[Cronet] Initial implementation of HttpURLConnection

components/cronet/android/java/src/org/chromium/net/urlconnection/CronetInputStream.java

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.net.urlconnection;
+
+import java.io.InputStream;
+import java.nio.ByteBuffer;
+
+/**
+ * An InputStream that is used by {@link CronetHttpURLConnection} to request
+ * data from the network stack as needed.
+ */
+class CronetInputStream extends InputStream {
+    private final CronetHttpURLConnection mHttpURLConnection;
+    // Indicates whether listener's onSucceeded or onFailed callback is invoked.
+    private boolean mResponseDataCompleted;
+    private ByteBuffer mBuffer;
+
+    /**
+     * Constructs a CronetInputStream.
+     * @param httpURLConnection the CronetHttpURLConnection that is associated
+     *            with this InputStream.
+     */
+    public CronetInputStream(CronetHttpURLConnection httpURLConnection) {
+        mHttpURLConnection = httpURLConnection;
+    }
+
+    @Override
+    public int read() {
+        if (mBuffer == null
+                || (!mBuffer.hasRemaining() && !mResponseDataCompleted)) {
+            // Requests more data from CronetHttpURLConnection.
+            mBuffer = mHttpURLConnection.requestData();
+        }
+        if (mBuffer.hasRemaining()) {
+            return mBuffer.get() & 0xFF;
+        }
+        return -1;
+    }
+
+    void setResponseDataCompleted() {
+        mResponseDataCompleted = true;
+    }
+}