src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/StringParser.java
changeset 58863 c16ac7a2eba4
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jfr/share/classes/jdk/jfr/internal/consumer/StringParser.java	Wed Oct 30 19:43:52 2019 +0100
@@ -0,0 +1,222 @@
+/*
+ * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.internal.consumer;
+
+import java.io.IOException;
+import java.nio.charset.Charset;
+
+public final class StringParser extends Parser {
+
+    public enum Encoding {
+        NULL(0),
+        EMPTY_STRING(1),
+        CONSTANT_POOL(2),
+        UT8_BYTE_ARRAY(3),
+        CHAR_ARRAY(4),
+        LATIN1_BYTE_ARRAY(5);
+
+        private byte byteValue;
+
+        private Encoding(int byteValue) {
+            this.byteValue = (byte) byteValue;
+        }
+
+        public byte byteValue() {
+            return byteValue;
+        }
+
+        public boolean is(byte value) {
+            return value == byteValue;
+        }
+
+    }
+    private final static Charset UTF8 = Charset.forName("UTF-8");
+    private final static Charset LATIN1 = Charset.forName("ISO-8859-1");
+
+    private final static class CharsetParser extends Parser {
+        private final Charset charset;
+        private int lastSize;
+        private byte[] buffer = new byte[16];
+        private String lastString;
+
+        CharsetParser(Charset charset) {
+            this.charset = charset;
+        }
+
+        @Override
+        public Object parse(RecordingInput input) throws IOException {
+            int size = input.readInt();
+            ensureSize(size);
+            if (lastSize == size) {
+                boolean equalsLastString = true;
+                for (int i = 0; i < size; i++) {
+                    // TODO: No need to read byte per byte
+                    byte b = input.readByte();
+                    if (buffer[i] != b) {
+                        equalsLastString = false;
+                        buffer[i] = b;
+                    }
+                }
+                if (equalsLastString) {
+                    return lastString;
+                }
+            } else {
+                for (int i = 0; i < size; i++) {
+                    buffer[i] = input.readByte();
+                }
+            }
+            lastString = new String(buffer, 0, size, charset);
+            lastSize = size;
+            return lastString;
+        }
+
+        @Override
+        public void skip(RecordingInput input) throws IOException {
+            int size = input.readInt();
+            input.skipBytes(size);
+        }
+
+        private void ensureSize(int size) {
+            if (buffer.length < size) {
+                buffer = new byte[size];
+            }
+        }
+    }
+
+    private final static class CharArrayParser extends Parser {
+        private char[] buffer = new char[16];
+        private int lastSize = -1;
+        private String lastString = null;
+
+        @Override
+        public Object parse(RecordingInput input) throws IOException {
+            int size = input.readInt();
+            ensureSize(size);
+            if (lastSize == size) {
+                boolean equalsLastString = true;
+                for (int i = 0; i < size; i++) {
+                    char c = input.readChar();
+                    if (buffer[i] != c) {
+                        equalsLastString = false;
+                        buffer[i] = c;
+                    }
+                }
+                if (equalsLastString) {
+                    return lastString;
+                }
+            } else {
+                for (int i = 0; i < size; i++) {
+                    buffer[i] = input.readChar();
+                }
+            }
+            lastString = new String(buffer, 0, size);
+            lastSize = size;
+            return lastString;
+        }
+
+        @Override
+        public void skip(RecordingInput input) throws IOException {
+            int size = input.readInt();
+            for (int i = 0; i < size; i++) {
+                input.readChar();
+            }
+        }
+
+        private void ensureSize(int size) {
+            if (buffer.length < size) {
+                buffer = new char[size];
+            }
+        }
+    }
+
+    private final ConstantLookup stringLookup;
+    private final CharArrayParser charArrayParser = new CharArrayParser();
+    private final CharsetParser utf8parser = new CharsetParser(UTF8);
+    private final CharsetParser latin1parser = new CharsetParser(LATIN1);
+    private final boolean event;
+
+    public StringParser(ConstantLookup stringLookup, boolean event) {
+        this.stringLookup = stringLookup;
+        this.event = event;
+    }
+
+    @Override
+    public Object parse(RecordingInput input) throws IOException {
+        byte encoding = input.readByte();
+        if (Encoding.CONSTANT_POOL.is(encoding)) {
+            long key = input.readLong();
+            if (event) {
+                return stringLookup.getCurrentResolved(key);
+            } else {
+                return stringLookup.getCurrent(key);
+            }
+        }
+        if (Encoding.NULL.is(encoding)) {
+            return null;
+        }
+        if (Encoding.EMPTY_STRING.is(encoding)) {
+            return "";
+        }
+        if (Encoding.CHAR_ARRAY.is(encoding)) {
+            return charArrayParser.parse(input);
+        }
+        if (Encoding.UT8_BYTE_ARRAY.is(encoding)) {
+            return utf8parser.parse(input);
+        }
+        if (Encoding.LATIN1_BYTE_ARRAY.is(encoding)) {
+            return latin1parser.parse(input);
+        }
+        throw new IOException("Unknown string encoding " + encoding);
+    }
+
+    @Override
+    public void skip(RecordingInput input) throws IOException {
+        byte encoding = input.readByte();
+        if (Encoding.CONSTANT_POOL.is(encoding)) {
+            input.readLong();
+            return;
+        }
+        if (Encoding.EMPTY_STRING.is(encoding)) {
+            return;
+        }
+        if (Encoding.NULL.is(encoding)) {
+            return;
+        }
+        if (Encoding.CHAR_ARRAY.is(encoding)) {
+            charArrayParser.skip(input);
+            return;
+        }
+        if (Encoding.UT8_BYTE_ARRAY.is(encoding)) {
+            utf8parser.skip(input);
+            return;
+        }
+        if (Encoding.LATIN1_BYTE_ARRAY.is(encoding)) {
+            latin1parser.skip(input);
+            return;
+        }
+        throw new IOException("Unknown string encoding " + encoding);
+    }
+}