services/core/java/com/android/server/am/UriPermissionOwner.java

/*
 * Copyright (C) 2010 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.server.am;

import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.ArraySet;

import com.google.android.collect.Sets;

import java.io.PrintWriter;
import java.util.Iterator;

final class UriPermissionOwner {
    final ActivityManagerService service;
    final Object owner;

    Binder externalToken;

    private ArraySet<UriPermission> mReadPerms;
    private ArraySet<UriPermission> mWritePerms;

    class ExternalToken extends Binder {
        UriPermissionOwner getOwner() {
            return UriPermissionOwner.this;
        }
    }

    UriPermissionOwner(ActivityManagerService service, Object owner) {
        this.service = service;
        this.owner = owner;
    }

    Binder getExternalTokenLocked() {
        if (externalToken == null) {
            externalToken = new ExternalToken();
        }
        return externalToken;
    }

    static UriPermissionOwner fromExternalToken(IBinder token) {
        if (token instanceof ExternalToken) {
            return ((ExternalToken)token).getOwner();
        }
        return null;
    }

    void removeUriPermissionsLocked() {
        removeUriPermissionsLocked(Intent.FLAG_GRANT_READ_URI_PERMISSION
                | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
    }

    void removeUriPermissionsLocked(int mode) {
        removeUriPermissionLocked(null, mode);
    }

    void removeUriPermissionLocked(ActivityManagerService.GrantUri grantUri, int mode) {
        if ((mode & Intent.FLAG_GRANT_READ_URI_PERMISSION) != 0
                && mReadPerms != null) {
            Iterator<UriPermission> it = mReadPerms.iterator();
            while (it.hasNext()) {
                UriPermission perm = it.next();
                if (grantUri == null || grantUri.equals(perm.uri)) {
                    perm.removeReadOwner(this);
                    service.removeUriPermissionIfNeededLocked(perm);
                    it.remove();
                }
            }
            if (mReadPerms.isEmpty()) {
                mReadPerms = null;
            }
        }
        if ((mode & Intent.FLAG_GRANT_WRITE_URI_PERMISSION) != 0
                && mWritePerms != null) {
            Iterator<UriPermission> it = mWritePerms.iterator();
            while (it.hasNext()) {
                UriPermission perm = it.next();
                if (grantUri == null || grantUri.equals(perm.uri)) {
                    perm.removeWriteOwner(this);
                    service.removeUriPermissionIfNeededLocked(perm);
                    it.remove();
                }
            }
            if (mWritePerms.isEmpty()) {
                mWritePerms = null;
            }
        }
    }

    public void addReadPermission(UriPermission perm) {
        if (mReadPerms == null) {
            mReadPerms = Sets.newArraySet();
        }
        mReadPerms.add(perm);
    }

    public void addWritePermission(UriPermission perm) {
        if (mWritePerms == null) {
            mWritePerms = Sets.newArraySet();
        }
        mWritePerms.add(perm);
    }

    public void removeReadPermission(UriPermission perm) {
        mReadPerms.remove(perm);
        if (mReadPerms.isEmpty()) {
            mReadPerms = null;
        }
    }

    public void removeWritePermission(UriPermission perm) {
        mWritePerms.remove(perm);
        if (mWritePerms.isEmpty()) {
            mWritePerms = null;
        }
    }

    public void dump(PrintWriter pw, String prefix) {
        if (mReadPerms != null) {
            pw.print(prefix); pw.print("readUriPermissions="); pw.println(mReadPerms);
        }
        if (mWritePerms != null) {
            pw.print(prefix); pw.print("writeUriPermissions="); pw.println(mWritePerms);
        }
    }

    @Override
    public String toString() {
        return owner.toString();
    }
}