FileRetriever.java

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * 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.
 */
package com.android.fasterphotos.data;

import android.graphics.Bitmap;
import android.media.ExifInterface;
import android.net.Uri;
import android.util.Log;
import android.webkit.MimeTypeMap;

import com.android.fastergallery.common.BitmapUtils;

import java.io.File;
import java.io.IOException;

public class FileRetriever implements MediaRetriever {
	private static final String TAG = FileRetriever.class.getSimpleName();

	@Override
	public File getLocalFile(Uri contentUri) {
		return new File(contentUri.getPath());
	}

	@Override
	public MediaSize getFastImageSize(Uri contentUri, MediaSize size) {
		if (isVideo(contentUri)) {
			return null;
		}
		return MediaSize.TemporaryThumbnail;
	}

	@Override
	public byte[] getTemporaryImage(Uri contentUri, MediaSize fastImageSize) {

		try {
			ExifInterface exif = new ExifInterface(contentUri.getPath());
			if (exif.hasThumbnail()) {
				return exif.getThumbnail();
			}
		} catch (IOException e) {
			Log.w(TAG, "Unable to load exif for " + contentUri);
		}
		return null;
	}

	@Override
	public boolean getMedia(Uri contentUri, MediaSize imageSize, File tempFile) {
		if (imageSize == MediaSize.Original) {
			return false; // getLocalFile should always return the original.
		}
		if (imageSize == MediaSize.Thumbnail) {
			File preview = MediaCache.getInstance().getCachedFile(contentUri,
					MediaSize.Preview);
			if (preview != null) {
				// Just downsample the preview, it is faster.
				return MediaCacheUtils.downsample(preview, imageSize, tempFile);
			}
		}
		File highRes = new File(contentUri.getPath());
		boolean success;
		if (!isVideo(contentUri)) {
			success = MediaCacheUtils.downsample(highRes, imageSize, tempFile);
		} else {
			// Video needs to extract the bitmap.
			Bitmap bitmap = BitmapUtils.createVideoThumbnail(highRes.getPath());
			if (bitmap == null) {
				return false;
			} else if (imageSize == MediaSize.Thumbnail
					&& !MediaCacheUtils.needsDownsample(bitmap,
							MediaSize.Preview)
					&& MediaCacheUtils.writeToFile(bitmap, tempFile)) {
				// Opportunistically save preview
				MediaCache mediaCache = MediaCache.getInstance();
				mediaCache.insertIntoCache(contentUri, MediaSize.Preview,
						tempFile);
			}
			// Now scale the image
			success = MediaCacheUtils.downsample(bitmap, imageSize, tempFile);
		}
		return success;
	}

	@Override
	public Uri normalizeUri(Uri contentUri, MediaSize size) {
		return contentUri;
	}

	@Override
	public MediaSize normalizeMediaSize(Uri contentUri, MediaSize size) {
		return size;
	}

	private static boolean isVideo(Uri uri) {
		MimeTypeMap mimeTypeMap = MimeTypeMap.getSingleton();
		String extension = MimeTypeMap.getFileExtensionFromUrl(uri.toString());
		String mimeType = mimeTypeMap.getMimeTypeFromExtension(extension);
		return (mimeType != null && mimeType.startsWith("video/"));
	}
}