TextValueSanitizer.java revision f60fb12d39774e2f626660d357a4384cdaf0e72c 
1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.service.autofill;
18
19import static android.view.autofill.Helper.sDebug;
20
21import android.annotation.NonNull;
22import android.annotation.Nullable;
23import android.annotation.TestApi;
24import android.os.Parcel;
25import android.os.Parcelable;
26import android.util.Slog;
27import android.view.autofill.AutofillValue;
28
29import com.android.internal.util.Preconditions;
30
31import java.util.regex.Matcher;
32import java.util.regex.Pattern;
33
34/**
35 * Sanitizes a text {@link AutofillValue} using a regular expression (regex) substitution.
36 *
37 * <p>For example, to remove spaces from groups of 4-digits in a credit card:
38 *
39 * <pre class="prettyprint">
40 * new TextValueSanitizer(Pattern.compile("^(\\d{4})\\s?(\\d{4})\\s?(\\d{4})\\s?(\\d{4})$"),
41 *     "$1$2$3$4")
42 * </pre>
43 */
44public final class TextValueSanitizer extends InternalSanitizer implements
45        Sanitizer, Parcelable {
46    private static final String TAG = "TextValueSanitizer";
47
48    private final Pattern mRegex;
49    private final String mSubst;
50
51    /**
52     * Default constructor.
53     *
54     * @param regex regular expression with groups (delimited by {@code (} and {@code (}) that
55     * are used to substitute parts of the {@link AutofillValue#getTextValue() text value}.
56     * @param subst the string that substitutes the matched regex, using {@code $} for
57     * group substitution ({@code $1} for 1st group match, {@code $2} for 2nd, etc).
58     */
59    public TextValueSanitizer(@NonNull Pattern regex, @NonNull String subst) {
60        mRegex = Preconditions.checkNotNull(regex);
61        mSubst = Preconditions.checkNotNull(subst);
62    }
63
64    /** @hide */
65    @Override
66    @TestApi
67    @Nullable
68    public AutofillValue sanitize(@NonNull AutofillValue value) {
69        if (value == null) {
70            Slog.w(TAG, "sanitize() called with null value");
71            return null;
72        }
73        if (!value.isText()) {
74            if (sDebug) Slog.d(TAG, "sanitize() called with non-text value: " + value);
75            return null;
76        }
77
78        final CharSequence text = value.getTextValue();
79
80        try {
81            final Matcher matcher = mRegex.matcher(text);
82            if (!matcher.matches()) {
83                if (sDebug) Slog.d(TAG, "sanitize(): " + mRegex + " failed for " + value);
84                return null;
85            }
86
87            final CharSequence sanitized = matcher.replaceAll(mSubst);
88            return AutofillValue.forText(sanitized);
89        } catch (Exception e) {
90            Slog.w(TAG, "Exception evaluating " + mRegex + "/" + mSubst + ": " + e);
91            return null;
92        }
93    }
94
95    /////////////////////////////////////
96    // Object "contract" methods. //
97    /////////////////////////////////////
98    @Override
99    public String toString() {
100        if (!sDebug) return super.toString();
101
102        return "TextValueSanitizer: [regex=" + mRegex + ", subst=" + mSubst + "]";
103    }
104
105    /////////////////////////////////////
106    // Parcelable "contract" methods. //
107    /////////////////////////////////////
108    @Override
109    public int describeContents() {
110        return 0;
111    }
112
113    @Override
114    public void writeToParcel(Parcel parcel, int flags) {
115        parcel.writeSerializable(mRegex);
116        parcel.writeString(mSubst);
117    }
118
119    public static final Parcelable.Creator<TextValueSanitizer> CREATOR =
120            new Parcelable.Creator<TextValueSanitizer>() {
121        @Override
122        public TextValueSanitizer createFromParcel(Parcel parcel) {
123            return new TextValueSanitizer((Pattern) parcel.readSerializable(), parcel.readString());
124        }
125
126        @Override
127        public TextValueSanitizer[] newArray(int size) {
128            return new TextValueSanitizer[size];
129        }
130    };
131}
132