AssetDownloader.java

/**
 * Copyright 2008 - 2015 The Loon Game Engine Authors
 * 
 * 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.
 * 
 * @project loon
 * @author cping
 * @email：javachenpeng@yahoo.com
 * @version 0.5
 */
package loon.html5.gwt.preloader;

import loon.html5.gwt.GWTScriptLoader;
import loon.html5.gwt.preloader.AssetFilter.AssetType;

import com.google.gwt.dom.client.ImageElement;
import com.google.gwt.dom.client.NativeEvent;
import com.google.gwt.typedarrays.shared.Int8Array;
import com.google.gwt.typedarrays.shared.TypedArrays;
import com.google.gwt.xhr.client.ReadyStateChangeHandler;
import com.google.gwt.xhr.client.XMLHttpRequest;
import com.google.gwt.xhr.client.XMLHttpRequest.ResponseType;

public class AssetDownloader extends IDownloader {

	public AssetDownloader() {
		super();
	}

	@SuppressWarnings("unchecked")
	public void load(String url, AssetType type, String mimeType,
			AssetLoaderListener<?> listener) {
		switch (type) {
		case Text:
			loadText(url, (AssetLoaderListener<String>) listener);
			break;
		case Image:
			loadImage(url, mimeType,
					(AssetLoaderListener<ImageElement>) listener);
			break;
		case Binary:
			loadBinary(url, (AssetLoaderListener<Blob>) listener);
			break;
		case Audio:
			loadAudio(url, (AssetLoaderListener<Void>) listener);
			break;
		case Directory:
			listener.onSuccess(null);
			break;
		default:
			throw new RuntimeException("Unsupported asset type " + type);
		}
	}

	public void loadText(String url, final AssetLoaderListener<String> listener) {
		XMLHttpRequest request = XMLHttpRequest.create();
		request.setOnReadyStateChange(new ReadyStateChangeHandler() {
			@Override
			public void onReadyStateChange(XMLHttpRequest xhr) {
				if (xhr.getReadyState() == XMLHttpRequest.DONE) {
					if (xhr.getStatus() != 200) {
						listener.onFailure();
					} else {
						listener.onSuccess(xhr.getResponseText());
					}
				}
			}
		});
		setOnProgress(request, listener);
		request.open("GET", url);
		request.setRequestHeader("Content-Type", "text/plain; charset=utf-8");
		request.send();
	}

	public void loadBinary(final String url,
			final AssetLoaderListener<Blob> listener) {
		XMLHttpRequest request = XMLHttpRequest.create();
		request.setOnReadyStateChange(new ReadyStateChangeHandler() {
			@Override
			public void onReadyStateChange(XMLHttpRequest xhr) {
				if (xhr.getReadyState() == XMLHttpRequest.DONE) {
					if (xhr.getStatus() != 200) {
						listener.onFailure();
					} else {
						Int8Array data = TypedArrays.createInt8Array(xhr
								.getResponseArrayBuffer());
						listener.onSuccess(new Blob(data));
					}
				}
			}
		});
		setOnProgress(request, listener);
		request.open("GET", url);
		request.setResponseType(ResponseType.ArrayBuffer);
		request.send();
	}

	public void loadAudio(String url, final AssetLoaderListener<Void> listener) {
		if (useBrowserCache) {
			loadBinary(url, new AssetLoaderListener<Blob>() {
				@Override
				public void onProgress(double amount) {
					listener.onProgress(amount);
				}

				@Override
				public void onFailure() {
					listener.onFailure();
				}

				@Override
				public void onSuccess(Blob result) {
					listener.onSuccess(null);
				}

			});
		} else {
			listener.onSuccess(null);
		}
	}

	public void loadImage(final String url, final String mimeType,
			final AssetLoaderListener<ImageElement> listener) {
		loadImage(url, mimeType, null, listener);
	}

	public void loadImage(final String url, final String mimeType,
			final String crossOrigin,
			final AssetLoaderListener<ImageElement> listener) {
		if (useBrowserCache || useInlineBase64) {
			loadBinary(url, new AssetLoaderListener<Blob>() {
				@Override
				public void onProgress(double amount) {
					listener.onProgress(amount);
				}

				@Override
				public void onFailure() {
					listener.onFailure();
				}

				@Override
				public void onSuccess(Blob result) {
					final ImageElement image = createImage();
					if (null != crossOrigin) {
						GWTScriptLoader.setCrossOrigin(image, "crossOrigin");
					}
					hookImgListener(image, new ImgEventListener() {
						@Override
						public void onEvent(NativeEvent event) {
							if (event.getType().equals("error")) {
								listener.onFailure();
							} else {
								listener.onSuccess(image);
							}
						}
					});
					if (isUseInlineBase64()) {
						image.setSrc("data:" + mimeType + ";base64,"
								+ result.toBase64());
					} else {
						image.setSrc(url);
					}
				}

			});
		} else {
			final ImageElement image = createImage();
			if (null != crossOrigin) {
				GWTScriptLoader.setCrossOrigin(image, "crossOrigin");
			}
			hookImgListener(image, new ImgEventListener() {
				@Override
				public void onEvent(NativeEvent event) {
					if (event.getType().equals("error")) {
						listener.onFailure();
					} else {
						listener.onSuccess(image);
					}
				}
			});
			image.setSrc(url);
		}
	}

	@Override
	public void clear() {
		// noop
	}

}