Switch to our own classes for JSON parsing

We leave in support for handling GSON types to keep this
diff as small as possible.

Author: shs96c

java/client/src/org/openqa/selenium/json/Input.java

@@ -0,0 +1,103 @@
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC licenses this file
+// to you 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 org.openqa.selenium.json;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.CharBuffer;
+import java.util.Objects;
+
+/**
+ * Similar to a {@link Readable} but with the ability to peek a single character ahead.
+ * <p>
+ * For the sake of providing a useful {@link #toString()} implementation, keeps a small circular
+ * buffer of the most recently read characters.
+ */
+class Input {
+
+  public static final char EOF = (char) -1;
+  private final Readable source;
+  private boolean read;
+  private char peekedChar;
+  private char[] lastRead = new char[128];
+  private int insertAt = 0;
+  private boolean filled = false;
+
+  public Input(Readable source) {
+    this.source = Objects.requireNonNull(source);
+  }
+
+  public char peek() {
+    init();
+    return peekedChar;
+  }
+
+  public char read() {
+    init();
+    read = false;
+    append();
+    return peekedChar;
+  }
+
+  @Override
+  public String toString() {
+    String preamble = "Last " + (filled ?  lastRead.length : insertAt) + " characters read: ";
+    if (!filled) {
+      return preamble + new String(lastRead, 0, insertAt);
+    }
+
+    // We filled the array. The insertion point would overwrite the first thing we should read.
+    char[] buf = new char[lastRead.length];
+    int lengthToRead = lastRead.length - insertAt;
+    System.arraycopy(lastRead, insertAt, buf, 0, lengthToRead);
+    System.arraycopy(lastRead, 0, buf, lengthToRead, insertAt);
+
+    return preamble + new String(buf);
+  }
+
+  private void init() {
+    if (read) {
+      return;
+    }
+
+    CharBuffer buf = CharBuffer.allocate(1);
+    int charsRead;
+    try {
+      charsRead = source.read(buf);
+    } catch (IOException e) {
+      throw new UncheckedIOException(e.getMessage(), e);
+    }
+    if (charsRead != 1) {
+      peekedChar = EOF;
+    } else {
+      peekedChar = buf.array()[0];
+    }
+    read = true;
+  }
+
+  private void append() {
+    if (peekedChar == Input.EOF) {
+      return;
+    }
+    lastRead[insertAt] = peekedChar;
+    insertAt = ++insertAt % lastRead.length;
+    if (insertAt == 0) {
+      filled = true;
+    }
+  }
+}

java/client/src/org/openqa/selenium/json/Json.java

@@ -18,8 +18,6 @@
 package org.openqa.selenium.json;
 
 import com.google.common.reflect.TypeToken;
-import com.google.gson.Gson;
-import com.google.gson.GsonBuilder;
 
 import java.io.IOException;
 import java.io.Reader;
@@ -32,12 +30,6 @@
 import java.util.Map;
 
 public class Json {
-  static final Gson GSON = new GsonBuilder()
-      .setLenient()
-      .serializeNulls()
-      .disableHtmlEscaping()
-      .create();
-
   public static final Type LIST_OF_MAPS_TYPE = new TypeToken<List<Map<String, Object>>>() {}.getType();
   public static final Type MAP_TYPE = new TypeToken<Map<String, Object>>() {}.getType();
   public static final Type OBJECT_TYPE = new TypeToken<Object>() {}.getType();