[Autofill] Autofill fails to fill credit card number when split across fields.

components/autofill/core/browser/credit_card_field.cc

Index: components/autofill/core/browser/credit_card_field.cc
diff --git a/components/autofill/core/browser/credit_card_field.cc b/components/autofill/core/browser/credit_card_field.cc
index 09dab1e48d796800fda5065ee6cb54075fd5697a..1d4b0ff5ee4bd064600583cfb917f3010e27ed4a 100644
--- a/components/autofill/core/browser/credit_card_field.cc
+++ b/components/autofill/core/browser/credit_card_field.cc
@@ -6,6 +6,8 @@
 
 #include <stddef.h>
 
+#include <algorithm>
+
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
@@ -19,6 +21,10 @@
 
 namespace autofill {
 
+// Credit card numbers are at most 19 digits in length.
+// [Ref: http://en.wikipedia.org/wiki/Bank_card_number]
+static const size_t kMaxValidCardNumberSize = 19;
+
 // static
 FormField* CreditCardField::Parse(AutofillScanner* scanner) {
   if (scanner->IsEnd())
@@ -58,7 +64,7 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
       // for the cardholder's first and last name if they have the labels "cfnm"
       // and "clnm".
       scanner->SaveCursor();
-      const AutofillField* first;
+      AutofillField* first;
       if (ParseField(scanner, base::ASCIIToUTF16("^cfnm"), &first) &&
           ParseField(scanner, base::ASCIIToUTF16("^clnm"),
                      &credit_card_field->cardholder_last_)) {
@@ -89,8 +95,31 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
     }
 
     pattern = base::UTF8ToUTF16(autofill::kCardNumberRe);
-    if (!credit_card_field->number_ &&
-        ParseField(scanner, pattern, &credit_card_field->number_)) {
+    AutofillField* current_number_field;
+    if (ParseField(scanner, pattern, &current_number_field)) {
+      // Avoid autofilling any credit card number field having very low or high
+      // |start_index| on the HTML form.
+      size_t start_index = 0;
+      if (!credit_card_field->numbers_.empty()) {
+        size_t last_number_field_size =
+            credit_card_field->numbers_.back()
+                ->credit_card_number_start_index() +
+            credit_card_field->numbers_.back()->max_length;

[Evan Stade, 2014/08/28 18:18:42]

nit: \n

[Pritam Nikam, 2014/09/01 09:03:35]

Done.

+        // In some cases, HTML form may have credit card number split across
+        // multiple input fields and either one or cumulatively having
+        // |max_length| more than |kMaxValidCardNumberSize|, mark these input
+        // form fields as invalid and skip autofilling them.

[Evan Stade, 2014/08/28 18:18:42]

Not sure if this would happen in the wild, but it seems like the last input
might not have a max size set. In this case, we could still fill in the credit
card just by stuffing whatever numbers we have left over from the first n-1
fields into the last field.

[Pritam Nikam, 2014/09/01 09:03:35]

This is already taken care with current logic.
Modified a unit test CreditCardFieldTest::ParseCreditCardNumberWithSplit to
reflect this along with a comment.

+        if (last_number_field_size == 0U ||
+            last_number_field_size >= kMaxValidCardNumberSize)

[Evan Stade, 2014/08/28 18:18:42]

nit: curlies

[Pritam Nikam, 2014/09/01 09:03:35]

Done.

+          // Mark that the credit card number splits are invalid. But keep
+          // scanning HTML form so that cursor moves beyond related fields.
+          credit_card_field->is_valid_card_number_split_ = false;
+
+        start_index = last_number_field_size;
+      }
+
+      current_number_field->set_credit_card_number_start_index(start_index);
+      credit_card_field->numbers_.push_back(current_number_field);
       continue;
     }
 
@@ -167,7 +196,8 @@ FormField* CreditCardField::Parse(AutofillScanner* scanner) {
   // a strong enough signal that this is a credit card.  It is possible that
   // the number and name were parsed in a separate part of the form.  So if
   // the cvc and date were found independently they are returned.
-  if ((credit_card_field->number_ || credit_card_field->verification_) &&
+  if ((!credit_card_field->numbers_.empty() ||
+       credit_card_field->verification_) &&
       (credit_card_field->expiration_date_ ||
        (credit_card_field->expiration_month_ &&
         credit_card_field->expiration_year_))) {
@@ -182,16 +212,27 @@ CreditCardField::CreditCardField()
     : cardholder_(NULL),
       cardholder_last_(NULL),
       type_(NULL),
-      number_(NULL),
       verification_(NULL),
       expiration_month_(NULL),
       expiration_year_(NULL),
       expiration_date_(NULL),
-      is_two_digit_year_(false) {
+      is_two_digit_year_(false),
+      is_valid_card_number_split_(true) {
+}
+
+CreditCardField::~CreditCardField() {
 }
 
 bool CreditCardField::ClassifyField(ServerFieldTypeMap* map) const {
-  bool ok = AddClassification(number_, CREDIT_CARD_NUMBER, map);
+  // Bail-out autofilling for invalid credit card number splits.
+  if (!is_valid_card_number_split_)
+    return false;
+
+  bool ok = true;
+  for (size_t index = 0; index < numbers_.size(); ++index) {
+    ok = ok && AddClassification(numbers_.at(index), CREDIT_CARD_NUMBER, map);
+  }
+
   ok = ok && AddClassification(type_, CREDIT_CARD_TYPE, map);
   ok = ok && AddClassification(verification_, CREDIT_CARD_VERIFICATION_CODE,
                                map);