MDnsSdListener.cpp: switch to libbase properties functions.

It's less code, it's clearer code, and it removes the sleeps while
waiting for a property to change (turning it into a wait on a futex) for
better responsiveness too.

Bug: http://b/302208409
Test: treehugger
Change-Id: I1d01ce639ad474ace5864a76d17e548c0f3b249c

1 files changed, 8 insertions, 28 deletions

diff --git a/server/MDnsSdListener.cpp b/server/MDnsSdListener.cpp
index 6955e8fc..7a9cb0bc 100644
--- a/server/MDnsSdListener.cpp
+++ b/server/MDnsSdListener.cpp
@@ -37,7 +37,7 @@
 #define DBG 1
 #define VDBG 1
 
-#include <cutils/properties.h>
+#include <android-base/properties.h>
 #include <log/log.h>
 #include <netdutils/ThreadUtil.h>
 #include <sysutils/SocketClient.h>
@@ -61,6 +61,8 @@ using android::net::mdns::aidl::IMDnsEventListener;
 using android::net::mdns::aidl::RegistrationInfo;
 using android::net::mdns::aidl::ResolutionInfo;
 
+using namespace std::chrono_literals;
+
 static unsigned ifaceIndexToNetId(uint32_t interfaceIndex) {
     char interfaceName[IFNAMSIZ] = {};
     unsigned netId;
@@ -388,35 +390,13 @@ MDnsSdListener::Monitor::~Monitor() {
     delete mRescanThread;
     if (VDBG) ALOGD("Monitor recycled");
 }
-#define NAP_TIME 200  // 200 ms between polls
-static int wait_for_property(const char *name, const char *desired_value, int maxwait)
-{
-    char value[PROPERTY_VALUE_MAX] = {'\0'};
-    int maxnaps = (maxwait * 1000) / NAP_TIME;
-
-    if (maxnaps < 1) {
-        maxnaps = 1;
-    }
-
-    while (maxnaps-- > 0) {
-        usleep(NAP_TIME * 1000);
-        if (property_get(name, value, nullptr)) {
-            if (desired_value == nullptr || strcmp(value, desired_value) == 0) {
-                return 0;
-            }
-        }
-    }
-    return -1; /* failure */
-}
 
 int MDnsSdListener::Monitor::startService() {
-    char property_value[PROPERTY_VALUE_MAX];
     std::lock_guard guard(mMutex);
-    property_get(MDNS_SERVICE_STATUS, property_value, "");
-    if (strcmp("running", property_value) != 0) {
+    if (android::base::GetProperty(MDNS_SERVICE_STATUS, "") != "running") {
         ALOGD("Starting MDNSD");
-        property_set("ctl.start", MDNS_SERVICE_NAME);
-        wait_for_property(MDNS_SERVICE_STATUS, "running", 5);
+        android::base::SetProperty("ctl.start", MDNS_SERVICE_NAME);
+        android::base::WaitForProperty(MDNS_SERVICE_STATUS, "running", 5s);
         return -1;
     }
     return 0;
@@ -426,8 +406,8 @@ int MDnsSdListener::Monitor::stopService() {
     std::lock_guard guard(mMutex);
     if (mHead == nullptr) {
         ALOGD("Stopping MDNSD");
-        property_set("ctl.stop", MDNS_SERVICE_NAME);
-        wait_for_property(MDNS_SERVICE_STATUS, "stopped", 5);
+        android::base::SetProperty("ctl.stop", MDNS_SERVICE_NAME);
+        android::base::WaitForProperty(MDNS_SERVICE_STATUS, "stopped", 5s);
         return -1;
     }
     return 0;