| |
| /* |
| * Copyright (C) 2010 Google Inc. |
| * |
| * 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. |
| */ |
| |
| // This file is a copy of caliper's InterleavedReader.java |
| // (from code.google.com, last change Sep 9 2011) |
| // with Android specific changes marked with "BEGIN android-changed". |
| |
| package vogar.monitor; |
| |
| import com.google.gson.JsonParser; |
| |
| import java.io.BufferedReader; |
| import java.io.Closeable; |
| import java.io.IOException; |
| import java.io.Reader; |
| |
| /** |
| * Reads a stream containing inline JSON objects. Each JSON object is prefixed |
| * by a marker string and suffixed by a newline character. |
| */ |
| public final class InterleavedReader implements Closeable { |
| |
| /** |
| * The length of the scratch buffer to search for markers in. Also acts as an |
| * upper bound on the length of returned strings. Not used as an I/O buffer. |
| */ |
| private static final int BUFFER_LENGTH = 80; |
| |
| private final String marker; |
| private final BufferedReader reader; |
| private final JsonParser jsonParser = new JsonParser(); |
| |
| public static final String DEFAULT_MARKER = "//ZxJ/"; |
| |
| public InterleavedReader(Reader reader) { |
| this(DEFAULT_MARKER, reader); |
| } |
| |
| public InterleavedReader(String marker, Reader reader) { |
| if (marker.length() > BUFFER_LENGTH) { |
| throw new IllegalArgumentException("marker.length() > BUFFER_LENGTH"); |
| } |
| this.marker = marker; |
| this.reader = reader instanceof BufferedReader |
| ? (BufferedReader) reader |
| : new BufferedReader(reader); |
| } |
| |
| /** |
| * Returns the next value in the stream: either a String, a JsonElement, or |
| * null to indicate the end of the stream. Callers should use instanceof to |
| * inspect the return type. |
| */ |
| public Object read() throws IOException { |
| char[] buffer = new char[BUFFER_LENGTH]; |
| // BEGIN android-changed: |
| // Double the lookahead size. This is a safety measure in the presence of |
| // new lines, where the line feed character is being skipped. The lookahead |
| // check in the BufferedReader class does not take these skipped characters |
| // into account. |
| reader.mark(BUFFER_LENGTH << 1); |
| // END android-changed. |
| int count = 0; |
| int textEnd; |
| |
| while (true) { |
| int r = reader.read(buffer, count, buffer.length - count); |
| |
| if (r == -1) { |
| // the input is exhausted; return the remaining characters |
| textEnd = count; |
| break; |
| } |
| |
| count += r; |
| int possibleMarker = findPossibleMarker(buffer, count); |
| |
| if (possibleMarker != 0) { |
| // return the characters that precede the marker |
| textEnd = possibleMarker; |
| break; |
| } |
| |
| if (count < marker.length()) { |
| // the buffer contains only the prefix of a marker so we must read more |
| continue; |
| } |
| |
| // we've read a marker so return the value that follows |
| reader.reset(); |
| String json = reader.readLine().substring(marker.length()); |
| return jsonParser.parse(json); |
| } |
| |
| if (count == 0) { |
| return null; |
| } |
| |
| // return characters |
| reader.reset(); |
| count = reader.read(buffer, 0, textEnd); |
| return new String(buffer, 0, count); |
| } |
| |
| @Override public void close() throws IOException { |
| reader.close(); |
| } |
| |
| /** |
| * Returns the index of marker in {@code chars}, stopping at {@code limit}. |
| * Should the chars end with a prefix of marker, the offset of that prefix |
| * is returned. |
| */ |
| int findPossibleMarker(char[] chars, int limit) { |
| search: |
| for (int i = 0; true; i++) { |
| for (int m = 0; m < marker.length() && i + m < limit; m++) { |
| if (chars[i + m] != marker.charAt(m)) { |
| continue search; |
| } |
| } |
| return i; |
| } |
| } |
| } |