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/*
* Copyright (C) 2012 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.
*/
package android.os;
/**
* Writes trace events to the kernel trace buffer. These trace events can be
* collected using the "atrace" program for offline analysis.
*
* This tracing mechanism is independent of the method tracing mechanism
* offered by {@link Debug#startMethodTracing}. In particular, it enables
* tracing of events that occur across processes.
*
* @hide
*/
public final class Trace {
// These tags must be kept in sync with frameworks/native/include/utils/Trace.h.
public static final long TRACE_TAG_NEVER = 0;
public static final long TRACE_TAG_ALWAYS = 1L << 0;
public static final long TRACE_TAG_GRAPHICS = 1L << 1;
public static final long TRACE_TAG_INPUT = 1L << 2;
public static final long TRACE_TAG_VIEW = 1L << 3;
public static final long TRACE_TAG_WEBVIEW = 1L << 4;
public static final long TRACE_TAG_WINDOW_MANAGER = 1L << 5;
public static final long TRACE_TAG_ACTIVITY_MANAGER = 1L << 6;
private static final long sEnabledTags = nativeGetEnabledTags();
private static native long nativeGetEnabledTags();
private static native void nativeTraceCounter(long tag, String name, int value);
private static native void nativeTraceBegin(long tag, String name);
private static native void nativeTraceEnd(long tag);
private Trace() {
}
/**
* Returns true if a trace tag is enabled.
*
* @param traceTag The trace tag to check.
* @return True if the trace tag is valid.
*/
public static boolean isTagEnabled(long traceTag) {
return (sEnabledTags & traceTag) != 0;
}
/**
* Writes trace message to indicate the value of a given counter.
*
* @param traceTag The trace tag.
* @param counterName The counter name to appear in the trace.
* @param counterValue The counter value.
*/
public static void traceCounter(long traceTag, String counterName, int counterValue) {
if ((sEnabledTags & traceTag) != 0) {
nativeTraceCounter(traceTag, counterName, counterValue);
}
}
/**
* Writes a trace message to indicate that a given method has begun.
* Must be followed by a call to {@link #traceEnd} using the same tag.
*
* @param traceTag The trace tag.
* @param methodName The method name to appear in the trace.
*/
public static void traceBegin(long traceTag, String methodName) {
if ((sEnabledTags & traceTag) != 0) {
nativeTraceBegin(traceTag, methodName);
}
}
/**
* Writes a trace message to indicate that the current method has ended.
* Must be called exactly once for each call to {@link #traceBegin} using the same tag.
*
* @param traceTag The trace tag.
*/
public static void traceEnd(long traceTag) {
if ((sEnabledTags & traceTag) != 0) {
nativeTraceEnd(traceTag);
}
}
}
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