AssetFileLibraryLicenseDataCollector.java

/*
*    Copyright (C) 2015 Haruki Hasegawa
*
*    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.h6ah4i.android.example.advrecyclerview.about;

import android.content.Context;
import android.content.res.AssetManager;
import android.net.Uri;
import android.util.Log;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class AssetFileLibraryLicenseDataCollector {
	private static final String TAG = "AssetLibLicenseCollect";

	private Context mContext;
	private String mBaseAssetDir;

	public static class LibraryInfo {
		public String mLibraryName;
		public String mLicenseText;
		public String mNoticeText;
		public Uri mLink;
	}

	public AssetFileLibraryLicenseDataCollector(Context context, String baseAssetDir) {
		mContext = context;
		mBaseAssetDir = baseAssetDir;
	}

	public List<LibraryInfo> collect() {
		ArrayList<LibraryInfo> list = new ArrayList<>();
		AssetManager assets = mContext.getAssets();
		try {
			String[] dirs = assets.list(mBaseAssetDir);

			// sort numerically
			final Pattern p = Pattern.compile("^([0-9]+).*$");
			Arrays.sort(dirs, new Comparator<String>() {
				public int compare(String s1, String s2) {
					try {
						Matcher m1 = p.matcher(s1);
						Matcher m2 = p.matcher(s2);
						if (m1.find() && m2.find()) {
							int n1 = Integer.parseInt(m1.group(1));
							int n2 = Integer.parseInt(m2.group(1));

							if (n1 == n2) {
								return s1.compareTo(s2);
							}

							return n1 - n2;
						} else {
							return s1.compareTo(s2);
						}
					} catch (RuntimeException e) {
						return s1.compareTo(s2);
					}
				}
			});

			for (String dirname : dirs) {
				LibraryInfo info = loadLicenseInfo(assets, mBaseAssetDir + "/" + dirname);

				if (info != null) {
					list.add(info);
				}
			}
		} catch (IOException e) {
			Log.e(TAG, "collect()", e);
		}

		return list;
	}

	private LibraryInfo loadLicenseInfo(AssetManager assets, String dirname) {
		String name = loadTextFile(assets, dirname + "/NAME");
		String license = loadTextFile(assets, dirname + "/LICENSE");
		String notice = loadTextFile(assets, dirname + "/NOTICE");
		Uri link = safeParseLinkUri(loadTextFile(assets, dirname + "/LINK"));

		if (name != null && (license != null || notice != null)) {
			LibraryInfo info = new LibraryInfo();

			info.mLibraryName = name;
			info.mLicenseText = license;
			info.mNoticeText = notice;
			info.mLink = link;

			return info;
		} else {
			Log.w(TAG, "Failed to load " + dirname);
			return null;
		}
	}

	private static Uri safeParseLinkUri(String s) {
		if (s == null) {
			return null;
		}

		final String[] lines = s.split("\n");

		if (lines.length == 0) {
			return null;
		}


		return Uri.parse(lines[0]);
	}

	// http://stackoverflow.com/questions/309424/read-convert-an-inputstream-to-a-string
	private static String loadTextFile(AssetManager assets, String path) {
		InputStream stream = null;
		try {
			stream = assets.open(path, AssetManager.ACCESS_STREAMING);
			java.util.Scanner s = new java.util.Scanner(stream).useDelimiter("\\A");
			return s.hasNext() ? s.next().trim() : "";
		} catch (IOException e) {
			// just ignore
		} finally {
			if (stream != null) {
				try {
					stream.close();
				} catch (IOException ignored) {
				}
			}
		}
		return null;
	}
}