modules: camera: Add scoped trace helper

This c++ helper class is normally provided by frameworks/native's
libutils, but cannot be used from the context of a hardware module.  For
now just add the required functionality locally in the hardware module.

Change-Id: I5b399cbeb1c017a95baf19456dbf20569e677fbe

modules/camera/Camera.cpp

@@ -25,6 +25,7 @@
 
 #define ATRACE_TAG (ATRACE_TAG_CAMERA | ATRACE_TAG_HAL)
 #include <cutils/trace.h>
+#include "ScopedTrace.h"
 
 #include "Camera.h"
 
@@ -62,11 +63,10 @@ Camera::~Camera()
 int Camera::open(const hw_module_t *module, hw_device_t **device)
 {
     ALOGI("%s:%d: Opening camera device", __func__, mId);
-    ATRACE_BEGIN(__func__);
+    CAMTRACE_CALL();
     pthread_mutex_lock(&mMutex);
     if (mBusy) {
         pthread_mutex_unlock(&mMutex);
-        ATRACE_END();
         ALOGE("%s:%d: Error! Camera device already opened", __func__, mId);
         return -EBUSY;
     }
@@ -77,18 +77,16 @@ int Camera::open(const hw_module_t *module, hw_device_t **device)
     *device = &mDevice.common;
 
     pthread_mutex_unlock(&mMutex);
-    ATRACE_END();
     return 0;
 }
 
 int Camera::close()
 {
     ALOGI("%s:%d: Closing camera device", __func__, mId);
-    ATRACE_BEGIN(__func__);
+    CAMTRACE_CALL();
     pthread_mutex_lock(&mMutex);
     if (!mBusy) {
         pthread_mutex_unlock(&mMutex);
-        ATRACE_END();
         ALOGE("%s:%d: Error! Camera device not open", __func__, mId);
         return -EINVAL;
     }
@@ -97,7 +95,6 @@ int Camera::close()
     mBusy = false;
 
     pthread_mutex_unlock(&mMutex);
-    ATRACE_END();
     return 0;
 }
 
@@ -132,16 +129,14 @@ const camera_metadata_t* Camera::constructDefaultRequestSettings(int type)
 int Camera::processCaptureRequest(camera3_capture_request_t *request)
 {
     ALOGV("%s:%d: request=%p", __func__, mId, request);
-    ATRACE_BEGIN(__func__);
+    CAMTRACE_CALL();
 
     if (request == NULL) {
         ALOGE("%s:%d: NULL request recieved", __func__, mId);
-        ATRACE_END();
         return -EINVAL;
     }
 
     // TODO: verify request; submit request to hardware
-    ATRACE_END();
     return 0;
 }
 

modules/camera/ScopedTrace.h

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#ifndef CAMERA_SCOPED_TRACE_H
+#define CAMERA_SCOPED_TRACE_H
+
+#include <stdint.h>
+#include <cutils/trace.h>
+
+// See <cutils/trace.h> for more tracing macros.
+
+// CAMTRACE_NAME traces the beginning and end of the current scope.  To trace
+// the correct start and end times this macro should be declared first in the
+// scope body.
+#define CAMTRACE_NAME(name) ScopedTrace ___tracer(ATRACE_TAG, name)
+// CAMTRACE_CALL is an ATRACE_NAME that uses the current function name.
+#define CAMTRACE_CALL() CAMTRACE_NAME(__FUNCTION__)
+
+namespace default_camera_hal {
+
+class ScopedTrace {
+public:
+inline ScopedTrace(uint64_t tag, const char* name)
+    : mTag(tag) {
+    atrace_begin(mTag,name);
+}
+
+inline ~ScopedTrace() {
+    atrace_end(mTag);
+}
+
+private:
+    uint64_t mTag;
+};
+
+}; // namespace default_camera_hal
+
+#endif // CAMERA_SCOPED_TRACE_H