::to_string(i) + "/" + std::to_string(j);
-                ASSERT_EQ(acquire_wake_lock(PARTIAL_WAKE_LOCK, id.c_str()), 0)
-                    << "id: " << id;
-                ASSERT_EQ(release_wake_lock(id.c_str()), 0)
-                    << "id: " << id;;
+                ASSERT_EQ(acquire_wake_lock(PARTIAL_WAKE_LOCK, id.c_str()), 0) << "id: " << id;
+                ASSERT_EQ(release_wake_lock(id.c_str()), 0) << "id: " << id;
             }
         });
     }
@@ -85,4 +87,50 @@ TEST(LibpowerTest, WakeLockStressTest) {
     }
 }
 
+// Returns true iff found.
+bool findWakeLockInfoByName(
+        const sp<ISuspendControlService>& service,
+        const std::string& name,
+        WakeLockInfo* info) {
+    std::vector<WakeLockInfo> wlStats;
+    service->getWakeLockStats(&wlStats);
+    auto it = std::find_if(wlStats.begin(), wlStats.end(),
+            [&name](const auto& x) { return x.name == name; });
+    if (it != wlStats.end()) {
+        *info = *it;
+        return true;
+    }
+    return false;
+}
+
+// Test RAII properties of WakeLock class.
+TEST(LibpowerTest, RAIIWakeLock) {
+    sp<IBinder> control =
+        android::defaultServiceManager()->getService(android::String16("suspend_control"));
+    ASSERT_NE(control, nullptr) << "failed to get the suspend control service";
+    sp<ISuspendControlService> controlService = interface_cast<ISuspendControlService>(control);
+
+    auto name = std::to_string(rand());
+    {
+        android::power::WakeLock wl{name};
+
+        WakeLockInfo info;
+        auto success = findWakeLockInfoByName(controlService, name, &info);
+        ASSERT_TRUE(success);
+        ASSERT_EQ(info.name, name);
+        ASSERT_EQ(info.pid, getpid());
+        ASSERT_TRUE(info.isActive);
+    }
+
+    // SystemSuspend receives wake lock release requests on hwbinder thread, while stats requests
+    // come on binder thread. Sleep to make sure that stats are reported *after* wake lock release.
+    std::this_thread::sleep_for(1ms);
+    WakeLockInfo info;
+    auto success = findWakeLockInfoByName(controlService, name, &info);
+    ASSERT_TRUE(success);
+    ASSERT_EQ(info.name, name);
+    ASSERT_EQ(info.pid, getpid());
+    ASSERT_FALSE(info.isActive);
+}
+
 }  // namespace android