walt: fix internal build system errors

Although external/walt is not part of a full build, the JNI it defines
includes an Android.mk which is somehow picked up in test builds. The
original code contains several unused parameter warnings that get
converted to errors during test builds, and this change cleans those up.

Bug: 37744894
Test: `mma -j48` in android/WALT/app/src/main/jni/ builds cleanly
Change-Id: I354df5d168bc4550df19258035fdb33ac7249831

3 files changed, 40 insertions, 22 deletions

diff --git a/android/WALT/app/src/main/jni/player.c b/android/WALT/app/src/main/jni/player.c
index 361d0a8..f532dbe 100644
--- a/android/WALT/app/src/main/jni/player.c
+++ b/android/WALT/app/src/main/jni/player.c
@@ -102,7 +102,7 @@ void createWaveTables(){
 }
 
 // this callback handler is called every time a buffer finishes playing
-void bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
+void bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, __attribute__((unused)) void *context)
 {
     if (bq == NULL) {
         __android_log_print(ANDROID_LOG_ERROR, APPNAME, "buffer queue is null");
@@ -136,7 +136,8 @@ void bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
     }
 }
 
-jlong Java_org_chromium_latency_walt_AudioTest_playTone(JNIEnv* env, jclass clazz){
+jlong Java_org_chromium_latency_walt_AudioTest_playTone(__attribute__((unused)) JNIEnv* env,
+                                                        __attribute__((unused)) jclass clazz){
 
     int64_t t_start = uptimeMicros();
     te_play = 0;
@@ -172,7 +173,8 @@ jlong Java_org_chromium_latency_walt_AudioTest_playTone(JNIEnv* env, jclass claz
 
 
 // create the engine and output mix objects
-void Java_org_chromium_latency_walt_AudioTest_createEngine(JNIEnv* env, jclass clazz)
+void Java_org_chromium_latency_walt_AudioTest_createEngine(__attribute__((unused)) JNIEnv* env,
+                                                           __attribute__((unused)) jclass clazz)
 {
     __android_log_print(ANDROID_LOG_VERBOSE, APPNAME, "Creating audio engine");
 
@@ -204,7 +206,8 @@ void Java_org_chromium_latency_walt_AudioTest_createEngine(JNIEnv* env, jclass c
     (void)result;
 }
 
-void Java_org_chromium_latency_walt_AudioTest_destroyEngine(JNIEnv *env, jclass clazz)
+void Java_org_chromium_latency_walt_AudioTest_destroyEngine(__attribute__((unused)) JNIEnv *env,
+                                                            __attribute__((unused)) jclass clazz)
 {
     if (bqPlayerObject != NULL) {
         (*bqPlayerObject)->Destroy(bqPlayerObject);
@@ -223,8 +226,11 @@ void Java_org_chromium_latency_walt_AudioTest_destroyEngine(JNIEnv *env, jclass
 }
 
 // create buffer queue audio player
-void Java_org_chromium_latency_walt_AudioTest_createBufferQueueAudioPlayer(JNIEnv* env,
-        jclass clazz, jint optimalFrameRate, jint optimalFramesPerBuffer)
+void Java_org_chromium_latency_walt_AudioTest_createBufferQueueAudioPlayer(
+        __attribute__((unused)) JNIEnv* env,
+        __attribute__((unused)) jclass clazz,
+        jint optimalFrameRate,
+        jint optimalFramesPerBuffer)
 {
     __android_log_print(ANDROID_LOG_VERBOSE, APPNAME, "Creating audio player with frame rate %d and frames per buffer %d",
                         optimalFrameRate, optimalFramesPerBuffer);
@@ -309,7 +315,8 @@ void Java_org_chromium_latency_walt_AudioTest_createBufferQueueAudioPlayer(JNIEn
     (void)result;
 }
 
-void Java_org_chromium_latency_walt_AudioTest_startWarmTest(JNIEnv* env, jclass clazz) {
+void Java_org_chromium_latency_walt_AudioTest_startWarmTest(__attribute__((unused)) JNIEnv* env,
+                                                            __attribute__((unused)) jclass clazz) {
     SLresult result;
 
     result = (*bqPlayerBufferQueue)->Clear(bqPlayerBufferQueue);
@@ -329,7 +336,8 @@ void Java_org_chromium_latency_walt_AudioTest_startWarmTest(JNIEnv* env, jclass
     warmedUp = 1;
 }
 
-void Java_org_chromium_latency_walt_AudioTest_stopTests(JNIEnv *env, jclass clazz) {
+void Java_org_chromium_latency_walt_AudioTest_stopTests(__attribute__((unused)) JNIEnv *env,
+                                                        __attribute__((unused)) jclass clazz) {
     SLresult result;
 
     result = (*bqPlayerPlay)->SetPlayState(bqPlayerPlay, SL_PLAYSTATE_STOPPED);
@@ -340,7 +348,8 @@ void Java_org_chromium_latency_walt_AudioTest_stopTests(JNIEnv *env, jclass claz
 }
 
 // this callback handler is called every time a buffer finishes recording
-void bqRecorderCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
+void bqRecorderCallback(__attribute__((unused)) SLAndroidSimpleBufferQueueItf bq,
+                        __attribute__((unused)) void *context)
 {
     tc_rec = uptimeMicros();
     assert(bq == recorderBufferQueue);
@@ -362,8 +371,11 @@ void bqRecorderCallback(SLAndroidSimpleBufferQueueItf bq, void *context)
 }
 
