PermissionsManager.java

/*
 * 				Firetweet - Twitter client for Android
 * 
 *  Copyright (C) 2012-2014 Mariotaku Lee <mariotaku.lee@gmail.com>
 * 
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 * 
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.getlantern.firetweet.util;

import android.content.Context;
import android.content.SharedPreferences;
import android.content.pm.PackageManager;
import android.os.Binder;
import android.os.Process;
import android.text.TextUtils;

import org.getlantern.firetweet.Constants;

import java.util.HashMap;
import java.util.Map;

import static android.text.TextUtils.isEmpty;

public class PermissionsManager implements Constants {

	private static final String[] PERMISSIONS_DENIED = { PERMISSION_DENIED };

	private final SharedPreferencesWrapper mPreferences;
	private final PackageManager mPackageManager;
	private final Context mContext;

	public PermissionsManager(final Context context) {
		mContext = context;
		mPreferences = SharedPreferencesWrapper.getInstance(context, PERMISSION_PREFERENCES_NAME, Context.MODE_PRIVATE);
		mPackageManager = context.getPackageManager();
	}

	public boolean accept(final String package_name, final String[] permissions) {
		if (package_name == null || permissions == null) return false;
		final SharedPreferences.Editor editor = mPreferences.edit();
		editor.putString(package_name, FiretweetArrayUtils.toString(permissions, '|', false));
		return editor.commit();
	}

	public boolean checkCallingPermission(final String... requiredPermissions) {
		return checkPermission(Binder.getCallingUid(), requiredPermissions);
	}

	public boolean checkPermission(final int uid, final String... requiredPermissions) {
		if (requiredPermissions == null || requiredPermissions.length == 0) return true;
		if (Process.myUid() == uid) return true;
		if (checkSignature(uid)) return true;
		final String pname = getPackageNameByUid(uid);
		final String[] permissions = getPermissions(pname);
		return FiretweetArrayUtils.contains(permissions, requiredPermissions);
	}

	public boolean checkPermission(final String pname, final String... requiredPermissions) {
		if (requiredPermissions == null || requiredPermissions.length == 0) return true;
		if (mContext.getPackageName().equals(pname)) return true;
		if (checkSignature(pname)) return true;
		final String[] permissions = getPermissions(pname);
		return FiretweetArrayUtils.contains(permissions, requiredPermissions);
	}

	public boolean checkSignature(final int uid) {
		final String pname = getPackageNameByUid(uid);
		return checkSignature(pname);
	}

	public boolean checkSignature(final String pname) {
		if (mContext.getPackageName().equals(pname)) return true;
		if (Utils.isDebugBuild()) return false;
		return mPackageManager.checkSignatures(pname, mContext.getPackageName()) == PackageManager.SIGNATURE_MATCH;
	}

	public boolean deny(final String package_name) {
		if (package_name == null) return false;
		final SharedPreferences.Editor editor = mPreferences.edit();
		editor.putString(package_name, PERMISSION_DENIED);
		return editor.commit();

	}

	public Map<String, String> getAll() {
		final Map<String, String> map = new HashMap<String, String>();
		for (final Map.Entry<String, ?> entry : mPreferences.getAll().entrySet()) {
			if (entry.getValue() instanceof String) {
				map.put(entry.getKey(), (String) entry.getValue());
			}
		}
		return map;
	}

	public String getPackageNameByUid(final int uid) {
		final String[] pkgs = mPackageManager.getPackagesForUid(uid);
		if (pkgs != null && pkgs.length > 0) return pkgs[0];
		return null;
	}

	public String[] getPermissions(final int uid) {
		return getPermissions(getPackageNameByUid(uid));
	}

	public String[] getPermissions(final String packageName) {
		if (isEmpty(packageName)) return new String[0];
		final String permissionsString = mPreferences.getString(packageName, null);
		if (isEmpty(permissionsString)) return new String[0];
		if (permissionsString.contains(PERMISSION_DENIED)) return PERMISSIONS_DENIED;
		return permissionsString.split("\\|");
	}

	public boolean revoke(final String packageName) {
		if (packageName == null) return false;
		final SharedPreferences.Editor editor = mPreferences.edit();
		editor.remove(packageName);
		return editor.commit();
	}

	public static boolean hasPermissions(final String[] permissions, final String... requiredPermissions) {
		return FiretweetArrayUtils.contains(permissions, requiredPermissions);
	}

	public static boolean isPermissionValid(final String permissionsString) {
		return TextUtils.isEmpty(permissionsString);
	}

	public static boolean isPermissionValid(final String... permissions) {
		return permissions != null && permissions.length != 0;
	}

	public static String[] parsePermissions(final String permissionsString) {
		if (isEmpty(permissionsString)) return new String[0];
		return permissionsString.split(SEPARATOR_PERMISSION_REGEX);
	}
}