[Merge M-53] Credit card editor for PaymentRequest UI.

chrome/android/java/src/org/chromium/chrome/browser/preferences/autofill/CreditCardNumberFormattingTextWatcher.java

Index: chrome/android/java/src/org/chromium/chrome/browser/preferences/autofill/CreditCardNumberFormattingTextWatcher.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/preferences/autofill/CreditCardNumberFormattingTextWatcher.java b/chrome/android/java/src/org/chromium/chrome/browser/preferences/autofill/CreditCardNumberFormattingTextWatcher.java
new file mode 100644
index 0000000000000000000000000000000000000000..42b98e894b241603062d2edaf6ae216eb60a41ae
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/preferences/autofill/CreditCardNumberFormattingTextWatcher.java
@@ -0,0 +1,99 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.preferences.autofill;
+
+import android.text.Editable;
+import android.text.TextUtils;
+import android.text.TextWatcher;
+
+/**
+ * Watch a TextView and if a credit card number is entered, it will format the number.
+ * Disable formatting when user:
+ * 1. Inputs dashes or spaces.
+ * 2. Removes separators in the middle of the string
+ * 3. Enters a number longer than 16 digits.
+ *
+ * Formatting will be re-enabled once text is cleared.
+ */
+public class CreditCardNumberFormattingTextWatcher implements TextWatcher {
+    /** Character for card number section separator. */
+    private static final String SEPARATOR = " ";
+
+    /**
+     * Whether to format the credit card number. If true, spaces will be inserted
+     * automatically between each group of 4 digits in the credit card number as the user types.
+     * This is set to false if the user types a dash or deletes one of the auto-inserted spaces.
+     */
+    private boolean mFormattingEnabled = true;
+
+    /**
+     * Whether the change was caused by ourselves.
+     * This is set true when we are manipulating the text of EditText,
+     * and all callback functions should check this boolean to avoid infinite recursion.
+     */
+    private boolean mSelfChange = false;
+
+    @Override
+    public void onTextChanged(CharSequence s, int start, int before, int count) {
+        if (mSelfChange || !mFormattingEnabled) return;
+        // If user enters non-digit characters, do not format.
+        if (count > 0 && hasDashOrSpace(s, start, count)) {
+            mFormattingEnabled = false;
+        }
+    }
+
+    @Override
+    public void beforeTextChanged(CharSequence s, int start, int count, int after) {
+        if (mSelfChange || !mFormattingEnabled) return;
+        // If user deletes non-digit characters, do not format.
+        if (count > 0 && hasDashOrSpace(s, start, count)) {
+            mFormattingEnabled = false;
+        }
+    }
+
+    @Override
+    public void afterTextChanged(Editable s) {
+        if (mSelfChange) return;
+        mSelfChange = true;
+
+        if (mFormattingEnabled) {
+            removeSeparators(s);
+            // If number is too long, do not format it and remove all
+            // previous separators.
+            if (s.length() > 16) {
+                mFormattingEnabled = false;
+            } else {
+                insertSeparators(s);
+            }
+        }
+        // If user clears the input, re-enable formatting
+        if (s.length() == 0) mFormattingEnabled = true;
+
+        mSelfChange = false;
+    }
+
+    public static void removeSeparators(Editable s) {
+        int index = TextUtils.indexOf(s, SEPARATOR);
+        while (index >= 0) {
+            s.delete(index, index + 1);
+            index = TextUtils.indexOf(s, SEPARATOR, index + 1);
+        }
+    }
+
+    public static void insertSeparators(Editable s) {
+        final int[] positions = {4, 9, 14 };
+        for (int i : positions) {
+            if (s.length() > i) {
+                s.insert(i, SEPARATOR);
+            }
+        }
+    }
+
+    public static boolean hasDashOrSpace(final CharSequence s, final int start,
+            final int count) {
+        return TextUtils.indexOf(s, " ", start, start + count) != -1
+                || TextUtils.indexOf(s, "-", start, start + count) != -1;
+    }
+}