[Web Payments] Common Payments validation

components/payments/payment_details_validation.cc

Index: components/payments/payment_details_validation.cc
diff --git a/components/payments/payment_details_validation.cc b/components/payments/payment_details_validation.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a346aaceba6cb9c8160b98e68e48fd67d5b79e19
--- /dev/null
+++ b/components/payments/payment_details_validation.cc
@@ -0,0 +1,189 @@
+// 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.
+
+#include "components/payments/payment_details_validation.h"
+
+#include <set>
+#include <vector>
+
+#include "components/payments/payment_request.mojom.h"
+#include "components/payments/payments_validators.h"
+
+namespace {
+
+// Validates ShippingOption or PaymentItem, which happen to have identical
+// fields, except for "id", which is present only in ShippingOption.
+template <typename T>
+bool validateShippingOptionOrPaymentItem(
+    const T& item,
+    const blink::mojom::PaymentItemPtr& total,
+    std::string* error_message) {
+  if (item->label.empty()) {
+    *error_message = "Item label required";
+    return false;
+  }
+
+  if (!item->amount) {
+    *error_message = "Currency amount required";
+    return false;
+  }
+
+  if (item->amount->currency.empty()) {
+    *error_message = "Currency code required";
+    return false;
+  }
+
+  if (item->amount->value.empty()) {
+    *error_message = "Currency value required";
+    return false;
+  }
+
+  if (item->amount->currency != total->amount->currency) {
+    *error_message = "Currencies must all be equal";
+    return false;
+  }
+
+  if (item->amount->currencySystem.has_value() &&
+      item->amount->currencySystem.value().empty()) {
+    *error_message = "Currency system can't be empty";
+    return false;
+  }
+
+  if (!payments::PaymentsValidators::isValidCurrencyCodeFormat(
+          item->amount->currency, item->amount->currencySystem.has_value()
+                                      ? item->amount->currencySystem.value()
+                                      : "",
+          error_message)) {
+    return false;
+  }
+
+  if (!payments::PaymentsValidators::isValidAmountFormat(item->amount->value,
+                                                         error_message)) {
+    return false;
+  }
+  return true;
+}
+
+bool validateDisplayItems(
+    const std::vector<blink::mojom::PaymentItemPtr>& items,
+    const blink::mojom::PaymentItemPtr& total,
+    std::string* error_message) {
+  for (const auto& item : items) {
+    if (!validateShippingOptionOrPaymentItem(item, total, error_message))
+      return false;
+  }
+  return true;
+}
+
+bool validateShippingOptions(
+    const std::vector<blink::mojom::PaymentShippingOptionPtr>& options,
+    const blink::mojom::PaymentItemPtr& total,
+    std::string* error_message) {
+  std::set<std::string> uniqueIds;
+  for (const auto& option : options) {
+    if (option->id.empty()) {
+      *error_message = "ShippingOption id required";
+      return false;
+    }
+
+    if (uniqueIds.find(option->id) != uniqueIds.end()) {
+      *error_message = "Duplicate shipping option identifiers are not allowed";
+      return false;
+    }
+    uniqueIds.insert(option->id);
+
+    if (!validateShippingOptionOrPaymentItem(option, total, error_message))
+      return false;
+  }
+  return true;
+}
+
+bool validatePaymentDetailsModifiers(
+    const std::vector<blink::mojom::PaymentDetailsModifierPtr>& modifiers,
+    const blink::mojom::PaymentItemPtr& total,
+    std::string* error_message) {
+  if (modifiers.empty()) {
+    *error_message = "Must specify at least one payment details modifier";
+    return false;
+  }
+
+  std::set<mojo::String> uniqueMethods;
+  for (const auto& modifier : modifiers) {
+    if (modifier->supported_methods.empty()) {
+      *error_message = "Must specify at least one payment method identifier";
+      return false;
+    }
+
+    for (const auto& method : modifier->supported_methods) {
+      if (uniqueMethods.find(method) != uniqueMethods.end()) {
+        *error_message = "Duplicate payment method identifiers are not allowed";
+        return false;
+      }
+      uniqueMethods.insert(method);
+    }
+
+    if (modifier->total) {
+      if (!validateShippingOptionOrPaymentItem(modifier->total, total,
+                                               error_message))
+        return false;
+
+      if (modifier->total->amount->value[0] == '-') {
+        *error_message = "Total amount value should be non-negative";
+        return false;
+      }
+    }
+
+    if (modifier->additional_display_items.size()) {
+      if (!validateDisplayItems(modifier->additional_display_items, total,
+                                error_message)) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+}  // namespace
+
+namespace payments {
+
+bool validatePaymentDetails(const blink::mojom::PaymentDetailsPtr& details,
+                            std::string* error_message) {
+  if (details->total.is_null()) {
+    *error_message = "Must specify total";
+    return false;
+  }
+
+  if (!validateShippingOptionOrPaymentItem(details->total, details->total,
+                                           error_message))
+    return false;
+
+  if (details->total->amount->value[0] == '-') {
+    *error_message = "Total amount value should be non-negative";
+    return false;
+  }
+
+  if (details->display_items.size()) {
+    if (!validateDisplayItems(details->display_items, details->total,
+                              error_message))
+      return false;
+  }
+
+  if (details->shipping_options.size()) {
+    if (!validateShippingOptions(details->shipping_options, details->total,
+                                 error_message))
+      return false;
+  }
+
+  if (details->modifiers.size()) {
+    if (!validatePaymentDetailsModifiers(details->modifiers, details->total,
+                                         error_message))
+      return false;
+  }
+  if (!PaymentsValidators::isValidErrorMsgFormat(details->error, error_message))
+    return false;
+  return true;
+}
+
+}  // namespace payments