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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 com.android.ddmuilib.logcat;
import java.util.regex.Pattern;
/**
* {@link RollingBufferFindTarget} implements methods to find items inside a circular buffer.
*/
public abstract class RollingBufferFindTarget implements IFindTarget {
private int mCurrentSearchIndex;
// Single element cache of the last search regex
private Pattern mLastSearchPattern;
private String mLastSearchText;
@Override
public boolean findAndSelect(String text, boolean isNewSearch, boolean searchForward) {
boolean found = false;
int maxIndex = getItemCount();
synchronized (this) {
// Find starting index for this search
if (isNewSearch) {
// for new searches, start from an appropriate place as provided by the delegate
mCurrentSearchIndex = getStartingIndex();
} else {
// for ongoing searches (finding next match for the same term), continue from
// the current result index
mCurrentSearchIndex = getNext(mCurrentSearchIndex, searchForward, maxIndex);
}
// Create a regex pattern based on the search term.
Pattern pattern;
if (text.equals(mLastSearchText)) {
pattern = mLastSearchPattern;
} else {
pattern = Pattern.compile(text, Pattern.CASE_INSENSITIVE);
mLastSearchPattern = pattern;
mLastSearchText = text;
}
// Iterate through the list of items. The search ends if we have gone through
// all items once.
int index = mCurrentSearchIndex;
do {
String msgText = getItem(mCurrentSearchIndex);
if (msgText != null && pattern.matcher(msgText).find()) {
found = true;
break;
}
mCurrentSearchIndex = getNext(mCurrentSearchIndex, searchForward, maxIndex);
} while (index != mCurrentSearchIndex); // loop through entire contents once
}
if (found) {
selectAndReveal(mCurrentSearchIndex);
}
return found;
}
/** Indicate that the log buffer has scrolled by certain number of elements */
public void scrollBy(int delta) {
synchronized (this) {
if (mCurrentSearchIndex > 0) {
mCurrentSearchIndex = Math.max(0, mCurrentSearchIndex - delta);
}
}
}
private int getNext(int index, boolean searchForward, int max) {
// increment or decrement index
index = searchForward ? index + 1 : index - 1;
// take care of underflow
if (index == -1) {
index = max - 1;
}
// ..and overflow
if (index == max) {
index = 0;
}
return index;
}
/** Obtain the number of items in the buffer */
public abstract int getItemCount();
/** Obtain the item at given index */
public abstract String getItem(int index);
/** Select and reveal the item at given index */
public abstract void selectAndReveal(int index);
/** Obtain the index from which search should begin */
public abstract int getStartingIndex();
}
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