/*
* Copyright (C) 2006 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 android.text;
/**
* Abstract class for filtering login-related text (user names and passwords)
*
*/
public abstract class LoginFilter implements InputFilter {
private boolean mAppendInvalid; // whether to append or ignore invalid characters
/**
* Base constructor for LoginFilter
* @param appendInvalid whether or not to append invalid characters.
*/
LoginFilter(boolean appendInvalid) {
mAppendInvalid = appendInvalid;
}
/**
* Default constructor for LoginFilter doesn't append invalid characters.
*/
LoginFilter() {
mAppendInvalid = false;
}
/**
* This method is called when the buffer is going to replace the
* range <code>dstart … dend</code> of <code>dest</code>
* with the new text from the range <code>start … end</code>
* of <code>source</code>. Returns the CharSequence that we want
* placed there instead, including an empty string
* if appropriate, or <code>null</code> to accept the original
* replacement. Be careful to not to reject 0-length replacements,
* as this is what happens when you delete text.
*/
public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart, int dend) {
onStart();
// Scan through beginning characters in dest, calling onInvalidCharacter()
// for each invalid character.
for (int i = 0; i < dstart; i++) {
char c = dest.charAt(i);
if (!isAllowed(c)) onInvalidCharacter(c);
}
// Scan through changed characters rejecting disallowed chars
SpannableStringBuilder modification = null;
int modoff = 0;
for (int i = start; i < end; i++) {
char c = source.charAt(i);
if (isAllowed(c)) {
// Character allowed.
modoff++;
} else {
if (mAppendInvalid) {
modoff++;
} else {
if (modification == null) {
modification = new SpannableStringBuilder(source, start, end);
modoff = i - start;
}
modification.delete(modoff, modoff + 1);
}
onInvalidCharacter(c);
}
}
// Scan through remaining characters in dest, calling onInvalidCharacter()
// for each invalid character.
for (int i = dend; i < dest.length(); i++) {
char c = dest.charAt(i);
if (!isAllowed(c)) onInvalidCharacter(c);
}
onStop();
// Either returns null if we made no changes,
// or what we wanted to change it to if there were changes.
return modification;
}
/**
* Called when we start processing filter.
*/
public void onStart() {
}
/**
* Called whenever we encounter an invalid character.
* @param c the invalid character
*/
public void onInvalidCharacter(char c) {
}
/**
* Called when we're done processing filter
*/
public void onStop() {
}
/**
* Returns whether or not we allow character c.
* Subclasses must override this method.
*/
public abstract boolean isAllowed(char c);
/**
* This filter rejects characters in the user name that are not compatible with GMail
* account creation. It prevents the user from entering user names with characters other than
* [a-zA-Z0-9.].
*
*/
public static class UsernameFilterGMail extends LoginFilter {
public UsernameFilterGMail() {
super(false);
}
public UsernameFilterGMail(boolean appendInvalid) {
super(appendInvalid);
}
@Override
public boolean isAllowed(char c) {
// Allow [a-zA-Z0-9@.]
if ('0' <= c && c <= '9')
return true;
if ('a' <= c && c <= 'z')
return true;
if ('A' <= c && c <= 'Z')
return true;
if ('.' == c)
return true;
return false;
}
}
/**
* This filter rejects characters in the user name that are not compatible with Google login.
* It is slightly less restrictive than the above filter in that it allows [a-zA-Z0-9._-+].
*
*/
public static class UsernameFilterGeneric extends LoginFilter {
private static final String mAllowed = "@_-+."; // Additional characters
public UsernameFilterGeneric() {
super(false);
}
public UsernameFilterGeneric(boolean appendInvalid) {
super(appendInvalid);
}
@Override
public boolean isAllowed(char c) {
// Allow [a-zA-Z0-9@.]
if ('0' <= c && c <= '9')
return true;
if ('a' <= c && c <= 'z')
return true;
if ('A' <= c && c <= 'Z')
return true;
if (mAllowed.indexOf(c) != -1)
return true;
return false;
}
}
/**
* This filter is compatible with GMail passwords which restricts characters to
* the Latin-1 (ISO8859-1) char set.
*
*/
public static class PasswordFilterGMail extends LoginFilter {
public PasswordFilterGMail() {
super(false);
}
public PasswordFilterGMail(boolean appendInvalid) {
super(appendInvalid);
}
// We should reject anything not in the Latin-1 (ISO8859-1) charset
@Override
public boolean isAllowed(char c) {
if (32 <= c && c <= 127)
return true; // standard charset
// if (128 <= c && c <= 159) return true; // nonstandard (Windows(TM)(R)) charset
if (160 <= c && c <= 255)
return true; // extended charset
return false;
}
}
}