 // create audio recorder
-jboolean Java_org_chromium_latency_walt_AudioTest_createAudioRecorder(JNIEnv* env,
-    jclass clazz, jint optimalFrameRate, jint framesToRecord)
+jboolean Java_org_chromium_latency_walt_AudioTest_createAudioRecorder(
+        __attribute__((unused)) JNIEnv* env,
+        __attribute__((unused)) jclass clazz,
+        jint optimalFrameRate,
+        jint framesToRecord)
 {
     SLresult result;
 
@@ -460,7 +472,8 @@ jboolean Java_org_chromium_latency_walt_AudioTest_createAudioRecorder(JNIEnv* en
 
 
 // set the recording state for the audio recorder
-void Java_org_chromium_latency_walt_AudioTest_startRecording(JNIEnv* env, jclass clazz)
+void Java_org_chromium_latency_walt_AudioTest_startRecording(__attribute__((unused)) JNIEnv* env,
+                                                             __attribute__((unused)) jclass clazz)
 {
     SLresult result;
 
@@ -496,7 +509,9 @@ void Java_org_chromium_latency_walt_AudioTest_startRecording(JNIEnv* env, jclass
     bqPlayerRecorderBusy = 1;
 }
 
-jshortArray Java_org_chromium_latency_walt_AudioTest_getRecordedWave(JNIEnv *env, jclass cls)
+jshortArray Java_org_chromium_latency_walt_AudioTest_getRecordedWave(
+        JNIEnv *env,
+        __attribute__((unused)) jclass cls)
 {
     jshortArray result;
     result = (*env)->NewShortArray(env, recorder_frames);
@@ -507,14 +522,17 @@ jshortArray Java_org_chromium_latency_walt_AudioTest_getRecordedWave(JNIEnv *env
     return result;
 }
 
-jlong Java_org_chromium_latency_walt_AudioTest_getTcRec(JNIEnv *env, jclass cls) {
+jlong Java_org_chromium_latency_walt_AudioTest_getTcRec(__attribute__((unused)) JNIEnv *env,
+                                                        __attribute__((unused)) jclass cls) {
     return (jlong) tc_rec;
 }
 
-jlong Java_org_chromium_latency_walt_AudioTest_getTeRec(JNIEnv *env, jclass cls) {
+jlong Java_org_chromium_latency_walt_AudioTest_getTeRec(__attribute__((unused)) JNIEnv *env,
+                                                        __attribute__((unused)) jclass cls) {
     return (jlong) te_rec;
 }
 
-jlong Java_org_chromium_latency_walt_AudioTest_getTePlay(JNIEnv *env, jclass cls) {
+jlong Java_org_chromium_latency_walt_AudioTest_getTePlay(__attribute__((unused)) JNIEnv *env,
+                                                         __attribute__((unused)) jclass cls) {
     return (jlong) te_play;
 }
diff --git a/android/WALT/app/src/main/jni/sync_clock.c b/android/WALT/app/src/main/jni/sync_clock.c
index 1591f88..e16b759 100644
--- a/android/WALT/app/src/main/jni/sync_clock.c
+++ b/android/WALT/app/src/main/jni/sync_clock.c
@@ -59,7 +59,7 @@ http://developer.android.com/reference/android/os/SystemClock.html
 https://android.googlesource.com/platform/system/core/+/master/libutils/Timers.cpp
 */
 int64_t uptimeMicros() {
-    struct timespec ts = {0};
+    struct timespec ts;
     clock_gettime(CLOCK_MONOTONIC, &ts);
     return ((int64_t)ts.tv_sec) * kMillion + ts.tv_nsec / 1000;
 }
@@ -67,11 +67,11 @@ int64_t uptimeMicros() {
 
 // Sleeps us microseconds
 int microsleep(int us) {
-    struct timespec ts = {0};
+    struct timespec ts;
     ts.tv_sec = us / kMillion;
     us %= kMillion;
     ts.tv_nsec = us*1000;
-    nanosleep(&ts, NULL);
+    return nanosleep(&ts, NULL);
 }
 
 
@@ -109,7 +109,7 @@ static int bulk_talk(int fd, int endpoint, char * buffer, int length) {
     // short enough to fail quickly if all transfers and retries fail with
     // timeout.
     const int kTimeoutMs = 20;
-    struct usbdevfs_bulktransfer ctrl = {0};
+    struct usbdevfs_bulktransfer ctrl;
     // TODO: need to limit request size to avoid EINVAL
 
     ctrl.ep = endpoint;
diff --git a/android/WALT/app/src/main/jni/sync_clock_jni.c b/android/WALT/app/src/main/jni/sync_clock_jni.c
index 15adfd5..22753fe 100644
--- a/android/WALT/app/src/main/jni/sync_clock_jni.c
+++ b/android/WALT/app/src/main/jni/sync_clock_jni.c
@@ -28,8 +28,8 @@ struct clock_connection clk;
 
 jlong
 Java_org_chromium_latency_walt_WaltUsbConnection_syncClock__III(
-    JNIEnv* env,
-    jobject thiz,
+    __attribute__((unused)) JNIEnv* env,
+    __attribute__((unused)) jobject thiz,
     jint fd,
     jint endpoint_out,
     jint endpoint_in